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G Lian

Publications and source records attributed to G Lian.

13 recordsLinked to original sources
PubMed2001

A selenium-containing catalytic antibody with Type I deiodinase activity.

Acting as a mimic of type I deiodinase (DI), a selenium-containing catalytic antibody (Se-4C5) prepared by converting the serine residues of monoclonal antibody 4C5 raised against thyroxine (T4) into selenocysteines, can catalyze the deiodination of T(4) to 3,5,3'-triiodothyronine (T(3)) with dithiothreitol (DTT) as cosubstrate. Investigations into the deiodinative reaction by Se-4C5 revealed the relationship between the initial velocity and substrate concentration was subjected to Michaelis-Menten equation and the reaction mechanism was ping-pong one. The kinetic properties of the catalytic antibody were a little similar to those of DI, with Km values for T(4) and DTT of approximately 0.8 microM and 1.8 mM, respectively, and V(m) value of 270 pmol per mg protein per min. The activity could be sensitively inhibited by PTU with a Ki value of approximately 120 microM at 2.0 microM of T(4) concentration, revealing that PTU was a competitive inhibitor for DTT.

Amino Acid Substitution↗
PubMed2001

Preparation and properties of a selenium-containing catalytic antibody as type I deiodinase mimic.

Conversion of thyroxine (T4) to 3,5,3'-triiodothyronine is an essential first step in controlling thyroid hormone action. Type I deiodinase (DI) can catalyze the conversion to produce the bulk of serum 3,5,3'-triiodothyronine. Acting as a mimic of DI, a selenium-containing catalytic antibody (Se-4C5) prepared by converting the serine residues of monoclonal antibody 4C5 raised against T4 into selenocysteines, can catalyze the deiodination of T4 with dithiothreitol (DTT) as cosubstrate. The mimic enzyme Se-4C5 exhibited a much greater deiodinase activity than model compound ebselen and another selenium-containing antibody Se-Hp4 against GSH. The coupling of selenocysteine with the combining pocket of antibody 4C5 endowed Se-4C5 with enzymatic activity. To probe the catalytic mechanism of the catalytic antibody, detailed kinetic studies were carried out in this paper. Investigations into the deiodinative reaction revealed the relationship between the initial velocity and substrate concentration. The characteristic parallel Dalziel plots demonstrated that Se-4C5-catalyzed reaction mechanism was ping-pong one, involving at least one covalent enzyme intermediate. The kinetic properties of the catalytic antibody were similar to those of DI, with Km values for T4 and DTT of approximately 0.8 microm and 1.8 mm, respectively, and a Vm value of 270 pmol per mg of protein per min. The activity could be sensitively inhibited by 6-propyl-2-thiouracil (PTU) with a K(i) value of approximately 120 microm at 2.0 microm T4 concentration. The PTU inhibition was progressively alleviated with the increasing concentration of added DTT, revealing that PTU was a competitive inhibitor for DTT.

Animals↗
PubMed1995

Developmental changes in seminiferous tubule extracellular matrix components of the mouse testis: alpha 3(IV) collagen chain expressed at the initiation of spermatogenesis.

The temporal expression of type IV collagen, laminin, and entactin in the basal laminae of the seminiferous tubule during development of the mouse testis was determined. Northern blot analysis was used to examine changes in testicular mRNA for alpha 1-alpha 5 type IV collagen (IV) chains in mice ranging in age from newborn to adult (60 days). Levels for mRNA alpha 1(IV) and alpha 2(IV) chains were highest in newborns through Day 5 and remained elevated through Day 10, but then sharply declined to adult values by Day 30. In sharp contrast, alpha 3(IV) and alpha 4(IV) chain levels were low in newborns, peaked at Day 10, and then declined to adult values by Day 30. 5(IV) mRNA was elevated in newborns and at Days 5 and 10 before dropping to adult levels by Day 30. Changes in the deposition of alpha 1, alpha 2, and alpha 3(IV) collagen chains, laminin, and entactin into the inner and outer basal laminae of the seminiferous tubule were determined from the beginning of tubule formation (embryonic Day 12.5) through adulthood by immunofluorescence microscopy using polyclonal antibodies for these constituents. The alpha 1 and alpha 2(IV) chains, laminin, and entactin were deposited into the inner basal lamina at embyronic Day 12.5 and into the newly formed outer basal lamina at Day 5 after birth. The alpha 3(IV) chains were deposited into both the inner and outer basal laminae at Day 5. Thus, testicular alpha 1-alpha 3(IV) mRNA levels coincide with the incorporation of detectable collagen chains into the seminiferous basal laminae, suggesting transcriptional control of these alpha (IV) chains. Expression of of the alpha 3(IV) chain coincides with the initiation of spermatogenesis, suggesting a functional role of this chain in spermatogonial proliferation.

Aging↗
PubMed1994

Ankle dislocation.

From 1980 to 1991, 14 patients with pure ankle dislocation unassociated with fracture were identified. All patients were young adults (18-41 years of age) with a male preponderance (11 of 14). The cause of injury in nine of the 14 cases was a motor vehicle accident and in the remainder, sporting events or fall from a height. Thirteen of the 14 injuries were open, and 12 patients underwent lateral ligamentous repair. Twelve of the 14 patients were available for follow-up, which ranged from 15 to 122 months. Two patients had poor results; the remainder (10 of 12) had good and excellent results. Interestingly, no patient had signs or symptoms of instability. One patient required immediate below-the-knee amputation for open dislocation associated with avulsion of soft tissue and neurovascular structures.

Adolescent↗
PubMed1992

Localization and synthesis of entactin in seminiferous tubules of the mouse.

Localization and synthesis of entactin in seminiferous tubules of mouse testis was studied by immunocytochemistry. Frozen sections from adult mice testes were subjected to anti-entactin and anti-laminin immunofluorescence. Both entactin and laminin were localized within the seminiferous tubule basement membrane and intertubular region of the testis. The addition of excess amount of entactin (but not fibronectin), premixed with anti-entactin antiserum, abolished the immunostain. Western blotting showed that a protein extract from a seminiferous tubule basement membrane preparation was recognized by anti-entactin anti-serum and comigrated with recombinant entactin. Enriched fractions of isolated primary Sertoli cells and peritubular myoid cells cultured for 6 days on a glass coverslip were able to synthesize and secrete entactin as detected by immunofluorescence microscopy. Entactin was also produced by TM3 (Leydig-like) and TM4 (Sertoli-like) cell lines as detected by both immunofluorescence and Western blotting. The distribution of entactin vs. laminin within both the cultured primary cells and the TM3 and TM4 cell lines differed. Entactin appeared mainly localized extracellularly. In contrast, laminin was mainly localized intracellularly. The above findings suggested that 1) entactin existed in the seminiferous tubule basement membrane and intertubular region of adult mice testis, co-localized with laminin; 2) entactin was synthesized by the cultured primary Sertoli cells and peritubular myoid cells and the TM3 and TM4 cell lines; 3) entactin was exocytosed with little intracellular accumulation, in contrast to an intracellular accumulation of laminin.

Animals↗
PubMed1992

Collagen in the developing larynx. Preliminary study.

The primary purpose of this study was to determine the types of collagen in the developing human larynx that contribute to the structural framework and function of various components of this organ. The infant larynx is much more than a mere miniature of the adult "voice box." There are many age-related differences that occur in the larynx from the newborn period to the adult period of life. While collagen has been studied in numerous tissues, both normal and diseased, there have been no studies of the whole organ content, types, and/or changes of collagen in the developing human larynx that may account for many of the clinical findings. This study may at least in part explain whether collagen differences may account for the structural changes and responses that are seen in clinical practice.

Child, Preschool↗
PubMed1992

Arthroplasty of the first metatarsophalangeal joint with a double-stem silicone implant. Results in patients who have degenerative joint disease failure of previous operations, or rheumatoid arthritis.

Sixty-six patients who had a total of eighty-six double-stem silicone implants in the first metatarsophalangeal joint were followed prospectively for an average of 5.8 years (range, two to fifteen years). There were two groups of patients: thirty-four patients (thirty-seven implants) who had degenerative joint disease (including those who had hallux rigidus or in whom a previous operation on a bunion had failed) and thirty-two patients (forty-nine implants) who had rheumatoid arthritis. The implants were used only if the patient was a candidate for an excisional arthroplasty or an arthrodesis; they were not used in patients who wished to maintain or adopt very active use of the foot (such as in running, jogging, and tennis) or to wear very high heels. Twenty-eight (82 per cent) of the thirty-four patients in the first group were completely satisfied and three (9 per cent) were somewhat satisfied. However, three patients (9 per cent), all of whom had had a failed bunionectomy, were dissatisfied; the ages of these three patients were less than the average age of all patients in the first group. Radiographs showed a fracture in three implants, but the patients had a good clinical result and an additional operation was not warranted. Twenty-seven (84 per cent) of the thirty-two patients in the second group were completely satisfied, four (13 per cent) were somewhat satisfied, and one (3 per cent) was dissatisfied. Radiographs showed a fracture in five implants. Four of the implants caused no symptoms, and the result was good; the fifth one was fragmented and was removed because of symptoms. Radiographs showed radiolucent areas around the implant and hypertrophic changes in many patients. There was no evidence of synovitis, such as that caused by silicone, either clinically or radiographically. We found that the double-stem silicone implant was effective in reconstructing the first metatarsophalangeal joint but emphasize our belief that it should be used only in carefully selected patients.

Adult↗
PubMed1992

Arthrodesis of the ankle in patients who have rheumatoid arthritis.

We reviewed thirty-two arthrodeses of the ankle in twenty-six patients who had rheumatoid arthritis. In seventeen patients (eighteen ankles), a compression arthrodesis was done and external fixation was used. In eight patients (twelve ankles), we used internal fixation with 6.5-millimeter cancellous-bone screws. In the remaining patient, an arthrodesis with external fixation was done in one ankle and internal fixation was used in the other ankle; data for the appropriate ankle are included in each group. The patients were followed for an average of thirty-three months. The two groups were comparable with respect to age, sex, preoperative medications, and severity of disease. The average time to fusion was nineteen weeks in the compression arthrodesis group and seventeen weeks in the internal fixation group. Of the nineteen ankles that had a compression arthrodesis, four failed to fuse; all of the failures were associated with infection. Infection developed in two additional patients, there was malposition of the fusion in three patients, and neurapraxia developed in three patients. Of the thirteen ankles that had internal fixation, three ankles failed to fuse; one of the failures was associated with infection. Infection developed in one additional ankle. In two patients, the ankle fused in excessive valgus. Comparison of the two groups revealed comparable rates of fusion: fusion occurred in fifteen of the nineteen ankles in the group that had compression arthrodesis and in ten of the thirteen ankles in the group that had internal fixation. The method of arthrodesis did not affect the time to fusion or the rate of complications.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Open versus closed nailing of femoral fractures in the polytrauma patient.

Thirty-four patients with severe multiple injuries underwent either open or closed nailing of 35 femoral fractures. Open nailing was performed in 17 femurs and closed nailing in 18 femurs. The average abbreviated injury score was 27 in both the open group (range: 17-45) and closed group (range: 22-36). Soft tissue injuries were present in eight (47%) cases in the open group compared to three (16%) in the closed group. The treatment protocol was similar in both groups. Intramedullary nailing was delayed an average of 11 days in the closed group. This was significantly different than the open group where the average time to nailing was less than 24 hours (p less than 0.001). Reamed nails were used in all cases except for two in the closed group. The median time to fracture healing was 5.0 months in the open group and 4.1 months in the closed group, with an average follow-up of 18 months in both groups. Two cases required reoperation (one nonunion and one shortening at the fracture site). Both these cases were in the open group. There were no superficial or deep infections in either group. Closed reamed intramedullary nailing is recommended for treatment of diaphyseal femur fractures in patients with severe coexistent injuries. Open nailing should be reserved for cases in which an adequate reduction cannot be achieved by closed methods.

Adult↗
PubMed1989

Treatment of major wound necrosis following total knee arthroplasty.

Following total knee arthoplasty, seven patients developed significant wound necrosis and dehiscence, requiring wound coverage with soft tissue flaps. Three patients had rheumatoid arthritis, three had degenerative arthritis, and one had osteosarcoma of the distal femur. Five different prostheses were used and the wound problems were discovered on average 21 days after arthroplasty. The average wound size was 6.0 cm2. Five were infected, four with Staphylococcus epidermidis and one with Staphylococcus aureus. All patients were treated with antibiotics and local debridement for an average of 10 days prior to the flap procedure. Medical gastrocnemius muscle flaps were used in two patients, unipedicle flaps transposed from the lateral thigh in three, and bipedicle flaps shifted from the medial thigh in two. Flaps were done an average of 56 days after arthroplasty, and knee rehabilitation was delayed an average of 76 days after arthroplasty. Patients were followed an average of 48 months after the flap procedure. Six patients had mild or no knee pain and one who remained infected had moderate constant pain. Three of the patients had greater than 90 degrees of knee motion and one had 75 degrees of motion. The remaining three had only 35 degrees of motion, due in part to significant preoperative contractures, infection, local radiation, and chemotherapy. Late infection developed in two patients at 20 and 45 months following the flap procedure. There was one excellent, three good, two fair, and one poor result using the Hospital for Special Surgery knee rating system at final follow-up examination.

Adolescent↗
PubMedDate not supplied

Entactin ultrastructural immunolocalization in the basal laminae of mouse seminiferous tubules and with only subtle changes following hypophysectomy.

While entactin has been recently reported in the mouse seminiferous tubule lamina propria at the light microscope level, the purpose of this paper was twofold: 1) to determine the ultrastructural localization of entactin with the two basal laminae that form the lamina propria of the mouse, and 2) to determine if immunoreactive entactin changes following hypophysectomy. The localization of entactin was demonstrated by three different means: 1) immunofluorescent localization in semi-thin cryosections of the testis, 2) immunoperoxidase staining in a preparation of isolated lamina propria, and 3) immuno-gold staining in ultra-thin sections of testis. These techniques all demonstrated that immunoreactive entactin is present in both the inner and outer basal laminae of the mouse seminiferous tubules and is co-localized with laminin. These results are consistent with previous work that demonstrated entactin is synthesized and secreted by both Sertoli and peritubular myoid cells. Because both Sertoli cells and peritubular myoid cells are androgen-responsive cells, we wanted to determine if hypophysectomy alters the testicular distribution of entactin. Changes in immunoreactive entactin and laminin in the basal laminae were observed in semi-thin cryosections of the testes from hypophysectomized mice up to 6 weeks after surgery. The results demonstrated that during this time period, while most of the spermatogenic cells degenerated, the intensity of immunoreactive entactin and laminin remained nearly unchanged, as the seminiferous tubule basal laminae took on an increasingly wavy appearance. This suggests that the relative concentration of entactin and laminin in the basal lamina is stable, and not dependent on the presence of normal spermatogenesis and pituitary hormones.

Animals↗