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H Lin

Publications and source records attributed to H Lin.

At least 379 records · Page 21Linked to original sources
PubMed1994

Arteriovenous shunt as a method of restoring venous drainage in rabbit ear replantation.

An arteriovenous (AV) shunt as a method of restoring venous drainage during replantation was examined by use of the rabbit ear model. The results were compared to ears replanted using one vein (1:1) or two veins (2:1) for venous drainage. The success rate for AV shunt replantations was found similar to that of replantations with a 1:1 ratio, but lower than that of ears with a 2:1 ratio. Postoperatively, ears replanted using an AV shunt or a 1:1 ratio revealed more swelling and lower tissue oxygenation than ears with a 2:1 ratio. After 10-14 days, all ears that survived were similar in appearance, regardless of method of replantation. Microscopic venules crossing the replanted interface appeared at seven days following surgery in all groups. The authors conclude that the AV shunt method offers an alternative to venous anastomosis when vein-to-vein reconstruction cannot be established.

Anastomosis, Surgical↗
PubMed1994

The representation of location in visual images.

By definition, visual image representations are organized around spatial properties. However, we know very little about how these representations use information about location, one of the most important spatial properties. Three experiments explored how location information is incorporated into image representations. All of these experiments used a mental rotation task in which the location of the stimulus varied from trial to trial. If images are location-specific, these changes should affect the way images are used. The effects from image representations were separated from those of general spatial attention mechanisms by comparing performance with and without advance knowledge of the stimulus shape. With shape information, subjects could use an image as a template, and they recognized the stimulus more quickly when it was at the same location as the image. Experiment 1 demonstrated that subjects were able to use visual image representations effectively without knowing where the stimulus would appear, but left open the possibility that image location must be adjusted before use. In Experiment 2, distance between the stimulus location and the image location was varied systematically, and response time increased with distance. Therefore image representations appear to be location-specific, though the represented location can be adjusted easily. In Experiment 3, a saccade was introduced between the image cue and the test stimulus, in order to test whether subjects responded more quickly when the test stimulus appeared at the same retinotopic location or same spatiotopic location as the cue. The results suggest that location is coded retinotopically in image representations. This finding has implications not only for visual imagery but also for visual processing in general, because it suggests that there is no spatiotopic transform in the early stages of visual processing.

Adolescent↗
PubMed1994

The Drosophila fs(1)Ya protein, which is needed for the first mitotic division, is in the nuclear lamina and in the envelopes of cleavage nuclei, pronuclei, and nonmitotic nuclei.

The Drosophila melanogaster fs (1) Ya gene encodes a nuclear envelope protein needed to initiate embryonic cleavage divisions. In cleavage stage embryos the fs (1) Ya gene product is localized to the nuclear envelope in a cell cycle dependent manner. We show here that fs(1)Ya protein is also present in polar bodies of early cleavage stage embryos as well as in endoreplicating yolk nuclei. This observation suggests that the fs(1)Ya protein is necessary but not solely responsible for embryonic mitosis. Furthermore, cell cycle stage dependent nuclear localization is also seen for ectopically produced fs(1)Ya protein in tissue culture cells, neuroblasts, and male accessory glands, which are free of maternal products. We therefore conclude that cell cycle dependent nuclear localization does not require any exclusively maternal products. Finally, our immunoelectron microscopy shows that the fs(1)Ya protein distribution parallels that of lamin, indicating that it is a nuclear lamina protein.

Animals↗
PubMed1994

Proton-lactate cotransport in the apical membrane of frog retinal pigment epithelium.

We studied lactate- and pyruvate-dependent proton transport across the apical membrane of frog RPE. The epithelium was mounted in a modified Ussing-chamber that allowed measurement of transepithelial potential and resistance while intracellular pH was measured with either intracellular microelectrodes or a pH-sensitive dye, 2',7'-bis(2-carboxyethyl)-5,6-carboxyfluorescein (BCECF). To estimate the rate of lactate influx from the change in intracellular pH, we used the NH4 pulse technique to measure intracellular buffering capacity and its dependence on intracellular pH. We found that the buffering capacity was 16 mM at pH1 = 7.28, and that it increased as intracellular pH decreased. Intracellular pH was monitored with the tissue bathed in nominally HCO3-free (Hepes buffered) Ringer. The perfusate on the apical side of the epithelium was then changed to a Ringer that contained between 5 and 100 mM lactate or pyruvate. When 10-100 mM lactate or pyruvate was added to the apical bath the cells acidified by 0.05-0.50 pH units. For each of these acidifications, the initial acid influx into the RPE cells was calculated from the intracellular buffering capacity and the initial rate of intracellular acidification. These influxes were plotted as functions of the concentrations of lactate or pyruvate and this relationship was analysed using Michaelis-Menten kinetics. The Km values were: 33 +/- 5 mM for lactate and 9 +/- 3 mM for pyruvate. There were no differences in the rates of acid influx caused by L- or D-lactate. The rates of acidification caused by 50 mM apical L-lactate were reversibly reduced by 56% after apical administration of probenecid (2 mM), and irreversibly reduced by 63% after apical administration of the SH-reagent mersalyl acid (2 mM). These results indicate the presence of a proton-lactate cotransport system in the apical membrane of the frog RPE.

Animals↗
PubMed1994

Inhibition of tumor necrosis factor production by lymphocytes from anti-TNF antibody-treated, cardiac-allografted rats.

Tumor necrosis factor-alpha (TNF) is a multifunctional cytokine involved in the immunopathologic consequences of allograft rejection. We have previously demonstrated that anti-TNF antibody treatment prolongs cardiac allograft survival in rats. To elucidate the mechanism of anti-TNF antibody in modulating the immune response, we investigated TNF production by spleen and lymph node cells from anti-TNF antibody-treated Lewis rats who received MHC-mismatched Brown Norway rat cardiac allografts. In 10 untreated rats, cardiac allografts were rejected at 6.8 +/- 0.6 days after transplantation (mean +/- SD). Anti-TNF antibody treatment enhanced graft survival to 12.7 +/- 1.4 days (P < 0.001 vs controls). In other anti-TNF antibody-treated recipients spleen and lymph node cells were isolated on Day 5 after transplant. TNF production was measured and showed significantly less TNF than those from untreated (no anti-TNF antibody), transplanted recipient rats (28.7 u/10(6) spleen cells vs 76.4 u/10(6) spleen cells at 2 hr and 4.6 u/10(6) lymph node cells vs 9.2 u/10(6) lymph node cells at 24 hr). Furthermore, following lipopolysaccharide stimulation, spleen cells from anti-TNF-treated rats again produced significantly less TNF than those from untreated transplanted rats (68.9 u/10(6) cells vs 189.4 u/10(6) cells at 2 hr). Finally, with allogeneic cell stimulation, anti-TNF treated rats again produced significantly less TNF than untreated transplanted rats (spleen cells, 2.2 u/10(6) cells vs 40.4 u/10(6) cells at 24 hr; lymph node cells, 1.2 u/10(6) cells vs 22.2 u/10(6) cells at 72 hr). These findings suggest that anti-TNF antibody treatment may not only neutralize TNF activity, but also suppress TNF production itself, providing a new insight into the regulation of TNF by anti-TNF antibody.

Animals↗
PubMed1994

The effect of combination cyclosporine and CTLA4-Ig therapy on cardiac allograft survival.

Transplant rejection requires not only T cell receptor/CD3 complex activation by foreign MHC, but also additional costimulatory signals, as T cell receptor activation alone is insufficient for induction of the immune response. The CD28 receptor on helper T cells, interacting with its ligand B7 on activated B cells or macrophages, provides this costimulus to support T cell activity. CTLA4Ig (a soluble CD28 receptor analog), binds B7 and inhibits CD28 activation. As cyclosporine (CsA) has many side effects and CTLA4Ig alone has a significant benefit upon cardiac allograft survival, we theorized that allograft survival could be improved by using CTLA4Ig with lowered dose CsA. In vitro, high-dose CTLA4Ig inhibited the mixed lymphocyte culture reaction (MLR) between MHC-incompatible rat strains. Furthermore, there was synergistic suppression of MLR by low-dose CTLA4Ig combined with low-dose CsA. In vivo studies used a cervical heterotopic transplant model. Control recipients received no immunotherapy. Experimental recipients received low-dose CsA (1.5 mg/kg/day im) x 14 days after transplant or CTLA4Ig (10, 50, or 150 micrograms IP x 7 days). Combination animals received both CTLA4Ig and CsA. These studies showed that low doses of CsA and CTLA4Ig were additive in vivo, although no additional benefit was seen when CsA was combined with high-dose CTLA4Ig. These data suggest that the combination of low-dose CsA plus CTLA4Ig may prove useful in clinical transplantation to maximize immunosuppression and minimize side effects.

Abatacept↗
PubMed1994

Comparison of a suture technique with the modified Kessler method: resistance to gap formation.

We performed an in vitro study using canine flexor tendons to compare the tensile properties of a suture technique for flexor tendon repair with the standard modified Kessler technique. The technique employs a central wire loop that connects the two transverse limbs of the modified Kessler suture. Both techniques were studied with and without a Lembert epitendinous stitch. The technique combined with an epitendinous suture provided the strongest resistance to gap formation, and its load at gap initiation was 100% greater than the load in tendons repaired with the modified Kessler and an epitendinous suture. Because of its increased resistance to gap formation, this suture technique may provide a safer margin for controlled early active motion after flexor tendon repair.

Animals↗
PubMed1994

pHi-dependent Cl-HCO3 exchange at the basolateral membrane of frog retinal pigment epithelium.

Intracellular pH (pHi) measurements in frog retinal pigment epithelium using the pH-sensitive dye 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein demonstrate that the basolateral membrane contains a pHi-sensitive Cl-HCO3 exchanger. In control Ringer solution, the removal of Cl from the basal bath alkalinized the cells by 0.07 +/- 0.03 (SD) pH units (n = 39) with an initial rate of 0.022 +/- 0.0013 pH units/min. This effect was blocked by 0.5 mM basal 4,4'-diisothiocyanostilbene-2,2'- disulfonic acid or the removal of HCO3 from both the apical and basal baths. The rate of the exchange is reduced by acidification and increased by alkalinization. Increasing apical bath K concentration ([K]o) from 2 to 5 mM approximates the [K]o change in the subretinal space of the intact eye following a transition from light to dark. This [K]o change alkalinized the cells by increasing the rate of the apical membrane Na-HCO3 cotransporter. In 5 mM apical [K]o, the initial rate of the 0 Cl-induced alkalinization was significantly increased to 304 +/- 13% (n = 4) of control (2 mM [K]o). These mechanisms regulate pHi and could also buffer changes in subretinal pH.

Animals↗
PubMed1994

Acidification stimulates chloride and fluid absorption across frog retinal pigment epithelium.

Radioactive tracers and a modified capacitance-probe technique were used to characterize the mechanisms that mediate Cl and fluid absorption across the bullfrog retinal pigment epithelium (RPE)-choroid. In control (HCO3/CO2) Ringer solution, 36Cl was actively absorbed (retina to choroid) at a mean rate of 0.34 mu eq.cm-2.h-1 (n = 34) and accounted for approximately 25% of the short-circuit current. Apical bumetanide (100 microM) or basal 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS; 1 mM) inhibited active Cl transport by 70 and 62%, respectively. Active Cl absorption was doubled, either by removing HCO3 from the bathing media or by elevating CO2 from 5 to 13%, and the increased flux was inhibited by apical bumetanide or basal DIDS. Open-circuit measurements of fluid absorption rate (Jv) and the net fluxes of 36Cl, 22Na, and 86Rb (K substitute) indicated that CO2-induced acidification stimulated NaCl and fluid absorption across the RPE. During acidification, bumetanide produced a twofold larger inhibition of Jv compared with control. Stimulation of net Cl absorption was most likely caused by inhibition of the the basolateral membrane intracellular pH-dependent Cl-HCO3 exchanger.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1994

Potassium-induced chloride secretion across the frog retinal pigment epithelium.

In the intact eye, a transition from light to dark increases K concentration ([K]o) from approximately 2 to 5 mM in the extracellular (subretinal) space between the photoreceptors and the retinal pigment epithelium (RPE) apical membrane. In control (HCO3/CO2) Ringer solution, 36Cl was actively absorbed across isolated bullfrog RPE (retina to choroid) at a rate of 0.31 +/- 0.02 (SE) mu eq.cm-2.h-1 (n = 15). Elevating apical [K]o from 2 to 5 mM reversed active 36Cl transport to secretion (choroid to retina), with a rate of 0.76 +/- 0.17 mu eq.cm-2.h-1. This reversal was completely inhibited by 1 mM 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS) in either the apical or basal bath. In open circuit, elevating [K]o induced a similar reversal of net 36Cl flux and inhibited fluid absorption by approximately 25%. Apical Ba2+ (1 mM), decreased CO2 (5 to 1%), or increased apical bath HCO3 concentration ([HCO3]o) also caused a DIDS-inhibitable reversal of active 36Cl flux. A 10-fold reduction of apical bath Na or [HCO3]o significantly inhibited [K]o, Ba2+, and low CO2-induced Cl secretion. All of these results can be understood in terms of an intracellular pH-dependent stimulation of the basolateral membrane Cl-HCO3 exchanger.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1994

Interaction between plasma potassium and epinephrine in coronary thrombosis in dogs.

BACKGROUND: Both plasma potassium ([K]) and epinephrine concentrations have been known to increase during exercise and decrease rapidly shortly after exercise; in addition, it is also known that exercise can promote coronary thrombosis in human and animal subjects. Many studies have shown that epinephrine has a stimulatory effect on coronary thrombosis; however, little information is available concerning the effect of raising plasma [K] on coronary thrombosis. The present study was designed to investigate the effect of raising plasma [K] and its interaction with epinephrine infusion on coronary thrombosis. METHODS AND RESULTS: A canine model of coronary thrombosis was used, and the frequency of cyclic blood flow reductions (CFRs) resulting from thrombus formation in the circumflex artery was analyzed in the study. By acutely raising plasma [K] to approximately 6.0 mEq/L, the frequency of CFRs was reduced from 8.0 +/- 0.6 to 3.7 +/- 1.0 in 40 minutes (P < .01). Epinephrine infusion (0.5 microgram.kg-1 x min-1) stimulated the frequency of CFRs from 7.1 +/- 0.5 to 11.5 +/- 0.7 in 40 minutes (P < .01). However, if plasma [K] was raised to approximately 6.0 mEq/L while the epinephrine infusion was continued, the frequency fell from 11.5 +/- 0.7 to 7.7 +/- 1.1 in 40 minutes (P < .01). CONCLUSIONS: The present study demonstrated that acutely raising plasma [K] inhibited coronary thrombosis in dogs and also blocked the potentiating effect of epinephrine on coronary thrombosis. These findings may suggest that raising plasma [K] exerts a protective effect against coronary thrombosis and that a rapid decrease in plasma [K], such as that occurring shortly after exercise, facilitates coronary artery thrombosis when the artery has a preexisting pathological condition.

Animals↗
PubMed1994

The Drosophila fusome, a germline-specific organelle, contains membrane skeletal proteins and functions in cyst formation.

Oogenesis in Drosophila takes place within germline cysts that support polarized transport through ring canals interconnecting their 15 nurse cells and single oocyte. Developing cystocytes are spanned by a large cytoplasmic structure known as the fusome that has been postulated to help form ring canals and determine the pattern of nurse cell-oocyte interconnections. We identified the adducin-like hts product and alpha-spectrin as molecular components of fusomes, discovered a related structure in germline stem cells and documented regular associations between fusomes and cystocyte centrosomes. hts mutations completely eliminated fusomes, causing abnormal cysts containing a reduced number of cells to form. Our results imply that Drosophila fusomes are required for ovarian cyst formation and suggest that membrane skeletal proteins regulate cystocyte divisions.

Animals↗
PubMed1994

IMMUNOLOCALIZATION OF H+-ATPase IN THE GILL EPITHELIA OF RAINBOW TROUT

The localization of proton pumps (H+-ATPase) in gill epithelia of rainbow trout [Oncorhynchus mykiss (Walbaum)] was elucidated by immunofluorescence microscopy, using rabbit polyclonal antibodies against the 70 kDa subunit of H+-ATPase purified from clathrin-coated vesicles of bovine brain. In the gill epithelia of freshwater trout, the immunostaining was uniformly distributed along the lamellae and generally concentrated in apical regions. It is concluded, therefore, that H+-ATPase is located in the apex of both chloride cells and epithelial cells of freshwater fish. Hypercapnic treatment resulted in a non-polarized and restrictive distribution of H+-ATPase in the chloride cell. No fluorescent staining was observed in the gill epithelium of seawater-adapted rainbow trout, except in some unidentified anucleate surface material. The presence of the 70 kDa subunit in fish gill epithelia was confirmed by Western blot. These results support the proposed role of a proton pump in sodium uptake in freshwater fish and demonstrate that the H+-ATPase in fish gills is of the vacuolar type, antigenically similar to the H+-ATPase in mammalian brain and kidney.

Journal Article↗
PubMed1994

[Time-resolved fluoroimmunoassay of microalbuminuria].

Time-resolved fluoroimmunoassay (TrFIA) has been recognized as the most promising one among the so-called nonisotopic immunoassays. It is well known for its inherent advantages, high sensitivity, specificity and stability, rapid determination and wide measurement range. We have developed a new TrFIA for determining microalbumin in urine by using monoclonal anti-HSA (human serum albumin) antibody and europium label. The quality of the assay and its preliminary clinical application have been evaluated.

Adult↗
PubMed1994

[Diagnosis and treatment of cornual obstruction by transcervical fallopian tube cannulation under hysteroscopy].

Transcervical cannulation of the proximal oviduct was performed with a tube catheter and flexible guidewire under hysteroscopic guidance to evaluate and treat intramural fallopian tube obstruction in 37 patients. Hysteroscopic cannulation with direct visualization by laparoscopy was successful in 69.2% of the obstructed tubes, 77.4% of the cases. 74% of the obstructed tubes diagnosed by HSG and/or laparoscopy was patent after hydrotubation and cannulation by hysteroscopy. Transcervical cannulation of the proximal oviduct is an effective method for evaluation and treatment of cornual obstruction.

Adult↗
PubMed1994

[Effects of lanthanum ion on beta-endorphin biosynthesis and release in rat pituitary cells].

By using the primary culture method for pituitary cells in CSFM established in our laboratory, we studied the effects of lanthanum ion (La3+) on the biosynthesis and release of beta-endorphin-like immunoreactive substances in rat pituitary cells. Anterior and intermediate/posterior pituitary cells from male rats were cultured with arachidonic acid (AA), cortisol, dexamethasone (DEX) and lanthanum chloride. RIA was used to determine beta-EP levels in culture medium and within cells. The results indicated that AA could obviously stimulate the release of beta-EP from pituitary cells at a concentration of 2 x 10(-5) mol/L, while cortisol at 10(-6)mol/L and DEX at 10(-7)mol/L inhibited this release. These data coincide with results reported in the literature and thereby prove the reliability of the method used. When incubated with pituitary cells, lanthanum chloride induced a dose- and time-dependent release of beta-EP. Namely, beta-EP release continuously increased for a period under the action of La3+ of different doses (10(-5)mol/L and 10(-7)mol/L). beta-EP content in cells showed similar changes. These results suggest that beta-EP biosynthesis and release in rat anterior and intermediate/posterior pituitary cells are stimulated by lanthanum ions. They also provide experimental evidence for explaining the analgesic mechanism of lanthanum ions at the cellular level.

Animals↗