Effect of acute feeding of diets of varying fatty acid composition on intestinal apolipoprotein expression in the newborn swine

The purpose of this study was to determine the effects of dietary fatty acids of varying chain lengths and degrees of saturation on intestinal apolipoprotein (apo) B and A-I expression in the newborn piglet. Two-day-old female piglets received one of three isocaloric formulas containing 48% of total calories (120 kcal/kg/24 h) as medium-chain triglycerides (MCT) from MCT oil, intermediate-chain saturated triglycerides (ICST) from coconut oil, or long-chain polyunsaturated triglycerides (LCPUT) from safflower oil by continuous duodenal infusion for 24 h. After in situ radiolabeling, jejunal and ileal mucosal apo B-48 and A-I were immunoprecipitated, and synthesis was expressed as percentage of total protein synthesis. Mucosal apo B and A-I mass was measured by ELISA as nanograms of apoprotein/microgram of total protein. Fifty percent less apo B jejunal synthesis was present in the ICST group versus the MCT and LCPUT groups (0.67 +/- 0.07, 1.19 +/- 0.20, and 1.25 +/- 0.15, respectively, mean +/- SEM, p < 0.05). Jejunal apo B mass was lower in the MCT group versus the ICST and LCPUT groups (0.10 +/- 0.02, 0.21 +/- 0.03, and 0.16 +/- 0.03, respectively, p < 0.05). Ileal apo B synthesis was lowest in the ICST group. No differences were found in ileal apo B mass. Two-fold higher jejunal apo A-I synthesis was found in the LCPUT group versus the MCT and ICST groups (14.18 +/- 1.69, 7.56 +/- 2.63, and 6.36 +/- 0.58, respectively, p < 0.01). No differences were found for jejunal apo A-I mass. In the ileum, the only difference was a higher apo A-I mass in the LCPUT group (p < 0.05). We conclude that in the newborn piglet intestinal apo B and A-I expression is acutely and differentially regulated by dietary lipid varying in fatty acid chain length and saturation. The patterns of regulation are complex and vary among specific apolipoproteins and regions of the small intestine and include co- and posttranslational mechanisms.

Osmotic properties of boar spermatozoa and their relevance to cryopreservation

A series of six experiments was conducted to determine the fundamental cryobiological properties of boar spermatozoa to develop optimal approaches for cryopreserving this important cell type. In the first experiments, boar spermatozoa samples were diluted in various osmolalities of experimental solutions (185-900 mOsmol kg-1) to provide hypo-, iso-, and hyperosmotic conditions. Equilibrium cell volumes (Expts 1 and 2) were measured after exposure for 3 min and the change in cell volume was measured over time using an electronic particle counter (Expt 3). The isosmotic cell volume was found to be 26.3 +/- 0.39 microns 3 (mean +/- SEM; n = 5). Over this range of osmolalities, boar spermatozoa behaved as linear osmometers (a linear volume versus 1/osm plot, r2 = 0.99) with an osmotically inactive cell fraction of 67.4 +/- 4.5%. The rate of water permeability (Lp) was determined to be 1.03 +/- 0.05 microns min-1 atm-1, which was consistent within and among donors (P > 0.130). A second series of experiments was performed to determine the effect of temperature and osmolality on boar sperm motility (Expt 4), and the effect of osmolality on the integrity of the sperm plasma membrane and its temperature dependence. Plasma membrane integrity was measured before and after boar spermatozoa were returned to an isosmolality (Expt 6). Motility was not affected at 30 degrees C, relative to that at room temperature, but was significantly decreased (P < 0.05) at 8 degrees C and 0 degree C (yielding a relative reduction to 85% and 35% of original motility, respectively; n = 6). Sperm motility was not significantly decreased (P > 0.05) until the osmolality reached 210 mOsmol kg-1, at which time motility began to decrease from 95% to 10% of the original value at 90 mOsmol kg-1. The integrity of the plasma membrane of boar spermatozoa was found to be dependent on temperature, donor and osmolality, decreasing significantly (P < 0.05) below room temperature, and below 185 mOsmol kg-1 (P < 0.05). There was no significant difference (P > 0.10) in the integrity of the plasma membrane of the samples before and after returning to 290 mOsmol kg-1, indicating that osmotic damage occurs during the initial change from isosmotic to hyposmotic media. These osmotic characteristics could be used to determine optimal conditions for cryopreservation of boar spermatozoa.

Transcriptional regulation of the insulin-like growth factor-I receptor gene: evidence for protein kinase C-dependent and -independent pathways

An important mechanism whereby growth factors stimulate vascular smooth muscle cell proliferation is by increasing insulin-like growth factor (IGF)-I receptor binding. To characterize the mechanisms involved, we studied transcription of the IGF-I receptor gene in rat aortic smooth muscle cells. Angiotensin II (100 nM) and basic fibroblast growth factor (5 ng/ml) caused a marked increase in IGF-I receptor messenger RNA (mRNA) levels, peaking at 3 h (215 +/- 16.8% and 85 +/- 7.4% above control, respectively). Nuclear run-on assays indicated that angiotensin II and fibroblast growth factor stimulated IGF-I receptor gene transcription by 2.1- and 2.5-fold, respectively. Down-regulation of protein kinase C, a serine/threonine kinase that is important in growth factor-activated signal transduction, completely inhibited fibroblast growth factor- but not angiotensin II-mediated up-regulation of IGF-I receptor mRNA. The protein kinase C inhibitors chelerythrine (3 microns), calphostin C (100 nM), and staurosporine (10 nM) also blocked fibroblast growth factor but not angiotensin II induction of IGF-I receptor mRNA. Thus, angiotensin II and fibroblast growth factor transcriptionally regulate the IGF-I receptor gene by protein kinase C-independent and -dependent pathways, respectively. In view of our prior data indicating that IGF-I receptor density is a critical determinant of vascular smooth muscle cell growth, our findings have particular relevance to understanding mechanisms whereby growth factors regulate vascular proliferation in vivo.

Epiphyseal lengthening operation--an improved technique

An improved method of epiphyseal lengthening operation and subsequent outer fixation are presented on the basis of experience in 30 cases. The operative technique is described in detail, including the different options of separative traction and osteotomy at subtrochanteric, distal part of the upper femur and lower tibial levels. The physiological and histological research concerning this method is discussed. The authors believe that this procedure is better than the other methods.

G-protein and tyrosine kinase receptor cross-talk in rat aortic smooth muscle cells: thrombin- and angiotensin II-induced tyrosine phosphorylation of insulin receptor substrate-1 and insulin-like growth factor 1 receptor

Insulin-like growth factor I is an autocrine/paracrine factor for vascular smooth muscle cells and is required for angiotensin II- and thrombin-induced mitogenesis. The insulin-like growth factor I-triggered signaling pathway involves autophosphorylation of the beta-subunit of its tyrosine kinase receptor and phosphorylation of insulin receptor substrate-1, the latter providing binding sites for proteins with src homology-2 domains. In rat aortic smooth muscle cells we observed that both angiotensin II and thrombin induced rapid tyrosine phosphorylation of insulin receptor substrate-1. Our results also demonstrated that these mitogens rapidly stimulated phosphorylation of the insulin-like growth factor 1 receptor beta-chain. These data demonstrate a novel interaction between the G-protein coupled angiotensin II and thrombin receptors and the tyrosine-kinase insulin-like growth factor I receptor.

Developmental expression and functional characterization of the potassium-channel subunit Kv3.1b in parvalbumin-containing interneurons of the rat hippocampus

The expression of the voltage-gated K(+)-channel subunit Kv3.1b in the developing hippocampus was determined by immunoblot and immunohistochemical techniques. Kv3.1b protein was detected first at postnatal day (P) 8. The Kv3.1b-immunopositive cell number per tissue section reached a maximum at P14 and was maintained through P40. In contrast, the Kv3.1b protein content of isolated membrane vesicles in immunoblots progressively increased through P40, suggesting an increase in Kv3.1b content per cell throughout this time period. Kv3.1b protein was expressed selectively in the somata, proximal dendrites, and axons of cells lying within or near the pyramidal cell layer, consistent with their being GABAergic inhibitory interneurons. Kv3.1b was present in approximately 80% of parvalbumin-positive interneurons. The developmental onset of Kv3.1b and parvalbumin immunoreactivity was identical. In contrast, Kv3.1b was mostly absent from the subset of somatostatin-positive inhibitory interneurons. Electrophysiological recordings were made from stratum pyramidale interneurons in which morphology and Kv3.1b-positive immunoreactivity were confirmed post hoc. Outward currents had voltage-dependent and biophysical properties resembling those of channels formed by Kv3.1b. The current blocked by low concentrations of 4-aminopyridine (4-AP) showed marked inactivation, suggesting that Kv3.1b may coassemble with other members of the Kv3 subfamily. In current-clamp recordings, concentrations of 4-AP that blocked the current through Kv3.1b channels allowed us tentatively to assign a role to Kv3.1b-containing channels in action-potential repolarization. These data demonstrate that Kv3.1b is regulated developmentally in a specific subpopulation of hippocampal interneurons and that channels containing this subunit may be a major determinant in imparting "fast-spiking" characteristics to these and other cells throughout the central nervous system containing the Kv3.1b subunit.

Evidence for expression of vasopressin V2 receptor mRNA in human lung

Studies using fetal sheep, goats, and guinea pigs indicate that vasopressin may play a role in preparing the fetal lung for the transition from a uterine to an air-breathing environment by slowing lung liquid secretion. The mechanism of vasopressin action is believed to occur through V2 receptors with subsequent activation of amiloride-sensitive sodium channels. However, the presence of the V2 receptor in human lung has not yet been documented. In the present study, expression of the vasopressin V2 receptor in fetal and adult human lung was examined using reverse transcription-polymerase chain reaction (RT-PCR), Northern blot analysis, and DNA sequencing. Using RT-PCR and primer pairs specific for the human V2 receptor, PCR products of the predicted sizes of 512 and 862 bp were obtained from adult human lung. DNA sequencing of the cloned PCR products revealed exact identity with the published sequence for the V2 receptor. Northern blot analysis revealed the expression of a approximately 1.9 kb mRNA in adult human lung as well as in kidney, but not in fetal human lung at 22-24 weeks of gestation. However, using the more sensitive RT-PCR assay the 862-bp product was successfully amplified from human fetal lung, although the data indicate the mRNA for this receptor is expressed in lower levels than in adult human lung or kidney. Using RT-PCR and primers specific for the rat V2 receptor, a PCR product of the predicted size of 461 bp was amplified from adult rat lung and kidney, despite an earlier report that this receptor mRNA is absent from the lung of this species. The role for the V2 receptor in adult human lung is unknown at this time, but, as in the human kidney and lungs of fetal sheep, goats, and guinea pigs, this receptor may play a role in fluid balance.

Biomechanical study on unilateral single-plane external fixer

Six tibias removed from 30-40 years old males, who died in an accident for in less than 12 hours, were osteotomized at one-third supra-medium segment. They were fixed by an unilateral adjustable external fixer (UAEF), to be used as a model of external fixation of tibial fracture (MEFTF). The compression, tension, torsion, antero-posterior and lateral bending strength, and the strength for vertically extracting the pins from the tibia were determined in the MEFTF. Within a certain range of load, the correlation of strain to stress was basically a linear relationship. These data provide a theoretical basis of biomechanics for the improvement of UAEF and for early exercises of fracture patients, such as extend-bending of the joint, raising the limb and walking with a walking stick.

A role for cAMP in angiotensin II mediated inhibition of cell growth in AT1A receptor-transfected CHO-K1 cells

G-protein coupled Angiotensin II receptors (AT1A), mediate cellular responses through multiple signal transduction pathways. In AT1A receptor-transfected CHO-K1 cells (T3CHO/AT1A), angiotensin II (AII) stimulated a dose-dependent EC50 = 3.3 nM) increase in cAMP accumulation, which was inhibited by the selective AT1, nonpeptide receptor antagonist EXP3174. Activation of protein kinase C, or increasing intracellular Ca2+ with ATP, the calcium ionophore A23187 or ionomycin failed to stimulate cAMP accumulation. Thus, AII-induced cAMP accumulation was not secondary to activation of a protein kinase C- or ca2+/calmodulin-dependent pathway. Since cAMP has an established role in cellular growth responses, we investigated the effect of the AII-mediated increase in cAMP on cell number and [3H]thymidine incorporation in T3CHOA/AT1A cells. AII (1 microM) significantly inhibited cell number (51% at 96 h) and [3H]thymidine incorporation of 68% at 24 h) compared to vehicle controls. These effects were blocked by EXP3174, confirming that these responses were mediated through the AT1 receptor. Forskolin (10 microM) and the cAMP analog dibutyryl-cAMP (1 mM) also inhibited [3H]thymidine incorporation by 55 and 25% respectively. We extended our investigation on the effect of AII-stimulated increases in cAMP, to determine the role for established growth related signaling events, i.e., mitogen-activated protein kinase activity an tyrosine phosphorylation of cellular proteins. AII-stimulated mitogen-activated protein kinase activity and phosphorylation of the 42 and 44 kD forms. These events were unaffected by forskolin stimulated increases in cAMP, thus the AII-stimulated mitogen-activated protein kinase activity was independent of cAMP in these cells. AII also stimulated tyrosine phosphorylation of a number of cellular proteins in T3CHO/AT1A cells, in particular at 127 kD protein. The phosphorylation of the 127 kD protein was transient, reaching a maximum at 1 min, and returning to basal levels within 10 min. The dephosphorylation of this protein was blocked by a selective inhibitor of cAMP dependent protein kinase A, H89-dihydrochloride and preexposure to forskolin prevented the AII-induced transient tyrosine phosphorylation of the 127 kD protein. These data suggest that cAMP, and therefore protein kinase A can contribute to AII-mediated growth inhibition by stimulating the dephosphorylation of substrates that are tyrosine phosphorylated in response to AII.

Extracellular dopamine in the medial preoptic area: implications for sexual motivation and hormonal control of copulation

Dopamine (DA) activity in the medial preoptic area (MPOA) contributes to the control of male rat sexual behavior. We tested (1) whether extracellular DA increases during precopulatory exposure to an estrous female and during copulation, (2) whether exposure to another male increases extracellular DA, (3) whether motor activity during copulation accounts for increased DA levels, and (4) whether concurrent or recent testosterone influences DA levels or copulation in castrates. Extracellular DA and its metabolites in male rats' MPOA were measured using microdialysis. DA level increased during precopulatory exposure to the female in all animals that subsequently copulated; this included all intact animals, all testosterone-treated castrates, and 9 of 14 1-week castrates treated with oil vehicle. DA levels did not increase in any animal that subsequently failed to copulate, including the remaining 1-week, and all 2-week, vehicle-treated castrates. When the barrier was removed and the animals were allowed to copulate, levels of DA and its metabolites continued to rise in intact males and in castrates that copulated. The DA response to the estrous female could not be attributed to nonsexual social stimuli, since exposure to another male was ineffective. The DA response to copulation could not be attributed primarily to motor activity, since animals running voluntarily in a running wheel did not show significantly increased DA. These and previous data suggest that DA released in the MPOA in response to an estrous female may contribute to sexual motivation and copulatory proficiency. Testosterone may promote copulation in part through permissive actions on dopamine release.

Abnormal polarization of EGF receptors and autocrine stimulation of cyst epithelial growth in human ADPKD

The underlying mechanism of the hyperproliferative response of human autosomal dominant polycystic kidney disease (ADPKD) epithelia was studied. Epidermal growth factor (EGF) protein is highly expressed in ADPKD cyst epithelia in vivo, and primary cultures are hyperesponsive to mitogenic stimulation by EGF in vitro. Doses of > 1 ng/ml EGF were highly mitogenic to ADPKD epithelia. 3H-labeled thymidine proliferation assays showed that cyst fluids and ADPKD epithelial cell-conditioned media also stimulated renal epithelial cell proliferation and contained EGF immunoreactivity (6, 30, and 37 kDa) as detected by Western blots. Radioimmunoassays detected mean levels of 2.87 and 1.4 ng/ml EGF in cyst fluids from early (proliferative) and end-stage ADPKD cysts, respectively. Scatchard analysis of 125I-labeled EGF binding to apical and basolateral membrane showed high-affinity binding to basolateral membranes of normal and ADPKD kidneys but additional unique high-affinity receptor binding to apical membranes of ADPKD but not normal kidneys. Cross-linking analysis and antiphosphotyrosine Western analysis demonstrated functionally active apical EGF receptors at 150-170 kDa. These results suggest mediation of cyst expansion via an autocrine loop involving EGF synthesis and processing by cyst epithelial cells, apical secretion into cyst lumens, and subsequent binding to and phosphorylation of apical membrane EGF receptors. These findings are consistent with a membrane protein polarization defect in ADPKD cyst epithelia.

The effect of collection temperature, cooling rate and warming rate on chilling injury and cryopreservation of mouse spermatozoa

The experiments presented here identify several factors that affect survival (motility) of cryopreserved mouse spermatozoa after freezing and thawing. Among these factors are: (i) the temperature at which spermatozoa are collected, (ii) the cooling rate to 0 degrees C and (iii) the warming rate from -196 degrees C to ambient. When excised epididymides were cooled to near 0 degrees (1-4 degrees C) and spermatozoa collected and mixed with cryoprotectant at that temperature, motilities after subsequent freezing and thawing were 8-10 times higher than when the spermatozoa were collected from the epididymides at 22 degrees C. In addition, the survival rates of spermatozoa warmed at rates ranging from 150 to 2000 degrees C min-1 were about five times higher than those in suspensions warmed at about 7500 degrees C min-1. The combination of a low collection temperature and the lower warming rates resulted in approximately 50% motility relative to unfrozen controls. Motility was reduced to 6-8% when the collection temperature was 22 degrees C, and to approximately 10% when frozen suspensions of spermatozoa collected in the cold were rapidly warmed from -196 degrees C. When spermatozoa collected at 22 degrees C were abruptly cooled to 0 degrees C, 40-80% of the cells suffered an irreversible loss of motility after warming. In contrast, when spermatozoa were cooled to 0 degrees C at 1 degree C min-1 and warmed (either rapidly or slowly), motilities were similar to those of uncooled controls (75-90%).(ABSTRACT TRUNCATED AT 250 WORDS)

The effects of bFGF on RCS rat eyes

Basic fibroblast growth factor (bFGF) has been implicated as a factor in retinal differentiation and disease. Recent studies have shown that subretinal or intravitreal injections of bFGF delay the retinal degeneration of the RCS rat but the global nature of this effect has been quantified for few test animals and the mechanism underlying this effect is not understood. In order to determine more accurately the global effects of intravitreal bFGF and to further elucidate the mechanism of bFGF promoted photoreceptor cell saving, we injected one of three bFGF doses into the vitreal cavities of young RCS rats. Using measurements from several eyes, we confirmed that a single intravitreal bFGF injection globally delays the RCS dystrophy. Test eyes contained fewer debris zone macrophages and more inner retinal macrophages than did control eyes at 1 month post injection. As bFGF's saving effect waned, the number of inner retinal macrophages decreased and the number of debris zone macrophages increased toward control levels. Dose-dependent cataract formation occurred in 100% of test eyes. Eyes that received the highest bFGF dose showed increased retinal vascularization at 1, 2 and 3 months post injection. The possible relationships between bFGF promoted photoreceptor survival and our findings are discussed.

Environments of the four tryptophans in the extracellular domain of human tissue factor: comparison of results from absorption and fluorescence difference spectra of tryptophan replacement mutants with the crystal structure of the wild-type protein

The local environments of the four tryptophan residues of the extracellular domain of human tissue factor (sTF) were assessed from difference absorption and fluorescence spectra. The difference spectra were derived by subtracting spectra from single Trp-to-Phe or Trp-to-Tyr replacement mutants from the corresponding spectrum of the wild-type protein. Each of the mutants was capable of enhancing the proteolytic activity of factor VIIa showing that the mutations did not introduce major structural changes, although the mutants were more susceptible to denaturation by guanidinium chloride. The difference spectra indicate that the Trp residues are buried to different extents within the protein matrix. This evaluation was compared with the x-ray crystal structure of sTF. There is excellent agreement between predictions from the difference spectra and the environments of the Trp residues observed in the x-ray crystal structure, demonstrating that difference absorption and particularly fluorescence spectra derived from functional single-Trp replacement mutants can be used to obtain information about the local environments of individual Trp residues in multi-tryptophan proteins.

Regulation of vascular smooth muscle cell insulin-like growth factor I receptors by phosphorothioate oligonucleotides. Effects on cell growth and evidence that sense targeting at the ATG site increases receptor expression

We have recently shown that insulin-like growth factor I (IGF I) is a mediator of angiotensin II-induced mitogenesis in vascular smooth muscle cells (Delafontaine, P., and Lou H. (1993) J. Biol. Chem. 268, 16866-16870). To study the role of the IGF I receptor in vascular smooth muscle cell growth, phosphorothioate oligonucleotides were used to modulate IGF I receptors. An antisense oligonucleotide targeting the ATG site inhibited basal and serum-induced DNA synthesis in vascular smooth muscle cells. Mismatch oligonucleotide had no effect, while surprisingly sense oligonucleotide increased IGF I receptor number and basal and serum-induced DNA synthesis. A 51% reduction in IGF I receptor number following exposure to 5 microM antisense oligonucleotide markedly inhibited angiotensin II-induced mitogenesis. A 70% increase in IGF I receptor number following exposure to 5 microM sense oligonucleotide resulted in a 4-fold increase in basal [3H]thymidine incorporation, and angiotensin II (1-1000 nM) had no additive stimulatory effect. An antisense oligonucleotide targeting a sequence starting at +109 base pairs (relative to ATG) also reduced IGF I receptor number, however, the corresponding sense oligonucleotide was without effect. These findings demonstrate that alterations in vascular smooth muscle cell IGF I receptor density play a critical role in the proliferative response of vascular smooth muscle cells to serum and to angiotensin II. In addition, the surprising observation that an ATG-directed sense oligonucleotide up-regulates IGF I receptors identifies a novel effect of oligonucleotides on gene expression.

Irrigation and traction therapy for open fracture with large-sized full-thickness skin-deficit and severely infected wound

In this paper the results of skeletal traction and irrigation therapy (STIT) used for open fracture complicated with large-sized full-thickness skin-deficit and infection wounds (OFIW) were presented. Fourteen patients of OFIW were treated by the plaster cast and wound dressing (PCWD), and 30 patients of OFIW were treated by STIT. The results indicated that after one week of treatment, the white blood cell count in the STIT group, compared to 17.6 +/- 1.0 x 10(9)/L from before treatment, returned to 8.8 +/- 0.8 x 10(9)/L, and in contrast, the cell count of the PCWD group was about 13.0 +/- 1.4 x 10(9)/L. All of wound exudate culture in the STIT group was negative, and those of 7 cases (7/14) in PCWD group were positive (P < 0.01). The symptoms and signs such as pain, fever and septic exudate on the wound in the STIT group were much milder than those in the PCWD group. There were 5 cases (35.7%) of toxicemia and septicemia, 2 cases (14.3%) of osteomyelitis, 2 cases (14.3%) of amputation, 1 case (7.1%) of delayed union and 3 cases (21.4%) of malunion in the PCWD group, and no complications in the STIT group.

Inhibition of vascular smooth muscle cell growth through antisense transcription of a rat insulin-like growth factor I receptor cDNA

Insulin-like growth factor I (IGF I) is an autocrine/paracrine growth factor that is produced in multiple tissues and is essential for normal developmental growth. Its effects are mediated by activation of a membrane-bound tyrosine kinase receptor, IGF IR. On the basis of the partial rat IGF IR alpha-chain cDNA sequence previously reported, we cloned cDNA encoding the full-length rat IGF IR. The deduced amino acid sequence predicts a 1370-amino acid receptor precursor, which includes signal sequence, a 707-amino acid alpha-chain, a 4-Arg cleavage site, and a 629-amino acid beta-chain. Overall, similarity to human IGF IR is 89% and 98% at the nucleotide and amino acid levels, respectively. Antisense IGF IR expression constructs in vectors incorporating Epstein-Barr virus replicative signals and the cytomegalovirus promoter/enhancer or the inducible human metallothionein IIa promoter/enhancer were assembled and stably transfected into cultured rat aortic smooth muscle cells. Clone CA9 (constitutively expressing abundant antisense IGF IR transcripts), clones MA5 and MA7 (expressing antisense IGF IR transcripts inducibly), and clones ME8 and ME10 (expressing vector alone) were characterized. There was a 57% reduction in IGF IR mRNA levels in clone CA9 after confluence compared with clone ME10. This resulted in a 51% decrease in IGF I binding sites in clone CA9, without a change in binding affinity (Kd), and a 55% and 57% reduction in DNA synthesis rates, basally and in response to 10 ng/mL IGF I, respectively. Clones MA5/MA7 similarly showed a 54% reduction in IGF IR number after confluence following exposure to 100 mumol/L ZnSO4 and a 44% and 58% reduction in DNA synthesis, basally and in response to 10 ng/mL IGF I, respectively. Growth curves indicated that proliferation of clone CA9 in the presence of 10% serum was reduced by 60% compared with clone ME10. Thus, cloning of cDNA encoding the full-length rat IGF IR indicates that this receptor is highly conserved. Antisense targeting of this receptor in vascular smooth muscle cells (VSMCs) demonstrates that a decrease in IGF IR density results in marked inhibition of VSMC proliferation. These findings indicate an important role for this ligand-receptor system in regulating VSMC growth. Specifically, they suggest that modulation of VSMC IGF IR density may be an important mechanism whereby growth of these cells is controlled.

Stable expression of a functional rat angiotensin II (AT1A) receptor in CHO-K1 cells: rapid desensitization by angiotensin II

The octapeptide angiotensin II mediates the physiological actions of the renin-angiotensin system through activation of several angiotensin II receptor subtypes; in particular the AT1. In many tissues, the presence of multiple angiotensin II receptor subtypes, together with a low number of receptors, makes it difficult to study biological responses to physiological concentrations (10(-11)-10(-9) M) of angiotensin II. Also, cultured cells show diminished angiotensin II receptor binding with respect to time in culture and passage number. To address these problems, we expressed the recombinant AT1A receptor in CHO-K1 cells. The stably transfected receptor was characterized using radioligand binding studies and functional coupling to cytosolic free calcium. Radioligand binding of [125I] angiotensin II to the angiotensin II receptor was specific, saturable, reversible and modulated by guanine nucleotides. Like the endogenous AT1A receptor, reported in a variety of tissues, the specific, noncompetitive, nonpeptide AII receptor antagonist, EXP3174, blocked binding of [125I] angiotensin II to the transfected receptor. Scatchard analysis demonstrated that the transfected receptor had a dissociation constant of 1.9 nM with a density of 3.4 pmol/mg protein. An important feature of many of the responses to angiotensin II is the rapid desensitization that occurs following agonist occupancy and the development of tachyphylaxis. In AT1A receptor transfected CHO-K1 cells, angiotensin II (10(-9) M) stimulated a rapid increase in cytosolic free calcium that was completely desensitized within 50 sec following receptor occupancy. Agonist induced desensitization was unaffected when receptor internalization was blocked by pretreatment with concanavalin A or incubation at 4 degrees C, and no changes in AT1A receptor affinity or number were observed. Receptor desensitization was also unaffected by inhibition or activation of protein kinase C. Thus, we have established a permanent, high-level transfectant of the AT1A receptor in CHO-K1 cells and have shown that these receptors rapidly desensitize following exposure to physiological concentrations of agonist. The mechanism of rapid desensitization is not related to receptor sequestration, internalization or controlled by PKC phosphorylation. This provides an excellent model for studying AII actions mediated through a specific receptor subtype, at subnanomolar concentrations.

[Clinical application of heparin--free hemodialysis by hemophan dialyzer]

Heparin-free hemodialysis (HFHD) is important in patient hemodialysis with ARF and CRF with hemorrhagic trend. Adsorption method HFHD was used clinically in patients in our hospital. The method showed that the positively charged hemophan membrane binds the negatively charged anticoagulant heparin. The result showed that adsorption method HFHD has good bioconcomitance, needs no special medicine and equipment, and never increase the load of heart. It is simple and has high successful rate ( > or = 90%).

[Construction and application of the chromosomal specific probe pool from human chromosome no. 7]

We constructed a chromosomal specific probe pool from human chromosome No. 7 using the techniques of chromosomal microdissection, PCR and chromosomal painting. A patient's pedigree with an abnormal chromosome No. 7 were analysed by the above probe pool.

Human spermatozoa glycerol permeability and activation energy determined by electron paramagnetic resonance

The permeability of human spermatozoa to glycerol and its activation energy were determined using electron paramagnetic resonance (EPR) techniques. EPR was used to monitor the aqueous cell volume change vs. time during the glycerol permeation process using the aqueous spin label 15N-tempone and the membrane impermeable broadening agent potassium trioxalatochromiate (chromium oxalate). The permeation process was completed in tens of seconds, requiring the use of a stopped-flow methodology. The glycerol permeability coefficient (Pg) was determined by fitting a simple theoretical model to the experimental data. The permeabilities of human spermatozoa in 1 molar and 2 molar glycerol at 20 degrees C are (10.3 +/- 0.3).10(-4) cm/min (mean +/- S.D.) and (6.0 +/- 1.4).10(-4) cm/min, respectively. The permeabilities of human spermatozoa in 2 molar glycerol at 30, 20, 10, and 0 degrees C are (8.3 +/- 1.3).10(-4) cm/min, (6.0 +/- 1.4).10(-4) cm/min, (2.1 +/- 0.4).10(-4) cm/min, and (1.1 +/- 0.3).10(-4) cm/min, respectively. The activation energy (Ea) for glycerol permeation between 30 degrees C and 0 degrees C was found to be 11.6 kcal/mol.

Case-control study of residential radon and lung cancer in Winnipeg, Manitoba, Canada

A case-control study of lung cancer in relation to exposure to radon in homes in Winnipeg, Manitoba, Canada, was conducted during 1983-1990. In total, 738 individuals with histologically confirmed incident cases of lung cancer were interviewed, along with 738 controls matched on age (+/- 5 years) and sex. Radon dosimeters were placed in all residences in which the study subjects had reported living within the Winnipeg metropolitan area for at least 1 year. Radon dosimetry was done by means of integrated alpha-track measurements over a 1-year period. In the homes monitored, the average level of radon-222 was about 120 becquerels (Bq)/m3 in the bedroom area and 200 Bq/m3 in the basement. After adjusting for cigarette smoking and education, no increase in the relative risk for any of the histologic types of lung cancer observed among the cases was detected in relation to cumulative exposure to radon.

Indomethacin inhibition of hog gastric H+/K(+)-ATPase arises from its effect on both the enzyme protein and the lipid bilayer

Indomethacin showed a dose-, time-, and pH-dependent, noncompetitive inhibitory effect on hog gastric H+/K(+)-ATPase. Four percent of total indomethacin in the buffer (0.20 mmol/liter) bound to the H+/K(+)-ATPase vesicles (15 micrograms/ml). It markedly quenched the intrinsic fluorescence of the enzyme, and decreased the membrane fluidity. Thus, the inhibitor effect of indomethacin may arise from both a direct effect on the hydrolytic and H+ transport functions of the enzyme and a disturbing effect on the lipid bilayer of the vesicle.

Long-term photoreceptor transplants in dystrophic and normal mouse retina

PURPOSE

To determine the long-term status of transgenic photoreceptors transplanted to the subretinal space of both rd mutant (receptorless) and normal mouse retina.

METHODS

Microaggregates of neural retina from transgenic mice containing lacZ-labeled photoreceptors were transplanted to the subretinal space of adult rd mutant and normal mice. The transplant site was examined by light and electron microscopy at monthly intervals up to 9 months after transplantation surgery.

RESULTS

Photoreceptors develop and survive well if transplanted with the proper orientation to the retinal pigment epithelium (RPE). The status of the photoreceptors, including outer segments and synaptic terminals, appear normal for at least 9 months after transplantation; they continue to express the lacZ reporter gene. Cones survive as well as rods. Transplants to the normal mouse develop normally, whereas the host photoreceptors displaced from the RPE degenerate. A barrier, formed by Müller cell processes, develops after photoreceptor degeneration in both normal and rd mouse retina and demarcates host from transplant tissue. Areas can be found in which neural processes have penetrated this barrier. There is no evidence of host-graft rejection.

CONCLUSION

Transplanted progenitor photoreceptors develop and survive well for long periods of time in either the rd mutant or normal retina if they are properly positioned. In the former, they reconstitute a photoreceptor layer; in the latter, they replace the host photoreceptor layer, which degenerates after being displaced from the RPE. Areas of potential contact between donor and host neurons exist in these transplants.

[Comparison of corneal topography and keratometer in patients with cataract preoperatively and postoperatively]

The comparison of corneal topography with keratometer in 200 patients (278 eyes) was made. The results revealed that Sim K values of corneal topography were 44.22D and 44.26D, mean diopters of keratometer were 44.16D and 44.23D in 150 eyes of 116 patients with cataract preoperatively. There was no significant difference between Sim K values of topography and diopters of keratometer (P > 0.05). The Sim K values of the topography were 46.37D and 43.06D and diopters of keratometer were 46.09D and 42.88D in 90 eyes of 67 patients who received cataract extraction with IOL implantation or second IOL implantation. No significance was found in results between Sim K values and diopters of keratometer in patients postoperatively (P > 0.05). Our investigation demonstrated that Sim K values of corneal topography were in agreements with diopters of keratometer in patients with cataracts preoperatively or postoperatively. However, corneal topography has great values in diagnosis of corneal diseases, traumatic astigmatism, severe non-rule stigmatisms, in which keratometer is often useless.

Water volume and osmotic behaviour of mouse spermatozoa determined by electron paramagnetic resonance

Experiments were conducted to determine the water volume and osmotic behaviour of mouse spermatozoa using an electron paramagnetic resonance technique using the spin label tempone, and the broadening agent potassium chromium oxalate. After a swim-up procedure, an average water volume of 43.3 micron3 of individual spermatozoa was obtained at 290 mosmol. If a water compartment of 59% is assumed, the total volume of mouse spermatozoa is 73.4 micron3. A plot of the relative water volume of mouse spermatozoa versus the reciprocal of buffer osmolality (Boyle van't Hoff plot) is linear in the range 250-900 mosmol of sodium chloride solutions (r2 = -.96). The Boyle van't Hoff plot intercept indicates that 13% of the spin-label accessible isotonic water is osmotically inactive.

Enhanced brain delivery of an anti-HIV nucleoside 2'-F-ara-ddI by xanthine oxidase mediated biotransformation

In order to enhance the brain delivery of 2'-F-ara-ddI,2'-F-ara-ddP 6 was synthesized and its in vitro and in vivo bioconversion reaction studied. For the study, a new efficient synthetic method for 2'-F-ara-ddP 6 was developed from 5-benzoyl-1,2-O-isopropylidene-3-deoxyribose 1. For in vitro study 2'-F-ara-ddP was incubated in pH 2, mouse liver homogenate, and mouse serum at 37 degrees C. No degradation was observed in pH 2 and serum, while in liver homogenate 2'-F-ara-ddP was almost completely converted to 2'-F-ara-ddI within 20 min (t1/2 = 3.54 min). In order to determine the role of xanthine oxidase in the conversion of 2'-F-ara-ddP to 2'-F-ara-ddI, in vitro studies were conducted in phosphate buffer (pH 7.4) in the presence or absence of allopurinol, in which the half-lives of 2'-F-ara-ddP were 7.4 and 3.4 h, respectively, indicating the conversions were catalyzed by the xanthine oxidase. A similar experiment with aldehyde oxidase isolated from the human liver did not affect the biotransformation. The biotransformation was also detected in the brain homogenate, although the rate of conversion was low and incomplete. In order to assess the bioconversion in vivo, pharmacokinetic studies of 2'-F-ara-ddP and 2'-F-ara-ddI were conducted in mice. The maximum serum concentrations of 2'-F-ara-ddI administered itself and as 2'-F-ara-ddP reached 48.1 +/- 10.00 and 89.3 +/- 26.0 microM and were observed in 1 and 0.25 h, respectively. The data indicate that 2'-F-ara-ddI is absorbed at a slower rate than that of 2'-F-raa-ddP. The bioavailability of the prodrug after oral administration was 60.7%. The concentration of 2'-F-ara-ddI following oral administration of 2'-ara-ddI was close to the detection limits while 2'-F-ara-ddI was detected at significantly higher concentrations in the brain after oral administration of 2'-F-ara-ddP. From this study, we have administered the enhanced brain delivery of anti-HIV nucleoside utilizing an in vivo biotransformation system.

[Effect of indomethacin on H+ transportation of pig gastric H+/K(+)-ATPase]

As a noncompetitive inhibitor of pig gastric H+/K(+)-ATPase, indomethacin inhibited the H+ transportation function of the enzyme, leading to not only the obvious dissipation of H+/K(+)-ATPase-generated H+ gradients, but also the decreasing of the H+ gradient formation ability of the enzyme. 4% of indomethacin was able to penetrate into the lipid bilayer of H+/K(+)-ATPase vesicles at 0.15 mg/ml protein concentration, which showed an influence of indomethacin to the membrane. Indomethacin reduced the membrane fluidity of H+/K(+)-ATPase vesicles significantly. It also damaged the conformation of membrane protein extraordinarily, which was evidenced by decreasing the intrinsic fluorescence of H+/K(+)-ATPase. From the results, we suggest that the effect of indomethacin on H+/K(+)-ATPase is taken place by its inhibition on H+/K(+)-ATPase protein, as well as by its influence on the membrane lipid bilayer of H+/K(+)-ATPase vesicles.

Determination of boar spermatozoa water volume and osmotic response

Boar spermatozoa water volume and osmotic response were determined by a shapeindependent method for measuring cellular volume, electron paramagnetic resonance (EPR), employing the spin label, tempone, and the broadening agent, potassium chromium oxalate (CrOx). A water volume of 18.4 +/- 1.6 mum(3) (X +/- SD) was obtained for individual boar spermatozoa at 290 milliosmolar (mOsm) which, after correction for the presence of cytoplasmic droplets, yields a boar sperm water volume of 13.0 to 15.0 mum(3). Assuming 59% of the total cell volume is water, the total cell volume of boar spermatozoa is 22.0 to 25.4 mum(3). In addition, the experiment indicated that the relative water volume versus the reciprocal of the external osmolality (Boyle van't Hoff plot) was linear over the range of 210 to 1500 mOsm of sodium chloride (r(2) = 0.996), supporting the hypothesis that boar spermatozoa act as ideal osmometers. A non-zero y axis intercept of 0.23 from the Boyle van't Hoff plot indicated a 23% spin label accessible, but osmotically inactive water component.

Assessment of the acrosomal status and viability of human spermatozoa simultaneously using flow cytometry

Acrosomal status and viability were evaluated simultaneously on human spermatozoa using flow cytometry. Samples were divided into three aliquots and randomly assigned to one of three treatments: (i) cryopreservation; (ii) 10 microM calcium ionophore [A23187 in dimethylsulphoxide (DMSO)] or (iii) DMSO alone (control). Acrosomal status was evaluated using monoclonal antibodies recognizing MH61 and CD46, respectively. Fluorescein-conjugated goat anti-mouse immunoglobulin (IgG) was used as a second antibody. Sperm viability was assessed using Hoechst 33258 (H258) exclusion. The following factors were analysed: (i) the specificity of the monoclonal antibodies for the human acrosome; (ii) the relative effectiveness of flow cytometry and direct fluorescent microscopy scoring and (iii) the acrosomal status and viability of the control, ionophore-treated, and cryopreserved spermatozoa. Across all treatments, the MH61 and CD46 monoclonal antibodies resulted in acrosomal status values (acrosome-reacted/viable spermatozoa) which were not significantly different (P > 0.05): control, 1.0 +/- 0.3% and 1.5 +/- 0.6% (mean +/- SEM); A23187, 42.8 +/- 3.5% and 38.1 +/- 3.5%; cryopreserved, 8.2 +/- 2.0% and 9.9 +/- 1.3%; respectively. However, acrosomal status among treatments differed significantly (P < 0.01). Flow cytometric and direct fluorescent microscopy assessments were significantly correlated (r2 = 0.96, P < 0.01). These results indicate that flow cytometry, using an acrosome-specific monoclonal antibody and a supravital dye, provides an objective and efficient method to evaluate human sperm acrosomal and viability status simultaneously.

Retinal pigment epithelial transplants and retinal function in RCS rats

PURPOSE

To determine if retinal pigment epithelium (RPE) transplantation maintains visual function in Royal College of Surgeons (RCS) strain of rats.

METHODS

Twelve RCS rats received RPE transplants at 16 to 20 days after birth. The retinas were studied electrophysiologically and histologically from 3 to 10 months after transplantation and compared with 11 RCS controls and 11 normal rats of comparable ages. A microelectrode was guided to the transplant site visible by its pigmentation in the albinotic RCS retina to detect responses.

RESULTS

Spontaneous ganglion cell activity was present in all retinas. Ganglion cell responses to light were detected in 9 of the 12 transplant eyes but not in any of the 11 controls. 96, 44, 140 units were encountered and 30%, 0%, 97% were driven by light respectively in transplant, control, and normal retinas. In transplants 36%, 29%, and 28% were driven at 3 to 4, 6 to 7, and 10 months after transplantation, respectively. Intraretinal ERGs with both a- and b-waves were recorded in 5 of the 8 transplants studied. None of the RCS controls studied had an IERG. The average IERG was 2.5 microV (SD = 1.9) in transplants and 59 microV (SD = 19) in normal retinas. The electrode track was traced to the transplant site in six of the seven retinas that were responsive to light and examined histologically.

CONCLUSION

RPE transplants to RCS rats maintain retinal function in the transplant site for long periods of time.

Effect of receiver fluid pH on in vitro skin flux of weakly ionizable drugs

In in vitro skin permeation experiments, the pH of viable epidermis is readily conditioned by the receiver fluid. For weakly ionizable compounds, the flux determined experimentally thus depends on the receiver fluid pH. The purpose of the present work is to characterize this pH effect, since nonphysiological conditions have often been used in the receiver fluid to enhance the solubility of the subject compounds. A transport model was developed to analyze the above-mentioned pH effect of the receiver fluid on the steady state flux of weakly ionizable drugs. The results showed that the skin flux had a strong dependence on pH for those compounds with high intrinsic partition coefficients. Experimentally, this pH effect was observed with a model acid and a model base. The skin flux was found to have a profound dependence on the receiver fluid pH. This dependence also correlates with the octanol/water partition coefficient of the molecule. It was concluded that the use of a physiological receiver fluid would be crucial for a realistic estimation of transdermal potential. The results also suggested that, for weakly ionizable compounds with high partition coefficients, the viable epidermis could be a significant transport barrier for systemic absorption.

Autocrine, endocrine and paracrine regulation of growth abnormalities in autosomal dominant polycystic kidney disease

Genetic polycystic kidney disease (ADPKD) is an autosomal dominant trait in man, the phenotypic expression of which is characterized by enormous cystic enlargement of renal tubules. Since this is, in part, a result of aberrant epithelial cell proliferation, the nature of this defect has been characterized by comparison of growth factor action on defined epithelial primary monolayer cultures derived from individually microdissected normal human renal proximal and distal tubules and ADPKD cyst-lining epithelia. Mitogenic assays showed an increased sensitivity of ADPKD epithelia to stimulation by the combination of the endocrine factors hydrocortisone (dexamethasone) and insulin, and Northern analysis suggested increased levels of insulin receptor steady state mRNA. The most potent, single mitogen was epidermal growth factor (EGF), and hypersensitivity to EGF in ADPKD epithelia was correlated with increased mRNA levels for EGF receptor in ADPKD kidneys. The localization in vivo of EGF immunoreactivity in ADPKD cyst-lining epithelia and in (apical) cyst fluids and the demonstration of EGF-receptor immunostaining and specific [125I]EGF binding to apical cell surfaces suggested an autocrine mechanism of growth stimulation by EGF in ADPKD epithelia. Transforming growth factor beta was an inhibitor of normal renal tubule proliferation but was unable to completely inhibit EGF stimulation in ADPKD cultures. Platelet-derived growth factor (PDGF) immunoreactivity which was also seen in ADPKD cyst epithelia, was not mitogenic to ADPKD epithelia but did stimulate division in ADPKD fibroblasts in vitro. This suggested a paracrine regulation of the observed fibrosis in ADPKD.

Measurement of human sperm intracellular water volume by electron spin resonance

An electron spin resonance technique using the spin label tempone and the broadening agent potassium chromium oxalate was used to measure the water volume of human sperm. The toxicity of tempone (5 mmol/L) and potassium chromium oxalate (50 mmol/L) to sperm was measured over a time span of 120 minutes using computer-assisted semen analysis. Tempone had no effect on any computer-assisted semen analysis parameters, including motility. Potassium chromium oxalate reduced sperm motility by an average of 24% during the first 30 minutes of exposure. After selection by swim-up and correction for the presence of dead cells and cytoplasmic droplets, a water volume of 20.0 +/- 2.9 microns3 was obtained. This yields a total volume of 33.9 microns3 if a water compartment of 59% by volume is assumed. These results are consistent with other shape-independent techniques for measuring volume, but larger than the generally accepted optical and electronic particle counter sizes.

Reconstruction of degenerate rd mouse retina by transplantation of transgenic photoreceptors

Photoreceptors from neonatal transgenic mice with normally developing retinas were transplanted to the subretinal spaces of 2-3-month-old rd mutant mice that lack photoreceptors. The transgenic mouse photoreceptors express high levels of the lac Z reporter gene product, beta-galactosidase, which facilitated tracking the transplanted cells. Two sources were used for these cells: (1) dissection of retinal microaggregates containing photoreceptors and (2) papain-dissociated photoreceptors. Host retinas were examined after transplantation. Both methods led to survival of photoreceptors for at least 2 mo after transplantation. Relatively mature outer segments were found only in transplanted microaggregates; this occurred optimally when the cells were adjacent to the retinal pigment epithelium (RPE). beta-galactosidase-labeled outer segments associated closely with the apical processes of the host RPE, which, together with labeled phagosomes in the RPE cells, suggested functional interaction between the transplanted photoreceptors and the host RPE. This study is the first to the authors' knowledge to show electron microscopically that a morphologically normal-appearing photoreceptor layer can be reconstructed in an otherwise photoreceptorless retina.

[Chemical constituents of the leaves of Acanthopanax trifoliatus (Linn) Merr]

Nevadensin (A), kaur-16-en-19-oic acid (B), taraxerol (C) and taraxerol-acetate (D) were isolated from the leaves of Acanthopanax trifoliatus. A and B were isolated for the first time. Pharmacological experiments have shown that nevadensin possesses expectorant and antitussive actions.

[Effect of Chinese-made vesnarinone on experimental heart failure of dog]

Intravenous drip of sodium pentobarbital 6 mg/kg per min induced obvious heart failure of anesthetic dogs (n = 11) followed by an infusion of 0.25 mg/kg per min to maintain the heart failure state. The Chinese-made vesnarinone 3 mg/kg was injected, followed by an infusion of 0.1 mg/kg per min, or the solvent in the same volume, for 30 min. Vesnarinone increased significantly and instantly the cardiac output and left ventricular maximum + dp/dt, which almost recovered to normal at the end of the infusion and also significantly increased 30 min after administration. The positive inotropic effect of vesnarinone was not accompanied by an increase in the heart rate and the blood pressure. The results of our experiment reveal that the Chinese-made vesnarinone has a potent and relatively selective positive action on heart failure of dogs.

Experimental studies of pancreatic transplantation after freezing and thawing

The successful rat pancreatic transplantation, after 30 minutes cryopreservation at -80 degrees C, is presented with the normal graft function till the 6th postoperative day maximum. The freezing device used by the authors is shortly described. The choice of optimal freezing and thawing parameters is discussed. Organ freezing is a hopeful method which could serve to preserve the solid organs for a long period of time. Our former experimental research showed that slow freezing (1-2 degrees C/min) and fast thawing (> 100 degrees C/min) had produced less damage to the pancreas of the rat [1]. Recently we performed rat pancreatic transplantation after freezing and thawing the donor pancreas with the parameters mentioned above.

Alterations of spinal dorsal horn substance P following electroacupuncture analgesia--a study of the formalin test with immunohistochemistry and densitometry

Substance P (SP), released from thin afferent terminals, is believed to be a neurotransmitter for pain transmission in the spinal dorsal horn. It has been demonstrated that in addition to analgesia, morphine increases the accumulation of SP possibly due to the inhibition of its release. The present work investigated the level of spinal SP like immunoreactivity (SPLI) following electroacupuncture analgesia in rats using immunohistochemistry and image analysis. Experiment results revealed that formalin injected into the hind paw elicited marked pain response and accumulation of SP in the spinal dorsal horn. Electroacupuncture of Tsu-San-Li could depress the pain response, however increasing further the SP accumulation. It is thus suggested that pain stimulation itself may activate the endogenous opioid mechanism to inhibit SP release and acupuncture is able to enhance the process. This may be one mechanism of acupuncture analgesia.

Monitoring photoreceptor transplants with nuclear and cytoplasmic markers

Two methods are described for identifying transplanted photoreceptors in a foreign host retina. One involves the use of [3H]thymidine to label the nuclei of photoreceptors which are dividing for 1 week after birth in myomorphic retina. These photoreceptors can be identified by autoradiography. The second involves the use of a transgenic mouse carrying a bovine rhodopsin promoter in tandem with the bacterial LacZ gene. These mice express beta-galactosidase in their rods. X-gal reaction allows these rods to be identified by routine light and electron microscopy. These methods have been used to follow photoreceptor transplants in adult Royal College of Surgeons strain rat and C3H mouse mutants which have lost virtually all their photoreceptors. Dissociated photoreceptors transplanted to the subretinal space of these animals survive for at least 3 months. The inner segment, cell body, and synaptic terminal of these transplanted photoreceptors remain morphologically normal; the outer segment, however, becomes rudimentary.

[Hypocrellin A induced photodamage to the fluidity of human erythrocyte membranes and membranes of some phospholipid liposomes]

In this paper, the photodamage of Hypocrellin A to the fluidity of human erythrocyte membranes and some kinds of membranes of phospholipid liposomes was investigated by measuring the changes in fluorescence polarization of the membranes. The results showed that the photosensitization effect of HA caused the decrease of membrane fluidity of the phospholipid (DPPC, DPPC/DPPE, phospholipid of erythrocyte membranes) liposomes. The DPPC and DPPC/DPPE liposomes were more sensitive to the damage than the phospholipid liposomes of erythrocyte membranes. To human erythrocyte membranes, the photodamage effect of HA caused its fluidity first increased and then, with the increment of illumination time, decreased. To spectrin-depleted and trypsin-treated erythrocyte membranes, this kind of change in fluidity was inhibited. All of the results indicated that phospholipids and proteins play different roles in the photodamage of HA to the fluidity of membranes. Membrane proteins, especially spectrin, were the key factor involved in the changes of the fluidity.

Transplanted photoreceptors identified in dystrophic mouse retina by a transgenic reporter gene

Dissociated photoreceptor cells from a transgenic strain of mice, containing a bovine promoter lac Z gene construct, were transplanted to the dystrophic retinas of a strain of mice (C3H, rd/rd) without obvious photoreceptors. The transgenic photoreceptor cells expressed beta-galactosidase and were distinguishable from the host retinal cells by light and electron microscopy after the 5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside histochemical reaction. These results showed that transplanted transgenic photoreceptor cells survived at least 1 month in the host retina and had a primitive outer segment and a well-developed synaptic terminal.