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.

[Preliminary studies on subtypes of respiratory syncytial virus in China]

An analysis of subtypes of 9 respiratory syncytial (RS) viruses isolated from Guangzhou and Nanjing areas of china was carried out with eight Sweden RS-subtype specific monoclonal antibodies (MAbs) and 7 internal anti-RS MAbs. All these MAbs directed against respectively the large Glycoprotein (G), fusion protein (F), nucleoprotein (NP), and phosphoprotein (P) components of the prototype Long strain of RS virus. The patterns of the reactions of these MAbs to the nine isolated strains of RS virus were compared with indirect immunofluorescence assay (IFA), alkaline phosphoesterase-anti alkaline phosphoesterase (APAAP) enzyme-linked assay and Western blotting. The antigenic variations were founded among the strains of RS virus, and two subtypes allocated to the subtype A and B of RS virus by using the eight RS-subtype specific MAbs. Seven out of the 9 isolated strains of RS virus belonged to the subtype A, and two were being to the subtype B. The antigenic diversities were also founded within the same subtype, and the main pronounced difference were observed on the G glycoprotein by using the internal anti-RS MAbs. These findings are potentially important both for vaccine development and for the understanding of clinical and epidemiological characteristics of RS virus.

[The effect of hypocrellin A on the lipid bilayer of erythrocyte membrane]

In this paper, using human erythrocyte membrane, the effect of Hypocrellin A on the lipid bilayer of the membrane was studied by measuring the change of the fluidity of the membrane, the energy transfer of the fluorescent probes, the shift of the fluorescent emission peaks, and the split of band-a of Hypocrellin A. The results showed that in the presence of HA, the fluidity of erythrocyte membrane was increased, the fluorescence intensity of the probes was decreased, and the fluorescence peaks shifted blue. These phenomena took place more seriously with the increment of HA concentration. Meanwhile, the band-a of HA excitation spectra was splitted. It was suggested from all of the results that HA could significantly perturb the lipid bilayer of erythrocyte membrane, there were interactions existing between the Hypocrellin A and the membrane. The HA was mainly located in the middle range of the membrane lipid bilayer when in high concentration (mainly to the 12-16 positions of the long chain fatty acid).

Transplantation of photoreceptors labeled with tritiated thymidine into RCS rats

Tritiated thymidine was administered to newborn rats to label photoreceptors, about 50% of which are still dividing. These photoreceptors were enzymatically dissociated and separated from the remainder of the retina after the infant rat matured. These labeled photoreceptors were then transplanted into a foreign host retina in the region of the outer nuclear layer. The hosts were ocular, albinotic, Royal College of Surgeons (RCS) rats, congenic to the normal donors and at least 4 months old, a time when virtually all the photoreceptors have degenerated from their retinas. The transplant site was examined at various times after transplantation by light microscope autoradiography. Labeled photoreceptor cell bodies were found in clusters in the outer nuclear layer region for as long as 3 months after transplantation surgery.

Reversed polarity of Na(+) -K(+) -ATPase: mislocation to apical plasma membranes in polycystic kidney disease epithelia

Autosomal dominant polycystic kidney disease (ADPKD) is a genetic disorder in which renal tubules become enormously enlarged due to fluid accumulation. Na(+) -K(+) -ATPase was compared in normal and cystic regions of whole kidneys and in confluent primary cultures of microdissected renal tubule and cyst-lining epithelia. Immunostaining with antibodies directed against the Na(+) -K(+) -ATPase catalytic alpha-subunit was confined to apical, luminal plasma membranes of ADPKD epithelia, which was a complete reversal of the normal renal tubule polarized location in basolateral membranes. Mislocated Na(+) -K(+) -ATPase was shown to be functionally active, because identical intense apical staining was observed by use of a cytochemical assay. In addition, biochemical assays showed a significant increase in these ouabain-inhibitable Na(+) -K(+) -ATPase specific activity levels in ADPKD kidneys compared with age-matched normal kidneys. Specific binding of [3H] ouabain was not only increased but also confined to the apical membrane vesicles prepared from cystic regions of ADPKD kidneys compared with normal age-matched controls, in which binding was confined to basolateral membrane vesicles. Although steady-state levels of Na(+) -K(+) -ATPase alpha- and beta-subunit in mRNAs were increased somewhat in ADPKD kidneys, this alone was not sufficient to account for the observed activation. Confluent ADPKD epithelia grown on dual-chamber, permeable membrane supports also showed reversed polarity of 22NaCl vectorial transport, because this was from basal to apical media compartments. Because this transport could also be blocked by ouabain, this suggested apical Na(+) -K(+) -ATPase was responsible and implicated altered polarity of Na(+) -K(+) -ATPase and resultant Na+ secretion as a mechanism for cyst formation in ADPKD. Because no reversal of polarity of other basolateral or apical membrane proteins was detected, an intracellular sorting defect specific for Na(+) -K(+) -ATPase is proposed.

Survival and synapse formation of transplanted rat rods

Isolated rods enzymatically removed from normal adult rat retina have been transplanted to the subretinal space of adult rats with a retinal dystrophy which has destroyed almost all the photoreceptors. These transplanted rods survive for months after transplantation during which time they form synapses with other retinal cells. Rod spherules with large amounts of synaptic vesicles and synaptic ribbons are found forming discreet contacts with pre- and post-synaptic densities in arrangements closely resembling those seen in the normal retina.

[Mean transit time and partial mean transit time of spirogram in 628 normal adolescents]

The mean transit time(MTT) and partial mean transit time(MTTp) were measured and analysed by "direct method" in 628 cases of normal adolescents in Cheng-du. The results showed that both MTT and MTTp were increased with age and prolonged with the decay of lung volume. Besides, the FVC-t curve was not single exponential in nature. The specific mean transit time (SMTT) was introduced by correcting MTT with 0.5 FVC and represented the MTT when unit volume of gas passed through just at that lung volume. SMTT was highly negatively correlated with age. This reflected the development and growth of the lung recoil and airway conductance in adolescents.

[Transdermal permeability of estradiol through human skin of different body regions in vitro]

Transdermal permeability of estradiol was carried out by using Valia-Chien double-compartment permeation cell for the following 6 skin regions with intact and without stratum corneum: chest, abdomen, hip, upper arm, thigh and back. The estradiol permeation rates and accumulative amounts within 72 h in vitro were examined by HPLC. The results showed that the permeation rates of intact skin from different regions of the body were significantly different (P less than 0.01), and for the skins without stratum corneum over different regions, the permeation rates or the permeation amounts were about 18-55 times higher than that for the intact skin. The results demonstrated that the stratum corneum acts as the rate-limiting barrier in the skin permeation of estradiol, and that the difference in estradiol permeation rates for different skin regions was mainly caused by the different extents of the barrier.

The effect of Mg2+ on mitochondrial F0.F1 ATPase and characteristics of the nucleotide binding sites

The interaction of Mg2+ with nucleotide-washed F0.F1 ATPase from pig heart was studied. Mg2+ had no effect on nucleotide-washed F0.F1 ATPase, but it competitively inhibited the hydrolytic activity of washed F0.F1 ATPase preincubated with ADP and slightly activated the hydrolytic activity of washed F0.F1 ATPase preincubated with ATP. In the last two cases, it revealed negative cooperativity. The effect of Mg2+ on F0.F1 ATPase is therefore closely related to the characteristics of the nucleotide binding sites on mitochondrial F0.F1 ATPase.

[Scavenging effect of EDTA-fluorocarbon microspheres on 210lead]

EDTA-fluorocarbon microspheres (EDTAFM), calcium disodium ethylene diaminetetraacetate (CaNa2EDTA), calcium- or zinc-diethylene triamine pentaacetate (Ca- or Zn-DTPA) were investigated for their ability to treat experimental lead intoxication in mice. The 48 ICR mice were divided into six groups. Group I = no treatment; The other groups were injected with single ip doses of 210Pb (10 mg Pb2+ +555 kBq/kg). After 24 h they were injected in the tail vein with the chelating agents (20 mg/kg) or an equal volume of 10% glucose (10 mg/kg). Each mouse was housed in one metabolic cage, and urine was collected daily for 3 d. After 3 d, the mice were sacrificed for comparison of lead distribution within the liver, kidney, femur and the entire carcass as measured by 0.047 Mev gamma emission from 210Pb. The results reveal that injection of EDTA-FM to lead poisoned mice pretreated with 210Pb was more effective than Zn- or Ca-DTPA and CaNa2EDTA in reducing the lead induced inhibition in the activity of blood ALAD, and that it increased the excretion of 210Pb into the urine. The hepatic, renal and femur 210Pb contents after treatment with EDTAFM were much more decreased than Zn- or Ca-DTPA and CaNa2-EDTA. The order of effectiveness was EDTAFM greater than Zn-DTPA greater than Ca-DTPA greater than CaNa2-EDTA.

Chromosomal localization of the gene for the human trifunctional enzyme, methylenetetrahydrofolate dehydrogenase-methenyltetrahydrofolate cyclohydrolase-formyltetrahydrofolate synthetase

A trifunctional protein in man, 5,10-methylenetetrahydrofolate dehydrogenase-5,10-methenyltetrahydrofolate cyclohydrolase-10-formyltetrahydrofolate synthetase, catalyzes three consecutive steps in the interconversion of tetrahydrofolate derivatives; these derivatives supply one-carbon units for intermediary metabolism. Somatic cell hybridization and in situ hybridization were used to localize the functional gene coding for this protein--to human chromosome 14q24, near the c-fos and TGF-beta 3 loci. A second hybridizing sequence, possibly a pseudogene, was identified near the centromere of the X chromosome, at Xp11.

Age-dependent effect of UV light in abnormal alpha neoprotein formation in the lens

The aim of this study was to determine whether or not alpha neoprotein formation can occur in the lens in response to a photolytic process. Alpha crystallin from young calf and aged bovine lenses was irradiated for up to 22 hours with UV light. After cortical alpha crystallin had been irradiated, it completely preserved its quaternary antigenic determinants. In contrast, 24.3% of the bovine nuclear alpha crystallin completely lost their quaternary determinants as a result of irradiation. The latter population of molecules still preserved the association of A chains with B chains, suggesting the formation of abnormal proteins. The exposure to UV irradiation can cause the formation of alpha neoproteins from aged but not from young alpha crystallin. Comparison of photolytic rates based on spectroscopic and chromatographic parameters also show an age-related increase in the susceptibility of alpha crystallin to photolyze. It is suggested that this increase is due to the age-related formation of a photosensitizer in alpha crystallin.

Cloning and expression of human nebulin cDNAs and assignment of the gene to chromosome 2q31-q32

We have isolated two nonoverlapping cDNAs encoding human nebulin, a muscle-specific protein. Northern hybridization analysis shows that nebulin is encoded by a huge message at least 25 kb in length. By hybridizing two nonoverlapping cDNAs to DNA isolated from rodent X human cell hybrids, we assign this presumably single-copy gene to human chromosome 2; sublocalization studies indicate that the nebulin gene is on the long arm of the chromosome, in the region 2q31-q32.

Suckling ability and maternal prolactin levels in hypothyroid rats

Long-Evans rats and their offspring were made hypothyroid by addition of the antithyroid goitrogen 6-N-propylthiouracil (PTU) to the drinking water (0.1%) from the day of parturition. Serum concentrations of prolactin (PRL), thyroid-stimulating hormone (TSH) and thyroxine (T4) were determined by double radioimmunoassay (RIA). From the fifth postnatal day, body weight of PTU-treated pups was significantly lower than that of control rats, and a strikingly elevated serum TSH level and nondetectable amount of T4 were measured both in PTU-exposed mothers and their offspring at Day 10 postpartum. To test the youngs' suckling capability and the amount of maternal milk production, 10- and 15-day-old normal and PTU-treated pups were separated from their mothers for 4 hr in the morning and then reunited and allowed to suckle. Normal pups gained body weight at the end of both the first and second hour postreunion, while PTU pups gained only during the first hour and lost weight in the second hour of testing. When the pups were exchanged between normal and PTU mothers, opposite results were obtained, indicating that the reduced gain in hypothyroid rats was not due to impaired suckling capability, or insufficient sensory stimulation for milk secretion but to a decreased milk production of PTU mothers. In accordance with this, in lactating hypothyroid rats both the basal (presuckling) level and the suckling-induced rise of serum PRL were found significantly depressed.