Pre-degenerated nerve grafts enhance regeneration by shortening the initial delay period

In the present study we tested how nerve grafts with different pre-degeneration periods (1-28 days) influenced the early regenerative response in the rat sciatic nerve. The sciatic nerve on the right side was crushed and after 1-28 days of pre-degeneration, a 10 mm segment was used as an autologous nerve graft and transposed to a freshly made 10 mm long nerve defect on the left side. The regeneration distance was measured by the sensory pinch test 2-10 days after nerve repair. A newly developed mathematical model was used to calculate regeneration rates and initial delay periods from the measured regeneration distances. Pre-degenerated nerve grafts improved nerve regeneration by decreasing the initial delay period as compared to fresh nerve grafts without affecting the regeneration rate. Only one day of pre-degeneration was sufficient to reduce the initial delay period from 3.6 days to 1.7 days. The maximal effect on the initial delay period was achieved after 3 days of pre-degeneration. The initial delay period at later pre-degeneration intervals (7-14 days) was about 1 day. The effect persisted for at least 28 days of pre-degeneration. The regeneration rate was 1.5 mm/day for fresh nerve grafts and between 1.8-2.1 mm/day for pre-degenerated grafts. The results suggest that the effects of pre-degeneration are not only due to the increased cell proliferation in the graft, but that also trophic and/or inflammatory mechanisms may be of importance. Grafts pre-degenerated by crush may have clinical implications since they are easy to perform if an elective nerve grafting procedure is planned.

Stage-specific oligonucleotide uptake in murine bone marrow B-cell precursors

Fluorescein isothiocyanate (FITC)-conjugated phosphodiester and phosphorothioate oligonucleotides were used in four-color flow cytometry with murine bone marrow cells stained with monoclonal antibody specific for the differentiation markers B220, S7 (CD43), and BP-1 to show possible stage-specific oligonucleotide uptake. Relatively low uptake was observed among pre-Pro- and early Pro-B cells. Late Pro-B- and pre-B cells had increased oligonucleotide uptake, whereas B cells had a lower level. Cell membrane binding of oligonucleotides varied during B-cell differentiation in parallel with internalization, which was documented by confocal microscopy. An FITC-conjugated polyanionic dextran sulfate also showed differentiation-related B-cell association, suggesting the presence of cell membrane binding sites specific for polyanions as opposed to a unique feature of the DNA backbone. Interpretation of antisense experiments in murine bone marrow cells will need to account for the heterogeneous oligonucleotide uptake among differentiating B cells.

High-performance anion exchange of small anions with polyethyleneimine-coated porous zirconia

The preparation and chromatographic characterization of an ion-exchange high-performance liquid chromatographic support by deposition and crosslinking of polyethyleneimine (PEI) on the surface of porous zirconia is described. Adsorption and evaporation methods were used for coating PEI onto the zirconia particles. These two stationary phases were compared by elemental analysis, ion-exchange capacity and by chromatography. High efficiency and good selectivity were observed for inorganic and organic anions. The addition of a strong, hard Lewis base to the mobile phase dramatically improved the peak shape and efficiency of para benzoic acid derivatives. PEI-coated zirconia showed a distinct elution sequence for organic anions when compared to bare zirconia or silica-based phases. The polyamine coated zirconia was stable over a pH range from 2.75 to 9. Flow studies, using nitrite as a probe solute, showed that both coating procedures produced packed columns with good mass-transfer properties.

Inhibition and inhibition kinetics of angiotensin converting enzyme activity by hemorphins, isolated from a peptic bovine hemoglobin hydrolysate

The inhibitory effect on angiotensin converting enzyme (ACE) activity by hemorphins isolated from an enzymatic bovine hemoglobin hydrolysate was reported. Inhibitory kinetics proved that inhibition mechanism was non-competitive. The stability of hemorphins towards ACE was studied.

[Clinical and pathological changes of ischemic necrosis of the femoral head in children]

A total of 54 cases (73 hips) with ischemic necrosis of the femoral head after treatment of CDH have been followed up with an average of 7 years. We found that 89% cases of type I and 70% of type II recovered to normal and 83% cases of type III and IV developed the coxa breva deformity due to injury of longitudinal growth plate of the proximal end of the femur. According to the value of ATD, the coxa breva was divided into three types. The L shape growth disturbance line revealed by X-ray is considered as a marker for determination of early epiphyseal plate injury by the authors.

Trophism, tropism, and specificity in nerve regeneration

Target-derived neurotrophic factors are of basic importance for survival of neurons. In the normal state, such neurotrophic factors, synthesized by the target tissues, are taken up by nerve terminals and transported by retrograde axonal transport in axons to the nerve-cell bodies to maintain their viability. After nerve injury, neurotrophic factors are synthesized by non-neuronal cells (Schwann cells and fibroblasts) in the nerve trunk, thereby supporting the outgrowth of axons. Neurite-outgrowth-promoting factors on cell surfaces (cell adhesion molecules, "recognition molecules") or in the extracellular matrix promote extension of the axons by providing an appropriate "adhesiveness" in the substrate. Both neurotrophic and neurite-outgrowth-promoting factors are essential for axonal growth after injury. Specificity in end-organ reinnervation is a complex phenomenon which may be based on physical factors at the zone of injury, as well as on molecular interaction between axons and substrate cells along the pathways and at the target level. Such processes may include molecular recognition of appropriate axons and maintenance of such axons by trophic mechanisms, as well as the pruning of inappropriate axons. The ultimate errors in target reinnervation are reflected in a cortical re-organization in the somatosensory cortex. The capacity of the brain to "reprogram" itself and adapt to this functional re-organization is critical for the ultimate recovery of functional sensory/motor function after nerve injuries.

Enantioselective and reversible inhibition of trypsin and alpha-chymotrypsin by phosphonate esters

Trypsin is inactivated by the levorotatory enantiomers (most likely PS) of 4-nitrophenyl 4-H-, 4-CH3-,4-OCH3-, and 4-Cl-phenacyl methylphosphonates (PMNs) with second-order rate constants between 231 and 884 M-1 s-1. 4-NO2-PMN hydrolyzes before inhibiting the enzyme. The second-order rate constants for the inactivation of alpha-chymotrypsin by the levorotatory enantiomers of the five PMNs are between 37,000 and 770,000 M-1 s-1, and those for the dextrorotatory enantiomers are between 400 and 640 M-1 s-1; the enantioselectivity is 90-1880. Specific rotation [alpha]22D of the faster-reacting enantiomer of 4-CH3-PMN with trypsin and alpha-chymotrypsin is -30 +/- 6 degrees. 31P NMR of the adducts shows a signal at 41.0 ppm, 10 ppm downfield from the parent compound. Results of molecular mechanics and dynamics calculations show that the principal interactions are between the phosphonyl group and constituents of the oxyanion hole and between the aromatic fragment and residues in the binding regions of the enzymes. Trypsin activity returns from its phenacyl methylphosphonyl adducts on the hour time scale and in reversed order to the rates of inactivation within the series. Recovery of alpha-chymotrypsin activity from the adducts formed with the (-) enantiomers is on a slower time scale still, whereas its recovery from the adducts formed with the (+) enantiomers is on the second to minute time scale. The data support a mechanism of reactivation involving rate-determining intramolecular displacement of Ser by the carbonyl hydrate of the phenacyl moiety. The pH-rate profiles for trypsin reactivation from its adducts indicate involvement of an ionizable group with pKa approximately 8.0. The pH dependence and solvent isotope effects are small in most cases. The compounds demonstrate favorable properties for controllable and temporary modulation of enzyme activity.

Hyperthermia complicates middle cerebral artery occlusion induced by an intraluminal filament

The present experiments were designed to study under what circumstances middle cerebral artery (MCA) occlusion by an intraluminal filament technique leads to hyperthermia and what the mechanisms are. We found that permanent MCA occlusion by this technique lead to a rise in body (core) temperature to 39.0-39.5 degrees C during the first 2-4 h, and to sustained hyperthermia thereafter (38.5-39.0 degrees C). After 2 h of transient MCA occlusion hyperthermia could only be avoided if anesthesia (with control of temperature) was maintained for 2 h of ischemia and 1 h of recirculation or, in unanesthetized animals, if external cooling was maintained for 2 h of ischemia and 2 h of recirculation. Control of temperature only during ischemia did not prevent a postischemic rise in temperature. One hour of MCA occlusion had less effect on body temperature. Results are presented which suggest that the hyperthermia observed is due to an interference, by the intraluminal filament, of circulation to hypothalamic centers regulating body temperature. It is speculated that the hyperthermia induced may blunt or obliterate the effect of drugs, normally considered to ameliorate brain damage due to focal ischemia.

Can sensory and motor collateral sprouting be induced from intact peripheral nerve by end-to-side anastomosis?

The possibility that collateral sprouting could occur from intact axons in an undamaged sciatic nerve was studied in the rat by suturing either a 7-day predegenerated or a fresh nerve segment in an end-to-side fashion to the sciatic nerve proper. Following a 14- or 35-day recovery period, the pinch reflex test was performed on the transplanted segment to demonstrate the presence of sensory axons. The majority of cases, using a predegenerated nerve segment but not a fresh segment, responded positively. Neurofilament staining and histological examination confirmed the presence of axons in the attached nerve segment. In another series of experiments, the proximal peroneal fascicle was ligated and cut. Following a 7-day predegeneration period the distal stump was sutured end-to-side to the ipsilateral tibial fascicle. After 90 days, stimulation of the tibial nerve proximal to the attached site induced substantial contraction in both the native gastrocnemius muscle and the foreign tibialis anterior muscle. These findings suggest that collateral sprouting may occur from intact axons, perhaps induced by factors emanating from the attached nerve segment, and subsequently make functional peripheral connections.

[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.

Alternative splicing of pre-mRNAs encoding the nonstructural proteins of minute virus of mice is facilitated by sequences within the downstream intron

mRNAs R1 and R2 of the parvovirus minute virus of mice encode the two essential viral regulatory proteins NS1 and NS2. Both RNAs are spliced between map units 44 and 46 (nucleotides 2280 and 2399); R2 RNAs are additionally spliced upstream between map units 10 and 39 (nucleotides 514 and 1989), using a nonconsensus donor and poor 3' splice site. The relative accumulation of R1 and R2 is determined by alternative splicing: there is twice the steady-state accumulation of R2 relative to that of R1 throughout viral infection, though they are generated from the same promoter and have indistinguishable stabilities. Here we demonstrate that efficient excision of the large intron to generate R2 is dependent on at least the initial presence, in P4-generated pre-mRNAs, of sequences within the downstream small intron. This effect is orientation dependent and related to the size of the intervening exon. Prior splicing of the small intron is unnecessary. Excision of the large intron is enhanced by changing its donor site to consensus, but only in the presence of the small intron sequences. Excision of the large intron is also enhanced by improving the polypyrimidine tract within its 3' splice site; however, in contrast, this change renders excision of the large intron independent of the downstream small intron. We suggest that sequences within the small intron play a primary role in efficient excision of the upstream large intron, perhaps as the initial entry site(s) for an element(s) of the splicesome, which stabilizes the binding of required factors to the polypyrimidine tract within the 3' splice site of the large intron.

[The alteration of histidase catalytic activity and the expression of the enzyme protein in rat primary hepatomas]

The catalytic activity of histidase and the expression of the enzyme protein were investigated in rat hepatomas induced by diethylnitrosamine. The results indicated that the activities of histidase in the hepatomas were significantly diminished as compared with normal rat livers (P < 0.01). Western blot analysis revealed that enzyme protein levels in hepatomas were markedly reduced. It is thus inferred that some factors which control expression of histidase protein may be altered during carcinogenesis. These findings lay a foundation for studying the relationship between the regulation and expression of the histidase gene and hepato carcinogenesis.

Synthesis of 11-substituted androstenediones and testosterones as human decidual cell growth inhibitors

11 alpha-Hydroxytestosterone (1a), 11 beta-hydroxytestosterone (1b), 11 alpha-methoxytestosterone (1c), 11 beta-methoxytestosterone (1d), 11-ketotestosterone (1e), and delta 9(11)-testosterone (1f) were synthesized from hydrocortisone (4b) or 11-epi-hydrocortisone (4a). The six target compounds, together with 11 alpha-methoxyandrostenedione (2c), 11 beta-methoxyandrostenedione, (2d) and their lead compound, testosterone (1), were found to effectively inhibit the growth and differentiation of human decidual cells in culture. There is no observable binding of these compounds to estrogen receptor of rabbit uterus. The introduction of a polar group (e.g., hydroxyl and carbonyl) to C-11 of androstenes decreases both the relative binding affinities to progesterone receptor and the inhibitory effects on human decidual cell growth, while the methylation of 11-hydroxyl group minimizes these effects. The similar effects of a polar group at C-11 of testosterone (1) on the inhibitory effects on human decidual cell growth and the relative binding affinities to progesterone receptor of rabbit uterus may suggest that one of the mechanisms of human decidual cell growth inhibition by these compounds is the anti-progestational activity of these androgens.

Effects of predegeneration on nerve regeneration through silicone Y-chambers

The effects of nerve predegeneration on the preferential growth of regenerating axons were studied using a silicone Y-chamber model. This system provided a choice for axons to grow towards two distal nerve options, either a 7-day predegenerated nerve segment (PNS) or a fresh nerve segment (FNS). The rat peroneal or tibial nerve was inserted into the proximal intlet and the PNS and FNS of the corresponding nerve were inserted into the distal outlets. At 28 days postoperative, the size of the distal regenerate was significantly greater (26%) towards the PNS for the tibial nerve group. The density and number of regenerated myelinated axons in the distal nerve segment was greater on the PNS for both the tibial (97 and 88%, respectively) and peroneal (221 and 221%, respectively) nerve groups. In contrast, the elevated density and number of nonvascular nuclei was relatively constant for both PNS and FNS. Immunocytochemical and ultrastructural evidence support the hypothesis that the early activation of Schwann cells is primarily responsible for the enhanced regeneration and maturation observed in PNS. It is suggested that PNS might improve the outcome after clinical repair of injured peripheral nerves.

Growth-inhibitory effects of coumarin (1,2-benzopyrone) and 7-hydroxycoumarin on human malignant cell lines in vitro

Coumarin (1,2-benzopyrone) is a natural substance that has shown antitumor activity in vivo. The major human metabolite of coumarin, 7-hydroxycoumarin (7-HC), is the active form of the drug. While the exact mechanism(s) of action of coumarin is unknown, it has been shown previously that this drug possesses immunomodulatory activity in vitro and in vivo. The present investigations examined the direct (non-immunological) antitumor effects of coumarin and 7-HC in vitro. Both coumarin and 7-HC were found to be growth-inhibitory (cytostatic) for the following human malignant cell lines: A549, ACHN, Caki-2, Dakiki, HS-Sultan, H727, HCT-15, HL-60, K562, LNCaP, PC-3, Du 145 COLO-232, MCF-7 and RP-1788. The growth inhibition was dependent on dose and time and was reversible upon removal of cells from medium containing the drug. Coumarin and 7-HC inhibited [3H]thymidine, [3H]uridine and [3H]leucine incorporation. In a similar fashion, coumarin and 7-HC inhibited the intracellular production of prostate-specific antigen by LNCaP cells. Coumarin and 7-HC stimulated apoptosis in HL-60 cells but not in other cell lines tested. It is concluded that coumarin and 7-HC have direct antitumor (cytostatic) activity as well as immunomodulatory activity. Further information is needed in order to determine which activities are responsible for antitumor activity in vivo.

Ozonolysis products of membrane fatty acids activate eicosanoid metabolism in human airway epithelial cells

When inhaled, ozone reacts at the airway luminal surface with unsaturated fatty acids contained in the extracellular fluid and plasma membrane to form an aldehyde and hydroxyhydroperoxide. The resulting hydroxyhydroperoxide degrades in aqueous systems to yield a second aldehyde and hydrogen peroxide (H2O2). Previously, we demonstrated that ozone can augment eicosanoid metabolism in bovine airway epithelial cells. To examine structure-activity relationships of ozone-fatty acid degradation products on eicosanoid metabolism in human airway epithelial cells, 3-, 6-, and 9-carbon saturated aldehydes and hydroxyhydroperoxides were synthesized and purified. Eicosanoid metabolism was evaluated by determination of total 3H-activity release from confluent cells previously incubated with [3H]arachidonic acid and by identification of specific metabolites with high performance liquid chromatography and radioimmunoassay. The major metabolites detected were prostaglandin E2, prostaglandin F2 alpha, and 15-hydroxyeicosatetraenoic acid. The 9-carbon aldehyde, nonanal, in contrast to 3- or 6-carbon aldehydes, stimulated release at concentrations > or = 100 microM, suggesting that the stimulatory effect increases with increasing chain length. When tested under identical conditions, the 3-, 6-, and 9-carbon hydroxyhydroperoxides were more potent than the corresponding aldehydes. Again, a greater effect was noted when the chain length was increased. One possible explanation for the increased potency of the hydroxyhydroperoxides over the aldehydes could be due to degradation of the hydroxyhydroperoxide into H2O2 and aldehyde. We consider this an unlikely explanation because responses varied with chain length (although each hydroxyhydroperoxide would produce an equivalent amount of H2O2) and because exposure to H2O2 alone or H2O2 plus hexanal produced a response dissimilar to 1-hydroxy-1-hexanehydroperoxide.(ABSTRACT TRUNCATED AT 250 WORDS)

TFEC, a basic helix-loop-helix protein, forms heterodimers with TFE3 and inhibits TFE3-dependent transcription activation

We have identified a new basic helix-loop-helix (BHLH) DNA-binding protein, designated TFEC, which is closely related to TFE3 and TFEB. The basic domain of TFEC is identical to the basic DNA-binding domain of TFE3 and TFEB, whereas the helix-loop-helix motif of TFEC shows 88 and 85% identity with the same domains in TFE3 and TFEB, respectively. Like the other two proteins, TFEC contains a leucine zipper motif, which has a lower degree of sequence identity with homologous domains in TFE3 and TFEB than does the BHLH segment. Little sequence identity exists outside these motifs. Unlike the two other proteins, TFEC does not contain an acidic domain, which for TFE3 mediates the ability to activate transcription. Like the in vitro translation product of TFE3, the in vitro-translated TFEC binds to the mu E3 DNA sequence of the immunoglobulin heavy-chain gene enhancer. In addition, the product of cotranslation of TFEC RNA and TFE3 RNA forms a heteromeric protein-DNA complex with mu E3 DNA. In contrast to TFE3, TFEC is unable to transactivate a reporter gene linked to a promoter containing tandem copies of the immunoglobulin mu E3 enhancer motif. Cotransfection of TFEC DNA and TFE3 DNA strongly inhibits the transactivation caused by TFE3. TFEC RNA is found in many tissues of adult rats, but the relative concentrations of TFEC and TFE3 RNAs vary considerably in these different tissues. No TFEC RNA was detectable in several cell lines, including fibroblasts, myoblasts, chondrosarcoma cells, and myeloma cells, indicating that TFEC is not ubiquitously expressed.

Lack of allelic polymorphism for the major outer membrane protein gene of the agent of guinea pig inclusion conjunctivitis (Chlamydia psittaci)

The major outer membrane protein gene (omp1) was sequenced for each of six Chlamydia psittaci (guinea pig inclusion conjunctivitis [GPIC]) strains isolated from guinea pigs. Five of the isolates were obtained in the United States during the 1960s and 1970s, including the prototype strain isolated by Murray in 1962. The other isolate was obtained from a guinea pig in England. The nucleotide sequence of the omp1 gene for each strain was identical. The lack of omp1 allelic polymorphism among GPIC isolates suggests that, unlike C. trachomatis, the GPIC agent lacks antigenic variation in the major outer membrane protein.

Modification of antisense phosphodiester oligodeoxynucleotides by a 5' cholesteryl moiety increases cellular association and improves efficacy

Phosphodiester oligodeoxynucleotides bearing a 5' cholesteryl (chol) modification bind to low density lipoprotein (LDL), apparently by partitioning the chol-modified oligonucleotides into the lipid layer. Both HL60 cells and primary mouse spleen T and B cells incubated with fluorescently labeled chol-modified oligonucleotide showed substantially increased cellular association by flow cytometry and increased internalization by confocal microscopy compared to an identical molecule not bearing the chol group. Cellular internalization of chol-modified oligonucleotide occurred at least partially through the LDL receptor; it was increased in mouse spleen cells by cell culture in lipoprotein-deficient medium and/or lovastatin, and it was decreased by culture in high serum medium. To determine whether chol-modified oligonucleotides are more potent antisense agents, we titered antisense unmodified phosphodiester and chol-modified oligonucleotides targeted against a mouse immunosuppressive protein. Murine spleen cells cultured with 20 microM phosphodiester antisense oligonucleotides had a 2-fold increase in RNA synthesis, indicating the expected lymphocyte activation. Antisense chol-modified oligonucleotides showed an 8-fold increase in relative potency: they caused a 2-fold increase in RNA synthesis at just 2.5 microM. The increased efficacy was blocked by heparin and was further increased by cell culture in 1% (vs. 10%) fetal bovine serum, suggesting that the effect may, at least in part, be mediated via the LDL receptor. Antisense chol-modified oligonucleotides are sequence specific and have increased potency as compared to unmodified oligonucleotides.

[Laser photocoagulation treatment of small malignant choroidal melanomas]

8 cases of malignant choroidal melanoma were treated with argon and krypton laser photocoagulation of average 11 sessions and followed up an average 56 months. Clinical complete regression was observed in 5 cases (62.5%), in whom the tumors measured from 1.0mm x 1.2mm x 1.5mm to 6.0mm x 4.5mm x 2.5mm. The other 3 cases (37.5%) recurred, in whom the tumors measured from 4.0mm x 2.0mm x 3.5mm to 11.5mm x 12.5mm x 3.5mm. The complications of treatment included branch retinal vein occlusion, retinal neovascularization, vitreous hemorrhage, macular edema and optic atrophy. These results suggested that laser photocoagulation was useful in the treatment of small malignant choroidal melanomas.

Comparison of cellular binding and uptake of antisense phosphodiester, phosphorothioate, and mixed phosphorothioate and methylphosphonate oligonucleotides

The effects of phosphorothioate (S-oligonucleotide) or terminal phosphorothioate-phosphodiester (S-O-oligonucleotides) or methylphosphonate-phosphodiester (MP-O-oligonucleotides) modifications on mouse spleen cell surface binding, uptake, and degradation were studied using fluorescein (FITC)-conjugated oligonucleotides. S-oligonucleotides had the highest cell binding and uptake, followed by S-O-, O-, and MP-O-oligonucleotides. Competition studies indicated that S-oligonucleotides have an increased affinity for cell membrane oligonucleotide binding sites, because they could completely block O-oligonucleotide binding at a molar ratio of just 0.1. Uptake of all oligonucleotides was higher in B cells than T cells and was increased by stimulation with the B-cell mitogen, lipopolysaccharide. Although our cells had been purified using conventional techniques to eliminate dead cells, there remained about 5% of cells that were dead or dying, as determined by flow cytometry using propidium iodide staining. Of note, oligonucleotide association with dead cells was approximately 50-fold greater than that with living cells. Confocal microscopy confirmed that the oligonucleotides in living cells were intracellular, and indicated little nuclear uptake by 4 h. While extensive degradation of intracellular O-oligonucleotides was apparent by 4 h, there was no detectable degradation of S-, S-O, or MP-O-oligonucleotides.

Isolation and characterization of two opioid peptides from a bovine hemoglobin peptic hydrolysate

Two opioid peptides were isolated from a bovine hemoglobin hydrolysate, by use of gel permeation (GP) and reverse phase (RP) high performance liquid chromatography (HPLC). Their primary structure and accurate molecular weights, determined by amino acid analysis and fast atom bombardment (FAB) mass spectrometry, were identical to fragments 31-40 (LVV-hemorphin-7) and 32-40 (VV-hemorphin 7) of the beta-chain of bovine hemoglobin. The same fragments occur in human hemoglobin in positions 32-41 and 33-41 of the beta-chain, respectively. The opioid potency of these peptides, exhibited by use of electrically stimulated muscle of isolated guinea-pig ileum (GPI), were significant and comparable with some others previously described. In addition, the location of the two opioid peptides, VV-hemorphin-7 and LVV-hemorphin-7, revealed the existence of a "strategic zone" both in the bovine and human beta-chains of hemoglobin.

The formation of a 'pseudo-nerve' in silicone chambers in the absence of regenerating axons

The formation of a regenerate between sciatic nerve segments or stumps inserted into Y-tunnelled silicone chambers was studied under conditions where regenerating axons were prevented from entering the chamber. This was accomplished by using an isolated segment of the nerve as a proximal insert. After one week, a cellular regenerate spanned the proximal and distal inserts. The size of the regenerate increased if circulation was preserved in the distal inserts. At four weeks, a perineurium-like sheath surrounded the regenerate and longitudinally oriented Schwann cell columns could be observed throughout the regenerate. A similar 'pseudo-nerve' formed towards a piece of distally inserted tendon. Thus, the information required for the formation of a nerve-like structure is inherent to the non-neuronal cells entering the chamber. Schwann cells, in contrast to regenerating axons, do not exhibit preferential growth towards nervous tissue.

Specificity of muscle reinnervation following repair of the transected sciatic nerve. A comparative study of different repair techniques in the rat

Specificity of muscle reinnervation and the recovery of muscle contractility were studied after repair of the transected rat sciatic nerve. Six different techniques were compared: epineurial suture, perineural suture, whole nerve graft, interfascicular grafts, skeletal muscle bridge and tubulization. Muscle tetanic force and specificity of reinnervation were evaluated 12 weeks after nerve repair. Recovery of tetanic force was superior after repair with epineurial sutures. There was no statistical significance between the other methods in respect of tetanic force. The specificity of muscle reinnervation was best after tubulization, repair with interfascicular grafts and perineurial suture.

Nonsense mutations inhibit splicing of MVM RNA in cis when they interrupt the reading frame of either exon of the final spliced product

mRNAs R1 and R2 of the autonomous parvovirus minute virus of mice (MVM), which encode the viral nonstructural proteins NS1 and NS2, respectively, are processed in an ordered splicing pathway in which R2 is generated from mature spliced R1. Introduction of translation termination signals into these genes alters the processing of these RNAs; there is a significant (up to fourfold) increase in the accumulated steady-state levels of R1 relative to R2, when compared with wild-type levels, although the total accumulated levels of R1 plus R2 remain the same. The increase in accumulated R1 relative to R2 in mutant infected or transfected murine cells is independent of RNA stability and transport and decreases, in a polar manner, with the distance of the inserted termination signal from the shared initiation codon for NS1 and NS2 at nucleotide 260. The increased ratio of R1 to R2 is a consequence of the artificially introduced translation termination signals acting in cis rather than in the absence of a functional viral gene product. These mutations have an effect when they interrupt previously open reading frames in either exon of the spliced product R2. Nonsense mutations that are located in the second exon of R2 inhibit splicing of R1 to R2 only when they interrupt an open reading frame (ORF) that has the potential, after normal splicing, to be joined in-frame with the initiating AUG. These results suggest that nonsense mutations inhibit splicing of R1 to R2 by influencing the mechanism by which exons are defined in murine cells.

Isolation and characterization of a bradykinin-potentiating peptide from a bovine peptic hemoglobin hydrolysate

A bradykinin potentiating peptide was isolated from a peptic bovine hemoglobin hydrolysate, by the use of reversed-phase high-performance liquid chromatography (RP-HPLC). Its primary structure, determined by fast atom bombardment (FAB) and tandem mass spectrometry (MS/MS), was identical to fragment 129-134 of the alpha-chain of bovine hemoglobin. The bradykinin potency of this peptide, as exhibited by the guinea-pig ileum contraction, was significant and comparable with some others previously described.

Investigation on the carcinogenic effects of coal tar pitch in rat respiratory tract by intratracheal instillations

The effects of coal tar pitch (CTP) on the tracheobronchial mucosa of Wistar rats were studied. Three groups of animals received 10 weekly intratracheal instillations of CTP at the cumulative doses of 6.48, 136.56 and 200 mg respectively. The control group of rats received 10 weekly intratracheal instillations of charcoal powder at a cumulative dose of 20 mg. The study in which the animals were killed serially revealed that CTP had conspicuous damage on the respiratory system of rats, especially on the bronchiolo-alveolar areas. The lesions induced by CTP ranged from hyperplastic, metaplastic and dysplastic changes to extensive cancers. These lesions were usually multifocal, and were more severe in the rats receiving higher dosages of CTP. The deposition of CTP particles within or adjacent to these lesions could be readily identified. Lung cancers occurred in 12.5% (4/32) and 25% (10/40) of the rats treated with 136.56 and 200 mg of CTP, whereas no tumors were found in control rats and the rats that received 6.48 mg of CTP. The overall cancer incidence significantly related to the cumulative dose of CTP. The histological types of lung cancers consisted of squamous cell carcinomas (10 out of the 14 lung cancers), adenocarcinoma (1/14), and combined squamous and adenocarcinomas (3/14). The development of CTP-induced rat lung cancers appears to derive from the hyperplasias of bronchiolo-alveolar epithelium, and processing stages of squamous metaplasias and/or dysplasias to carcinomas. The present results confirmed the carcinogenic effects of CTP on the respiratory system of rats, and provided experimental evidence for human lung carcinogenesis, particularly in those occupationally exposed to coal tars or tar products.

Reinnervation of muscles in rats after repair of transsected sciatic nerves with Y-shaped and X-shaped silicone tubes. Muscle reinnervation after nerve repair

Reinnervation of the gastrocnemius and anterior tibial muscles was assessed by measurements of tetanic force after repair of sciatic nerves with Y-shaped or X-shaped silicone tubes in rats. The transsected proximal stump of either the tibial or the peroneal fascicle was introduced into the opening of a Y-shaped silicone tube, or both fascicles were introduced into an X-shaped tube. The distal tibial and peroneal fascicles were inserted into the distal outlets of the tubes leaving a gap of 4 mm between proximal and distal stumps. In the X-shaped tubes the proximal inserts were placed opposite or adjacent to their respective distal parts. Sixteen weeks later reinnervation was evaluated by measurements of tetanic force of the gastrocnemius and anterior tibial muscles after electrical stimulation of the fascicles. There was preferential reinnervation in both types of tubes. In Y-shaped tubes about 90% of the tetanic force could be recorded from both muscles after stimulation of the peroneal and tibial fascicles, respectively. Recovery was lower in the X-shaped tubes, amounting to about 75%. Contractions evoked by misrouted fibres were similar (roughly 40%) in both models. We conclude that motor axons preferentially, but not exclusively, selected a path to reinnervate their original target muscle.

Effect of some additives on the biostability of a poly(etherurethane) elastomer

Four materials based on a single poly-(etherurethane) (PEU) prepared from MDI and PTMEG but differing in additives were studied in the cage implant system. The two additives studied were Santowhite powder at the 1% level and Methacrol 2138F 5%. Methacrol 2138F appeared to be immiscible with the base PEU and was dispersed in discrete domains about 0.5-micron in size. The retrieved PEU specimens were also cleaned and examined in the optical and scanning electron microscopes, and the size and density of adherent foreign body giant cells (FBGCs) were measured at implantation times up to 10 weeks. Methacrol 2138F had no effect on the density, coverage or size distribution of adherent FBGCs, but leaching of Methacrol 2138F was considered to be responsible for extensive pitting of the PEU surface. On the other hand, Santowhite powder appeared to inhibit formation of FBGCs, and while surface cracking and flaking were observed as early as 3 weeks postimplantation on some PEUs, the Santowhite powder effectively inhibited surface cracking and flaking up to the longest implantation time studied.

[Effect of acupuncture on intestinal motion and sero-enzyme activity in perioperation]

The authors study on abdominal surgical patients (39 cases) who were randomly divided into the acupuncture and control group. In the acupuncture group, the needle inserted into Zusanli (St.36) and Sanyinjiao (Sp. 6) points at 12-24 h after operation and observed the time of the first excretion through anus. Sero-enzyme activity of GPT, GOT and gamma-GT determined before operation and at 1, 3, 5, 7 days after operation. The results showed that the time of excretion in the acupuncture group (57.78 +/- 23.94 h) was obviously faster than the control one (86.14 +/- 20.43 h), P less than 0.001). It suggested that acupuncture has the effect of promoting intestinal motion. After operation sero-enzyme activity was raised 2-3 times than before. It showed that the surgical trauma directly or indirectly impair cells to release enzyme into blood, but the time of reversing to normal level of sero-enzyme activity in the acupuncture group was obviously faster. There is possibility that acupuncture has the effect of regulating reactivity of organism on trauma and promoting the repair of damaged cell.

The effects of the combination of phentolamine and vasopressin on hepatic and systemic hemodynamics in cirrhotic portal hypertensive dog model

The experimental study was aimed at elucidating the effects of phentolamine and vasopressin used separately or in combination on hepatic and systemic hemodynamics in cirrhotic portal hypertensive dogs. The results showed that either of the two drugs used separately could lead to reduction in portal venous pressure and could also influence systemic hemodynamics or lower hepatic blood flow. When phentolamine in combination with vasopressin was administered, no side-effect could be found on hepatic and systemic hemodynamics, suggesting that the drugs used in combination could efficaciously decrease portal hypertension and counteract their respective side-effect. This combination therapy will be useful in treating bleeding from esophageal variceal rupture in cirrhotic patients with portal hypertension.

Effect of drying on regenerating rat sciatic nerve

To study the effects of drying on regeneration, crush lesions were made on the sciatic nerve of 38 rats and the injured area was then air-dried for various periods of time (0-60 min). The regeneration distance of sensory nerve fibres was measured by the pinch reflex test three or six days later. Regeneration was significantly impaired by drying the nerve for 30 or 60 min, but shorter periods (10 min) also seemed to affect axonal outgrowth. Regeneration distances were increased in nerves that were subjected to drying and then allowed to recover for a week (conditioning interval) before the nerve was crushed. The results show that drying of a peripheral nerve is detrimental to nerve regeneration, and we suggest that nerves should not be exposed to air for more than a few minutes during operation without irrigation.

Definition of a sequence, RYVVLPR, within laminin peptide F-9 that mediates metastatic fibrosarcoma cell adhesion and spreading

A synthetic peptide from the inner globule of the B1 chain of laminin, termed peptide F-9 (RYVVLPRPVCFEKGMNYTVR; residues 641-660), has been shown to have heparin-binding and cell adhesion-promoting activities for diverse cell types (Charonis et al., J. Cell. Biol., 107: 1253-1260, 1988). In this study, the metastatic murine fibrosarcoma cell line, UV-2237-MM, adhered and spread on surfaces coated with laminin and peptide F-9 in a concentration- and time-dependent fashion. Cells migrated toward laminin in Boyden microchemotaxis chambers but not toward peptide F-9. However, exogenous soluble peptide F-9 inhibited both the adhesion and migration of cells toward laminin. Polyclonal antibodies raised against peptide F-9 were capable of inhibiting laminin-mediated cell adhesion and migration. Peptide F-9 is located 265 residues from CDPGYIGSR, another sequence on the B1 chain of laminin which has been reported by others to promote cell adhesion (Graft et al., Cell, 48: 989-996, 1987). In contrast to peptide F-9, various control peptides including CDPGYIGSR did not promote the adhesion, spreading, or migration of the UV-2237-MM fibrosarcoma cells. In addition, neither exogenous peptide CDPGYIGSR nor antibodies raised against peptide CDPGYIGSR were capable of inhibiting laminin-mediated cell adhesion or migration. These results indicate that peptide F-9, but not peptide CDPGYIGSR, represents a major fibrosarcoma cell adhesion-promoting domain on intact laminin. A series of overlapping peptides were synthesized which contained various portions of the parent peptide F-9. The use of these peptides in cell adhesion assays demonstrated that the sequence RYVVLPR from the amino terminus of peptide F-9 was essential for cell adhesion-promoting activity.

[Study on change in zinc concentration for diabetic cataractous lenses in rats by means of XIXA]

The SD rats were injected with streptozotocin to induce diabetic cataract. Element Zn as well as K, Ca, Mn, Fe, Cu, Pb, Se, etc. in the eye lenses was determined by means of X-ray induced X-fluorescence analysis (XIXA). Compared to values for normal healthy rats, the concentration of Zn and Fe in the cataractous lenses increased, the concentration of K decreased, and that of the others did not change prominently. The change in Zn concentration was probably to meet the needs of the metabolic adjustment in the eye lenses, which would not be the reason for directly inducing diabetic cataract.

Cellular interactions with biomaterials: in vivo cracking of pre-stressed Pellethane 2363-80A

The phenomenon of stress cracking of Pellethane 2363-80A (PEU) was investigated using the cage implant system. A cytotoxic polyvinylchloride (PVC) and a silicone rubber containing an anti-inflammatory steroid were used to create inflammatory environments in which the biostability of the pre-stressed PEU was tested. These coimplants provided alternative in vivo environments to study in vivo polymer interactions. The inflammatory responses to the implanted cages were monitored by analyzing the exudates aspirated from the cages at different implantation times over 21 days. The pre-stressed PEU specimens were retrieved after 5, 10, and 15 weeks postimplantation and examined by optical microscopy (OM) and scanning electron microscopy (SEM). The results support the conclusion that in vivo cracking of stressed (strained) Pellethane 80A is related to cell-polymer interactions. Severe cracking or rupture of the implanted PEU specimens was observed as early as 5 weeks postimplantation. Molecular chain degradation of the implanted specimens was evident from molecular weight measurements. Neither surface cracking nor degradation of macromolecules was found on the pre-stressed PEU specimens with the added cytotoxic PVC implanted over 15 weeks. No cracking was observed on the pre-stressed specimens in the presence of steroid silicone rubber, even after 10 weeks implantation.

[Experimental studies of specific neuro-chemotaxis in peripheral nerve regeneration in the rat]

In this paper are reported the results of a systematic study of chemotactic effect and other features of the regeneration of severed peripheral nerve in rat. The results revealed that (1) the proximal stumps of tibial and peroneal nerves tended to grow to their original distal stumps, (2) motor branch and sensory branch also showed preferential growth to the homojunctional patterns of nerve grafts, (3) using muscle and skin as targets, these not only attracted nerve growth, out also selectively attracted motor branch and sensory branch. Our results indicate that during rat peripheral nerve regeneration there exists neurotropism as evidenced by tissue specificity, topographic specificity, functional pattern specificity and target specificity. Based on these findings, the possible mechanism of neurochemotropism is discussed. Distance between the stumps, selective use of experimental chamber material and the clinical significance of this neurotropic research are also discussed.