Incidence of posterior capsular plaque in cataract surgery

OBJECTIVE

To determine the incidence of posterior capsular plaque detected during cataract surgery, its association with age and type of cataract, and its impact on vision.

SETTING

Raghudeep Eye Clinic and Iladevi Cataract & IOL Research Centre, Ahmedabad, India.

METHODS

This prospective study comprised 256 consecutive eyes having extracapsular cataract extraction with posterior chamber intraocular lens implantation. The presence of plaque on the posterior capsule was noted and charted. Plaque peeling or posterior capsulorhexis was not done at the time of surgery. Mean patient age was 59 years (range 24 to 83 years). Follow-up was up to 1 year.

RESULTS

The overall incidence of plaque was 10.16%. The incidence by type of cataract was 5.13%, nuclear sclerotic; 12.50%, posterior subcapsular; 9.68%, mixed; 27.27%, mature (P < .05). The difference in incidence according to cataract type was highly significant between patients older than 50 years and those younger than 50 years (P < .001). At the end of 1 year, 61.54% of patients with plaque maintained a visual acuity of 20/20 to 20/30; 30.77%, 20/40; 7.69%, 20/60 or worse.

CONCLUSION

The incidence of plaque was higher in eyes with mature cataract at any age and in eyes with posterior subcapsular cataract in younger patients. Its presence was compatible with reasonable vision at the end of 1 year.

Effect of lipid solubility on the development of chronic cross-tolerance between ethanol and different alcohols and barbiturates

Tolerance to ethanol and cross-tolerance to other alcohols (n-propanol, n-butanol, t-butanol, isobutanol, t-amyl alcohol, n-amyl alcohol, and benzyl alcohol) and barbiturates (pentobarbital, secobarbital, amobarbital, thiopental, barbital and phenobarbital) that differ in lipid:water partition coefficient was examined in rats after chronic pretreatment with ethanol. Tolerance and cross-tolerance were studied with three different measures (hypothermia, tilt-plane, and rotarod). Tolerance to ethanol resulted in significant cross-tolerance to alcohols with low lipid solubility (n-propanol and t-butanol), whereas no cross-tolerance was seen with alcohols of high lipid solubility (isobutanol, n-amyl alcohol, t-amyl alcohol and benzyl alcohol). Cross-tolerance to n-butanol (which has intermediate lipid solubility) appeared to be metabolic rather than functional. Tolerance to ethanol also resulted in significant cross-tolerance to barbital and phenobarbital, but not to pentobarbital, secobarbital, amobarbital or thiopental. These studies suggest that lipid solubility is an important factor in relation to specificity of cross-tolerance to alcohols and barbiturates.

Specific cleavage of the large subunit of replication factor C in apoptosis is mediated by CPP32-like protease

Recent evidence suggests that the growing family of cysteine proteases related to the interleukin-1beta-converting enzyme (ICE) is of central importance in mediating apoptosis. Proteolytic cleavage of a small group of cellular substrates by these enzymes in association with the onset of apoptosis has been reported. In the present study, we searched a protein data base for potential death substrates possessing the CPP32 cleavage site, DEVD, and identified several candidates including RFC140, the large subunit of replication factor C, which we subsequently demonstrated to be specifically cleaved in a variety of cell types undergoing apoptosis in response to different cytotoxic agents, whereas no degradation is observed in a cell line resistant to etoposide-induced apoptosis. The abrogation of RFC140 cleavage in apoptotic extracts by Ac-DEVD-CHO, a potent inhibitor of CPP32, together with the finding that a CPP32 consensus cleavage sequence, DEVD, exists in RFC140, suggests that CPP32 or a close relative is responsible for RFC140 degradation in apoptosis.

Effect of NMDA antagonists on rapid tolerance to benzodiazepines

We have reexamined the effect of NMDA antagonists [(+)MK-801 and ketamine] on rapid tolerance to chlordiazepoxide. (+)MK-801 and ketamine blocked the development of rapid tolerance to chlordiazepoxide, but this effect was dependent on the dose ratio of the NMDA antagonist to that of the benzodiazepine used to produce rapid tolerance. Furthermore, NMDA antagonists blocked both learned and unlearned tolerance to chlordiazepoxide. It appears that in addition to impairment of memory and learning, NMDA antagonists may also influence some other mechanism involved in the production of drug-tolerance.

Size-Exclusion Chromatography of Carboxyl-terminated Dendrimers as a Model for Permeation of Charged Particles into Like-Charged Cavities

In order to examine the permeation of small charged colloids into cavities of like charge, size-exclusion chromatography was carried out with carboxyl-terminated dendritic polymers on a porous glass stationary phase. Chromatographic partition coefficients KSEC were measured for solute diameters ranging from 2 to 8 nm, at neutral pH, and ionic strengths from 0.01 to 0.09 M, and were reported relative to those of noninteracting solutes of equal size (pullulan and Ficoll). The experimental results were compared to values calculated using the treatment of F. G. Smith III and W. M. Deen for charged spheres in cylindrical pores of like charge (J. Colloid Interface Sci. 78, 44 (1980); 91, 571 (1983)). The measured degrees of permeation were typically 20-100% larger than the calculated values, the discrepancies being greatest for the larger solutes at high ionic strength. It is shown that the tendency of the calculations to overestimate the repulsion are likely to arise from linearization of the Poisson-Boltzmann equation.

Characterization of the Phenomenon of rapid tolerance to ethanol

Motor impairment (tilt-plane) and hypothermia tests were used to further characterize the phenomenon of rapid tolerance to ethanol. Five experiments were carried out to clarify the relationship between rapid and chronic tolerance. The first experiment demonstrated that the extent of tolerance on day 2 produced by the single dose of 4 g/kg alcohol on day 1 was similar to that resulting from two divided doses, administered 2 h apart. In the second experiment, a linear relationship between treatment dose and rapid tolerance development was demonstrated in that higher day 1 treatment doses resulted in greater rapid tolerance development. In the third, a parallel dose-response relationship, similar to that known for chronic tolerance, was observed for rapid tolerance. In the fourth experiment, we compared the development of rapid tolerance under three different conditions: (a) in groups of rats that were not subjected to testing at all (no testing); on day 1, (b) in groups of rats that were not tested on the apparatus but handled at all test times on day 1 (dummy testing); and (c) in groups of rats that were tested at all test times on day 1 (testing or intoxicated group). No testing on day 1 failed to produce rapid tolerance to ethanol whereas testing and dummy testing of animals on day 1 after pretreatment with ethanol-produced rapid tolerance to ethanol on day 2. In the last experiment, immediate posttrial administration of ketamine was found not to block rapid tolerance development. These findings provide additional support for similarities between the mechanisms of rapid and chronic tolerance.

D-cycloserine enhances rapid tolerance to ethanol motor incoordination

In a recent study, we showed that D-cycloserine, an agonist at the glycine site of the NMDA receptor, enhances the development of rapid tolerance to ethanol. In the present study, we report that the acquisition of rapid tolerance to the motor incoordination effect of ethanol (tilt-plane test) was increased only when D-cycloserine was injected before, but not after, the intoxicated practice under ethanol. The effect of D-cycloserine on tolerance when this agonist was administered in divided doses before and after test was similar to that obtained when D-cycloserine was injected before test. Higher doses of D-cycloserine did not produce a further enhancement of rapid tolerance. Moreover, when the dose of ethanol on day 1 was large enough to induce rapid tolerance per se, D-cycloserine did not further enhance the tolerance. The enhancement of tolerance by D-cycloserine was antagonized by previous administration of ketamine. The enhancement of ethanol tolerance by D-cycloserine and the antagonism of this effect by ketamine cannot be attributed to changes in pharmacokinetics of ethanol. Taken together, these results confirm the participation of the NMDA receptor system in the development of tolerance to ethanol, and reinforce earlier findings about the involvement of learning in tolerance.

Influence of nitric oxide synthase inhibition on the development of rapid tolerance to ethanol

We recently reported that the nitric oxide (NO) synthase inhibitor L-nitroarginine (L-NA) blocks the development of rapid tolerance to the motor incoordinating effect of ethanol in the tilt-plane test. To clarify the mechanism of L-NA blockade of tolerance, four additional experiments were carried out using the same test. The first demonstrated that L-NA prevented the development of rapid tolerance to ethanol when injected prior to ethanol either on both Days 1 and 2 or only on Day 1. In the second experiment, tolerance was blocked only when L-NA was injected before but not after behavioral testing on Day 1. In the third, L-NA blocked the enhancement of rapid tolerance to ethanol induced by D-cycloserine (CS), an agonist at the N-methyl-D-aspartate (NMDA) receptor. In the last experiment, L-NA pretreatment did not influence blood ethanol disappearance curves on Day 1, or ethanol concentrations in brain, tail blood or decapitated trunk blood on Day 2. These data argue against state-dependent learning as the basis of the L-NA effect, and confirm and extent our previous observation that NO plays a role in the development of rapid tolerance to ethanol.

Isolation of three novel human genes encoding G protein-coupled receptors

We have cloned and mapped the chromosomal location of three novel human genes encoding G protein-coupled receptors that we have named GPR6, GPR5, and GPR4. The entire coding region for each of these genes was contained on single exons. Gene GPR6 encoded a receptor that shared closest identity (71% in the transmembrane regions) with the human orphan receptor GPR3 and was localized to chromosome 6 (q21-q22.1). Northern blot analysis revealed that GPR6 transcripts were abundant in the human putamen and to a lesser extent in the frontal cortex, hippocampus, and hypothalamus. Gene GPR5 encoded a receptor that most closely resembled the orphan receptor RBS11 (48% in the transmembrane regions) and the MIP 1 alpha/RANTES receptor (45% in the transmembrane regions) and was localized to chromosome 3 (p21.3-p21.1). Gene GPR4 shared identity (40% in the transmembrane regions) with the human platelet-activating factor receptor and was localized to chromosome 19 (q13.2-q13.3).

The conformation of the sialyl Lewis X ligand changes upon binding to E-selectin

High-field NMR spectroscopy has been used to study the complex formed by the tetrasaccharide sialyl Lewis X and its receptor, E-selectin. Transferred NOEs demonstrate a specific interaction between the protein and ligand and enable measurement of the dissociation constant for the complex to be between approximately 1.1 and 2.0 mM. Differences between Overhauser spectra for free and bound sialyl Lewis X highlight a conformational change upon binding. This can be pinpointed to a change in the torsion angle of the glycosidic link between the sialyl and galactosyl residues and used to select a likely "bound" conformation from four low-energy species. Docking the bound form of sialyl Lewis X onto a model of the lectin domain of E-selectin suggests that the conformational change upon binding results primarily from steric interactions.

Effect of NMDA antagonists on rapid and chronic tolerance to ethanol: importance of intoxicated practice

Recent studies from our laboratory have shown that NMDA antagonists ((+)MK-801 and ketamine) inhibit the development of both rapid and chronic tolerance to the motor-impairing (moving belt test) and hypothermic effects of ethanol. The present experiments were designed to determine a) the generality of this inhibition, by using a different test of motor function, the tilt-plane test, and b) the possible importance of the experimental paradigm (i.e., with and without intoxicated practice), for the effect of the NMDA antagonist on ethanol tolerance. Daily administration of ethanol 3.3 g/kg for 5 days produced the same degree of tolerance on this test, whether it was given as a single dose of 3.3 g/kg before the daily training session or as divided doses of 2.3 g/kg before and 1 g/kg immediately after the session. The inhibitory effect of a single dose of (+)MK-801 (0.25 mg/kg IP) on rapid tolerance did not last longer than 1 day. Therefore, daily administration of the NMDA antagonists was necessary to block development of chronic tolerance. Daily injection of (+)MK-801 (0.25 mg/kg IP) failed to block chronic tolerance, but inclusion of a second dose of (+)MK-801 daily, and progressive increase of this second dose during the chronic treatment period did block chronic tolerance. Unlike (+)MK-801, ketamine does not have motor-impairing effects of its own, and does not potentiate those of ethanol; it was, therefore, used in the remaining experiments. Groups of rats received ethanol (3.3 g/kg) or saline, either before a daily practice session on the tilt-plane or after it.(ABSTRACT TRUNCATED AT 250 WORDS)

Interaction between N-methyl-D-aspartate (NMDA) and serotonin (5-HT) on ethanol tolerance

Earlier work from this laboratory had shown that 5-HT is involved in the development of tolerance to ethanol, and that enhancement of 5-HT levels by L-tryptophan accelerated tolerance development. To explore the possibility that NMDA receptors are involved in the 5-HT effect on tolerance, we examined the effect of a noncompetitive N-methyl-D-aspartate (NMDA) antagonist [(+)MK-801] on the ability of L-tryptophan to enhance tolerance to the effect of ethanol on tilt-plane test performance by the rat. L-Tryptophan treatment resulted in the development of rapid tolerance to a dose of ethanol that failed to produce such tolerance by itself. However, prior administration of (+)MK-801 blocked the L-tryptophan effect on rapid tolerance development, in a dose-dependent manner. These results suggest that NMDA receptors are involved in the 5-HT enhancement of ethanol tolerance.

Tissue-specific distribution of malondialdehyde modified proteins in diabetes mellitus

A potential mechanism of diabetes-related tissue damage is modification of various proteins by lipid peroxidation by-products such as malondialdehyde (MDA). To determine the extent of MDA derivatization of various proteins in diabetes mellitus, Western blots were carried out using a specific anti-MDA antiserum to study proteins in plasma and various tissues of control and streptozotocin (STZ)-induced diabetic rats. The concentration of MDA-proteins was highest in plasma compared to other tissues tested. Diabetes was associated with a reduction in MDA-protein content of plasma, lung and liver while in the heart, testicle, cerebrum and kidney the MDA-protein concentration was not altered. Insulin treatment of diabetic rats normalized MDA-protein content of plasma but not in the lung or liver. A large interindividual variability in various protein species was observed within a group. This was partly attributed to polymerization of MDA-proteins. It is concluded that although diabetes is associated with increased lipid peroxidation the content of MDA-proteins in plasma and in some tissues is decreased.

Age-related changes in tissue content of malondialdehyde-modified proteins

One of the possible mechanisms of the age-related modifications of proteins is the result of reaction with malondialdehyde (MDA), a lipid peroxidation byproduct. To determine the effect of age on the extent of MDA derivatization of proteins in plasma and various tissues, male Fisher 344 rats at 4, 12 and 26 months of age were studied. Protein electrophoresis and immunoblotting was carried out using a specific antiserum against MDA-protein complexes. The concentration of MDA-proteins in plasma (mean +/- SD of optical density in 50 micrograms protein) was 201.6 +/- 47.7 in 4 month old rats, 197.4 +/- 67 in 12 month old rats and 101.4 +/- 22.7 in 26 month old rats (P < 0.01). The MDA protein content of testicle, liver and heart was increased in 12 month old rats compared to 4 and 26 months old rats. There were no age-related differences in MDA-protein content of lung, brain, and kidney. Because of the interindividual variability of MDA-protein profiles within an age group distinct age-related changes in the distribution of various MDA protein bands could not be documented.

Effect of D-cycloserine on rapid tolerance to ethanol

We recently reported that the noncompetitive NMDA antagonists, (+)MK-801 and ketamine, block the development of rapid tolerance to ethanol. In the present article, we show that D-cycloserine (CS), an agonist at the glycine site of the NMDA receptor that enhances learning and memory, also enhances the development of rapid tolerance to ethanol. Rats were pretreated on day 1 with saline or CS, followed 30 min later by ethanol (2.3 g/kg, IP) or saline. At the end of motor impairment testing on the tilt-plane apparatus, a second injection of CS (3 mg/kg, IP, each time) or saline was given, followed 30 min later by ethanol or saline. Ethanol pretreatment alone (at this dose) did not result in rapid tolerance to ethanol on day 2. However, the group pretreated with CS and ethanol on day 1 showed significant tolerance on day 2 compared to other groups. Pretreatment with CS on day 1 did not affect the motor impairment response to the first exposure to ethanol whether this was on day 1 or day 2. In another experiment, administration of (+)MK-801 (0.25 mg/kg, IP) prior to CS abolished the rapid tolerance enhancement by CS. These findings are further evidence that the NMDA system, which requires activation by the glycine receptor, plays a major role in the development of at least some forms of ethanol tolerance.

Frequency and severity of HCV infection following orthotopic liver transplantation. Effect of donor and recipient serology for HCV using a second generation ELISA test

HCV is the principal etiologic agent of post-transfusion (PTH) hepatitis. The incidence and course of HCV hepatitis in liver transplant recipients is not well established. To resolve this information deficit, all records of recipients of single liver transplant (OLTx) between March 1986 and March 1990 at the University of Pittsburgh in whom both the donor and recipients' pre-OLTx sera were available (n = 516) were reviewed. All sera were assayed for HCV antibody using a second generation ELISA method developed by Abbott Laboratories. On the basis of the anti-HCV status of the donor and recipient pre-OLTx sera, four groups could be classified: group I (donor-, recipient-) n = 375; group II (donor-, recipient+) n = 111; group III (donor+, recipient-) n = 25; and group IV (donor+, recipient+) n = 5. Post OLTx liver biopsies were obtained for a clinical indication in 473 of these 516 patients. The prevalence of anti-HCV among recipients pre-OLTx was 22.5% (116/516) which is three times greater than the 5.8% (30/516) prevalence in the donors. Histologic hepatitis not ascribable to any cause other than HCV occurred in 76/516 (15%) recipients: 42 in group I; 28 in group II; 6 in group III and none in group IV. The overall risk of HCV hepatitis at 6 months, 1 year and 2 years post-OLTx was 4.8% (25/516), 7.6% (39/516) and 10.1% (52/516), respectively. At each of these time intervals, no significant difference between groups for the prevalence of HCV hepatitis was evident.(ABSTRACT TRUNCATED AT 250 WORDS)

Types, causes, and therapies of hepatitis occurring in liver transplant recipients

Liver transplantation (OLTx) has become a common life-saving procedure for individuals with chronic advanced liver disease. It is also used in the clinical treatment of patients with fulminant hepatic failure and those with primary neoplastic disease of the liver. Despite its overall success in restoring meaningful life to those who undergo the procedure, the posttransplant life of a liver allograft recipient is not without hazard. A common problem following liver transplantation is the finding of abnormal liver injury tests reflecting a "hepatitis" that can not be ascribed to allograft rejection. The majority of such cases are a consequence of either a technically flawed operation, drug-induced liver injury, or one or another form of viral hepatitis. Each of these problems is discussed in the following clinical review.

Effect of NMDA receptor antagonists on rapid tolerance to ethanol

Hypothermia and motor impairment (tilt-plane test) were used to assess whether N-methyl-D-aspartate (NMDA) receptors play a role in the development of rapid tolerance to ethanol, i.e., tolerance to a second dose of ethanol given 24 h after the effect of the first dose of ethanol had disappeared. Results showed that (+)-MK-801 and ketamine blocked the development of rapid tolerance to ethanol on both tests. Since these drugs did not modify blood or brain alcohol levels in any of the groups, the blockade of ethanol rapid tolerance cannot be attributed to changes in pharmacokinetics of ethanol. These data suggest that the role of NMDA receptors in ethanol tolerance may be similar to their role in memory and learning, involving a facilitation of transmission in certain synapses.

Inhibition of nitric oxide synthesis impairs rapid tolerance to ethanol

To examine whether nitric oxide was involved in the development of rapid tolerance to the motor-incoordinating effects of ethanol (tilt-plane test), three experiments were undertaken in a rapid tolerance paradigm in rats. The first experiment tested the effect of the nitric oxide synthase inhibitor, L-nitro-arginine, on the acquisition of ethanol tolerance. The second compared the effects of L-nitro-arginine with those of its inactive isomer, D-nitro-arginine. The third examined whether overload with the substrate L-arginine would prevent the action of L-nitro-arginine on rapid tolerance. The results demonstrated that L-nitro-arginine prevented the development of rapid tolerance, while D-nitro-arginine was ineffective. An excess of the substrate L-arginine reversed the inhibitory action of L-nitro-arginine on tolerance development. These data suggest that nitric oxide may play a role in the development of tolerance to ethanol. The role of nitric oxide in ethanol tolerance may be similar to its role in memory and learning, involving facilitation of transmission in certain NMDA synapses.

Mechanism of induction of c-fos by ultraviolet B (290-320 nm) in mouse JB6 epidermal cells

The UVB (290-320 nm) portion of the solar spectrum possesses the highest activity for the induction of skin cancer and has the capacity to stimulate epidermal proliferation. We report that UVB is a transcriptional inducer of the c-fos protooncogene in mouse JB6 epidermal cells. Induction is biphasic with an immediate early peak at 30-60 min and a second broader peak 8 h following irradiation. The immediate early phase is suppressed by inhibitors of nuclear adenosine diphosphoribose transferase. For UVB induction, the formation of full-length messages is less efficient than of early, short messages, while both types of messages are produced at similar rates following serum stimulation. Experiments with stable transfectants with reporter constructs linked to 5'-upstream sequences of c-fos indicate that UVB and serum stimulation both require the sequences from -345 to -285 which contain the joint DSE-AP-1 enhancer motifs for efficient induction. Mobility shift data reveal that the complement of c-Fos and c-Jun proteins which bind to the fos-AP-1 octanucleotide decrease immediately following irradiation. Increased binding of Fos and Jun is observed 8-24 h later. UVB did not cause an observable change in the nuclear proteins which bind to the dyad symmetry element oligonucleotide in vitro. Fos protein was detected among the binding proteins. We propose that the two phases of UVB-induced c-fos expression occur by quite different mechanisms. The immediate early phase is inhibited by adenosine diphosphoribose transferase inhibitors because poly-ADP ribosylation of chromosomal proteins is required for the resealing of UVB-induced DNA strand breaks which otherwise retard message elongation. The production of an autocrine factor may be responsible for the late phase of c-fos induction.

Oxidant carcinogenesis and antioxidant defense

Growth promotion by oxidants is observed with cultured human and mouse fibroblasts as well as epidermal cells. It is expected to play a role in inflammation, fibrosis, and tumorigenesis. Indeed, oxidants trigger (patho)physiological reactions that resemble those induced by growth and differentiation factors. For example, active oxygen activates protein kinases, causes DNA breakage, and induces the growth competence-related protooncogenes c-fos and c-myc. The cellular antioxidant defenses affect the consequences of oxidant exposure. Transfectants of mouse epidermal cells that overproduce Cu,Zn-superoxide dismutase (SOD) were sensitized to the toxic effects of an extracellular burst of O2-. plus H2O2, whereas overproducers of catalase (CAT) were protected. Transfection of SOD overproducers with CAT corrected their hypersensitivity. Inducibility of the protooncogene c-fos by oxidants was diminished in SOD and CAT overproducers, albeit probably for different reasons. It is concluded that a fine balance of the multiple components of the antioxidant defense determines the growth response of cells to oxidative stress. In studies of the mechanism of the transcriptional induction of c-fos by oxidants, we identified the joint DSE-AP1 elements (dyad symmetry element, DSE) as major enhancer motifs in the 5'-upstream regulatory sequences of c-fos. Oxidants also increased the de novo synthesis of protein factors that bind to the fos-AP1 enhancer motif. Protein kinase and ADPR transferase inhibitors suppressed the transcriptional induction of c-fos as well as the increase in factor binding to fos-AP1. We conclude that protein phosphorylation and protein polyADP-ribosylation are required for the transcriptional induction of c-fos and the synthesis of protein factors that bind to fos-AP1. It is likely that the FOS and JUN proteins are among these factors and that they participate in the regulation of c-fos expression by oxidants.

Hepatitis C testing. Comparison of Ortho's EIA and RIBA II tests in 1,182 patients undergoing primary liver transplantation

Plasma samples from 1,182 patients undergoing primary liver transplantation were tested for anti-hepatitis C (HCV) virus by two methods: Ortho HCV ELISA Test System (EIA) and Chiron RIBA HCV Test System (RIBA II). The EIA results, 0 or +, were recorded first, followed by RIBA results, N = negative, P = positive, or I = indeterminate. Concordant results--0N, + P, + I--were found in 1,076 (91%), and discordant results were found in 106 (9%). The EIA optical density did not relate to concordant or discordant results. Band patterns were described by stating the band position (1, 2, 3, or 4) and inserting a dash (-) if no band was visualized. Most + P samples fell into two patterns: 47% showed all four bands, pattern 1234, and 15% showed the two-band pattern, 34. When the EIA was negative, 0P, the opposite was seen: 8% showed the 1234 pattern and 81% showed the 34 pattern. There were 226 samples that formed bands (+ P, 149; 0P, 31; + I, 15; 0I, 31). The frequency of bands was as follows: 4, 32%; 3, 31%; 2, 19%; and 1, 18%. Band 2 and the EIA test detected antibodies to the same c100-3 fragment and showed 74% concordance. No explanation is apparent for the lower concordance rate here than that between the EIA test and bands 3 = 96% or 4 = 88%. The EIA and RIBA II tests, together with positive liver function tests and abnormal tissue pathologic findings, provide a basis for the diagnosis of HCV.

Incidence, prevalence, and clinical course of hepatitis C following liver transplantation

Hepatitis C virus (HCV) is the agent responsible for posttransfusion hepatitis. The incidence, timing, and clinical course of HCV positive hepatitis in liver transplant recipients are unknown. Three hundred and seventeen donor-recipient liver transplant pairs were grouped on the basis of their pretransplant HCV antibody status. The biopsy findings were examined. Four distinct groups were identified on the basis of HCV serology: group I, both were negative; group II, donor was negative and recipient was positive; group III, donor was positive and recipient was negative; group IV, both were positive. The prevalence of anti-HCV positivity in recipients was 13.6%. The rate of seroconversion was 9.2%. Histologic hepatitis not ascribable to any specific cause other than non-A, non-B (NANB) hepatitis occurred in 13.8%. The incidence of histologic chronic active hepatitis was 1.6%, and none progressed to cirrhosis. The concordance rate for a positive anti-HCV serology and NANB hepatitis was 2.8%. Of the 35 patients (group II and IV) with positive anti-HCV serology pretransplant, only 17 were positive posttransplantation. Based on these data it can be concluded that posttransplant NANB hepatitis occurred in 13.8% of liver recipients. Twenty percent of these were anti-HCV positive. Progression to histologic chronic active hepatitis occurs over a period of 1-5 years in 1.6% of cases.

Ketamine retards chronic but not acute tolerance to ethanol

Motor impairment (tilt-plane test) was used to investigate whether the noncompetitive N-methyl-D-aspartate (NMDA) antagonist ketamine prevents the development of chronic and acute tolerance to ethanol. Rats were treated with ethanol or saline in the presence and absence of ketamine (separate groups) for 10 days and tested for ethanol tolerance in the absence of ketamine on the fifth and tenth days. In other studies, the effect of ketamine on acute tolerance to ethanol was examined. Rats that received ethanol daily without ketamine showed significant tolerance to ethanol on days 5 and 10, but those receiving ethanol plus ketamine daily showed significantly less tolerance to ethanol. Thus, ketamine interfered with the development of chronic tolerance just as it had been found previously to prevent rapid tolerance. In contrast, ketamine failed to block acute tolerance to ethanol. These results would suggest that the phenomena of acute tolerance and chronic tolerance have differences not previously reported.

Differential inhibition by NMDA antagonists of rapid tolerance to, and cross-tolerance between, ethanol and chlordiazepoxide

We have recently found that the non-competitive N-methyl-D-aspartate (NMDA) antagonists, (+)MK-801 and ketamine, block the development of rapid tolerance to ethanol. In the present report we show that they also block rapid cross-tolerance from chlordiazepoxide to ethanol as well as ethanol to chlordiazepoxide. However, NMDA antagonists fail to block the development of rapid tolerance to chlordiazepoxide. Our results suggest that NMDA antagonists may affect not only the acquisition of rapid tolerance or cross-tolerance to sedatives but also the ability to express that tolerance or cross-tolerance, depending on the drugs used. It is also possible that the phenomena of rapid tolerance and rapid cross-tolerance have basic differences not previously reported in the literature.

Effect of (+)MK-801 and ketamine on rapid tolerance to ethanol

The motor impairment (tilt-plane test) responses to ethanol were significantly reduced on days 2, 3, 4, or 5 in rats receiving ethanol (2.3 and 1.7 g/kg) 24 and 22 h earlier, compared to the control group pretreated with saline. Administration of (+)MK-801, prior to behavioral testing with ethanol on day 1, inhibited the development of tolerance on all these days. Tolerance and the inhibitory effect of (+)MK-801 could no longer be seen if the second injection of ethanol was given on day 7, 8 or 11. Administration of (+)MK-801 on day 1 but after behavioral testing with ethanol did not block the development of rapid tolerance to ethanol on day 2. Administration of another commonly employed NMDA antagonist, i.e., ketamine, prior to ethanol on day 1, also blocked the development of rapid tolerance to ethanol. The findings suggest that NMDA antagonists block rapid tolerance by preventing some adaptation that occurs during intoxicated practice.

Rapid tolerance and cross-tolerance as predictors of chronic tolerance and cross-tolerance

Hypothermia and motor impairment (tilt-plane) tests were used to assess the phenomenon of rapid tolerance to ethanol and cross-tolerance to various alcohols, benzodiazepines, and barbiturates that differ in lipid:water partition coefficients. The hypothermic and motor impairment responses to ethanol were significantly reduced on day 2 in rats receiving ethanol (2 doses of 2 g/kg each for the hypothermia test and 2.3 and 1.7 g/kg for the tilt-plane test) 24 and 22 h earlier compared to the control group pretreated with saline. Ethanol pretreatment resulted in rapid cross-tolerance, on both tests, to the various alcohols (n-propanol, n-butanol, and t-butanol) and the benzodiazepines (chlordiazepoxide, diazepam, oxazepam, and flurazepam) tested. Ethanol pretreatment also conferred clear rapid cross-tolerance to barbital and phenobarbital, but did not result in rapid cross-tolerance to pentobarbital, secobarbital, amobarbital, or thiopental. The results on rapid cross-tolerance on both tests seen in these studies parallel the results obtained in chronic tolerance and cross-tolerance studies reported recently. These results suggest that rapid tolerance and cross-tolerance can be used as predictors of chronic tolerance and cross-tolerance.

The balance between Cu,Zn-superoxide dismutase and catalase affects the sensitivity of mouse epidermal cells to oxidative stress

Oxidants are toxic, but at low doses they can stimulate rather than inhibit the growth of mammalian cells and play a role in the etiology of cancer and fibrosis. The effect of oxidants on cells is modulated by multiple interacting antioxidant defense systems. We have studied the individual roles and the interaction of Cu,Zn-superoxide dismutase (SOD) and catalase (CAT) in transfectants with human cDNAs of mouse epidermal cells JB6 clone 41. Since only moderate increases in these enzymes are physiologically meaningful, we chose the following five clones for in-depth characterization: CAT 4 and CAT 12 with 2.6-fold and 4.2-fold increased catalase activities, respectively, SOD 15 and SOD 3 with 2.3-fold and 3.6-fold increased Cu,Zn-SOD activities, respectively, and SOCAT 3 with a 3-fold higher catalase activity and 1.7-fold higher Cu,Zn-SOD activity than the parent JB6 clone 41. While the increases in enzyme activities were moderate, the human cDNAs were highly expressed in the transfectants. As demonstrated for the clone SOD 15, this discordance between message concentrations and enzyme activities may be due to the low stability of the human Cu,Zn-SOD mRNA in the mouse recipient cells. According to immunoblots the content of Mn-SOD was unaltered in the transfectants. While the activities of glutathione peroxidase were comparable in all strains, the concentrations of reduced glutathione (GSH) were significantly lower in SOD 3 and SOD 15. This decrease in GSH may reflect a chronic prooxidant state in these Cu,Zn-SOD overproducers.(ABSTRACT TRUNCATED AT 250 WORDS)

Tolerance to ethanol and cross-tolerance to pentobarbital and barbital in four rat strains

Chronic ethanol treatment by gastric intubation conferred tolerance to ethanol-induced motor impairment and hypnosis in four different rat strains: Fischer 344, Long-Evans, Sprague-Dawley, and Wistar. Cross-tolerance to barbital was also observed in all strains after chronic treatment with ethanol. However, chronic ethanol treatment failed to produce cross-tolerance to pentobarbital-induced motor impairment and hypnosis in any of the four strains. The demonstration of cross-tolerance to barbital and the lack of it to pentobarbital after chronic ethanol treatment confirms and extends recent observations on the specificity of the site and/or mechanism of action of sedative-hypnotic drugs that differ in lipid solubility.

Rapid tolerance as an index of chronic tolerance

Hypothermia and motor impairment (tilt-plane test) were used to assess the phenomenon of rapid cross-tolerance between ethanol and pentobarbital in rats. The hypothermic and motor-impairment responses were significantly reduced on day 2 in animals receiving ethanol on day 1, compared to the control group pretreated with saline. Ethanol pretreatment, however, did not result in rapid cross-tolerance to pentobarbital on either test. Pentobarbital pretreatment on day 1 resulted in rapid tolerance to pentobarbital on day 2. However, in contrast to the lack of rapid cross-tolerance to pentobarbital after pretreatment with ethanol, pentobarbital pretreatment clearly conferred rapid cross-tolerance to ethanol. Determination of ethanol and pentobarbital blood levels suggested that pharmacokinetic alterations did not contribute significantly to the observed rapid tolerance and cross-tolerance. The asymmetry of rapid cross-tolerance seen in these studies mimics the results obtained by us in chronic tolerance and cross-tolerance studies reported recently. These results suggest that rapid tolerance and cross-tolerance can be used as predictors of chronic tolerance and cross-tolerance.

Comparison of sensitivity and alcohol consumption in four outbred strains of rats

Differences in alcohol consumption and in sensitivity to the effects of ethanol were investigated in four outbred rat strains: Fischer 344, Long-Evans, Sprague-Dawley and Wistar. Alcohol consumption was measured in all four strains in three separate subgroups for each strain, using three different concentrations of ethanol (5, 10 and 20% v/v). An intermittent forced alternate-day ethanol presentation procedure (ethanol as the sole fluid for one day followed by only water the next day), as well as a two-bottle choice paradigm, were employed for this purpose. Ethanol-induced hypothermia and motor impairment (tilting plane test) were used to assess sensitivity. Significant differences in alcohol consumption were found among these strains. The Long-Evans strain consumed the highest and Fischer 344 the lowest amount of ethanol. Wistar and Sprague-Dawley were intermediate. However, the strains did not differ in sensitivity to ethanol. Similarly, determination of sensitivity to ethanol on day 0 in separate groups of these four strains (same age and weight, and obtained at the same time from the same supplier) did not reveal graded differences in sensitivity (hypothermia and motor impairment) corresponding to differences in alcohol consumption. These results suggest that sensitivity does not correlate with alcohol consumption.

Evidence that mutacin II production is not mediated by a 5.6-kb plasmid in Streptococcus mutans

Here we present evidence that the cryptic 5.6-kb plasmid found in certain strains of Streptococcus mutans is not involved in mutacin production. This evidence comes from demonstrating similarities between a plasmid-less strain T8 and a group II plasmid strain UA96. Both produce what appears to be an identical mutacin based on spectrum of activity and physiological properties. Also, T8 and UA96 are members of the same immunity group (group II). Genotypically, both strains appear similar except for plasmid content based on DNA fingerprinting profiles. T8 and UA96 exhibit identical hybridization patterns following transformation of T8 with a mutacin-negative (bac-1::Tn916) sequence from a Tn916-insertionally inactivated mutant of UA96. This transformation also resulted in the mutacin-negative phenotype in T8 transformants, showing recombination between a mutacin-associated gene in UA96 and its apparent homologous sequence in T8. Moreover, when a plasmid containing a putative repeat element from UA96 (pPC264) was used as a probe, it hybridized to the same five EcoRI fragments in both T8 and UA96. Collectively, these data, coupled with data from other sources, indicate that the plasmid resident in mutacin II strains is not involved in mutacin production.

Mediation of muscarinic stimulation of pepsinogen secretion in the frog

The in vitro release of pepsinogen secretion by the isolated esophagus of the American bullfrog was studied with an improved model system. The tissue was mounted in a double chamber that preserves mucosal polarity and provides both control and test segments, each 1 cm2 from the same tissue. Pepsinogen secretion was severalfold higher than previously found with mucosal strips and could be sustained for several hours. Bethanechol (BCh) caused concentration-dependent (0.1-50 microM) pepsinogen secretion with a Vmax of 74 +/- 12 micrograms X mg prot-1 X h-1 or 50-60% of total pepsinogen; Km was 3 microM and 500 microM BCh stimulated at less than the Vmax value. Atropine specifically blocked BCh and pA2 = 9.3. In the presence of 100 microM isobutylmethyxanthine, BCh produced a dose-dependent increase in tissue cAMP but not cGMP. BCh remained effective in Ca2+-free medium. In calcium-free medium EGTA concentration dependently (0.2-5 mM) suppressed the pepsinogen response to BCh. The evidence thus far suggests that cholinergic stimulation of pepsinogen secretion in the tissue acts via both cAMP and Ca2+. More specific studies would be required for absolute confirmation of either or both apparent mechanisms and to resolve how they interact.

Initial sensitivity versus acquired tolerance to ethanol in rats selectively bred for ethanol sensitivity

Chronic tolerance to ethanol-induced sleep, motor impairment (moving belt test), and hypothermia were examined in two lines of rats that had been selectively bred for their different initial sensitivities to ethanol. In agreement with previous work (Mayer et al. 1982, 1983), the least-affected (LA) rats were found to be less sensitive than their most-affected (MA) counterparts in all three tests. Chronic treatment with ethanol resulted in a more rapid and more marked tolerance development in MA animals than in LA ones. The two lines did not differ in final level of tolerance achieved for either sleep time or hypothermia. However, significant differences were observed with respect to the moving belt test, in that at the end of chronic ethanol treatment the MA animals were more resistant to ethanol than the LA ones. These studies support the existence of a relationship, but not necessarily a direct genetic linkage, between initial sensitivity and acquired tolerance.

Liquid chromatographic determination of oxfendazole in swine feeds

A relatively simple analytical method is presented for determination of oxfendazole (2-(methoxycarbonylamino)-5-phenylsulfinyl-benzimidazole) at levels as low as 0.012% in swine feeds, using cation exchange liquid chromatography (LC). The sample was extracted with a solvent mixture of methanol-glacial acetic acid (90 + 10) at 45 degrees C, using a gyrorotory shaker. Plant pigments and other feed excipients were removed using zinc acetate treatment and pH-controlled extraction. Oxfendazole was further separated from the remaining interferences and quantitatively determined by LC on a Partisil SCX column with acetonitrile-0.01M phosphate buffer as mobile phase. The method is stability-specific, linear, precise, and accurate at 80-120% labeled strength (relative standard deviation 0.9-1.7 with mean recovery of 98-99%). Supporting data at a level of 0.0135% oxfendazole in swine feed indicated that this method is capable of complete recovery of oxfendazole from medicated swine feeds.

Interferon production by human marrow stromal cells

We have demonstrated that normal human bone marrow stromal cells can be induced to produce high levels of beta-interferon (IFN). One of three randomly selected human stromal cell lines produced beta-IFN in similar amounts to one of the best beta-IFN producer cell lines produced beta-IFN in similar amounts to one of the best beta-IFN producer cell lines (MG-63 osteosarcoma cells). The marrow stromal cell lines did not produce gamma-IFN, though a low level of alpha-IFN was apparently produced. The stromal cell lines differ from usual producer cell lines in that they can be subcultured for a much longer growth period and also maintain the ability to producer IFN. The cells are karyotypically normal and are not virus transformed. Such cell lines may be useful in the production of human IFN as well as allowing studies on the role of IFN in stromal cell-haemopoietic cell interactions.

Effect of naloxone on ethanol- and pentobarbital-induced narcosis

Single or repeated subcutaneous administrations of naloxone in doses of up to 4 mg X kg-1 did not alter the time for onset or the duration of ethanol- or pentobarbital-induced narcosis in rats. An increase in the naloxone dosage to 50 mg X kg-1 s.c. resulted in a small reduction of ethanol-induced sleep duration. Repeated i.p. or i.v. administrations of much higher doses of naloxone (300-400 mg X kg-1 and 120-180 mg X kg-1, respectively) did produce significant reductions in ethanol-induced narcosis. However, similar naloxone doses, when administered alone, i.v., had marked convulsant effect. It appears that naloxone, in low doses, is not an effective antidote for narcosis caused by ethanol or pentobarbital at the ethanol and pentobarbital doses tested, whereas the antagonism of ethanol-induced sleep by high doses of naloxone may be due to the analeptic action of this drug.

Induction of labor in the high-risk pregnancy with PGF 2 alpha

The induction of labor in the high-risk patient is accompanied by an increased incidence of cesarean section partly due to failed induction. A series of 50 high-risk patients induced with intravenous prostaglandin F 2 alpha is presented. Forty-five were successfully induced, 35 of whom delivered vaginally. Failed inductions occurred in 5 patients. The overall success rate was 90%, and cesarean section rate was 25.5%. There was an increased incidence of late decelerations in the PGF 2 alpha groups as compared to spontaneous and Pitocin-stimulated labors. While the success was high, the use of a drug which itself may caused fetal cardiovascular changes is not desirable, especially in those pregnancies already at risk.

Characterization of gastric mucosal membranes. VIII. The localization of peptides by iodination and phosphorylation

Two fractions of gastric mucosal membranes obtained by Ficoll-sucrose density gradient centrifugation were studied by a variety of techniques to localize the polypeptides. Gel electrophoresis showed the presence of five major polypeptides and several minor ones. Only one of these, 82,000 daltons, was available for iodination in the intact tissue. The two membrane fractions differed in their accessibility to peroxidase. The denser fraction showed two major defined iodination peaks at 82,000 and 102,000 daltons. Freeze-thawing and iodinating with 131-I produced additional labeling of peaks as well as relabeling the 82,000-dalton component, showing it was accessible from both sides of the membrane. The two major components were also sensitive to cross-linking, the 102,000 polypeptide being especially sensitive to --SH oxidation. Proteolysis with trypsin removed both components in the denser membrane fraction, in addition to inhibiting the K+-ATPase and K+-p-nitrophenylphosphatase of that fraction. Phosphorylation with [gamma-32-P]ATP labeled the 102,000-dalton component and K+, HCO3- minus and p-nitrophenylphosphate reduced the level of labeling. Hence the 102,000 region contains a subunit of the ATPase, is readily iodinated in inside-out vesicles, and is the most available for interpeptide S--S cross-linking.