Increase in the level of mRNA for 3-hydroxyanthranilate 3,4-dioxygenase in brain of epilepsy-prone El mice

We had shown that production of quinolinic acid is high in the brain of epilepsy-prone El mice and that this is due to an increase in the activity of 3-hydroxyanthranilate 3,4-dioxygenase (3-HAO, EC 1.13.11.6). We demonstrated here that the level of mRNA for 3-HAO was markedly increased in the brain of El mice.

[Comparison between anomia with word comprehension difficulty and Gogi aphasia due to lobar atrophy]

We used naming and pointing tests and a proverb completion task to compare two cases of aphasia that exhibited a selective disturbance of word processing. One patient had anomia with word comprehension difficulty due to partial ablation of the left temporal lobe and the other patient had Gogi aphasia due to lobar atrophy with left temporal predominance. We presented 90 pictures of common objects divided into 9 categories in the naming and pointing tests, and used 10 well-known Japanese proverbs as stimuli in the proverb completion task. Performance of the naming and pointing tests was severely impaired in both patients. In the patient with anomia, words the patient could not name or point to varied from session to session and phonemic cue effects were frequently observed. The proverb completion phenomenon was positive. These findings indicate that the patient had an obstruction of the access route to the intact word store or a partial rarefaction of the word store itself. In the patient with Gogi aphasia, the words the patient could not name or point to were consistent from one occasion to another, and no phonemic cue effects or signs of familiarity were observed at all. The proverb completion phenomenon was totally negative. These findings indicate that the patient has lost the word store itself. MR images in the case of anomia revealed a lesion extending from the anterior to the central portion of the inferior part of the left temporal lobe. In the case of Gogi aphasia, the MR images displayed knife-edged focal atrophy in the anterior aspect of both temporal lobes, more prominently on the left.(ABSTRACT TRUNCATED AT 250 WORDS)

[Effects of plasma albumin on theophylline concentration in lung tissue]

To study the relationship between plasma and lung tissue theophylline concentrations, we changed the number of binding sites for theophylline on serum albumin. Cefazoline, which competes with theophylline for those binding sites, was given to rats, and free theophylline was separated by ultrafiltration. The dose of cefazoline was directly related to the percentage of free theophylline and was inversely related to the plasma total theophylline concentration. The plasma free theophylline concentration, however, was unchanged at the lower doses of cefazoline and was low only at the highest dose. The concentration of theophylline in lung tissue was inversely related to the dose of cefazoline. The concentration of 1, 3-dimethyluric acid, a major metabolite of theophylline, was also inversely related to the dose of cefazoline, which suggests that the metabolic rate of theophylline did not increase. Excretion of theophylline via the urine might be accelerated by its diuretic action. We conclude that when the binding of theophylline to plasma proteins is altered in rats, the concentration of free theophylline in plasma does not reflect the concentration of theophylline in lung tissue. Instead, the total theophylline concentration in plasma can be used as an index of the concentration in lung tissue.

[Rapid diagnosis of adenoviral conjunctivitis by enzyme-linked immunosorbent assay (Adenoclone)]

We evaluated an enzyme-linked immunosorbent assay test (Adenoclone) for the rapid diagnosis of adenovirus infection in 589 cases of acute follicular conjunctivitis. Of 255 cases of adenoviral conjunctivitis proven by positive virus isolation. Adenoclone was positive in 51.0% by visual determination and 40.4% by spectrophotometry. Twenty-seven of 130 cases giving visually positive results were interpreted to be negative by spectrophotometry. In 334 adenovirus-negative cases, Adenoclone was negative in 99.1% and 99.4 by visual and spectrophotometric determination, respectively. Adenoclone was less sensitive in cases of adenovirus 3, 4 or 37, infections than in those of adenovirus 8, and also showed lower sensitivity in cases presenting mild conjunctivitis. Adenoclone is a rapid and easy test with high specificity but low sensitivity, and thus the test seems to be helpful in diagnosing adenoviral conjunctivitis.

[Characteristics of participants in community-based rehabilitation programs and their levels of independence in activities of daily living]

To clarify characteristics of participants in community-based rehabilitation programs provided by local municipalities (cities, towns, and villages) and effect of the program on their levels of independence in activities of daily living (ADL), a cross-sectional study was performed on 422 participants in 49 municipalities in Kochi Prefecture. 1. Mean age of participants was 68.3 +/- 9.0, and 77.7% of them were stroke patients. 2. The mean interval between disease onset and program participation was 40.4 months, and the mean duration of program participation was 54.5 months. 3. At the start of rehabilitation programs and at the time of the investigation (December 1993), about 90% of the participants had good levels of independence in ADL (Rank A and over according to the standard of the Ministry of Health and Welfare). 4. The frequency of rehabilitation programs and the presence of occupational therapists were positively associated with the improvement of levels of independence in ADL. In particular, the frequency of rehabilitation programs was associated with improvement of quality of life in self-supporting participants (Rank J2), and the presence of occupational therapists was associated with the improvement of ADL in semi-bed-ridden participants (Rank A). 5. After adjusting for age and sex, using multiple logistic regression analysis, type of diseases (non-stroke), hospital rehabilitation immediately after onset, higher levels of independence in ADL at the start of rehabilitation programs, and higher frequency of rehabilitation programs were significantly associated with improvements in levels of independence in ADL. Shorter interval between disease onset and program participation, and the presence of occupational therapists were also associated with improvements in levels of independence in ADL, although the relation did not reach statistical significance.

IL-2 signaling involves recruitment and activation of multiple protein tyrosine kinases by the IL-2 receptor

The IL-2 receptor (IL-2R) consists of three subunits, the IL-2R alpha, IL-2R beta, and IL-2R gamma chains, the last of which is also used in the receptors for IL-4, IL-7, IL-9, IL-13, and IL-15. The IL-2-induced proliferative signals emanate from the cytoplasmic domains of IL-2R beta and IL-2R gamma, but the nature and function of the signaling molecules that transmit these signals are not fully understood. Here we summarize our current understanding of the mechanisms by which IL-2R transmit signals by using multiple protein kinases. In fact, at least four protein tyrosine kinases (PTKs) are physically associated with IL-2R: p56lck (and its members), Syk PTK, and the Janus kinases, Jak1 and Jak3. cDNA expression studies revealed that the activation of these PTKs is critical for IL-2-induced proliferative signal transmission. Our findings indicate that a unique property of the IL-2R cytoplasmic domains is to recruit a variety of signaling molecules, which may suggest a mechanism by which these PTKs and other signaling molecules function in concert.

Detection of MspI RFLP in human THY1 gene by the polymerase chain reaction

THY1 gene encodes a cell surface glycoprotein predominantly expressed in brain and peripheral nerves. Human THY1 gene region on chromosome 11q23 has been implicated in susceptibility to type 1 diabetes (Wong et al., 1991). Two primers derived from the sequences flanking the polymorphic MspI site in intron 2 of the human THY1 gene (Gatti et al., 1988) were selected for RCP to amplify a 566 bp fragment that spans the MspI polymorphism. Polymorphism was detected by MspI digestion of the PCR product.

Cytotoxic effects of postharvest fungicides, ortho-phenylphenol, thiabendazole and imazalil, on isolated rat hepatocytes

The cytotoxic effects of ortho-phenylphenol (OPP), imazalil (IMZ) and thiabendazole (TBZ) on isolated rat hepatocytes were investigated. Addition of IMZ and OPP to hepatocyte suspensions at a concentration of 0.75 mM resulted in acute cell death, accompanied by depletion of intracellular levels of glutathione and protein thiols. Both compounds rapidly depleted cellular ATP which consistently preceded the cell death. In addition, the cell death caused by IMZ was accompanied by the accumulation of intracellular malondialdehyde, indicating initiation of lipid peroxidation. During a 3-hr incubation period, TBZ did not affect these parameters. In mitochondria isolated from rat liver, IMZ and OPP impaired respiration related to oxidative phosphorylation. Based on these results, the order of toxic potency is IMZ > OPP > TBZ.

Insulin receptor gene polymorphism and hyperinsulinemia in hypertensive patients

Although insulin resistance often occurs in association with hypertension, considerable variation is observed in the degree of insulin resistance among hypertensive patients. Since there is evidence of a genetic basis in the development of insulin resistance in hypertension, we analyzed the contribution of genetic factors to insulin resistance in hypertensive patients. Sixty-six Japanese hypertensive patients were studied. These patients were divided into two groups (hyperinsulinemia group and normoinsulinemia group) according to plasma insulin response during a 75-g oral glucose tolerance test (75g-OGTT). Insulin receptor gene (INSR) was studied for association with insulin resistance in hypertensive patients. A microsatellite polymorphism in intron-2 of the insulin receptor gene was analyzed by the polymerase chain reaction method. Five alleles were detected in the INSR microsatellite. The frequency of C/C genotype in the hyperinsulinemia group was significantly higher than that in the normoinsulinemia group (73% vs. 43%, p = 0.02). There was no difference in genotype frequency of INSR between hypertensive patients and control subjects. When the hypertensive patients were divided into two groups, the frequency of C/C genotype in the hyperinsulinemia group was significantly higher than that in the control group (73% vs. 45%, p = 0.014). There was no significant difference between the normoinsulinemia group and control group. These data suggest that the insulin receptor gene may contribute to insulin resistance in hypertensive patients with hyperinsulinemia.

Activation of phospholipase A2 and acylation of lysophospholipids: the major regulators for platelet activating factor production in rat neutrophils

Rat inflammatory neutrophils induced arachidonic acid release and platelet-activating factor (PAF) production in response to opsonized zymosan (OPZ) dose-dependently. Phospholipase A2 activity also increased dose-dependently, paralleling the increases in arachidonic acid and PAF. The time courses of the activities of phospholipase A2 and acetyltransferase, and the amounts of free arachidonic acid, lyso-PAF, and PAF demonstrated that activation of the enzymes in the remodeling pathway could be required for PAF production in rat neutrophils, which agrees with the documented fact for macrophages. Phospholipase A2 could be a rate-limiting enzyme for PAF production, since an increased lyso-PAF amount or addition of exogenous lyso-PAF reflected the increase in PAF formation in the cells. This phospholipase A2 activity in rat neutrophils could be attributed to cytosolic type phospholipase A2, because the activity was mostly suppressed by a specific antibody to cytosolic phospholipase A2. As previously reported, pretreatment of neutrophils with the acyl-CoA synthetase inhibitor, triacsin C, or the acyltransferase inhibitor, merthiolate, enhanced PAF production as well as arachidonic acid release by the cells in response to OPZ. Triacsin C inhibited arachidonoyl-CoA production and merthiolate suppressed the transacylation of lyso-PAF to 1-alkyl-2-arachidonoyl-GPC. These results suggest that these inhibitors of acylation of lyso-PAF caused accumulation of lyso-PAF, which resulted in enhancement of PAF production when phospholipase A2 and acetyltransferase were activated by OPZ. Thus the activation of cytosolic phospholipase A2 and the acylation of lyso-PAF by such as arachidonic acid could be regulating factors for PAF production in stimulated rat neutrophils.

Effects of adriamycin, an anticancer drug showing testicular toxicity, on fertility in male rats

Adriamycin (ADR), an anticancer drug,was intravenously administered to Slc:SD male rats at doses of 0, 1 and 2 mg/kg once a week for 4 or 9 weeks before pairing, and the treatment period and parameters suitable for detection of male fertility disorder were examined. No adverse effects were observed on the copulation index, fertility index and spermatozoa, but testicular weights were low in the 1 and 2 mg/kg groups after 4-week treatment. In the 2 mg/kg group after 9-week treatment, 11 of 12 males had died or became moribund, and no successful pregnancies were observed. The males in the 1 and 2 mg/kg groups after 9-week treatment had decreased weights of the genital organs, an extremely decreased number of sperm and low sperm motility as well as a low implantation rate and a decreased number of live fetuses. Microscopically, the numbers of spermatogonia were decreased in the 1 and 2 mg/kg groups after 4-week treatment, whereas the numbers of even spermatozoa were diminished and genital organs showed atrophy after 9-week treatment. These results indicate that 4-week treatment before pairing is sufficient to detect effects of ADR on the testis, especially on spermatogonia, and that microscopic findings and testis weight are appropriate parameters for detection of male fertility disorders.

A mutation in the glucagon receptor gene (Gly40Ser): heterogeneity in the association with diabetes mellitus

A possible pathogenic mutation in the glucagon receptor gene causing a Gly to Ser change at codon 40 (Gly40Ser) was reported to be associated and linked with non-insulin-dependent diabetes mellitus (NIDDM), in France and Sardinia. Since the frequency of the mutation (Gly40Ser), about 5% in the French population of familial NIDDM and 8% in randomly chosen diabetic patients in Sardinia, was much higher than that of any of the previously reported mutations in candidate genes, it is important to clarify whether the contribution of this mutation to NIDDM is universal. In this study, we investigated the association of this mutation with diabetes mellitus in a large number of Japanese diabetic patients (383 NIDDM and 53 insulin-dependent diabetic patients) by polymerase chain reaction-restriction fragment length polymorphism analysis. None of the Japanese diabetic patients showed Gly40Ser mutation and the association of this mutation with NIDDM was significantly different (p < 4.10(-5) vs French, p < 3.10(-6) vs Sardinian by Fisher's exact test). The results not only indicate that the mutation plays little, if any, role in susceptibility to diabetes in Japan, but also indicate the genetic heterogeneity in NIDDM and further emphasize the importance of studies on genetic susceptibility to NIDDM and other complex traits in different ethnic groups.

NS-3(CG3703), a TRH analog, ameliorates scopolamine-induced memory disruption in rats

The effects of a metabolically stable TRH analog, N-[[(3R, 6R)-6-methyl-5-oxo-3-thiomorpholinyl]carbonyl]-L-histidyl-L- prolinamide tetrahydrate (NS-3, CG3703) on the scopolamine-induced memory disruption in maze performance tests were investigated in rats. a) In the delayed nonmatching-to-sample (DNMS) task using a T-maze, NS-3 (0.3 mg/kg) produced a significant reversal of the marginal disruption of choice accuracy induced by scopolamine (0.3 mg/kg) at the short (5 s) and long (120, 480 s) interval delays. Physostigmine (0.5 mg/kg) produced a significant reversal only at a 5-s interval delay. b) In the eight-arm radial maze task, NS-3 (0.3 mg/kg) significantly reversed the deficit of choice accuracy induced by scopolamine (0.3 mg/kg), whereas neither TRH (3-30 mg/kg) nor physostigmine (0.1-1 mg/kg) had any effect. The consistent reversal of these maze-learning performances by NS-3, but not by TRH or physostigmine, may be due to its potent enhancement of cholinergic and noradrenergic neuronal activities.

Genetic and clinical correlates of season of birth of schizophrenics

The genetic and clinical characteristics of 55 patients with schizophrenia and 138 control patients (with major psychiatric disorders), were studied in relation to the season of birth. The morbid risk (MR) of schizophrenia was significantly higher among relatives of the schizophrenic probands born in Spring than among those of the psychiatric controls born in the same season. The MR of schizophrenia was also significantly higher among relatives of schizophrenic probands born in Winter or Spring (6.9%) than in those of schizophrenic probands born in Summer or Autumn (0%). Among the schizophrenic cases, Winter births were marginally related to the paranoid subtype, whereas other clinical variables showed no clear relationship with the season of birth.

Involvement of benzodiazepine/GABA-A receptor complex in ethanol-induced state-dependent learning in rats

State-dependent learning (SDL) induced by ethanol (EtOH) was investigated on the step-through passive avoidance task in rats. Pretraining injection of EtOH dose-dependently reduced step-through latency in the test session 24 h after the training. Injection of EtOH (1.0 g/kg) before both the training and test sessions, however, failed to reduce the latency. These results show that EtOH produces SDL. The failure of learning performance in SDL (dissociation in SDL) induced by EtOH was blocked by bicuculline, Ro15-4513 and picrotoxin injected before the training session. The success of learning performance in SDL (non-dissociation in SDL) induced by EtOH was also blocked by bicuculline, Ro15-4513 and picrotoxin injected before the test session. The antagonism of Ro15-4513 against EtOH was blocked by flumazenil. In the substitution test, pretest injection of EtOH produced non-dissociation in SDL in the both of pretraining diazepam-and muscimol-treated rats. On the other hand, neither pretest injection of diazepam nor muscimol produced non-dissociation in the pretraining EtOH-treated rats: asymmetrical cross-substitution between EtOH and diazepam and between EtOH and muscimol was observed. These results suggest that the EtOH-induced SDL is partially mediated by the benzodiazepine (BDZ)/GABA-A receptor complex.

In Situ Detection of Surface SiH(n) in Synchrotron-Radiation-Induced Chemical Vapor Deposition of a-Si on an SiO(2) Substrate

The sensitivity and linearity of infrared reflection absorption spectroscopy (IRAS) has been significantly improved by using a buried-metal-layer (BML) substrate having an SiO(2)(15 nm)/Al(200 nm)/Si(100) structure, instead of a plain Si(100) substrate. By applying this BML-IRAS technique to the in situ observation of synchrotron-radiation-induced chemical vapor deposition of amorphous Si (a-Si) on an SiO(2) surface using Si(2)H(6) gas, the vibrational spectra of surface SiH(n) species in this reaction system have been observed for the first time with sufficient sensitivity for submonolayer coverage. The main silicon hydride species after deposition at 423 K are surface SiH(2) and SiH. Surface SiH(3) and SiH(2) are observed to be easily decomposed by synchrotron radiation irradiation. The decomposition rate of SiH by synchrotron radiation irradiation is much slower than those of SiH(2) and SiH(3).

m-calpain in rat growth plate chondrocyte cultures: its involvement in the matrix mineralization process

m-Calpain, a Ca(2+)-dependent neutral cysteine proteinase (EC 3.4.22.17), has been demonstrated to be present in the lower hypertrophic zone of the rat growth plate. Using the pelleted culture system as an in vitro model of rat epiphyseal chondrocyte differentiation, we studied m-calpain contents and activities in pelleted cultures during chondrocyte differentiation and the role of m-calpain in the mineralization process. m-Calpain was demonstrated immunohistochemically in epiphyseal chondrocytes, and immunoreactive m-calpain content in cells increased with terminal differentiation into hypertrophic cells. Immunoblotting also showed the association of the increase in m-calpain in cell pellets and in cell culture medium with development of the culture. Ca(2+)-dependent caseinolytic activities of m-calpain extracted from cell pellets and from the medium increased with chondrocyte differentiation, coincident with the increase in enzyme content. The inhibition of m-calpain by the addition of calpastatin, a specific inhibitor of calpain, caused suppression of matrix mineralization in pelleted cultures; the addition of E-64c, a specific inhibitor of cysteine proteinases, during the mineralization stage also caused a significant inhibition of the matrix mineralization. The addition of E-64c resulted in altered composition of proteoglycan monomers and aggregates in cell pellets and in suppression of mineral growth. These findings support an important role of cysteine proteinases, especially m-calpain, in the regulation of the cartilage mineralization process through proteoglycan degradation.

Angiotensin I-converting enzyme gene polymorphism is associated with myocardial infarction, but not with retinopathy or nephropathy, in NIDDM

OBJECTIVE

To clarify the relationship between the angiotensin I-converting enzyme (ACE) gene polymorphism and diabetic micro- and macroangiopathy in patients with non-insulin-dependent diabetes mellitus (NIDDM).

RESEARCH DESIGN AND METHODS

We examined 267 NIDDM patients with various stages of diabetic retinopathy, 61 patients with myocardial infarction (MI), and 136 patients without MI. An insertion/deletion polymorphism of the ACE gene was typed by polymerase chain reaction.

RESULTS

Although no association was found between ACE gene polymorphism and diabetic retinopathy or nephropathy, this polymorphism was associated with MI in the patients with NIDDM. Homozygotes for the deletion polymorphism (DD genotype) were found more frequently in diabetic patients with MI (31.1%) than in diabetic patients without ischemic heart disease (16.9%), with a relative risk of 2.22 (95% confidence interval 1.11-4.46, P = 0.024).

CONCLUSION

These data indicate that ACE gene polymorphism is associated with MI, but not with retinopathy or nephropathy, in patients with NIDDM and suggest that the ACE gene confers susceptibility to diabetic macroangiopathy but not to microangiopathy.

Fetal pancreas transplantation in miniature swine. V. The functional and immunodulatory effects of ultraviolet light on fetal pig islets

We have used the pig as a large animal model for studies of fetal pancreas transplantation. Fetal pig pancreas (FPP) has also been proposed as a potential source of endocrine cells for the treatment of diabetes mellitus. Among the approaches to prevent rejection, the irradiation of donor islets with ultraviolet B light has been used for its immunomodulating properties. Our goal was to study in vitro the effects of UV-B irradiation of FPP on the function and immunogenicity of the tissue. FPP were collagenase-digested and cultured for 1-29 days prior to UV-B irradiation. Static incubation tests were used to measure glucose-theophylline stimulated insulin release. Data obtained at 300 J/m2 revealed no impairment of insulin release (78% to 129% of controls, P = ns). At 500 J/m2, a significant reduction of glucose-theophylline stimulated insulin release was observed with 50-60-day-old FPP (35% to 66% of controls, P < 0.05), but not with 80-day-old FPP (93% of controls, P = ns). At both doses, prolonged observation in culture did not show any alteration of the growth and proliferation of islet cell clusters. UV-irradiated (300 J/m2) adult and fetal pig islet allografts released C-peptide and survived > 200 days. The immunogenicity of irradiated tissues was determined in vitro with allogeneic mixed islet-lymphocyte cultures (MILC). Proliferative responses of allogeneic lymphocytes to UV-irradiated FPP were very significantly decreased by 52-91% at both 300 and 500 J/m2 doses. This effect was observed from 1 to 10 days following UV irradiation and was not modulated by exposure of the tissues to gamma-interferon. We conclude that UVB-irradiation of FPP at a dose of 300 J/m2 does not alter its endocrine function and growth and is effective in reducing tissue immunogenicity. This treatment may be a useful approach for fetal islet transplantation in large animal models.

Involvement of cholinergic systems in the deficit of place learning in Morris water maze task induced by baclofen in rats

Effects of oxotremorine on the deficit of place learning in the Morris water maze task induced by baclofen and scopolamine were examined to determine the involvement of brain cholinergic systems in the deficit of learning induced by baclofen. Rats were given 4 training trials per day with the submerged platform at a fixed location in the maze for 4 days. On day 4, rats were required to swim in the pool without the platform after the 4th training trial (probe test). Baclofen as well as scopolamine dose-dependently increased the escape latency in the training trials. In the probe test, baclofen as well as scopolamine dose-dependently reduced the duration in the quadrant where the platform had been originally located. Increased latency in the training trials and reduced duration in the probe test induced by scopolamine were dose-dependently attenuated by oxotremorine. Increased latency and reduced duration in the baclofen-treated rats were improved by oxotremorine as well as 2-hydroxysaclofen. Baclofen but not scopolamine induced motor incoordination in the rotarod test. Oxotremorine failed to improve motor incoordination induced by baclofen. These results suggest that cholinergic systems may be involved in the deficit of place learning induced by baclofen, and that the ameliorative effects of oxotremorine may not be due to improvement of motor incoordination.

Activation of Stat5 by interleukin 2 requires a carboxyl-terminal region of the interleukin 2 receptor beta chain but is not essential for the proliferative signal transmission

The high-affinity interleukin 2 (IL-2) receptor (IL-2R) consists of three subunits: the IL-2R alpha, IL-2R beta c, and IL-2R gamma c chains. Two members of the Janus kinase family, Jak1 and Jak3, are associated with IL-2R beta c and IL-2R gamma c, respectively, and they are activated upon IL-2 stimulation. The cytokine-mediated Jak kinase activation usually results in the activation of a family of latent transcription factors termed Stat (signal transducer and activator of transcription) proteins. Recently, the IL-2-induced Stat protein was purified from human lymphocytes and found to be the homologue of sheep Stat5/mammary gland factor. We demonstrate that the human Stat5 is activated by IL-2 and that Jak3 is required for the efficient activation. The cytoplasmic region of the IL-2R beta c chain required for activation of Stat5 is mapped within the carboxyl-terminal 147 amino acids. On the other hand, this region is not essential for IL-2-induced cell proliferation.

Preferential formation of the hydroperoxide of linoleic acid in choline glycerophospholipids in human erythrocytes membrane during peroxidation with an azo initiator

The formation of phospholipid hydroperoxides was monitored in human red blood cell (RBC) membranes that had been peroxidized with an azo initiator. Peroxidation of RBC membranes caused a profound decrease in the amount of polyunsaturated fatty acids and concomitantly hydroperoxides, as primary products of peroxidation, appeared in the phospholipids. Hydroperoxides were predominantly generated in choline glycerophospholipid (CGP), while the extent of formation of ethanolamine glycerophospholipid (EGP) hydroperoxides was low and their presence was transient. Hydroxy and hydroperoxy moieties in CGP were identified as 9-hydroxy and 13-hydroxy octadecanoic acid, derived from linoleic acid, by gas chromatography-mass spectrometric analysis. No consistent generation of hydroperoxide from arachidonic acid was evident in CGP. The CGP-hydroperoxide accounted for approximately 76% of linoleic acid consumed during peroxidation of RBC membranes. The prominent generation of phospholipid hydroperoxides was observed in the linoleic acid-rich membranes from rabbit RBC, indicating that the level of linoleic acid in phospholipids determines, in part, the extent of formation of phospholipid hydroperoxides. Aldehydic phospholipids, as secondary products of peroxidation, were detected in oxidized membranes. EGP was the most prominent aldehydic phospholipid, while negligible amounts of aldehydic CGP were formed. This study indicates that the process of oxidation of individual phospholipids clearly differs among phospholipids and depends on the structure of each.