Circadian rhythm of autonomic activity in patients with obstructive sleep apnea syndrome

BACKGROUND AND HYPOTHESIS

Although the immediate effects of sleep apnea on hemodynamics and the neurological system have been studied, little is known about the circadian rhythm of heart rate variability in patients with obstructive sleep apnea syndrome (OSAS). The purpose of the present study was to investigate the effects of sleep apnea on the autonomic activity during daytime, which may play some role in the pathogenesis of cardiovascular complications in OSAS.

METHODS

We studied 18 middle-aged male patients with OSAS and 10 age-matched control subjects. Patients with OSAS were classified according to the severity of OSAS: patients with an apnea index (AI) < 20 were considered to have mild OSAS (Group 1, n = 8) and patients with an AI > or = 20 were considered to have severe OSAS (Group 2, n = 10). Heart rate variability was calculated from the 24-h ambulatory electrocardiograms by the Fourier transformation. Power spectra were quantified at 0.04-0.15 Hz [low frequency power (LF)ln(ms2)] and 0.15-0.40 Hz [high frequency power (HF)ln(ms2)]. The HF component and the ratio of LF to HF were used as indices of the parasympathetic and sympathetic activity, respectively.

RESULTS

The circadian rhythms of the LF, HF, and LF/HF ratio differed significantly in Group 2 compared with Group 1 and control subjects (p < 0.05). Hypertension (> 160/95 mm Hg) was found in 7 (70.0%) of 10 patients in Group 2, and in 1 (12.5%) of 8 patients in Group 1. Echocardiographic evidence of left ventricular hypertrophy (LVH) (an interventricular septal thickness or a left ventricular posterior wall thickness > or = 12 mm) was found in 3 (30.0%) of 10 patients in Group 2, and in 1 (12.5%) of 8 patients in Group 1. The mean HF from 4 A.M. to 12 noon was significantly lower in Group 2 than in Group 1 and the control group, and it correlated significantly with the lowest nocturnal SaO2 (r = 0.58, p < 0.05). The mean LF/HF ratio during the same period was significantly higher in Group 2 than in Group 1 and the control group, and it correlated significantly with total time of the nocturnal oxygen saturation < 90% (r = 0.64, p < 0.005) and the lowest nocturnal SaO2 (r = 0.56, p < 0.05). Ventricular tachycardia was found in the early morning in one patient, ST-T depression in two patients, and sinus arrest in two patients in Group 2.

CONCLUSION

These findings suggest that sleep-disordered breathing associated with severe oxygen desaturation might influence heart rate variability not only during sleep but also during daytime. OSAS per se might contribute to altered circadian rhythm in autonomic activity leading to the development of cardiovascular diseases.

Differences in arousal response between aged and middle-aged patients with obstructive sleep apnea syndrome

The aim of this study is to show the clinical significance of the differences in arousal response at a termination of apnea/hypopnea between aged and middle-aged patients with obstructive sleep apnea syndrome (OSAS). We polygraphically assessed electrocardiographic (ECG) and electroencephalographic (EEG) arousal. Electrocardiographic arousal was defined as an abrupt increase in heart rate at a termination of apnea/hypopnea. Our findings showed that EEG and ECG arousal at a termination of apnea/hypopnea were significantly suppressed in aged patients with OSAS, which might provide useful information on the pathophysiology, of OSAS.

Daytime sleepiness and automobile accidents in patients with obstructive sleep apnea syndrome

We evaluated the rate of automobile accidents and daytime sleepiness using the Epworth sleepiness scale (ESS) in 44 patients with obstructive sleep apnea syndrome (OSAS). We defined the automobile accident score as a sum of two points for every one automobile accident and one point for every near-miss accident. Automobile accidents and near-misses were found in 54.5% and 50.0% in patients with OSAS. Automobile accident score was significantly correlated with the ESS score (r=0.56, P < 0.01). Our findings suggest that ESS score may be useful in detecting patients with the potential risk of automobile accidents associated with daytime sleepiness.

Induction of convulsive seizures by acoustic priming in a new genetically defined model of epilepsy (Noda epileptic rat: NER)

Noda epileptic rat (NER) is a mutant rat, found in a Crj: Wistar colony, which exhibits a tonic clonic convulsion spontaneously about once per 30 h from 14 weeks of age. We performed modified acoustic priming, that is, repeated weekly sound stimulations from 3 weeks of age. In addition, characteristics of audiogenic seizure (AGS), and ictal/interictal electroencephalograms (EEGs) were examined. We also studied the effect of repeated weekly stimulations from 14 weeks of age on AGS susceptibility in another NER. From 9 weeks of age, the NER primed from 3 weeks of age had a high incidence (100%) of AGS: a typical seizure was composed of sudden wild running and/or jumping (WRJ) followed by clonic or tonic-clonic convulsion. The severity and the duration of the AGS were intensified and prolonged with an increase in age, respectively. By contrast, the NER repeatedly stimulated from the age of 14 weeks, rarely showed AGS (20-40(%). The majority of the seizures in this NER were WRJ. The cortical and hippocampal EEG during the tonic convulsion showed a low-voltage spike-wave (5-7 Hz). This evolved into a high-amplitude spike- or polyspike-waves associated with the clonic convulsion. Immediately after cessation of the seizures, the EEG showed a flattening or diffuse slowing. In interictal EEG analysis, sporadic spikes predominantly in the hippocampus and spike-wave bursts in both the cortex and hippocampus occurred from 11 and 20 weeks of age, respectively. These results indicate that AGS susceptibility in NER can be induced consistently by modified acoustic priming and this rat strain is a new genetic model useful for experimental studies of human epilepsy.

Participation of P450-dependent oxidation of isoniazid in isonicotinic acid formation in rat liver

By determining the formation amount of isonicotinic acid (INA) from isonicotinic acid hydrazide (isoniazid:INH) in isolated rat hepatocytes, we were able to identify the involvement of the oxidative cleavage of the acid hydrazide. INA formation from INH increased significantly using the isolated hepatocytes prepared from rats pretreated with phenobarbital (PB), 3-methylcholanthrene (3MC), dexamethazone (DEX) and rifampicin (RIF), respectively, in comparison to the control group. On the other hand, a remarkable decrease in INA formation from INH was observed by the addition of such P450 inhibitor as metyrapone or cimetidine as well as an amidase inhibitor bis(p-nitrophenyl)phosphate (BNPP) to the isolated hepatocytes prepared from PB-pretreated rats. By further experiments using rat hepatic microsomes, the oxidative pathway of INA formation in INH metabolism was determined to be P450-dependent, since NADPH and oxygen were both essential for the oxidative pathway of INH to INA and the amount of INA formation was also significantly increased by P450 inducers. Regarding acetylisoniazid (AcINH) and isonicotinic acid amide (INAA), however, INA formation by P450 was little observed in the microsomal experiments.

A fatal Pegosomum sp. (Trematoda: Echinostomatidae) infection in a wild cattle egret (Bubulcus ibis) from Japan

An adult cattle egret (Bubulcus ibis) caught in Kobe of Hyogo Prefecture, Japan, in December 1995 died of a severe infection associated with the trematode parasite Pegosomum sp. At necropsy, 22 trematode parasites were found in the lumen of the bile duct, and the duct wall was markedly thickened. Histopathologically, severe cholangitis and cholecystitis were observed in close association with the parasites in the bile duct. Severe Pegosomum sp. infection may be one of the factors contributing to the mortality of wild cattle egrets. This is the first reported case of the genus Pegosomum infection in wild birds of Japan.

Prognosis of the middle-aged and aged patients with obstructive sleep apnea syndrome

The long-term natural course of obstructive sleep apnea syndrome (OSAS) is studied in order to determine whether severity of nocturnal oxygen desaturation associated with apnea/hypopnea, body mass index (BMI), and hypertension influence survival in young (<40 years), middle-aged (40-64 years), and aged (> or = 65 years) using a questionnaire survey. One hundred and forty-eight patients with OSAS aged 17-78 years (136 men, 12 women, mean 52.0+/-12.3 years), who were diagnosed by standard polysomnography (PSG) between 1983 and 1993, participated in the study. The survey revealed 15 deaths and 101 survivors; 32 subjects could not be located. The survival rate was 71.4% (95% confidence interval: 55.6-87.2%). The survival rate in patients with OSAS was significantly lower than that in the age and sex-adjusted control Japanese population (87.6%). In the young group, only one death (a 19-year-old woman) occurred unexpectedly during sleep. The patient showed an apnea/hypopnea index (AHI) of 33 per h and the length of time that the nocturnal oxygen saturation (SaO2) fell below 90% (time of SaO2 <90%) of 205 min. The survival rate in middle-aged patients with OSAS was significantly lower than that in the age and sex-adjusted control Japanese population (79.2 vs 91.0%), but this pattern was not seen among the aged. Time of SaO2 <90% was significantly longer in the middle-aged patients than in the aged patients, but AHI did not differ between the two groups. Moreover, it was significantly correlated with AHI in middle-aged patients, but not in the aged patients. The survival rate was significantly lower in patients with hypertension than in the patients without such complications in the middle-aged group (57.9 vs 90.4%). Cox proportional-hazard regression model including age, hypertension, BMI, AHI, lowest SaO2, and time of SaO2 <90% showed that hypertension was only significantly associated with lower survival rate in total group and middle-aged patients, but not in the young or aged patients. The prognosis in patients with OSAS may differ among the generations. The prognosis in the middle-aged population may depend on the role of OSAS on the complications of hypertension or severity of oxygen desaturation, but not on AHI only.

Inhibition of growth of human vascular smooth muscle cells by overexpression of p21 gene through induction of apoptosis

The senescent cell-derived inhibitor (sdi)-1 protein (p21 product) has been identified as a downstream mediator of the tumor suppressor p53 in the regulation of cell cycle progression through a G1 phase checkpoint. Given the importance of cell cycle inhibition for the treatment of restenosis, in this study we focused on the function of p21 gene in inhibiting proliferation of vascular smooth muscle cells (VSMC). To test the hypothesis, we transfected human p21 gene into human aortic VSMC using hemagglutinating virus of Japan-liposome-mediated transfer. Initially, we examined the successful transfection of human p21 gene into VSMC. p21 protein was increased in VSMC transfected with p21 vector as compared with control vector. Accompanied by increased p21 protein, transfection of p21 vector resulted in a significant decrease in number of VSMC induced by 2% serum (P<.01). Although p21 has been reported to play an important role in the regulation of apoptosis in some cells, apoptosis mediated by p21 is still controversial. Therefore, we hypothesized that overexpression of p21 mediates apoptosis in human VSMC, in addition to the blockade of cell cycle progression. First, we assessed the concordance between morphologic analysis and apoptosis as determined by nuclear staining with Hoechst 33342. Cells transfected with p21 gene exhibited the characteristic features of cell shrinkage, membrane blebbing, and rounding that are typical of apoptotic death. Of greater interest, a significant increase in apoptotic cells was observed in VSMC transfected with p21 vector as compared with control vector (P<.01). These results were confirmed by the measurement of DNA fragmentation. Consistent with nuclear staining, DNA fragmentation in VSMC transfected with human p21 gene was significantly increased as compared with that in VSMC transfected with control vector (P<.05). To study the molecular mechanisms of apoptosis mediated by overexpression of p21 gene, the protein levels of bax, a promoter of apoptosis, and bcl-2, an inhibitor of apoptosis, were also measured by Western blotting. Overexpression of p21 gene significantly increased protein of bax (P<.05), whereas transfection of p21 gene did not alter bcl-2 protein. Importantly, the ratio of bax to bcl-2 was significantly increased in VSMC transfected with human p21 vector as compared with control vector (P<.05). Overall, these results demonstrated that inhibition of VSMC growth by overexpression of human p21 gene was accompanied by induction of apoptosis through an inappropriate increase in bax protein. These results suggest that regulation of cell cycle by p21 may be closely linked to programmed cell death/apoptosis in human VSMC.

Detection of immunoglobulin G and A antibodies to rubella virus in urine and antibody responses to vaccine-induced infection

Urine and serum samples from 89 healthy volunteers and three healthy individuals who underwent rubella vaccination were tested for immunoglobulin G (IgG), IgA, and IgM to rubella virus (RV) by enzyme-linked immunosorbent assay methods. Subjects with positive (n = 68) or negative (n = 21) results for serum IgG were exactly the same as those with the corresponding results for urinary IgG. Both urinary and serum IgG levels remained elevated from the 3rd or 4th week after vaccination until the end of the study. Both urinary IgA and serum IgM levels tended to increase rapidly between the 3rd and 5th week and then gradually decrease until the end of the study, but the levels of both remained positive except for one sample each at the end (26th week). On the other hand, the ratio of anti-RV IgA titer to anti-RV IgG titer in urine (urinary anti-RV IgA/IgG ratio) increased rapidly between the 3rd and 4th week after vaccination and then rapidly returned to the ratio levels of the subjects positive for serum IgG from among the healthy volunteers. In summary, detection of urinary anti-RV IgG should be useful for screening for previous RV infection, and measurement of urinary anti-RV IgA/IgG ratio might be useful for diagnosing recent infection.

NER rat strain: a new type of genetic model in epilepsy research

PURPOSE

We characterized and evaluated as an animal model of epilepsy NER, a new epileptic rat strain, which was developed by inbreeding rats with spontaneous tonic-clonic seizures in a stock of Crj:Wistar.

METHODS

Animals were monitored through the inbreeding course, and video-EEGs were recorded selectively. External seizure-provoking stimuli were applied to NER and to a control parental strain. F1, F2, and backcross progenies were produced between NER and a nonepileptic unrelated strain. Pathologic study included hematoxylin-and-eosin (HE), Klüver-Barrera's, modified Bodian silver, and neo-Timm's staining.

RESULTS

After the F9 generation, 94%-98% of NER exhibited spontaneous tonic-clonic convulsions, beginning with neck and forelimb clonus, wild jumping/running, opisthotonic posturing, and evolving to tonic, then clonic convulsion, followed by postictal flaccidity. Most seizure onsets occurred between 2-4 months of age, and the incidence was 0.45 +/- 0.21 seizures in 12 h. Ictal cortical and hippocampal EEGs were characterized by high-voltage spikes followed by diffuse spike-and-wave or polyspike-and-wave complexes. NER revealed seizure susceptibility to pentylenetetrazol, tossing, and transcorneal electroshock, but not to tactile, photic, or acoustic stimuli, or to transauricular electroshock. Mating experiments revealed that 0% (0/46) of the animals in F1, 25.5% (13/51) in F2, and 63.6% (56/88) in backcross progenies exhibited spontaneous tonic-clonic convulsions without sex difference. For all these epileptic traits, no pathologic changes were demonstrated in the CNS.

CONCLUSIONS

NER frequently exhibited spontaneous convulsions, controlled by a major autosomal recessive gene for epilepsy, that are comparable to generalized tonic-clonic seizures in humans. This can serve as a new genetic model in epilepsy research.

Advanced gastric carcinoma in a de Brazza's guenon (Cercopithecus neglectus)

A necropsy case of advanced gastric carcinoma in a 20-year-old female de Brazza's guenon (Cercopithecus neglectus) was studied, Grossly, an excavated carcinoma mass, 60 x 55 x 35 mm in size, was located in the cardiac region of the stomach. Multiple disseminated nodules had implanted on the diaphragm and omentum. The tumor consisted of intestinal-type adenocarcinoma cells and showed infiltrative growth beyond the serosa. The morphologic features of this tumor closely resembled those of advanced gastric carcinomas in human patients.

Nitric oxide metabolites in the cisternal cerebral spinal fluid of patients with subarachnoid hemorrhage

OBJECTIVE

To investigate nitric oxide (NO) metabolism after subarachnoid hemorrhage (SAH).

METHODS

We measured the concentrations of the NO metabolites, nitrite and nitrate, in cerebrospinal fluid (CSF) obtained from the cisternal drainage of patients with SAH. Studies were performed for 31 patients who had undergone surgical obliteration of bleeding aneurysms within 3 days of their hemorrhage. The concentrations of nitrite and nitrate in the CSF were measured for 14 days using a nitrate/nitrite kit and samples that were obtained on a daily basis from the cisternal drainage.

RESULTS

Compared with the control values in the CSF (2.6 +/- 0.4 mumol/L, n = 14) obtained from patients with hemifacial spasm, trigeminal neuralgia, or nonruptured aneurysms, the concentrations of nitrite and nitrate in the CSF were significantly elevated in the acute stage of SAH and remained elevated. The concentration of NO metabolites may correlate with the amount of bleeding, inasmuch as the values in patients in Fisher Group 3 (n = 25) were higher than those in patients in Fisher Group 2 (n = 6). The concentration of nitrate was higher than that of nitrite, suggesting that NO in the subarachnoid space is mainly absorbed by hemoglobin and degraded to nitrate. No differences were demonstrated in patients treated with high doses of methylprednisolone (n = 17) compared with those treated with usual-dose steroids (n = 14). Steroids are known to prevent the formation of inducible NO synthase mediated by inflammatory cytokines.

CONCLUSION

NO metabolism in the brain is stimulated after SAH. Nitrate is the dominant NO metabolite in CSF after SAH. The involvement of inducible NO synthase in the pathophysiology of NO metabolism after SAH was not clearly suggested based on the present data.

[Evaluation of electrocardiographic left ventricular hypertrophy with both QRS voltage and ST-T change using echocardiography]

The purpose of the present study is to determine whether electrocardiographic QRS voltage criteria with ST-T change is useful in the diagnosis of left ventricular hypertrophy (LVH) using echocardiography. One hundred men including 59 with hypertension (HT), 9 with hypertrophic cardiomyopathy (HCM), and 32 without any cardiovascular disease were enrolled in this study. All of them had the electrocardiographic evidence of LVH by Sokolow-Lyon voltage criteria (RV5 or RV6 > 2.6 mV, SV1+RV5 or SV1+RV6 > or = 3.5 mV). They were classified into three groups based on ST-T pattern as follows: Normal ST-T (group N): normal ST-T in twelve leads; Early strain ST-T (group ES): ST depression, flat T (T/R < 1/10), diphasic T or T wave inversion < 0.1 mV in V5 or V6; and Strain ST-T (group S): inverted T wave in V5 and V6. Echocardiographic LVH was determined when either interventricular septal thickness (IVST) or left ventricular posterior wall thickness (LVPWT) > or = 12 mm was present. According to this echocardiographic evidence, 31.7%(20/63) of group N, 75.0% (12/16) of group ES, and 100% (21/21) of group S were diagnosed. There were significant correlations between QRS voltage indices (RV5, RV6, SV1+RV5 and SV1+RV6) and IVST, (IVST+LVPWT)/2, and LV mass in group S(r = 0.650 to 0.858, p < 0.05) but not in group N. Values for IVST and LV mass were significantly greater in group S than in group ES or N. The electrocardiographic diagnosis of LVH with both QRS voltage and ST-T change thus appeared to be more useful than that with QRS voltage criteria alone.

Identification of core B cell epitope in the synthetic peptide inducing cross-inhibiting antibodies to a surface protein antigen of Streptococcus mutans

A surface protein antigen (PAc) of Streptococcus mutans, in particular, A-region of the molecule, has been considered as a possible target for the development of an effective anticaries vaccine. This region might be implicated in the induction of dental caries via interaction with salivary components. We have recently specified a unique peptide, TYEAALKQYEADL, as one of the minimum peptides that completely corresponds to the amino acid sequence of a part of the A-region. The unique peptide contains both T and B cell epitopes for the induction of cross-reacting antibodies to the PAc. In this study, we synthesized valine or glycine-substituted peptide analogs of this peptide and examined core B cell epitopes of this unique peptide by using ELISA inhibition assay. As a result, the core amino acid residues of -Y------Y---- for B cell recognition were found to likely be not only important amino acids stabilizing the structure, but also might be essential for induction of the cross-inhibiting antibodies against PAc. These results will hopefully provide us with useful information for the design of an effective anticaries peptide vaccine.

[Mitral valve prolapse and autonomic activity in normal women]

We examined relationships between mitral valve prolapse (MVP) and circadian rhythm of autonomic activity using spectral analysis of heart rate variability and echocardiography in 31 normal women. The heart rate variability was calculated from 24-hour ambulatory electrocardiogram by Fourier transformation. The power spectra were quantified at 0.04-0.15 Hz (low frequency power (LF) 1n (ms2)) and 0.15-0.40 Hz (high frequency power (HF) 1n (ms2)). The HF component and the ratio of LF/HF were used as indices of parasympathetic and sympathetic activity, respectively. MVP was present in 22.6%. There were no significant differences in left ventricular dimension between subjects with MVP (group MVP (+)) and subjects without MVP (group MVP(-)). Number of ventricular premature contractions in group MVP(+) tend to be higher compared with that in group MVP(-). The level of high frequency power at 0-5 am in group MVP(+) was significantly higher than that in group MVP(-), which parasympathetic activity during sleep in MVP(+) group was higher compared with that in group MVP(-). The evaluation of autonomic activity using spectral analysis of heart rate variability for 24-hour ambulatory electrocardiogram might provide useful information about the pathology of MVP.

[A novel epilepsy animal model (NER)]

A mutant showing convulsive seizures spontaneously in a CJ: Wistar colony was named the Noda epileptic rat (NER). The NER exhibits tonic-clonic convulsion without any external stimuli once every 30 h. However, we succeeded in inducing similar convulsive seizures by applying priming sound stimuli (95 dB, 8 kHz, 30 sec) from 3 weeks of age in all 24 NER examined. When the effects of clinically available antiepileptics were tested on the seizures of such primed NER, the most potent agents were carbamazepine, diazepam, valproate, phenobarbital and trimethadione, while phenytoin and zonisamide showed lower potency. Furthermore, ethosuximide was not effective in inhibiting the seizures. In hippocampal slices of NER with convulsive seizures, repetitive firing accompanied by long-lasting depolarization was observed when a single stimulation was delivered to the mossy fibers in the CA3 pyramidal cell. This depolarization shift was completely blocked with a Ca2+ antagonist (nicardipine 10 nM). The long-lasting hyperpolarization that followed the repetitive firing was also observed with mossy fiber stimulation in the hippocampal CA3 pyramidal cells of the NER. These findings suggest that Ca2+ channel abnormality of the hippocampal CA3 pyramidal cells may be involved in the convulsive seizures.

Suppressed cardiac and electroencephalographic arousal on apnea/hypopnea termination in elderly patients with cerebral infarction

The goal of the present investigation is to show the clinical significance of arousal response at termination of apnea/hypopnea in patients with sleep apnea syndrome (SAS) after cerebral infarction. We polygraphically assessed "cardiac arousal," which is defined as an abrupt increase in heart rate at a termination of sleep apnea/hypopnea, and electroencephalographic (EEG) arousal. There were six elderly subjects, bedridden after cerebral infarction, with SAS aged 71-87 years (mean 72.3 years) and 11 age-matched patients with SAS aged 61-78 years (mean 62.3 years) as controls. The following sleep parameters were measured: number of apneas per hour (apnea index [AI]), number of hypopneas per hour (hypopnea index [HI]), summation of the two (apnea/hypopnea index [AHI]), and duration in which nocturnal oxygen saturation was decreased below 90% (duration of SaO2 < 90%). We calculated the ratio of apnea/hypopnea per hour with cardiac arousal to total apnea/hypopneas (XI) (% cardiac arousal [XI/AHI x 100]) and the ratio of that with EEG arousal (YI) (% EEG arousal [YI/AHI x 100]). Between the two groups, we found no significant difference in body mass index, the ratio of central apnea to total apnea/hypopnea, AHI, duration of apnea/hypopnea, lowest SaO2, and duration of SaO2 < 90%. Compared with controls, % cardiac and % EEG arousals were significantly lower in patients with cerebral infarction. In contrast, the ratio of HI to AHI was significantly higher in patients with cerebral infarction than in control subjects. Our findings indicate that cardiac and EEG arousals at termination of apnea/hypopnea are significantly suppressed in elderly patients with SAS after cerebral infarction, which may provide useful information on the pathophysiology of SAS in patients with cerebrovascular disease.

beta-Adrenoreceptor antagonistic actions and mutagenicities of R(+)- and S(-)-enantiomers of N-desisopropylpropranolol and its N-acetyl conjugate

Enantiospecific acetyl conjugation was examined in the rat liver 105000 x g supernatant (cytosol) system using racemic 1-amino-3-(1-naphthyloxy)-2-propanol (NDP), a N-desisopropyl metabolite of propranolol. From the results of chiral separative determination of the samples by HPLC using a Chiralcel OD-R column, more remarkable enantiospecificity was observed in the R(+)-enantiomer on NDP elimination and N-acetyl conjugate (AcNDP) formation. Next, the strength of beta-adrenoceptor antagonistic actions and mutagenicities was compared between R(+)- and S(-)-enantiomers of NDP and AcNDP, respectively. In the case of NDP, both enantiomers possessed weak beta1-adrenoceptor antagonistic effects on isoproterenol-induced positive inotropic and chronotropic actions in the left and right atria isolated from a guinea pig. These actions of R(+)- and S(-)-NDP were 1700-times and 100-times less potent, respectively, than those of propranolol. beta2-Adrenoceptor antagonistic actions of R(+)- and S(-)-NDP in the trachea were 1600-times and 200-times less potent, respectively, than those of propranolol. Enantiospecificity was observed in the beta-adrenoceptor antagonistic action of S(-)-NDP, while R(+)-NDP and both enantiomers of AcNDP appeared to be negligible in this action. On the other hand, the mutagenicities of each enantiomer were examined by the Ames method using 13 kinds of Salmonella typhimurium strains. In the case of AcNDP, the numbers of colonies increased according to the substrate concentration only when rat liver 9000 x g supernatant fraction (S-9 mixture) was added to the plates containing TA100, YG1029, TA104 and YG3003, and then enantiospecificity was observed in the mutagenicity of S(-)-AcNDP. Thus, the ultimate mutagen might be an active metabolite formed mainly from S(-)-AcNDP. Despite of the addition of rat liver S-9 mixture, R(+)-AcNDP and both enantiomers of NDP did not indicate mutagenicity.

Sites and types of UV-induced mutations leading to inactivation of the growth-arresting activity in p21 (sdi1/cip1/waf1) cDNA

The p53-regulated gene product p21 (sdi1,cip1,waf1) negatively regulates cell growth and has been suggested to be a potential tumour-suppressor gene. To determine the sites and types of mutations which inactivate the growth-arresting activity in sdi1 cDNA, plasmids containing sdi1 cDNA and the neomycin-resistant gene were irradiated with UV light and transfected into CHO cells. The UV irradiation increased number of the geneticin-resistant colonies which should have the UV-mutated sdi1 cDNA. Sdi1 mRNA was expressed in 23 out of 36 colonies (64%). In 13 sdi1 cDNA sequences analysed, mutations were found at codon 46 in nine cDNAs, and one each at codons 34, 54, 66 and 73. All the mutation sites are in the CDK-binding region. Ten mutations (77%) (codons 46 and 66) are C to T transition mutation at the dipyrimidine sequences, which is the major type of the UV-induced mutation.

Does the cell wall skeleton from Bacille Calmette-Guérin directly induce interferon-gamma, independent of interleukin-12?

Interleukin-12 (IL-12), known to be a strong inducer of interferon-gamma (IFN-gamma), plays a vital role in activating the immune surveillance system against intracellular pathogens and malignant tumors. The authors have found that cancer patients showing marked IFN-gamma induction after inoculation with BCG-CWS (the cell wall skeleton from Bacille Calmette-Guérin) have a good prognosis. The present study was undertaken to determine whether the level of IL-12 is increased prior to, or along with, IFN-gamma induction in the serum of patients inoculated with BCG-CWS. Unexpectedly, we found no detectable amount of IL-12 in the serum throughout the entire time course. This suggests that a novel IFN-gamma inducing factor (IGIF) or another unknown IFN-gamma inducer may be working in place of IL-12 in the BCG-CWS system.

Chiral separation of 10,11-dihydro-10, 11-trans-dihydroxycarbamazepine, a metabolite of carbamazepine with two asymmetric carbons, in human serum

Chiral separation of 10, 11-dihydro-10, 11-trans-dihydroxycarbamazepine (CBZ-diol), a metabolite of carbamazepine (CBZ) with two asymmetric carbons, in serum taken from epileptic patients receiving CBZ alone for a long period, was performed by high-performance liquid chromatography using a polysaccharide stationary phase with n-hexane-ethanol (75:25, v/v) as the mobile phase. The enantiomeric ratio (S,S-/R,R-CBZ-diol) was 10.74 +/- 1.13 (mean +/- S.D.), which could demonstrate the presence of the stereospecificity in the hydrolysis of 10, 11-dihydro-10, 11-epoxycarbamazepine (CBZ-epoxide) to CBZ-diol and/or in the conversion of CBZ-diol to some metabolite such as 9-hydroxymethyl-10-carbamoylacridan. This is the first paper to report the determination of each enantiomer and the enantiomeric ratio of CBZ-diol in serum of epileptic patients who received CBZ.

Determination of isonicotinic acid in the presence of isoniazid and acetylisoniazid. Studies on isonicotinic acid formation from isoniazid in isolated rat hepatocytes

In comparison with the hepatocytes obtained from intact rats and rats pretreated with phenobarbital or 3-methylchoranthrene, the amount of isonicotinic acid (INA) formed from isoniazid (INH) increased substantially after incubation at 37 degrees C using the pretreated hepatocytes. This suggests an oxidative pathway for INA formation from INH, apart from hydrolysis. In order to explore the exact mechanism of INA formation in the hepatocytes, an HPLC assay for INA in the presence of INH and acetylisoniazid was developed. In this assay, INA was extracted after the preparation of an ion pair with tetra-n-butylammonium hydroxide, and analysed using an ODS column and a mobile phase consisting of 0.067 M potassium dihydrogenphosphate solution-methanol (96:4, v/v). The method is simple, accurate and especially suitable for INA determination after incubation of INH in isolated rat hepatocytes.

Pancreatic calculi superimposed upon slow growing pancreatic cancer

We report on a 59 year old male patient with cancer of the head of the pancreas, upon which pancreatic calculi were superimposed during the 3 year clinical course. Pancreatic calculi were noted in the main pancreatic duct (MPD) on both computed tomographic scans and ultrasonographs of the abdomen approximately 10 months after the recognizable dilatation of the MPD. Existence of the calculi was confirmed by autopsy. Elemental analysis and infrared spectrophotometry of the calculi demonstrated that the main constituent of the calculi was calcium carbonate. Histopathological examination showed that the pancreatic cancer was moderately differentiated adenocarcinoma. Immunohistochemical studies revealed that pancreatic stone protein (lithostathine) was present in the cytoplasm of tumour cells. In this case, pancreatic cancer progressed to obstruct the MPD unusually slowly, resulting in stagnation of pancreatic secretion and subsequent formation of the calculi.