[NMR analysis of a contaminant in heparin]

Recently, it has been reported that certain lots of heparin are associated with an acute, rapid onset of serious side effects indicative of allergic reaction, and (1)H NMR is one of the convenience but strong analytical methods to identify a contaminant in heparin. However, an NMR signal from the contaminant in some cases is overlapped with a satellite peak from heparin, leading a misunderstanding of the presence of the contaminant. Here, we show the satellite peak observed close to the NMR signal of the contaminant, and recommend the (13)C decoupling NMR to discriminate the satellite peak from the contaminant.

Characterization of a proteolytic enzyme derived from a Bacillus strain that effectively degrades prion protein

AIMS

The purpose of this paper was to screen candidate bacterial strains for the production of proteases suitable for application to the degradation of pathogenic forms of prion protein (PrP(Sc)). This paper describes the biochemical characteristics and proteolytic activity of the isolated protease.

METHODS AND RESULTS

After screening more than 200 bacterial proteases for keratinolytic activity, we identified a Bacillus stain that produced a protease exhibiting high-degradation activity against a scrapie PrP(Sc). Sequence analysis indicated that this serine-protease belonged to the Subtilisin family and had optimum pH and temperature ranges of 9-10 and 60-70 degrees C. Western blotting analysis revealed that the protease was also capable of decomposing bovine spongiform encephalopathy-infected brain homogenate. In addition, the protease was demonstrated to degrade dried PrP(Sc) that had become firmly attached to a plastic surface considerably more effectively than proteinase K or PWD-1, a previously reported keratinase.

CONCLUSIONS

These results indicate that the isolated protease exhibited higher activity for PrP(Sc) degradation compared with other proteases examined.

SIGNIFICANCE AND IMPACT OF THE STUDY

This protease could be used under moderate conditions for the decontamination of precision instruments that are susceptible to PrP(Sc) contamination.

Species-specificity of a panel of prion protein antibodies for the immunohistochemical study of animal and human prion diseases

Monoclonal antibodies to the prion protein (PrP) have been of critical importance in the neuropathological characterization of PrP-related disease in men and animals. To determine the influence of species-specific amino-acid substitutions recognized by monoclonal antibodies, and to investigate the immunohistochemical reactivity of the latter, analyses were carried out on brain sections of cattle with bovine spongiform encephalopathy, sheep with scrapie, mice infected with scrapie, and human beings with Creutzfeldt-Jakob disease (CJD) or Gerstmann-Sträussler-Sheinker disease (GSS). Immunoreactivity varied between the antibodies, probably as the result of differences in the amino-acid sequence of the prion protein in the various species. Some monoclonal antibodies against mouse recombinant PrP gave strong signals with bovine, ovine and human PrP(Sc), in addition to murine PrP(Sc), even though the amino-acid sequences determined by the antibody epitope are not fully identical with the amino-acid sequences proper to the species. On the other hand, in certain regions of the PrP sequence, when the species-specificity of the antibodies is defined by one amino-acid substitution, the antibodies revealed no reactivity with other animal species. In the region corresponding to positions 134-159 of murine PrP, immunohistochemical reactivity or species-specificity recognized by the antibodies may be determined by one amino acid corresponding to position 144 of murine PrP. Not all epitopes recognized by a monoclonal antibody play an important role in antigen-antibody reactions in immunohistochemistry. The presence of the core epitope is therefore vital in understanding antibody binding ability.

Both host prion protein 131-188 subregion and prion strain characteristics regulate glycoform of PrP Sc

Prion proteins (PrPs) contain 2 N-linked glycosylation sites and are present in cells in 3 different forms. An abnormal isoform of prion protein (PrP(Sc)) has different glycoform patterns for different prion strains. However, the molecular basis of the strain-specific glycoform variability in prions has remained elusive. To understand the molecular basis of these glycoform differences, we analyzed PrP(Sc) in 2 lines of transgenic mice (MHM2 and MH2M with PrP null background) that expressed a chimeric PrP. Our result indicated that PrP 131-188 (substitutions at I139M, Y155N, and S170N) contributed to both PrP(C) and PrP(Sc) glycoform ratios. Furthermore, the PrP(Sc) glycoform pattern within these transgenic mice showed a subtle difference depending on the inoculated prion. This study indicated that the PrP(Sc) glycoform ratio was influenced by both host PrP(C) and the prion strain.

Specific detection of prion antigenic determinants retained in bovine meat and bone meal by flow microbead immunoassay

AIMS

The purpose of this study was to develop an effective method for detecting prion (PrP) antigenic determinants remaining in bovine meat and bone meal (MBM) using pressurized fluid extraction (PSE) equipment and flow microbead immunoassay (FMI).

METHODS AND RESULTS

Using the FMI, bovine recombinant PrP could be determined quantitatively in the 7 pmol-7 nmol range using anti-PrP peptide polyclonal antibody-coupled microbeads and anti-PrP monoclonal antibody (SAF61) as a detection antibody. PSE extraction at 120 degrees C for 5 min under high pressure was most effective for eluting PrP determinants from bovine MBMs. The FMI was capable of detecting PrP determinants in bovine MBM extracts with high specificity and indicated that the MBMs contained high levels of PrP determinants. This assay was also applied to the detection of PrP(Sc) determinants in bovine MBM spiked with a scrapie-infected brain at a weight ratio of 50 : 1.

CONCLUSIONS

These data indicate that this assay was effective for the specific detection of PrP determinants contained in bovine MBM extracts.

SIGNIFICANCE AND IMPACT OF THE STUDY

To our knowledge, this is the first report detailing the detection of PrP determinants in bovine MBM. The assay could be applied to securing the safety of bovine MBM.

Common carotid intima-media thickness is predictive of all-cause and cardiovascular mortality in elderly community-dwelling people: Longitudinal Investigation for the Longevity and Aging in Hokkaido County (LILAC) study

Several cohort studies have examined the association of carotid intima-media thickness (IMT) with the risk of stroke or myocardial infarction in apparently healthy persons. We investigated the predictive value of IMT of cardiovascular mortality in elderly community-dwelling people, beyond the prediction provided by age and MMSE, assessed by means of a multivariate Cox model. Carotid IMT and plaque were evaluated bilaterally with ultrasonography in 298 people older than 75 years (120 men and 178 women, average age: 79.6 years). The LILAC study started on July 25, 2000. Consultations were repeated every year. The follow-up ended on November 30, 2004. During the mean follow-up span of 1152 days, 30 subjects (21 men and nine women) died. Nine deaths were attributable to cardiovascular causes (myocardial infarction: two men and three women; stroke: two men and two women). The age- and MMSE-adjusted relative risk (RR) and 95% confidence interval (95% CI) of developing all-cause mortality was assessed. A 0.3 mm increase in left IMT was associated with a RR of predicted 1.647 (1.075-2.524), and a similar increase in right IMT with a RR of 3.327 (1.429-7.746). For cardiovascular mortality, the corresponding RR values were 2.351 (1.029-5.372) and 2.890 (1.059-7.891), respectively. Carotid IMT assessed by ultrasonography is positively associated with an increased risk of all-cause and cardiovascular death in elderly community-dwelling people.

Depressive mood is independently related to stroke and cardiovascular events in a community

By means of a multivariate Cox model, we investigated the predictive value of a depressive mood on vascular disease risk in middle-aged community-dwelling people. In 224 people (88 men and 136 women; mean age: 56.8 +/- 11.2 years) of U town, Hokkaido (latitude: 43.45 degrees N, longitude: 141.85 degrees E), a chronoecological health watch was started in April 2001. Consultations were repeated every 3 months. Results at the November 30, 2004 follow-up are presented herein. 7-day/24-h blood pressure (BP) and heart rate (HR) monitoring started on a Thursday, with readings taken at 30-min intervals between 07:00 h and 22:00 h and at 60-min intervals between 22:00 h and 07:00 h. Data stored in the memory of the monitor (TM-2430-15, A and D company, Japan) were retrieved and analyzed on a personal computer with a commercial software for this device. Subjects were asked to answer a self-administered questionnaire inquiring about 15 items of a depression scale, at the start of study and again after 1-2 years. Subjects with a score higher by at least two points at the second versus first screening were classified as having a depressive mood. The other subjects served as the control group. The mean follow-up time was 1064 days, during which four subjects suffered an adverse vascular outcome (myocardial infarction: one man and one woman; stroke: two men). Among the variables used in the Cox proportional hazard models, a depressive mood, assessed by the Geriatric Depression Scale (GDS), as well as the MESOR of diastolic (D) BP (DBP-MESOR) and the circadian amplitude of systolic (S) BP (SBP-Amplitude) showed a statistically significant association with the occurrence of adverse vascular outcomes. The GDS score during the second but not during the first session was statistically significantly associated with the adverse vascular outcome. In univariate analyses, the relative risk (RR) of developing outcomes was predicted by a three-point increase in the GDS scale (RR = 3.088, 95% CI: 1.375-6.935, P = 0.0063). Increases of 5 mmHg in DBP-MESOR and of 3 mmHg in SBP-Amplitude were associated with RRs of 2.143 (95% CI: 1.232-3.727, P = 0.0070) and 0.700 (95% CI: 0.495-0.989, P = 0.0430), respectively. In multivariate analyses, when both the second GDS score and the DBP-MESOR were used as continuous variables in the same model, GDS remained statistically significantly associated with the occurrence of cardiovascular death. After adjustment for DBP-MESOR, a three-point increase in GDS score was associated with a RR of 2.172 (95% CI: 1.123-4.200). Monday endpoints of the 7-day profile showed a statistically significant association with adverse vascular outcomes. A 5 mmHg increase in DBP on Monday was associated with a RR of 1.576 (95% CI: 1.011-2.457, P = 0.0446). The main result of the present study is that in middle-aged community-dwelling people, a depressive mood predicted the occurrence of vascular diseases beyond the prediction provided by age, gender, ABP, lifestyle and environmental conditions, as assessed by means of a multivariate Cox model. A depressive mood, especially enhanced for 1-2 years, was associated with adverse vascular outcomes. Results herein suggest the clinical importance of repetitive assessments of a depressive mood and the need to take sufficient care of depressed subjects. Another result herein is that circadian and circaseptan characteristics of BP variability measured 7-day/24-h predicted the occurrence of vascular disease beyond the prediction provided by age, gender, depressive mood and lifestyle, as assessed by means of a multivariate Cox model. Earlier, we showed that the morning surge in BP on Mondays was statistically significantly higher compared with other weekdays. Although a direct association between the Monday surge in BP and cardiovascular events could not be demonstrated herein, it is possible that the BP surge on Monday mornings may also trigger cardiovascular events. We have shown that depressive people exhibit a more prominent circaseptan variation in SBP, DBP and the double product (DP) compared to non-depressed subjects. In view of the strong relation between depression and adverse cardiac events, studies should be done to ascertain that depression is properly diagnosed and treated. Chronodiagnosis and chronotherapy can reduce an elevated blood pressure and improve the altered variability in BP and HR, thus reducing the incidence of adverse cardiac events. This recommendation stands at the basis of chronomics, focusing on prehabilitation in preference to rehabilitation, as a public service offered in several Japanese towns.

Arterial stiffness independently predicts cardiovascular events in an elderly community — Longitudinal Investigation for the Longevity and Aging in Hokkaido County (LILAC) study

We investigated the predictive value of arterial stiffness to assess cardiovascular risk in elderly community-dwelling people by means of a multivariate Cox model. In 298 people older than 75 years (120 men and 178 women, average age: 79.6 years), brachial-ankle pulse wave velocity (baPWV) was measured between the right arm and ankle in a supine position. The LILAC study started on July 25, 2000, consultation was repeated yearly, and the last follow-up ended on November 30, 2004. During this follow-up span of 1227 days, there were nine cardiovascular deaths, the cause of death being myocardial infarction for two men and three women or stroke for two men and two women. In Cox proportional hazard models, baPWV as well as age, Mini-Mental State Examination (MMSE), Hasegawa Dementia Scale Revised (HDSR) and the low-frequency/high-frequency (LF/HF) ratio showed a statistically significant association with the occurrence of cardiovascular death. A two-point increase in MMSE and HDSR score significantly protected against cardiovascular death, the relative risk (RR) being 0.776 (P = 0.0369) and 0.753 (P = 0.0029), respectively. The LF/HF ratio also was significant (P = 0.025), but the other indices of HRV were not. After adjustment for age and HDSR, a 200 cm/s increase in baPWV was associated with a 30.2% increase in risk (RR = 1.302, 95% CI: 1.110-1.525), and a 500 cm/s increase in baPWV with a 93.3% increase in risk (RR = 1.933, 95% CI: 1.300-2.874, P = 0.0011), whereas the LF/HF ratio was no longer associated with a statistically significant increase in cardiovascular mortality. In elderly community-dwelling people, arterial stiffness measured by means of baPWV predicted the occurrence of cardiovascular death beyond the prediction provided by age, gender, blood pressure and cognitive functions. baPWV should be added to the cardiovascular assessment in various clinical settings, including field medical surveys and preventive screening. The early detection of risk by chronomics allows the timely institution of prophylactic measures, thereby shifting the focus from rehabilitation to prehabilitation medicine, as a public service to several Japanese towns.

Fractal analysis of heart rate variability and mortality in elderly community-dwelling people — Longitudinal Investigation for the Longevity and Aging in Hokkaido County (LILAC) study

AIM

Fractal analysis of heart rate (HR) variability (HRV) has been used as a new approach to evaluate the risk of mortality in various patient groups. Aim of this study is to examine the prognostic power of detrended fluctuation analysis (DFA) and traditional time- and frequency-domain analyses of HR dynamics as predictors of mortality among elderly people in a community.

METHODS

We examined 298 people older than 75 years (average age: 79.6 years) and 1-h ambulatory ECG was monitored. During the last 10 min, deep respiration (6-s expiration and 4-s inspiration) was repeated six times in a supine position. Time-domain and frequency-domain measures were determined by the maximum entropy method. Scaling exponents of short-term (<11 beats, alpha 1) and longer-term (>11 beats, alpha 2) were determined by the DFA method. Six estimates, obtained from 10-min segments, were averaged to derive mean values for the entire recording span. These average values were denoted Alpha 1 and Alpha 2, estimates obtained during the first 10-min segment Alpha 1 S and Alpha 2 S, and those during the last 10-min segment Alpha 1E and Alpha 2E, respectively. The LILAC study started on July 25, 2000 and ended on November 30, 2004. We used Cox regression analysis to calculate relative risk (RR) and 95% confidence interval (CI) for all-cause mortality. Significance was considered at a value of P < 0.05.

RESULTS

Gender, age and Alpha 2E showed a statistically significant association with all-cause mortality. In univariate analyses, gender was significantly associated with all-cause mortality, being associated with a RR of 3.59 (P = 0.00136). Age also significantly predicted all-cause mortality and a 5-year increase in age was associated with a RR of 1.49 (P = 0.01809). The RR of developing all-cause mortality predicted by a 0.2-unit increase in Alpha 2E was 0.58 (P = 0.00390). Other indices of fractal analysis of HRV did not have predictive value. In multivariate analyses, when both Alpha 2E and gender were used as continuous variables in the same model, Alpha 2E remained significantly associated with the occurrence of all-cause mortality (P = 0.02999). After adjustment for both gender and age, a 0.2-unit increase in Alpha 2E was associated with a RR of 0.61 (95% CI: 0.42-0.90, p = 0.01151).

CONCLUSION

An intermediate-term fractal-like scaling exponent of RR intervals was a better predictor of death than the traditional measures of HR variability in elderly community-dwelling people. It is noteworthy that the longer-term (alpha 2) rather than the short-term fractal component (alpha 1) showed predictive value for all-cause mortality, which suggests that an increase in the randomness of intermediate-term HR behavior may be a specific marker of neurohumoral and sympathetic activation and therefore may also be associated with an increased risk of mortality.

Chronomic community screening reveals about 31% depression, elevated blood pressure and infradian vascular rhythm alteration

Depression, which is a risk factor for cardiac morbidity and mortality, is not an unusual occurrence among individuals with coronary heart disease (CHD), but evidence concerning its role in the pathogenesis of this condition is less clear. Ambulatory blood pressure monitoring (ABPM) has become an important tool in the diagnosis and management of hypertension. Several previous studies have indicated that various kinds of target organ damage and cardiovascular morbidity are more strongly associated with a diagnosis by ABPM than through spot-checks in a clinical setting. This study investigated whether depressive mood was associated with changes in the about-weekly (circaseptan) and half-weekly (circasemiseptan) variations in blood pressure (BP) and heart rate (HR), including a BP surge on Mondays, in community-dwelling subjects monitored chronomically for the time structure (chronome) of their BP and HR variabilities. From April 2001 to April 2003, 217 subjects (85 men and 132 women; mean age: 56.8 +/- 11.3 yr) from U town, Hokkaido (latitude: 43.45 degrees N, longitude: 141.85 degrees E), self-monitored their BP and HR for 7 days starting around 11 a.m. on Thursday, and took readings at 30-minute intervals between 7 a.m. and 10 p.m., then at 60-minute intervals between 10 p.m. and 7 a.m. The data were retrieved and analyzed on a PC with appropriate commercial software (TM-2430-15; A&D Co., Japan). Subjects were asked about 15 items on a depression rating scale through a self-administered questionnaire. When the score amounted to 5 or higher, subjects were considered to be depressive. Student's t-test, a one-way analysis of variance (ANOVA), and cosinor methods with parametric tests were also used. A p-value below 0.05 was considered to indicate statistical significance (below 0.10: borderline statistical significance). Depression rating scales were obtained for 192 out of the 217 subjects enrolled in this study. Depression scores were (>) 5 in 72 subjects. The average values of systolic (S) and diastolic (D) BP were statistically significantly higher in depressed subjects (SBP: 129.2 vs 124.5 mmHg; p = 0.034; DBP: 79.0 vs 76.5 mmHg; p = 0.041). The 7-day average for HR did not differ between subjects with depression scores of < 5 or > 5. DBP dipping was less in the depressed subjects (16.30 vs 18.22%; p = 0.048). The dipping ratios of SBP and HR showed no statistically significant difference. In the group with depression scores of < 5, HR variability (estimated by the SD of HR and HR dip) was higher during vacations and lower on Mondays. The 24-h BP measures showed a novelty effect and a surge on Mondays. In the depressed group, a prominent circaseptan rhythm appeared to replace the novelty effect, vacation dip, and Monday surge. The results of this investigation indicate the clinical importance of the monitoring of depressed subjects. Fewer than 7 days of monitoring means a greater risk of false diagnosis, and thus a therapeutic decision including potentially unnecessary or inappropriate long-term treatment. Records shorter than 7 days would not have detected circaseptan BP dysrhythmia associated with a depressive state. Prominent circaseptans can provide new indications on the mechanisms underlying the strong relation between depression and adverse cardiac events. Future studies should aim at determining whether the treatment of depression, especially from the standpoint of a chronodiagnosis and chronotherapy, can reduce the incidence of adverse cardiac events, and whether this depends upon restoring normal BP and HR variability, i.e. anormal BP and HR chronome.

Positive impact of social intervention on disturbed neurobehavioral function in an elderly community-dwelling population: Longitudinal investigation for longevity and aging in Hokkaido county (LILAC)

Several kinds of health consultation and rehabilitation for functional disorders aimed at stroke prevention and maintenance of cognitive function in an elderly population in Hokkaido county, Japan. Changes in cardiovascular and neurobehavioral endpoints between 2000 and 2002 were assessed in 72 of 115 subjects over 75 years of age. Direct social intervention, including lifestyle modification can have a positive impact, notably on subjects with cardiovascular disorders.

Effect of H2 blockers on the circadian rhythm of intragastric acidity

Most patients with peptic ulcer or gastro-oesophageal reflux disease develop nocturnal pain (epigastric and retrosternal pain from midnight to early morning), which often disappears before breakfast. Such pain may be related to a disturbance of the circadian rhythm of gastric acid secretion. Helicobacter pylori is a known aetiological agent of peptic ulcer disease and patients with gastritis or ulcers now undergo infection eradication therapy. However, this can result in the onset or exacerbation of gastro-oesophageal reflux disease. There has been a marked increase in the number of patients with oesophagitis rather than peptic ulcer and because most are negative for H. pylori, attention has centred on the status of their gastric acid secretion. Some patients with oesophagitis complain of nocturnal pain despite treatment with a proton pump inhibitor, and in those cases a short course of an H2 blocker can be very effective. We used a portable pH meter to study, in a cross-over fashion, the changes in the circadian rhythm of gastric acid secretion caused by two H2 blockers, laftidine and famotidine, in 10 H. pylori-negative subjects. There was a significant difference in the rhythm between baseline (no treatment) and when laftidine or famotidine were administered, with mean values for amplitude of 28.1, 13.80 and 10.82, respectively; for the midline estimating statistic of rhythm (MESOR), 22.7, 10.80, and 11.54; and for acrophase, 324.0. 312.3, and 274.5 (p < 0.001). The H2 blockers suppressed the normal circadian rhythm of intragastric acidity, which rises in the evening until the middle of the night and then drops in the morning.

Geomagnetic disturbance associated with decrease in heart rate variability in a subarctic area

BACKGROUND

Physical environmental variables, such as the natural variation in the geomagnetic field in and around the earth, influence biological processes and human health. The effect of geomagnetic disturbances on heart rate variability (HRV) in healthy students in a subarctic area is studied herein.

SUBJECTS AND METHODS

Seven-day records by Holter ECG were obtained from eight clinically healthy subjects in Alta, Norway (70 N). Frequency- and time-domain measures of HRV were compared between 24-hour spans of high geomagnetic disturbance versus quiet conditions.

RESULTS

A 5.9% increase in the 24-hour average of HR (P = 0.020) and a 25.2% decrease in HRV (P = 0.002) were documented on days of high geomagnetic disturbance. The decrease in spectral power was found primarily at frequencies lower than 0.04 Hz and was not statistically significant around 3.6 sec.

CONCLUSIONS

The physiological mechanism involved may be other than the parasympathetic, usually identified with spectral power centered around 3.6 sec, a spectral region wherein no statistically significant differences were found.

Impact of circadian amplitude and chronotherapy: relevance to prevention and treatment of stroke

The long-acting calcium antagonist nifedipine reduces the incidence of stroke in Eastern Asia, as shown by the Shanghai Trial Of Nifedipine in the Elderly (STONE) and the Systolic Hypertension in China (Syst-China) trials. Recent trials in Japan have shown that benidipine may be more efficient than the former drug in preventing strokes in the elderly. Benidipine, commonly prescribed in Japan for a definite depressor effect, reportedly without causing remarkable fluctuations in blood pressure (BP), is investigated herein from a chronobiological viewpoint. Eighteen subjects (nine women and nine men, 39 to 87 years of age) with essential hypertension (office and ambulatory systolic, S/diastolic, D BP values above 160/95 mm Hg and 130/80 mm Hg, respectively) were enrolled in this investigation. Ambulatory BP was monitored at 30-min intervals for at least 24 h (ABPM-630, Colin Medical) before and after 4 weeks of crossover treatment with nifedipine tablets (twice daily, 20 mg/d) and benidipine (once daily, 4 mg/d, in the morning). The results indicate that: 1) benidipine and nifedipine reduce 24-h daytime (10:00-20:00) and nighttime (00:00-06:00) averages of SBP and DBP (P < 0.001); 2) the circadian double amplitude of BP is decreased after treatment with benidipine (from 28.6 to 21.1 mm Hg SBP and from 19.7 to 15.2 mm Hg DBP; P< 0.05), while the day-night difference in SBP is increased after treatment with nifedipine (18.6 vs 27.9 mm Hg, P< 0.01); and 3) the increase in the day-night difference of heart rate (HR) is significant after treatment with benidipine (13.6 vs 18.8 beats per minute, bpm; P< 0.05), but not with nifedipine. We have previously evaluated the usefulness of the circadian amplitude of BP as a prognostic tool of cardiovascular outcome, and found that an excessive circadian SBP or DBP amplitude was associated with an increased risk of vascular disease. The fact that benidipine reduces the circadian BP amplitude may be one reason for the superiority of this treatment over nifedipine in preventing an adverse outcome. A reduced heart rate variability (HRV) also predicts adverse cardiovascular outcomes in patients with overt cardiovascular disease and in hypertensive subjects. The fact that benidipine increases the day-night difference in HR may be another reason for the positive effects of this treatment.

Intragastric acidity and circadian rhythm

Most patients with peptic ulcers or gastroesophageal reflex disease develop subjective symptoms of epigastralgia and retrosternal pain during the period of time from the middle of the night to the early dawn (nocturnal pain). Such pain often disappears before breakfast. Disturbed circadian rhythm of gastric acid secretion may have a close relationship with the onset and aggravation of acid-related diseases. On the other hand, Helicobacter pylori has been considered to be an etiological agent of duodenal ulcer, and H. pylori eradication has been conducted in patients with gastritis and peptic ulcers. However, such eradication therapy sometimes results in the onset or deterioration of gastroesophageal reflux diseases. In this context, the question of whether the circadian rhythm of gastric acid secretion varies in accordance with the presence or absence of H. pylori infection is of interest. In the present study, we examined the fluctuation in intragastric acidity via a portable pH meter in 10 H. pylori-positive and 10 H. pylori-negative subjects. As a result, a significant difference in the circadian rhythmicity was observed between the H. pylori-negative and the H. pylori-positive group, with mean values for each parameter of 28.1 and 13.3 for amplitude, 22.7 and 12.4 for the midline-estimating statistic of rhythm (MESOR), and 324.0 and 321.0 for acrophase, respectively (P < 0.001). In both H. pylori-positive and negative groups, a tendency was observed toward an increase in intragastric acidity during the time period from the middle of the night to the early dawn, and toward a decrease in intragastric acidity during the early morning. In the H. pylori-positive group, the values for intragastric acidity over time were lower, and the degree of amplitude was smaller as compared to the H. pylori-negative group. Further, H. pylori-positive individuals were at a more advanced stage of the disease.

Homozygosity and linkage disequilibrium mapping of autosomal recessive distal myopathy (Nonaka distal myopathy)

Autosomal recessive distal myopathy or Nonaka distal myopathy (NM) is characterized by its unique distribution of muscular weakness and wasting. The patients present with spared quadriceps muscles even in a late stage of the disease. The hamstring and tibialis anterior muscles are affected severely in early adulthood. We have localized the NM gene to the region between markers D9S319 and D9S276 on chromosome 9 by linkage analysis. To further refine the localization of the NM gene, we conducted homozygosity and linkage disequilibrium analysis for 14 patients from 11 NM families using 18 polymorphic markers. All of the patients from consanguineous NM families were found to be homozygous for six markers located within the region between markers D9S2178 and D9S1859. We also provided evidence for significant allelic associations between the NM region and five marker loci. Examination of the haplotype analysis identified a predominant ancestral haplotype comprising the associated alleles 199-160-154-109 (marker order: D9S2179-D9S2180-D9S2181-D9S1804), present in 60% of NM chromosomes and in 0% of parent chromosomes. On the basis of the data obtained in this study, the majority of NM chromosomes were derived from a single ancestral founder, and the NM gene is probably located within the 1.5-Mb region between markers D9S2178 and D9S1791.

Glycidol degrades scrapie mouse prion protein

Agents of transmissible spongiform encephalopathy (prion) are known to be extremely resistant to physicochemical inactivation procedures such as heat, radiation, chemical disinfectants such as detergents, alcohols, glutaraldehyde, formalin, and so on. Because of its remarkable resistance, it is difficult to inactivate prion. Chemical inactivation seems to be a practical method because it is applicable to large or fixed surfaces and complicated equipment. Here, three epoxides: beta-propiolactone, propylene oxide, and glycidol (GLD) were examined of their inactivation ability against scrapie-mouse prion protein (PrP(Sc)) under various conditions of chemical concentration, incubation time, and temperature. Among these chemicals, GLD worked most effectively and degraded PrP into small fragments. As a result of the bioassay, treatment with 3% GLD for 5 hr and 5% GLD for 2, 5 hr or 12 hr at room temperature prolonged the mean incubation time by 44, 30, 110 and 73 days, respectively. From dose-incubation time standard curve, the decrease in infectivity titers were estimated as 10(3) or more. Therefore, degradation of PrP(Sc) by GLD decreased the scrapie infectivity. It is also suggested that pH and salt concentrations influence the effect of GLD. Although further study is necessary to determine the optimal condition, GLD may be a potential prion disinfectant.

Immunohistochemical detection of apolipoprotein E within prion-associated lesions in squirrel monkey brains

The interaction of various amyloid precursors and apolipoprotein E (apoE) is important for Congophilic amyloid formation. As for cerebral amyloidoses, although the correlation between amyloid beta protein (Abeta) and apoE in Alzheimer's disease (AD) has been clarified, the interaction of prion protein isoform (PrPsc) and apoE in several types of prion diseases (PDs) has not been examined in detail. ApoE colocalization has been confirmed in Congophilic PrPsc plaques, but to clarify the participation of apoE in the early stage of PDs, apoE deposition in immature lesions without Congophilic amyloid in PDs needs to be examined. In the present study two squirrel monkeys were inoculated with mouse PrPsc derived from sheep scrapie, and showed signs of severe spongiform degeneration. These lesions were immunohistochemically characterized as patchy perivacuolar and diffuse synaptic lesions without Congophilic amyloid. The central portion of the assemblies involving a few patchy perivacuolar lesions was detected by methenamine silver staining and appeared as a plaque-like lesion. ApoE was colocalized in all the plaque-like lesions and in half of the patchy perivacuolar lesions, but not in any diffuse synaptic lesions. These immunohistochemical characteristics indicated that apoE colocalization occurred in moderate mature lesions in PDs, and apoE might play an important role in the aggregation of PrPsc after a conformational change from cellular PrP isoform to PrPsc.

[Three-dimensional imaging of hepatic and intrahepatic portal veins with helical CT: determination of optimal volume of contrast medium by intravenous injection using MIP technique]

In this study, the optimal volume of contrast medium in the liver for three-dimensional (3D) imaging of the hepatic and portal veins by helical CT were determined by intravenous injection using the MIP technique. In the 48 cases examined, CT images of the liver were obtained following the administration of contrast medium (90, 120, or 150 ml and 1.0 <, < or = 1.5 ml; 1.5 <, < or = 2.0 ml; 2.0 <, < or = 2.5 ml or 2.5 <, < or = 3.0 ml/kg) for determination of the optimal volume. The mean body weight of the patients was 59 kg. Contrast medium (Iopamidol 300 mgl/ml) was injected at a rate of 3 ml/sec, and scanning was initiated 70 sec after the beginning of injection. Images were obtained throughout the entire liver using 5-mm collimation. MIP images were graded from poor to excellent based on their visualization of the hepatic vessels. Images produced with 120 ml of contrast medium presented excellent images of hepatic vessels, superior to those produced with 90 ml (hepatic vein: p < .001, portal vein: p < .001). Images produced with 2.0 <, < or = 2.5 ml/kg of contrast medium presented excellent images of the portal vein, superior to those produced with 1.5 <, < or = 2.0 ml/kg ml (p < 0.05). It is evident from the present data that a contrast medium volume of more than 120 ml or 2.0 <, < or = 2.5 ml/kg is sufficient for three-dimensional imaging of hepatic vessels. These images may be a useful diagnostic tool in patients with hepatic disease.

Blood pressure variability assessed by semiautomatic and ambulatorily functional devices for home use

As a basis for chronobiologic analyses and thereby for screening deviant blood pressure, measurements are advocated, preferably with ambulatorily functional instrumentation at half-hour intervals around-the-clock for an initial span of 7 days. When only manual instrumentation is available, 3-hourly measurements during waking and one measurement, preferably by a companion, around mid-sleep is recommended to detect a blood pressure disorder. Such screening is warranted for a reasonably reliable diagnosis, particularly in order to recognize circadian blood pressure overswinging (Circadian Hyper-Amplitude-Tension, CHAT) and to separate this new disease risk syndrome from an elevation of the time structure (chronome)-adjusted average (MESOR), that is MESOR-hypertension, and from the coexistence of the two foregoing conditions.

Characterization of antibodies raised against bovine-PrP-peptides

To analyze the antigenicity of peptides derived from bovine prion protein (PrP) cDNA, we immunized rabbits with four synthetic peptides and compared the immunoreactivity of antibodies to PrPs from various species by immunoblotting and immunohistochemistry. Two of the antibodies reacted strongly with all PrPs. The other antibodies, raised against overlapping peptides close to two glycosylation sites, did not recognize PrPSc-mouse but did recognize PrPSc-sheep which contains two sugar residues and PrPCJD with or without a sugar residue. Our results suggest that these antibodies may have species-specificity for both glycosylation status and amino acid sequences of the protein. In conclusion, we identified two regions in bovine-PrP which appear suitable for raising antibodies that detect various kinds of PrPs, and one region (Ab103-121) which appears suitable for raising antibodies that detect several species of PrPs. These antibodies may be useful for diagnosing prion diseases and for researching their pathogenesis.

Detection methods of possible prion contaminants in collagen and gelatin

We describe methods for the preparation of collagen and gelatin samples to detect possible prion contaminants using Western blotting of a major component of prions, PrPSc. A commercially available collagen solution containing 2% athero-collagen was spiked with rodent adapted scrapie prion and used as the prion-contaminating collagen. The methods developed center on the enzymatic reduction of the collagen solution viscosity with protease treatments and on the concentration of the prion from the protease-digests with polyethylene glycol-#6000 and NaCl. Recovery of the spiked prion as a partially protease-resistant core fragment of PrPSc fluctuated from 30% to 46% of the input amount.

Molecular structure of canine LINE-1 elements in canine transmissible venereal tumor

We determined the 4251-bp sequence of open reading frame 2 (ORF2) of canine LINE-1 retroposon that encodes 1275 amino acids. The truncated LINE-1 inserts associated with transmissible venereal tumor (TVT) of dogs contained the 1378-bp LINE-1 insert (TVT-LINE) flanked by 10-bp direct repeats upstream to c-myc gene. The TVT-LINE elements were composed of 416 bp inverse sequences homologous to the complementary strand of the LINE-1, a 5-bp deletion and 962-bp sequences homologous to the 3' region of the LINE-1.

[Evaluation on the clinical background on early death in patients with pulmonary tuberculosis during the past five years]

We evaluated the clinical background of early death (within 3 months after admission to our hospital) in patients with active pulmonary tuberculosis during the past five years (1992-1996). Among 65 active pulmonary tuberculosis patients who died during the past five years, 32 (49%) died directly of tuberculosis. Thirteen (41%) of those 32 patients died of acute respiratory failure and 9 patients (28%) died in emacitation state. Twenty two patients (69%) died within 3 months after admission to our hospital (the early death group) and 10 patients (31%) died after 3 months (the late death group). Thirteen patients (59%) in the early death group died of acute respiratory failure. On the other hand, none in the late death group died of acute respiratory failure but 4 patients died of chronic heart and/or respiratory failure and 4 patients died in emarciation state. Compared to the patients in the late death group, more patients in the early death group had long total delays (patient's and doctor's delays), had coexisiting diseases, had fallen into acute respiratory failure, and were under malnutrition. We evaluated the nutritional condition of patients using the Onodera's PNI (Prognostic Nutritional Index; 10 x serum almumin concentration + 0.005 x peripheral lymphocyte count) and the PNI value was lower among the patients in the early death group than among those in the late death group. To prevent death due to tuberculosis, we emphasize that it is important to start anti-tuberculosis therapy before patients fall into acute respiratory failure and/or malnutrition.

Rapid analysis of allelic variants of the sheep PrP gene by oligonucleotide probes

A rapid method to determine the allelic variants of the sheep PrP gene was developed. DNA samples from 128 Suffolk sheep (39 rams and 89 ewes) were screened by using polymerase chain reactions and dot-blot hybridization with 32P-labeled nine allele-specific oligonucleotide probes corresponding to the polymorphic PrP codons 112, 136, 154 and 171. Three allelic variants of the PrP gene, PrP(MARQ), PrP(TARQ) and PrP(MARR), were found in the flocks. Among those variants, nearly half of the ewes had alleles of the 171-Arg variant that is closely associated with resistance to natural scrapie. Assessments of allelic mutations of the PrP gene may help to select the scrapie-resistant progenitors in the flocks.

Differences in the evolutionary pattern of feline panleukopenia virus and canine parvovirus

Canine parvovirus (CPV) suddenly appeared in the late 1970s after which it showed continuous antigenic changes. Virological and molecular genetic analyses mainly focused on feline panleukopenia virus (FPLV) were conducted in this study because FPLV is the suspected ancestor of CPV; the way in which FPLV evolves may help to explain the emergence of CPV. Analysis of escape mutants against FPLV-specific monoclonal antibody showed that viruses possessing CPV-like properties were not easily detected in FPLV virus stocks. Phylogenetic analysis revealed that the nonstructural protein 1 (NS1) and capsid protein 2 (VP2) genes of FPLV changed with time. A similar tendency, however, was not observed in the FPLV VP2 proteins. In contrast, the topology of the phylogenetic tree of VP2 proteins of CPV basically concurred with that of the VP2 genes. Analysis of the ratio of nonsynonymous and synonymous substitutions revealed that synonymous substitutions exceeded nonsynonymous substitutions in both the NS1 and VP2 genes of FPLV, even when the analysis focused on specific regions in the VP2 gene that are known to be located on the capsid surface. Comparison of the CPV VP2 genes revealed that nonsynonymous substitution was found to dominate over synonymous substitution in one specific region in the VP2 gene. These results suggested that FPLV has changed mainly by random genetic drift. In contrast, after the appearance of CPV, changes in the CPV VP2 gene appear to be partly selected by certain positive selection forces. CPV and FPLV are known to be closely related viruses genetically and biologically, but the evolutionary mechanisms of the two viruses appeared to be different.

Virus inactivation in superoxide dismutase preparations by ultraviolet light irradiation

Viral inactivation in superoxide dismutase (SOD) derived from human red cells was carried out by ultraviolet light C (UVC) irradiation. With 400 J/m2 UVC irradiation, the titer of canine parvovirus (CPV, a nonenveloped virus), M13 bacteriophage (M13, a nonenveloped phage) and vesicular stomatitis virus (VSV, an enveloped virus), which were spiked into SOD solution, were reduced by > 4.6 log10 (detection limit), 7.0 log10 and 6.2 log10, respectively. The SOD activity was maintained and the band pattern of SOD on an electrophoresis gel was not changed even by 1000 J/m2 UVC irradiation. These results indicate that UVC irradiation is a promising method for the inactivation of both enveloped and nonenveloped viruses in SOD preparations while maintaining its activity.

Chicken monoclonal antibodies against synthetic bovine prion protein peptide

Chicken monoclonal antibodies (mAbs) were developed against bovine prion protein (PrP) peptide. Chickens immunized with bovine PrP peptide B204 (amino acid residues 204-220) coupled to keyhole limpet hemocyanin produced specific antibodies to the peptide as determined by an enzyme-linked immunosorbent assay (ELISA) using the B204 peptide coupled to ovalbumin as target antigen. From a fusion experiment using the chicken fusion partner cell line MuH1 and immune spleen cells, 19 mAbs reactive with B204 were generated. These mAbs were subdivided into five groups based on competitive ELISA using B204 and four 10-amino acid peptides. These five groups included all combinations expected based on comparison of amino acid sequences among the five species, bovine, mouse, human, sheep and hamster, examined. These results indicate that the chicken mAb system is a suitable technique for immunological analysis of PrP in mammals.

Characterization of differentially expressed genes in the bovine T lymphoma cell line

A differential display (D.D.) analysis was made to detect differentially expressed genes in a bovine T lymphoma cell line, BTL-26, derived from the calf type of sporadic bovine lymphosarcoma. A D.D. analysis comparing BTL-26 with the bovine epithelial cell line CKT-1 and healthy bovine thymocytes yielded 24 cDNA clones. The DNA sequencing analysis followed by a homology search showed that 20 of the 24 cDNA clones had no significant homology to any sequences in DNA data base. The remaining four genes were homologous to known sequences. Northern blot hybridization among BTL-26, CKT-1 and healthy bovine thymocytes showed that a cDNA clone, BC8, was differentially expressed in BTL-26. The cloning of full-length cDNA for the BC8 clone and its DNA sequences showed that the BC8 clone is a bovine nuclear domain protein homologous to the human NDP52 gene. Northern blot analysis showed that the BC8 clone bovine NDP52 was predominantly expressed in tumor cell line BTL-26, compared with the transcripts from several bovine tissues.

Characterization of the sheep apolipoprotein E (ApoE) gene and allelic variations of the ApoE gene in scrapie Suffolk sheep

Apolipoprotein E (ApoE) plays a central role in lipid transport and is suggested to be involved in neuronal repair. Human ApoE epsilon 4 allele is known as a risk factor for Alzheimer's disease, and an association of the human ApoE genotype with the human prion disease, Creutzfeldt-Jakob disease, is suggested, albeit controversial. We analyzed the sheep ApoE gene to determine whether any association between the sheep ApoE genotype and the sheep prion disease, scrapie, existed. The sheep ApoE cDNA contained an open reading frame (ORF) consisting of 948 base pairs (bp) that encoded 316 amino acids (aa). The sheep ApoE gene was composed of four exons separated by three introns, and the ORF was encoded by three exons, designated exons 2, 3, and 4. Nucleotide sequence analysis also showed the presence of one G/T nucleotide polymorphism in the ORF that resulted in an Ala/Ser amino-acid substitution at codon 258. PCR-restriction fragment length polymorphism analysis of genomic DNA showed the presence of three sheep ApoE genotypes that were the result of the homologous and heterologous combinations of the two alleles. We analyzed the sheep ApoE genotypic and the allelic frequencies in scrapie and control Suffolk sheep, but they did not significantly differ from those in the control sheep, even though PrP genotype-matched populations were compared. The ApoE genotype appeared not to be associated with the progression of the disease when looking at the age at death. These results indicated that in Suffolk sheep, none of the ApoE genotypes was associated with scrapie.

Genomic structure of the bovine PrP gene and complete nucleotide sequence of bovine PrP cDNA

The present authors previously reported the nucleotide sequence of the 5' half of a cDNA encoding bovine prion protein (PrP) and the genomic structure of the bovine PrP gene encoding the 5' -untranslated region. Here they report the extent of intron 2 of the bovine PrP gene and the nucleotide sequence of the 3' half of bovine PrP cDNA that had not been determined before. This newly sequenced 3' half of the bovine PrP cDNA consisted of 2149 bp. The entire 3'-untranslated region (3'-UTR) was found to be encoded by a single exon, exon 3. One nucleotide polymorphism was found in the 3'-UTR. The length of intron 2 was estimated to be about 14 kbp. The structure of bovine PrP gene can be defined by combining the present results and previous reports on the bovine PrP gene.

Photoinactivation of virus infectivity by hypocrellin A

We investigated the photoinactivation of virus infectivity by hypocrellin A and its mechanism. The titers of vesicular stomatitis virus (VSV) and human immunodeficiency virus type 1 (HIV-1), both of which are enveloped viruses, were reduced upon illumination with hypocrellin A in a concentration-dependent manner, whereas canine parvovirus, a nonenveloped virus, was not killed. The removal of oxygen or addition of sodium azide or beta-carotene both inhibited VSV inactivation. Mannitol and superoxide dismutase had no effect on VSV inactivation. These results indicate that singlet oxygen was involved in the process of VSV inactivation. Of the three major VSV membrane proteins, peripheral membrane protein M was most damaged by the hypocrellin A phototreatment.

Instability of the 12-nucleotide repeat in c-myb gene of bovine T-lymphoma cells

Insertion of a 12-nucleotide repeat in c-myb gene exon 9 was observed in about 15% of sporadic bovine T-lymphomas. The 12-nucleotide repeat in the T-lymphoma cells showed deletion and insertion of the repeat units during cultivation of the cells. To know whether deficiency in DNA loop repair is involved in the instability of the repeat, abilities to bind and correct the loop structure in nuclear extracts were examined. The nuclear extracts of all examined cells had ability to bind and correct the loop structure. These data suggest that instability of the 12-nucleotide repeat in bovine T-lymphoma cells might be independent of deficiency of DNA loop repair function.

Deletion of c-myb exon 9 induced by insertion of repeats

A simple repeat was found to be inserted into exon 9 of the c-myb gene in three out of 20 bovine T lymphomas. The repeat was composed of multiple copies of a 12-nucleotide motif and had no significant homology to the sequences reported so far. Tumor cells containing the repeat expressed two kinds of c-myb mRNA: (1) are that included the repetitive sequence in exon 9, and (2) are that lacked the whole sequence of exon 9. Transfection of an expression vector containing exon and intron sequences and reverse transcriptase-polymerase chain reaction (RT-PCR) analysis of the mRNA demonstrated that the insertion of the repeat enhanced exon skipping of the transfected minigene. These observations imply that the insertion of the repeat may enhance exon skipping of the c-myb pre-mRNA. Although the transcription-activating activity by the c-Myb with the repeat was low, that by the c-Myb without exon 9 was three- to eightfold higher than the wild-type c-Myb. These data suggest that insertion of the 12-nucleotide repeat in codon 359 may result in c-Myb proteins having high- and low-transcription-activating activity.

Alternative usage of exon 1 of bovine PrP mRNA

Here we report two types of bovine prion protein (PrP) mRNA that possessed different lengths of the 5'-untranslated region and were expressed in various bovine tissues. The two mRNA species were transcribed from identical positions but differed in the usage of the splice site for exon 1/intron. One mRNA possessed exon 1 consisting of 53 nucleotides and the other possessed exon 1 consisting of 168 nucleotides. Usage of exons 2 and 3 was identical for the two mRNA species. The two mRNA species were detected in all but spleen tissue; the mRNA possessing 168-nt exon 1 was not detected in bovine spleen. This is the first report on the tissue-specific alternative splicing of PrPc mRNA in any other species. Only a low level of PrPc appeared to be present in bovine spleen. These results suggested the possibility that the mRNA possessing 53-nt exon 1 was inefficiently translated into Prp; however, in vitro translation analysis showed no marked difference in translational efficiency between the two mRNA species.

Characterization of the bovine prion protein gene: the expression requires interaction between the promoter and intron

We cloned the part of the bovine PrP gene which contains the 5'-flanking region, exon 1, exon 2 and intron 1 to analyze its promoter region. The 5' non-coding region of the bovine PrP gene consisted of three exons and two introns, and its organization was similar to that of the mouse, rat and sheep PrP genes. The 5'-flanking region of the bovine PrP gene from the transcription start site to nucleotide position -88 was (G + C)-rich (78%) and contained three potential binding sites for the transcription factor Sp1, but no CCAAT-box or TATA-box. This region showed high homology (89%) with that of the sheep PrP gene, but relatively low homology (approximately 46-62%) with the same region of the mouse, rat, hamster and human PrP genes. The position from -88 to -30 within the 5'-flanking region of the bovine PrP gene showed major promoter activity. However, this region was able to function properly only in collaboration with the region at +123 to +891 of intron 1 of the bovine PrP gene.

p53 mutation as a potential cellular factor for tumor development in enzootic bovine leukosis

Mutations of p53 in the lymphocytes from peripheral blood and from tumoral lymph nodes in six naturally occurring bovine leukemia virus (BLV)-infected cows were examined. A point mutation of the p53 gene was found in three of six (50%) BLV-infected cows. These p53 gene mutations resulted in amino acid substitutions of codons 144, 167 and 241. The BLV-infected cow in the tumor stage had abnormally proliferating monoclonal B-lymphocytes having the p53 mutation. However, the mutation was not found in somatic cells, except for tumor cells. These results show that p53 mutation plays an important role in the pathogenesis of BLV-induced neoplasms, and that the B-lymphocyte bearing p53 mutations may be a target cell for tumor formation of enzootic bovine leukosis.

Sensitive enzyme-linked immunosorbent assay for detection of PrP(Sc) in crude tissue extracts from scrapie-affected mice

An enzyme-linked immunosorbent assay (ELISA) was developed that detects PrP(Sc) in crude extracts from brain and spleen tissue of scrapie-affected mice with high sensitivity and specificity. Brain tissue was homogenized in 8% Zwittergent 3-12 and 0.5% Sarkosyl. The homogenate was treated with collagenase and DNase I and then subjected to proteinase K digestion. Precipitates containing PrP(Sc) were obtained by ultracentrifugation. Spleen tissue was homogenized in 4% Triton X-100 and 0.5% Sarkosyl, and the homogenate was treated firstly with collagenase and DNase I, and secondly with proteinase K. PrP(Sc) was then extracted with 6.25% Sarkosyl and precipitated through salting-out with NaCl and by ultracentrifugation. When PrP(Sc) was dissolved in 3-4 M guanidine thiocyanate and adsorbed to microtiter plates, strong and specific reactions to the formation of antigen-antibody complexes could be detected by ELISA. The sensitivity of PrP(Sc)-detection for this ELISA, as measured by serial dilution of scrapie material in tissue homogenates from uninfected animals, was equal or higher than that attained by Western blot. This ELISA is more rapid than Western blot and seems to be more suitable for screening large numbers of animals. It also has potential application for the diagnosis of the transmissible spongiform encephalopathies.

Epitope mapping of a monoclonal antibody specific to feline panleukopenia virus and mink enteritis virus

To obtain monoclonal antibodies (MAbs) specific to feline panleukopenia virus (FPLV) and mink enteritis virus (MEV), 15 hybridomas secreting MAbs against MEV-Abashiri were established and the properties of the MAbs were analyzed. The cross-reactivity of MAbs revealed that one MAb, P2-215 was specific for FPLV and MEV, whereas the remaining fourteen MAbs reacted with canine parvovirus (CPV), FPLV, and MEV. Epitope analyses using various CPV/MEV chimeric viruses revealed that the MAb P2-215 recognized the epitope comprised of amino acid 93-Lys in VP2, which is known to be FPLV and MEV-specific.

Characterization of differentiation antigens expressed in bovine lymphosarcomas

To characterize the cell-surface antigens expressed in tumour cells derived from bovine leukosis and to determine their cell lineages, the immunophenotypes of the tumour cells from 13 bovine lymphosarcomas were examined with 13 monoclonal antibodies (mAbs). Of 13 cattle with lymphosarcomas, four were identified clinically as having the thymic-type sporadic bovine leukosis (SBL) and one as having the skin-type; two had enzootic bovine leukosis (EBL) and six were untypable. Flow cytometric analysis revealed that the tumour cells from nine cases were of T-cell lineage (BoCD5+, BoCD2+ or BoCD2-) and two were of B-cell lineage (MHC-II+, BoCD5+, IgM+); there were two bovine leukaemia virus-infected cattle (EBL). T-cell tumours appeared to originate from immature (BoCD4-, BoCD8-) T cells, but there was no significant relationship between clinical type (EBL, calf-, skin- and thymic-type) and tumour-cell immunophenotype.

Differentiation of vaccine virus from field isolates of feline panleukopenia virus by polymerase chain reaction and restriction fragment length polymorphism analysis

In an attempt to distinguish feline panleukopenia virus (FPLV) live vaccine strains from FPLV field isolates in Japan, we compared restriction fragment length polymorphisms (RFLP) of polymerase chain reaction (PCR)-amplified fragments of live FPLV vaccine strains with those of FPLV Japanese field isolates. On the basis of nucleotide sequence differences between PLI-IV, a live vaccine strain, and FPV-483, a recent field isolate, two restriction enzymes, Dra I and Afa I, were selected for PCR-RFLP analysis of nucleotide (nt) differences at nt 3695 and 4508, respectively. Three live vaccine strains including the PLI-IV strain could be distinguished from the Japanese field isolates by their PCR-RFLP patterns by Afa I, but one live vaccine strain was indistinguishable from the Japanese isolates when Dra I and Afa I were used. The Japanese field isolates were divided into two groups by the profile of PCR-RFLP patterns generated by Dra I and Afa I, suggesting that PCR-RFLP analysis using several enzymes provides a good genetic estimate of strain differentiation. No isolate that shows a Dra I-negative/Afa I-negative pattern has emerged in Japan, indicating the possibility that the live vaccine viruses with a Dra I-negative/Afa I-negative pattern, such as the PLI-Iv strain, are candidates for use as live FPLV vaccine strain in Japan where they can be genetically distinguished from field strains.

Improvement of PrPSc-detection in mouse spleen early at the preclinical stage of scrapie with collagenase-completed tissue homogenization and Sarkosyl-NaCl extraction of PrPSc

Scrapie in sheep has recently become again a target of control measures and eradication programs. Crucial for the effectiveness of these measures is the detection of infected sheep during the long and potentially hazardous incubation period. However, routine-diagnosis is mostly limited to clinical examinations when disease becomes apparent, and to postmortem investigations. Through the detection of the scrapie-specific isoform of the prion protein (PrPSc) by Western blot in the spleen and lymph nodes from scrapie-infected mice and sheep, we have shown previously that diagnosis during the preclinical stage is possible. We introduce here an improved method for the diagnosis of mouse scrapie shortly after infection. Through a homogenization procedure that includes a collagenase digestion step, and through extraction and salting-out of PrPSc by Sarkosyl and NaCl, respectively, we were able to detect PrPSc in spleen tissue of intraperitoneally infected mice seven days postinfection. Moreover, the new protocol makes sample-handling easier and reduces the hands-on time. We also successfully enriched PrPSc from spleen tissue through immobilized metal affinity chromatography (IMAC); however, for the diagnosis at the earliest stage of infection, extraction of PrPSc by Sarkosyl and NaCl was more effective.

Predominant p53 mutations in enzootic bovine leukemic cell lines

The role of the p53 tumor suppressor gene in bovine lymphosarcomas, a fragment of about 100 bp corresponding to approximately 97% of the open reading frame of the p53 gene was first amplified from single-strand cDNA originated from calf thymus by polymerase chain reaction PCR) and sequenced to obtain the bovine wild-type p53 gene. At the amino acid level, the omologies of the bovine p53 gene with the human, mouse, chicken and cat p53 genes were 0.9%, 72.8%, 52.7% and 82.3%, respectively. Moreover, eight bovine leukemic cells lines were studied for alterations in the p53 gene. These lines showed no significant somatic alterations in southern blot analysis, and expressed 2.5 kb p53-specific transcripts in Northern blot analysis. In mutation analysis using the reverse transcriptase-PCR technique, we detected three missense point mutations in four of these bovine leukemic cell lines. These mutations occurred in the 'hotspots' of the p53 gene. Thus p53 mutations predominantly occur in BLV-transformed cell lines and seem to be necessary for development of enzootic bovine leukosis (EBL).

Potential transforming-ability by internal deletion of the bovine c-myb gene

Two kinds of bovine c-Myb, the 75 kDa full-length (FL) c-Myb from the thymic type of sporadic bovine lymphosarcoma (SBL) cells, and 65 kDa deleted (DEL) c-Myb, which is an internally deleted form (85 amino acids corresponding to the negative regulatory domain) from calf-type SBL were found. To investigate the relationship between internal deletion and transforming capacity, we constructed retroviral vectors carrying cDNA that encoded either FL- or DEL-Myb protein, and transfected them to mouse fetal liver cells. In spite of the high trans-activating capacity of DELMyb, DELMyb and FLMyb showed no significant difference in oncogenic capability by measurement of colony formation in soft agar or in methylcellulose medium. Thus, the internal deletion of the c-myb gene is competent for transactivation but not directly relevant to transformation of mouse hemopoietic cells.