Machine learning-based clinical decision support system for treatment recommendation and overall survival prediction of hepatocellular carcinoma: a multi-center study

The treatment decisions for patients with hepatocellular carcinoma are determined by a wide range of factors, and there is a significant difference between the recommendations of widely used staging systems and the actual initial treatment choices. Herein, we propose a machine learning-based clinical decision support system suitable for use in multi-center settings. We collected data from nine institutions in South Korea for training and validation datasets. The internal and external datasets included 935 and 1750 patients, respectively. We developed a model with 20 clinical variables consisting of two stages: the first stage which recommends initial treatment using an ensemble voting machine, and the second stage, which predicts post-treatment survival using a random survival forest algorithm. We derived the first and second treatment options from the results with the highest and the second-highest probabilities given by the ensemble model and predicted their post-treatment survival. When only the first treatment option was accepted, the mean accuracy of treatment recommendation in the internal and external datasets was 67.27% and 55.34%, respectively. The accuracy increased to 87.27% and 86.06%, respectively, when the second option was included as the correct answer. Harrell's C index, integrated time-dependent AUC curve, and integrated Brier score of survival prediction in the internal and external datasets were 0.8381 and 0.7767, 91.89 and 86.48, 0.12, and 0.14, respectively. The proposed system can assist physicians by providing data-driven predictions for reference from other larger institutions or other physicians within the same institution when making treatment decisions.

Yttrium-90 Radioembolization Is Associated with Better Clinical Outcomes in Patients with Hepatocellular Carcinoma Compared with Conventional Chemoembolization: A Propensity Score-Matched Study

Background

Both trans-arterial radioembolization (TARE) and conventional trans-arterial chemoembolization (TACE) can effectively control hepatocellular carcinoma (HCC) in patients who are not suitable for curative resection. This study compared the effectiveness of TARE and conventional TACE as the initial trans-arterial treatment for hepatocellular carcinoma (HCC) assessed by tumor response and clinical outcomes.

Material and Methods

Data were retrospectively analyzed the propensity score-matched cohort for overall survival (OS), progression-free survival (PFS), and intrahepatic PFS in patients who have received TARE or TACE as the first HCC treatment from March 2012 to December 2017.

Results

A total of 138 patients initially treated with TARE (n = 54) or TACE (n = 84) was included in this study. Of 138 patients, median age was 59 years and the mean follow-up period was 27.6 months. TARE showed better OS (hazard ratio [HR] = 0.54, 95% confidence interval [CI] = 0.31–0.92, log-rank P = 0.02), better PFS (HR = 0.51, 95% CI = 0.36–0.97, log-rank P = 0.04), and better intrahepatic PFS (HR = 0.51, 95% CI = 0.30–0.88, log-rank P = 0.01) compared with TACE. TARE was an independent prognostic factor for OS (adjusted HR [aHR] = 0.52, 95% CI = 0.30–0.90, P = 0.02), PFS (aHR = 0.57, 95% CI = 0.35–0.94, P = 0.03), and intrahepatic PFS (aHR = 0.49, 95% CI = 0.28–0.84, P = 0.01).

Conclusion

TARE as initial trans-arterial treatment is associated with better clinical outcomes such as longer OS compared with TACE in patients with HCC.

Comparison of Overall Survival between Surgical Resection and Radiofrequency Ablation for Hepatitis B-Related Hepatocellular Carcinoma

Simple Summary

The effectiveness of surgical resection and radiofrequency ablation in early hepatocellular carcinoma is still controversial because previous studies show conflicting results. In addition, previous studies did not consider the antiviral treatment-related factors, even though there is now robust evidence that antiviral therapy is crucial for determining the prognosis of patients with chronic hepatitis B-related liver cancer. After adjusting for the antiviral treatment, we demonstrated that radiofrequency ablation may provide comparable overall survival to resection in the treatment of very early or early hepatocellular carcinoma, although recurrence-free survival is marginally shorter than in the resection group.

Abstract

It remains controversial whether surgical resection, compared to radiofrequency ablation (RFA), improves overall survival (OS) in patients with early hepatocellular carcinoma (HCC). This study aimed to compare OS after RFA with that after resection for HCC. This retrospective study included patients who underwent RFA or surgical resection as initial treatment for hepatitis B virus (HBV)-related HCC at a very early or early stage. A total of 761 patients (RFA, n = 194; resection, n = 567) from Seoul National University Hospital (Seoul, South Korea) and 1277 patients (RFA, n = 352; resection, n = 925) from the Korean Primary Liver Cancer Registry were included in the hospital and nationwide cohorts, respectively. Primary and secondary endpoints were OS and recurrence-free survival (RFS), respectively. Additional analysis was performed when the history of the antiviral treatment and the type of prescribed nucleos(t)ide analogue were confirmed. The rate of complications was compared between the two treatment groups in the hospital cohort. Baseline characteristics were balanced, using inverse probability of treatment weighting (IPTW). In the hospital cohort, the RFA group had a smaller mean tumor size (1.7 vs. 3.9 cm) but a higher proportion of cirrhotic patients than the resection group (85.6% vs. 63.1%) (both p < 0.01). During 81.0 (interquartile range, 62.3–107.1) months of follow-up, there was no difference in OS (adjusted hazard ratio (aHR) = 0.870, 95% confidence interval (CI) = 0.400–1.897, p = 0.73) and RFA was associated with shorter RFS (aHR = 1.562, 95% CI = 1.099–2.219, p = 0.01) after employing IPTW. Antiviral treatment was independently associated with longer OS (aHR = 0.444, 95% CI = 0.251–0.786, p = 0.01) as well as RFS (aHR = 0.544, 95% CI = 0.391–0.757, p < 0.01) in the hospital cohort. In the nationwide cohort, there was no difference in OS (aHR = 0.981, 95% CI = 0.661–1.456, p = 0.92) between the two treatment groups when adjusted for antiviral treatment, which was a negative independent risk factor for mortality (aHR = 0.655, 95% CI = 0.451–0.952, p = 0.03) after IPTW. Among patients treated with tenofovir (n = 96) or entecavir (n = 184) in the hospital cohort, there was no difference in either OS (aHR = 0.522, 95% CI = 0.058–4.724, p = 0.56) or RFS (aHR = 1.116, 95% CI = 0.738–1.688, p = 0.60). The overall incidence of complications was higher in the resection group (26.3%) than in the RFA group (13.9%) (p < 0.01). RFA may provide comparable OS to resection in the treatment of very early or early HCC with a lower rate of complications, although RFS is marginally shorter than in the resection group after adjusting for antiviral treatment. Regardless of the type of NA, antiviral treatment in patients with HBV-related HCC is strongly associated with both OS and RFS.

Maintenance of skeletal muscle mass during FOLFIRINOX is a favorable prognostic factor in pancreatic cancer patients

Objective

The study aimed to investigate the effect of body composition changes during chemotherapy on clinical outcomes in patients with pancreatic cancer.

Results

In patients with locally advanced pancreatic cancer (LAPC), the cross-sectional area of skeletal muscle (SM) and adipose tissue (AT) at the level of third lumbar vertebra was measured. The SM and AT ratios indicated the changes during chemotherapy. The patients were classified into three groups based on these ratios: group 1, ≥ 1.00; group 2, 0.85–0.99; group 3, < 0.85. The overall survival (OS) and surgical resection rates were estimated. Fifty-eight patients with LAPC who received first-line FOLFIRINOX were analyzed. Fifteen (25.9%) patients who underwent resection showed maintained BMI, SM, and AT as compared to the patients who did not undergo resection. As the SM ratio decreased, the risk for death increased significantly. Further, the resection rate was significantly higher in patients with maintained SM compared to those with low SM ratio. On the contrary, the change in AT ratio was not associated with OS and resection rate; however, significant decrease in AT more than 15% showed poor clinical outcomes. Maintenance of SM during chemotherapy is a reliable prognostic factor indicating longer OS and higher resection rate.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13104-021-05681-x.

Effectiveness of Transarterial Chemoembolization-First Treatment for Advanced Hepatocellular Carcinoma: A Propensity Score Matching Analysis

Background

Still in real-world practice, advanced hepatocellular carcinoma (HCC) patients are treated with transarterial chemoembolization (TACE). This study compared the therapeutic effectiveness of initial TACE treatment and initial sorafenib treatment in advanced HCC patients.

Patient and Methods

Advanced HCC patients initially treated with sorafenib or TACE were included in this study. Treatment crossover due to an unfavorable response to initial treatment was allowed. Propensity score (PS) matching was applied for balancing baseline characteristics. The primary outcome was overall survival (OS) and the secondary outcomes included tumor response.

Results

A total of 554 patients were included in this study: 85 were initially treated with sorafenib (the sorafenib-first group) and 469 with TACE (the TACE-first group). In the entire cohort, the TACE-first group was associated with lower risk of death [adjusted hazard ratio (HR)=0.75, P=0.04]. In the PS-matched cohort (85 patients per group), the TACE-first group showed longer OS than the sorafenib-first group in both univariable (HR=0.68, P=0.02) and multivariable analyses (adjusted HR=0.58, P=0.002). Specifically, within both the entire and the PS-matched cohorts, the TACE-first group showed longer OS in subgroups with major portal vein tumor thrombosis (HR=0.72, P=0.048; HR=0.52, P=0.003) or infiltrative HCC (HR=0.42, P<0.001; HR=0.30, P=0.004, respectively). The objective response rate was higher in the TACE-first group (29.3% vs 14.7%, P=0.03) within the PS-matched cohort.

Conclusion

For advanced HCC, initial TACE leads to longer OS with a more favorable tumor response than initial sorafenib treatment. Intrahepatic tumor control with initial locoregional therapy may be a potent strategy for advanced HCC.

Empirical Treatment With Carbapenem vs Third-generation Cephalosporin for Treatment of Spontaneous Bacterial Peritonitis

BACKGROUND & AIMS

Third-generation cephalosporins (TGCs) are recommended as first-line antibiotics for treatment of spontaneous bacterial peritonitis (SBP). However, antibiotics against multidrug-resistant organisms (such as carbapenems) might be necessary. We aimed to evaluate whether carbapenems are superior to TGC for treatment of SBP.

METHODS

We performed a retrospective study of 865 consecutive patients with a first presentation of SBP (275 culture positive; 103 with TGC-resistant bacterial infections) treated at 7 referral centers in Korea, from September 2013 through January 2018. The primary outcome was in-hospital mortality. We made all comparisons using data from patients whose baseline characteristics were balanced by inverse probability of treatment weighting.

RESULTS

Of patients who initially received empirical treatment with antibiotics, 95 (11.0%) received carbapenems and 655 (75.7%) received TGCs. Among the entire study cohort, there was no significant difference in in-hospital mortality between the carbapenem (25.8%) and TGC (25.3%) groups (adjusted odds ratio [aOR], 0.97; 95% CI, 0.85-1.11; P = .66). In the subgroup of patients with high chronic liver failure-sequential organ failure assessment (CLIF-SOFA) scores (score of 7 or greater, n = 314), carbapenem treatment was associated with lower in-hospital mortality (23.1%) than in the TGC group (38.8%) (aOR, 0.84; 95% CI, 0.75-0.94; P=.002). In contrast, among patients with lower CLIF-SOFA scores (n = 436), in-hospital mortality did not differ significantly between the carbapenem group (24.7%) and the TGC group (16.0%) (aOR, 1.06; 95% CI, 0.85-1.32; P = .58).

CONCLUSIONS

For patients with a first presentation of SBP, empirical treatment with carbapenem does not reduce in-hospital mortality compared to treatment with TGCs. However, among critically ill patients (CLIF-SOFA scores ≥7), empirical carbapenem treatment was significantly associated with lower in-hospital mortality than TGCs.

Risk and Risk Score Performance of Hepatocellular Carcinoma Development in Patients With Hepatitis B Surface Antigen Seroclearance

INTRODUCTION

Hepatocellular carcinoma (HCC) can develop among chronic hepatitis B patients after hepatitis B surface antigen (HBsAg) seroclearance. However, whether HCC risk after HBsAg seroclearance differs between antiviral therapy (AVT)-induced or spontaneous seroclearance cases and ways to identify at-risk populations remain unclear.

METHODS

A retrospective cohort of 1,200 adult chronic hepatitis B patients who achieved HBsAg seroclearance (median age: 56 years; 824 men; 165 with cirrhosis; 216 AVT-induced cases) were analyzed. The risk of HCC after HBsAg seroclearance and the performance of 6 HCC prediction models were assessed.

RESULTS

During a median of 4.8 years of follow-up (range: 0.5-17.8 years), HCC developed in 23 patients (1.9%). The HCC incidence rate was higher in the AVT-induced cases than that in the spontaneous cases (3.9% vs 0.9% at 5 years). AVT and cirrhosis were independent factors associated with HCC, with HCC incidence rates of 0.5%, 1.2%, 4.0%, and 10.5% at 5 years for spontaneous/no-cirrhosis, AVT-induced/no-cirrhosis, spontaneous/cirrhosis, and AVT-induced/cirrhosis patients, respectively. Among the 6 predictive HCC models tested, Chinese University-HCC score (0.82) showed the highest C-statistics, which was followed by guide with age, gender, HBV DNA, core promoter mutations and cirrhosis (0.81).

DISCUSSION

AVT-induced HBsAg seroclearance was associated with higher HCC risk, especially for patients with cirrhosis, indicating that they need careful monitoring for HCC risk. The HCC risk models were able to stratify the HCC risk in patients with HBsAg seroclearance.

Discontinuation of nucleos(t)ide analogues is not associated with a higher risk of HBsAg seroreversion after antiviral-induced HBsAg seroclearance: a nationwide multicentre study

OBJECTIVE

Direct comparison of the clinical outcomes between nucleos(t)ide analogue (NA) discontinuation versus NA continuation has not been performed in patients with chronic hepatitis B who achieved HBsAg-seroclearance. Whether NA discontinuation was as safe as NA continuation after NA-induced surface antigen of HBV (HBsAg) seroclearance was investigated in the present study.

DESIGNS

This multicentre study included 276 patients from 16 hospitals in Korea who achieved NA-induced HBsAg seroclearance: 131 (47.5%) discontinued NA treatment within 6 months after HBsAg seroclearance (NA discontinuation group) and 145 (52.5%) continued NA treatment (NA continuation group). Primary endpoint was HBsAg reversion and secondary endpoints included serum HBV DNA redetection and development of hepatocellular carcinoma (HCC).

RESULTS

During follow-up (median=26.9 months, IQR=12.2-49.2 months), 10 patients (3.6%) experienced HBsAg reversion, 6 (2.2%) showed HBV DNA redetection and 8 (2.9%) developed HCC. Compared with NA continuation, NA discontinuation was not associated with HBsAg reversion in both univariable (HR=0.45, 95% CI=0.12 to 1.76, log-rank p=0.24) and multivariable analyses (adjusted HR=0.65, 95% CI=0.16 to 2.59, p=0.54). The cumulative probabilities of HBsAg reversion at 1, 3 and 5 years were 0.8%, 2.3% and 5.0% in the NA discontinuation group, and 1.5%, 6.3% and 8.4% in the NA continuation group, respectively. NA discontinuation was not associated with higher risk of either HBV redetection (HR=0.83, 95% CI=0.16 to 4.16, log-rank p=0.82) or HCC development (HR=0.53, 95% CI=0.12 to 2.23, log-rank p=0.38).

CONCLUSION

The discontinuation of NA was not associated with a higher risk of either HBsAg reversion, serum HBV DNA redetection or HCC development compared with NA continuation among patients who achieved HBsAg seroclearance with NA.

Effectiveness of nivolumab versus regorafenib in hepatocellular carcinoma patients who failed sorafenib treatment

Background/Aims

Several treatment options are currently available for patients with hepatocellular carcinoma (HCC) failing previous sorafenib treatment. We aimed to compare the effectiveness of regorafenib and nivolumab in these patients.

Methods

Consecutive HCC patients who received regorafenib or nivolumab after failure of sorafenib treatment were included. Primary endpoint was overall survival (OS) and secondary endpoints were time to progression, tumor response rate, and adverse events. Inverse probability of treatment weighting (IPTW) using the propensity score was conducted to reduce treatment selection bias.

Results

Among 150 study patients, 102 patients received regorafenib and 48 patients received nivolumab. Median OS was 6.9 (95% confidence interval [CI], 3.0–10.8) months for regorafenib and 5.9 (95% CI, 3.7–8.1) months for nivolumab (P=0.77 by log-rank test). In multivariable analysis, nivolumab was associated with prolonged OS (vs. regorafenib: adjusted hazard ratio [aHR], 0.54; 95% CI, 0.30–0.96; P=0.04). Time to progression was not significantly different between groups (nivolumab vs. regorafenib: aHR, 0.82; 95% CI, 0.51–1.30; P=0.48). HRs were maintained after IPTW. Objective response rates were 5.9% and 16.7% in patients treated with regorafenib and nivolumab, respectively (P=0.04).

Conclusions

After sorafenib failure, the use of nivolumab may be associated with improved OS and better objective response rate as compared to using regorafenib.

P1348 Impact of left ventricular ejection fraction and aortic valve sclerosis on cardiovascular outcome in patients with acute ischemic stroke

Purpose

Various echocardiographic parameters in the same patient were systemically evaluated for their prognostic significance in AIS.

Methods

A total of 900 patients with AIS who underwent transthoracic echocardiography (TTE) (72.6 ± 12.0 years and 60% male) were retrospectively reviewed. Composite events including all-cause mortality, non-fatal stroke, non-fatal myocardial infarction, and coronary revascularization were assessed during clinical follow-up.

Results

During a median follow-up of 3.3 years (interquartile range, 0.6-5.1 years), there were 151 (16.8%) composite events. Univariable analyses showed that low left ventricular ejection fraction (LVEF) (&lt; 60%), increased peak tricuspid regurgitation (TR) velocity (&gt; 2.8 m/s) and aortic valve (AV) sclerosis were associated with composite events (P &lt; 0.05 for each). In the multivariable analyses after controlling for potential confounders, LVEF &lt; 60% (hazard ratio [HR], 1.90; 95% confidence interval [CI], 1.30-2.77; P = 0.001) and AV sclerosis (HR, 1.56; 95% CI, 1.10-2.21; P = 0.013) were independent prognostic factors associated with composite events. Multivariable analysis showed that HR for composite events gradually increased according to LVEF and AV sclerosis: HR was 2.8-fold higher in the highest-risk group than in the lowest group (P = 0.001).

Conclusions

In patients with AIS, LVEF &lt; 60% and the presence of AV sclerosis predicts the future vascular events. Patients with AIS exhibiting reduced LVEF and AV sclerosis may benefit from aggressive secondary prevention

Abstract P1348 Figure. COX plot for composite event

P3453Gender difference in impact of ischemic heart disease on long-term outcome in patients with heart failure reduced ejection fraction

Background

Ischemic heart disease (IHD) is a major underlying etiology in patients with heart failure (HF). Although the impact of IHD on HF is evolving, there is a lack of understanding of how IHD affects long-term clinical outcomes and uncertainty about the role of IHD in determining the risk of clinical outcomes by gender.

Purpose

This study aims to evaluate the gender difference in impact of IHD on long-term clinical outcomes in patients with heart failure reduced ejection fraction (HFrEF).

Methods

Study data were obtained from the nationwide registry which is a prospective multicenter cohort and included patients who were hospitalized for HF composed of 3,200 patients. A total of 1,638 patients with HFrEF were classified into gender (women 704 and men 934). The primary outcome was all-cause death during follow-up and the composite clinical events of all-cause death and HF readmission during follow-up were also obtained. HF readmission was defined as re-hospitalization because of HF exacerbation.

Results

133 women (18.9%) were died and 168 men (18.0%) were died during follow-up (median 489 days; inter-quartile range, 162–947 days). As underlying cause of HF, IHD did not show significant difference between genders. Women with HFrEF combined with IHD had significantly lower cumulative survival rate than women without IHD at long-term follow-up (74.8% vs. 84.9%, Log Rank p=0.001, Figure 1). However, men with HFrEF combined with IHD had no significant difference in survival rate compared with men without IHD (79.3% vs. 83.8%, Log Rank p=0.067). After adjustment for confounding factors, Cox regression analysis showed that IHD had a 1.43-fold increased risk for all-cause mortality independently only in women. (odds ratio 1.43, 95% confidence interval 1.058–1.929, p=0.020). On the contrary to the death-free survival rates, there were significant differences in composite clinical events-free survival rates between patients with HFrEF combined with IHD and HFrEF without IHD in both genders.

Figure 1

Conclusions

IHD as predisposing cause of HF was an important risk factor for long-term mortality in women with HFrEF. Clinician need to aware of gender-based characteristics in patients with HF and should manage and monitor them appropriately and gender-specifically. Women with HF caused by IHD also should be treated more meticulously to avoid a poor prognosis.

Acknowledgement/Funding

None

Prognosis of surgical hernia repair in cirrhotic patients with refractory ascites

BACKGROUND

Abdominal wall hernias are common in patients with ascites. Elective surgical repair is recommended for the treatment of abdominal wall hernias. However, surgical hernia repair in cirrhotic patients with refractory ascites is controversial. In this study, we aimed to evaluate the outcomes of elective surgical hernia repair in patients with liver cirrhosis with and without refractory ascites.

METHOD

From January 2005 to June 2018, we retrospectively reviewed the records of consecutive patients with liver cirrhosis who underwent a surgical hernia repair.

RESULTS

This study included 107 patients; 31 patients (29.0%) had refractory ascites. Preoperatively, cirrhotic patients with refractory ascites had a higher median model for end-stage liver disease (MELD) score (13.0 vs 11.0, P = 0.001) than those without refractory ascites. The 30-day mortality rate (3.2% vs 0%, P = 0.64) and the risk of recurrence (hazard ratio 0.410; 95% CI 0.050-3.220; P = 0.39) did not differ significantly between cirrhotic patients with refractory ascites and cirrhotic patients without refractory ascites. Among cirrhotic patients with refractory ascites, albumin (P = 0.23), bilirubin (P = 0.37), creatinine (P = 0.97), and sodium levels (P = 0.35) did not change significantly after surgery.

CONCLUSION

In advanced liver cirrhosis patients with refractory ascites, hernias can be safely treated with elective surgical repair. Mortality rate within 30 days did not differ by the presence or absence of refractory ascites. Elective hernia repair might be beneficial for treatment of abdominal wall hernia in cirrhotic patients with refractory ascites.

Additional fibrate treatment in UDCA-refractory PBC patients

BACKGROUND & AIMS

There is no proven treatment for ursodeoxycholic acid (UDCA)-refractory primary biliary cholangitis (PBC) other than obeticholic acid. Although fibrates have been reported to improve biochemical parameters, the long-term effects remain unclear. This study evaluated the effect of fibrate on clinical outcomes of UDCA-refractory PBC.

METHODS

Patients whose alkaline phosphatase (ALP) was not normalized with at least 13 mg/kg of UDCA treatment for >1 year were included from two tertiary referral centres. The primary outcome was ALP normalization. Secondary outcomes included the development of cirrhosis and hepatic deterioration. Immortal time bias was adjusted using the Mantel-Byar method.

RESULTS

A total of 100 UDCA-refractory PBC patients were included: 71 patients received UDCA alone (the UDCA group) and 29 patients received UDCA plus additional fibrate treatment of 160 mg/d fenofibrate or 400 mg/d bezafibrate (the fibrate/UDCA group). During the follow-up period, the probability of ALP normalization was significantly higher in the fibrate/UDCA group (hazard ratio [HR] = 5.00, 95% confidence interval = 2.87-8.27, P < 0.001). Among 58 non-cirrhotic patients (43 in the UDCA group and 15 in the fibrate/UDCA group), 19 patients (44.1%) in the UDCA group and none in the fibrate/UDCA group developed cirrhosis (HR = 0.12, P = 0.04). Hepatic deterioration (Child-Pugh score increase or signs of decompensated cirrhosis) occurred in 17 patients (23.9%) of the UDCA group and none in the fibrate/UDCA group in which the difference was significant (HR = 0.12, P = 0.04).

CONCLUSIONS

In patients with UDCA-refractory PBC, additional fibrate treatment is associated with a higher probability of ALP normalization and a lower risk of cirrhosis development and hepatic deterioration.

[THE DIAGNOSTIC APPROACHES TO VERIFICATION OF STREPTOCOCCUS INFECTION IN PATIENTS WITH INFECTIOUS MONONUCLEOSIS]

The Rostovskii state medical university of Minzdrav of Russia, 344022 Rostov-on-Don, Russia The analysis is applied concerning significance of laboratory techniques of verification of streptococcus infection (bacteriological analysis, detection of anti-streptolysin O in pair serums) in 148 patients with infectious mononucleosis aged from 3 to 15 years. The content of anti-streptolysin O exceeded standard in 41 ± 4.8% of patients with concomitant in acute period and in 49.5 ± 4.9% during period of re-convalescence. This data differed from analogous indicator in patients with negative result of examination on streptococcus infection independently of period of disease (9.3 ± 2.8%). The exceeding of standard of anti-streptolysin O was detected more frequently (t ≥ 2, P ≥ 95%) in patients with isolation of Streptococcus pyogenes (56.9 ± 5.8%) than in patients with Streptococcus viridans (31.2 ± 6.5%). The concentration of anti-streptolysin 0 in patients with concomitant streptococcus infection varied within limits 200-1800 IE/ml. The minimal level of anti-streptolysin O (C = 200 IE/mI) was detected independently of type of isolated Streptococcus and period of disease. The high levels of anti-streptolysin O were observed exclusively in patients with isolation of Streptococcus pyogenes. In blood serum ofpatient with concomitant streptococcus infection (Streptococcus pyogenes + Streptococcus viridans) increasing of level of anti-streptolysin O was detected in dynamics of diseases from minimal (C = 200 IE/ ml) to moderately high (200 < C < 400 IE/mI). It is demonstrated that to identify streptococcus infection in patients with infectious mononucleosis the anamnesis data is to be considered. The complex bacteriological and serological examination ofpatients is to be implemented This is necessary for early detection ofpatients with streptococcus infection and decreasing risk of formation of streptococcus carrier state.

[ESOPHAGITIS, CAUSED BY HERPES SIMPLEX VIRUS: CASE REPORT]

The clinical observation of the patient at the age of 56 years, with lesions of the esophagus by the herpes simplex virus has been presented. The patient complained of odynophagia and dysphagia. Treatment with proton pump inhibitors in outpatient stage was not effective. On endoscopic examination revealed multiple ulcers in all parts of the esophagus. Herpes simplex virus has been detected in biopsy specimens of esophageal mucosa by the PCR method. Treatment with acyclovir led to rapid and complete clinical recovery. Analysis of the literature allowed making the conclusion about the importance and actuality this demonstration.

[Apoptogenic activity of microbes-associants during Epstein-Barr virus infection]

AIM

Study apoptogenic activity of-microbes-associants during Epstein-Barr virus infection (EBVI) on the model of mice peritoneal macrophages in vitro.

MATERIALS AND METHODS

Evaluation of apoptosis induced by bacteria isolated from EBVI patients was carried out by characteristic morphological changes of macrophages in smears stained by May-Grunwald with additional staining by Romanowsky-Giemsa.

RESULTS

All the EBVI microbes-associants were established to have apoptogenic activity, however, the highest pathogenic potential was noted in Streptococcus pyogenes.

CONCLUSION

The presence of apoptogenic activity in bacterial microflora accompanying EBVI against immune system cells could serve as means of their survival and be the pathogenetic basis for prolonged persistence in the organism.

MET in gastric carcinomas: comparison between protein expression and gene copy number and impact on clinical outcome

Background:

The aim of this study was to compare gene copy number (GCN) and protein expression of MET and to evaluate their prognostic roles in gastric carcinomas.

Methods:

MET protein expression and gene amplification (GA) status were determined by immunohistochemistry (IHC) and silver in-situ hybridisation (SISH), respectively, in a large series of gastric carcinoma.

Results:

Protein overexpression was observed in 104 of 438 cases, with IHC 2+ in 94 and IHC 3+ in 10, and high polysomy of chromosome 7 and GA were found in 61 and 13 of 381, respectively. Direct comparison revealed a significant correlation between high level of protein expression and increased GCN. All cases with GA showed protein overexpression. Furthermore, all with IHC 3+ showed GA except 1, even which could be categorised as GA according to the ASCO/CAP guideline for human epidermal growth factor receptor 2 assessment. IHC 3+ and GA were significantly associated with poor prognosis.

Conclusion:

MET IHC reflects well on GA, and therefore, it could be a primary screening test for patient selection for anti-MET therapy if GA is a major determinant of drug responsiveness. Also, the prognostic role of MET indicates that anti-MET therapy is a very promising modality in adjuvant treatment for gastric cancer.

BubR1 as a prognostic marker for recurrence-free survival rates in epithelial ovarian cancers

BACKGROUND

Epithelial ovarian cancer is one of the most lethal malignancies, and has a high recurrence rate. Thus, prognostic markers for recurrence are crucial for the care of ovarian cancer. As ovarian cancers frequently exhibit chromosome instability, we aimed at assessing the prognostic significance of two key mitotic kinases, BubR1 and Aurora A.

METHODS

We analysed paraffin-embedded tissue sections from 160 ovarian cancer patients whose clinical outcomes had been tracked after first-line treatment.

RESULTS

The median recurrence-free survival in patients with a positive and negative expression of BubR1 was 27 and 83 months, respectively (P<0.001). A positive BubR1 expression was also associated with advanced stage, serous histology and high grade. In contrast, Aurora A immunostaining did not correlate with any of the clinical parameters analysed.

CONCLUSION

BubR1, but not Aurora A, is a prognostic marker for recurrence-free survival rates in epithelial ovarian cancers.

Phase II study and biomarker analysis of cetuximab combined with modified FOLFOX6 in advanced gastric cancer

This prospective study was conducted with the Korean Cancer Study Group to evaluate the efficacy and safety of cetuximab combined with modified FOLFOX6 (mFOLFOX6) as first-line treatment in recurrent or metastatic gastric cancer and to identify potential predictive biomarkers. Patients received cetuximab 400 mg m⁻² at week 1 and 250 mg m⁻² weekly thereafter until disease progression. Oxaliplatin (100 mg m⁻²) and leucovorin (100 mg m⁻²) were administered as a 2-h infusion followed by a 46-h continuous infusion of 5-fluorouracil (2400 mg m⁻²) every 2 weeks for a maximum of 12 cycles. Biomarkers potentially associated with efficacy were analysed. Among 38 evaluable patients, confirmed response rate (RR) was 50.0% (95% CI 34.1–65.9). Median time-to-progression (TTP) was 5.5 months (95% CI 4.5–6.5) and overall survival (OS) 9.9 months. Eleven patients having tumour EGFR expression by immunohistochemistry with low serum EGF and TGF-α levels showed a 100% RR compared to 37.0% in the remaining 27 patients (P<0.001). Moreover, ligand level increased when disease progressed in seven out of eight patients with EGFR expression and low baseline ligand level. No patient exhibited EGFR amplification or K-ras mutations. Gastric cancer patients with EGFR expression and low ligand levels had better outcomes with cetuximab/mFOLFOX6 treatment.

Prognostic implications of type and density of tumour-infiltrating lymphocytes in gastric cancer

The study aims to determine whether type and density of tumour-infiltrating lymphocytes (TILs) can predict the clinical course in gastric cancer. Gastric carcinomas (n=220) were immunostained for CD3, CD8, CD20, and CD45RO and evaluated for clinicopathologic characteristics. Number of TILs that immunostained positively for each marker were counted using NIH ImageJ software. Tumours were grouped into low- and high-density groups for each marker (CD3, CD8, CD45RO). The densities of CD3(+), CD8(+), and CD45RO(+) TILs were found to be independent predictors of lymph node metastasis by multivariate analysis with odds ratios (95% CI) of 0.425 (0.204-0.885), 0.325 (0.150-0.707), and 0.402 (0.190-0.850), respectively. Kaplan-Meier survival analysis revealed that patients in the high-density groups for CD3, CD8, and C45RO had a significantly longer survival time than the patients in the corresponding low-density groups, respectively. In multivariate survival analysis, the densities of CD3(+), CD8(+), and CD45RO(+) TILs remained independent prognostic factors with hazard ratios (95% CI) of 0.549 (0.317-0.951), 0.574 (0.347-0.949), and 0.507 (0.298-0.862), respectively. In conclusion, density of TILs was found to be independently predictive of regional lymph node metastasis and patient survival in gastric cancer.

EGFR in gastric carcinomas: prognostic significance of protein overexpression and high gene copy number

AIMS

Epidermal growth factor receptor (EGFR) expression has been observed in a variety of solid tumours with the potential of new targeted therapeutic agents. The aim was to evaluate the EGFR status of gastric carcinoma (GC) using immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH).

METHODS AND RESULTS

The EGFR status was evaluated in GC tissues from 511 patients using IHC and FISH. In addition, the clinicopathological characteristics were examined and the results were compared with the EGFR status. One hundred and forty cases (27.4%) showed EGFR overexpression by IHC. EGFR overexpression was associated with older age (P = 0.001), moderately or poorly differentiated histology (P = 0.001) and higher stage disease (P = 0.046). Sixteen cases (3.1%) showed high polysomy and 12 cases (2.3%) had gene amplification by FISH. The correlation between IHC and FISH results was statistically significant (P < 0.001). The patients with GC who had EGFR overexpression had an unfavourable prognosis and multivariate analysis showed that EGFR overexpression was a possible independent unfavourable prognostic factor.

CONCLUSIONS

EGFR overexpression was observed in a subset of cases with GC and was associated with an unfavourable prognosis. It will be important to evaluate EGFR status to interpret future clinical trials properly using EGFR targeted agents.

Characteristics of KIT-negative gastrointestinal stromal tumours and diagnostic utility of protein kinase C theta immunostaining

AIMS

To characterise KIT-negative gastrointestinal stromal tumours (GISTs) clinically, pathologically, immunohistochemically and genetically, and to establish the usefulness of protein kinase C theta (PKC) as a diagnostic marker in KIT-negative GIST.

METHODS

252 consecutive cases of GIST were evaluated for clinicopathological characteristics and immunostained for various antibodies. Mutational analyses of KIT and platelet-derived growth factor receptor alpha (PDGFRA) were also performed in 62 cases.

RESULTS

20 (7.9%) GISTs showed negative immunostaining for KIT. KIT-negative GISTs were more likely to originate from omentum or peritoneum, have an epithelioid histology, and be classified as high risk. The overall survival rate of patients with KIT-negative GISTs (5-year survival rate 68.7% (SD 10.7%)) was lower than that of patients with KIT-positive GISTs (5-year survival rate, 79.9% (3.0%)) (p = 0.042, log-rank test). Negative KIT expression was an independent prognostic factor in multivariate Cox regression analysis when the risk of aggressive behaviour and the status of imatinib treatment were adopted as covariates. KIT-negative GISTs also showed lower expression rates of CD34, Bcl-2, and PKC than KIT-positive GISTs; mutational analysis revealed that 30% of KIT-negative GISTs harboured a PDGFRA exon 18 mutation. Immunostaining on PKC showed that 93.9% of all GISTs expressed PKC protein. However, 21.9% of 64 mesenchymal tumours other than GIST also showed positivity on PKC.

CONCLUSIONS

KIT-negative GISTs had characteristics that differ from those of KIT-positive GISTs, and negative KIT expression was an independent prognostic indicator for overall survival of patients. Although PKC is a sensitive diagnostic marker for GIST, its usefulness is limited because of low sensitivity and low specificity in KIT-negative GISTs.

Acute symptomatic seizures in CNS infection

To determine the frequency and aetiology of acute symptomatic seizures in central nervous system (CNS) infections and to assess the clinical factors predicting the occurrence of the seizures, we retrospectively reviewed the medical records of patients diagnosed with CNS infections from 2000 to 2005. One hundred and forty-seven patients were included in the study. The clinical variables between those with and without acute symptomatic seizures were compared. Of the 147 patients, 23% (34/147) had acute symptomatic seizures. A significant relation between clinical variables and the occurrence of acute symptomatic seizures was found: encephalitis as the aetiology of the CNS infection, Glasgow Coma Scale (GCS) < or =12, and neurological deficits. By multiple logistic regression analysis, age of onset >42 years, encephalitis, and GCS < or =12 were found to be independently significant clinical variables for predicting the occurrence of acute symptomatic seizures. Encephalitis and GCS < or =12 are significant clinical variables for predicting the occurrence of acute symptomatic seizures in CNS infection, suggesting that patients with a greater extent of parenchymal damage are more vulnerable to acute symptomatic seizures.

Maternal serum highly sensitive C-reactive protein in normal pregnancy and pre-eclampsia

OBJECTIVE

To establish reference values for highly sensitive C-reactive protein (hsCRP) in normal pregnancy and determine whether disease severity could be predicted by serum hsCRP concentration in women with severe pre-eclampsia (PE).

METHODS

Blood samples were collected from 25 pregnant women with severe PE and 202 healthy pregnant women who were divided into 4 groups by pregnancy duration. Levels of hsCRP were determined by the immunonephelometric method. Mean arterial pressure, time between delivery and diuresis, and mean ratio of systolic to diastolic blood flow velocity in uterine arteries were used as indicators of the severity of PE.

RESULTS

The median values of hsCRP in each group were 0.76 mg/L (0.16-13.61 mg/L), 1.53 mg/L (0.39-20.31 mg/L), 2.08 mg/L (0.50-9.45 mg/L), and 2.28 mg/L (0.44-8.11 mg/L) and showed a trend toward increase. Serum levels of hsCRP were positively correlated with each severity indicator of PE.

CONCLUSIONS

This study showed that hsCRP levels were positively correlated to pregnancy duration in healthy women and could be used as a severity marker in women with severe PE.

Right heart dysfunction in post-tuberculosis emphysema

SETTING

University-affiliated general hospital.

OBJECTIVE

To evaluate the pump performance of right heart before and after exercise in post-tuberculosis emphysema.

DESIGN

In patients with post-tuberculosis or primary emphysema (similar lung volumes), body plethysmography, arterial blood gas analysis and echocardiography were performed at rest and after exercise. Right heart pump performance was evaluated with the ejection fraction.

RESULTS

At rest, in post-tuberculosis emphysema, diffusing capacity (mean +/- SE 72.7 +/- 3.9 vs. 91.0 +/- 7.1% of reference) and right ventricular ejection fraction (57.5 + 1.4 vs. 61.3 +/- 1.2%) were lower and PaCO2 (42.7 +/- 1.1 vs. 38.6 +/- 0.7 mmHg) was higher, while lung compliance, airway resistance, PaO2, and alveolar-arterial oxygen difference were not different. After exercise, PaO2 (65.6 +/- 2.8 vs. 80.5 +/- 3.5 mmHg) and right ventricular ejection fraction (51.2 +/- 2.4 vs. 59.6 +/- 1.7%) were lower and PaCO2 (47.0 +/- 1.5 vs. 40.9 +/- 1.5 mmHg) was higher in post-tuberculosis emphysema, whereas alveolar-arterial oxygen difference was not different. PaCO2 and alveolar-arterial oxygen difference increased, and PaO2 and right ventricular ejection fraction decreased in post-tuberculosis emphysema, while they did not significantly change in primary emphysema.

CONCLUSION

In post-tuberculosis emphysema, the impairment of gas exchange was more serious. Global assessment should be focused on right heart dysfunction which might be more affected than in primary emphysema.

Knowledge and performance of the universal precautions by nursing and medical students in Korea

BACKGROUND

Like the health care workers, nursing and medical students have to go through clinical practices; accordingly, they run a high risk of being exposed to bloodborne diseases. But there are few studies on the realities of preventive education or measures to be taken after exposure to such diseases. The purpose of this study was to identify a knowledge of universal precautions and their performance in practice among the nursing and medical students in Korea.

METHOD

This study was based on survey questionnaires with a total of 714 nursing and medical students for the period between November 2, 1998, and April 30, 2000.

RESULTS

The average knowledge level of the universal precautions was 267.8 +/- 21.3 (scores ranged from 150 to 300). The knowledge level of the universal precautions of the nursing students (270.4 +/- 19.4) was higher than that of the medical students (261.0 +/- 24.4; P =.000). The average performance level of the universal precautions was 52.7 +/- 6.2 (scores ranged from 14 to 70). The students of the nursing college showed a higher performance level of the universal precautions (53.2 +/- 5.9; P =.002). The correlation between knowledge and performance of the universal precautions showed a weak and positive correlation (r =.317; P=.000).

CONCLUSION

The study demonstrated that the knowledge level of the nursing students about universal precautions was relatively higher than that of medical students. The group that receives education about universal precautions has a higher level of knowledge and performance of the universal precautions than that group that receives no such education. The education about universal precautions is indispensable; it is desirable to raise the relative importance for the curriculum of both nursing and medical colleges.

The advantages of On-line transesophageal echocardiography guide during percutaneous balloon mitral valvuloplasty

The purpose of this study was to evaluate the potential advantages of on-line transesophageal echocardiography during percutaneous balloon mitral valvuloplasty (PBMV). One hundred thirty-four consecutive patients who underwent PBMV were included in this study. Group 1 included 64 patients who underwent PBMV under fluoroscopy guide only, and group 2 included 70 patients who underwent PBMV under on-line transesophageal echocardiography guide. Inoue balloons were used in all cases. The mitral valve area after valvuloplasty was comparable between the 2 groups. The procedure time was significantly shorter in group 2 (99 +/- 48 min vs 64 +/- 22 min, P <.0001 ), and the average fluoroscopy time was shorter in group 2 without statistical significance (30 +/- 17 min vs 19 +/- 15 min, P =.25 ). Five (7.8%) patients in group 1 and 2 (2.8%) patients in group 2 underwent surgery because of procedure-related complications. The limitation of this study was the learning curve of the operator, because the 2 groups were treated serially. In conclusion, transesophageal echocardiography can be used effectively during balloon mitral valvuloplasty, and it may help to reduce the rate of complications resulting from trans-septal catheterization and balloon valvuloplasty and to reduce procedure time and fluoroscopy time.

Metabotropic glutamate receptor mGluR2/3 immunoreactivity in the mouse superior colliculus: co-localization with calbindin D28K

We have studied the distribution of mGluR2/3 in the mouse superior colliculus (SC) with antibody immunocytochemistry and the effect of enucleation on this distribution. We also compared this labeling to that for calbindin D28K. Anti-mGluR2/3-immunoreactive (IR) cells formed distinctive laminar patterns within the lower optic and upper intermediate gray layers. By contrast, anti-calbindin D28K-IR cells formed obvious laminar patterns in three layers: one within the zonal and upper superficial gray layers, a second within the optic and intermediate gray layers, and the third within the deep gray layer. The distribution of mGluR2/3-IR cells thus matches the second layer of calbindin D28K cells. Two-color immunofluorescence revealed that more than half (52.5%) of mGluR2/3-IR cells were also labeled with antibody to calbindin D28K. The majority of mGluR2/3-IR cells were small to medium-sized round/oval or stellate cells. Immunoreactivity for mGluR2/3 was clearly reduced in the contralateral SC following unilateral enucleation. The present results show that mGluR2/3 has a unique cellular sublaminar organization in SC that includes some calbindin D28K-IR cells. The effects of enucleation suggest that the retinal projection may control the expression of mGluR2/3 in some cells in the mouse SC.

Equilibrium and non-equilibrium partition of tritium between organics and tissue water of different biological systems

The biological tritium fractionation factor, accompanying the equilibrium partition of tritium between the organic and the aqueous phases of the biosystem through isotope effects on the enzyme reactions of its metabolism, has been determined. The ratio (R) of the specific activities of organically bound tritium and tissue water tritium has been measured under special conditions to eliminate analytical as well as biological interfering effects that possibly alter the experimental R value. Two plant categories with distinct photosynthetic CO2-fixation pathways, adapted to their different water use efficiency, namely barley (C3 plant) and maize (C4 plant), have been compared in order to estimate the natural variation of the biological tritium fractionation factors among different biosystems.

Cardiac amyloidosis diagnosed by endomyocardial biopsy

A 56-year-old male patient who had a history of syncopal attack was diagnosed as having cardiac amyloidosis. His ECG finding showed a pattern of inferior and anteroseptal wall infarction with Wenckebach AV block.

Echocardiographic examination revealed that the LV posterior wall and interventricular septum were markedly thickened with granular sparkling.

We demonstrated the amyloid deposit in the myocardium by endomyocardial biopsy.

Pathology showed a green white birefringence by polarizing illumination and amyloid fibril in electron microscopic study.

Lymphocyte proliferation and nucleoid sedimentation in a case of premature aging distinct from Werner's syndrome

Lymphocyte proliferation and nucleoid sedimentation were studied in a patient with premature aging resembling the Werner's syndrome (WS). Onset of patchy brown hyperpigmentations at the age of 9 months permitted distinction from classical WS and suggested a WS-like premature aging disease. By photometric recording of density changes during cell culture, we examined the course of cell proliferation after PHA stimulation over 7 days and compared these results to those obtained in two normal controls. Cultured cells of the patient displayed an aberrant proliferation pattern characterized by continuous growth without an initial reduction phase. The markedly reduced proliferative capacity of purified cells from the patient could in part be corrected by fetal bovine serum. The cells of the patient displayed a characteristic nucleoid sedimentation profile after ultraviolet irradiation indicating retarded DNA replication, which may be a common feature of various premature aging diseases. The absence of thermolability of cell proliferation and the presence of a high number of chromatid aberrations disclosed differences from classical WS.

The reduction of allyl alcohols by Clostridium species is catalyzed by the combined action of alcohol dehydrogenase and enoate reductase

Cells, as well as crude extracts of Clostridium kluyveri or Clostridium spec. La 1, catalyze the hydrogenation of (E)- or (Z)-2-butenol to n-butanol. No single enzyme could be detected which directly accomplishes this reaction. It turned out that the reduction occurs as follows: 2-butenol leads to 2-butenal leads to n-butanal leads to n-butanol. The first step is catalyzed by the NAD-dependent alcohol dehydrogenase in C. kluyveri, the second by the recently detected enoate reductase which reduces not only nonactivated alpha, beta-unsaturated acylates but also alpha, beta-unsaturated aldehydes in a NADH-dependent reaction and the third step is again catalyzed by alcohol dehydrogenase. In Clostridium La 1 the alcohol dehydrogenase is NADP-dependent. The rate of the reduction of 2-butenol to n-butanol depends not only on the enzymes, but also on the ratio NAD(P)/NAD(P)H. In the presence of methylviologen cation radical which is formed by the reduction of methylviologen by the system H2/hydrogenase, the ratio NAD(P)/NAD(P)H is too small for the dehydrogenation of 2-butenol to 2-butenal. This explains the antagonistic effect of methylviologen in the hydrogenation of allyl alcohols and 2-enoates by both Clostridium species. Furthermore, the mechanism explains the finding that from a preparative point of view ethanol is a better electron donor than hydrogen for the stereospecific reduction of allyl alcohols.

[DNA repair in xeroderma pigmentosum]

DNA-repair of two patients affected with xeroderma pigmentosum was evaluated in lymphocytes after UV-exposure by mitotic index, sister chromatid exchange (SCE) and nucleoid sedimentation. The first patient showed no increase in SCE-rate and a sedimentation profile typical of repair deficient cells. In the second patient an increase in SCE-rate and a considerable, but delayed DNA-repair activity in nucleoid sedimentation was found indicating 2 genetically different defects of DNA-repair. In the second patient a defect of postreplication repair is assumed.

Demonstration of heterogeneity in xeroderma pigmentosum

Two cases of xeroderma pigmentosum were studied at the cytogenetic and molecular level. DNA repair impairment was revealed in case 1 by a nucleoid sedimentation technique whereas a half diminished rate of DNA repair could be demonstrated in case 2. This may be a further case of a xeroderma pigmentosum variant.

[The influence of highly purified hCG on the immunocompetence of human lymphocytes and DNA repair system]

PHA-stimulation of human T-lymphocytes, a parameter of cellular immunocompetence, can be suppressed by highly purified human chorionic gonadotropin (hCG) in a dose-dependent manner. This was shown spectrophotometrically and by the mitosis index. Our results are in agreement with H3-thymidine incorporation studies. We further investigated the DNA repair system in UV-light- and hCG-explsed lymphocytes. It could be shown that DNA repair-replication is disturbed by hCG. Such repair disturbances may cause reduced H3-thymidine incorporation in PHA-stimulated and hCG-treated lymphocytes. It is probably on this molecular level that hCG influences the immunocompetence of human lymphocytes.

[Reciprocal translocation t (5p--;19p+) in three generations (author's transl)]

A reciprocal translocation t (5p-;19p+) in 3 generations is reported. Three carriers with this translocation were healthy, the propositus with the same translocation showed cheilopalatochisis bilaterally, microphthalmus, coloboma of the retina and dysplasia of the hip joints. The cytogenetically unremarkable father of the propositus exhibited micropthalmus and coloboma of the disc and a bifid uvula. It was supposed that there is no correlation between caryotype and phenotype in the propositus. His abnormalities might be induced genetically by the father. The risk data for the descendants of carriers with balanced translocations are discussed.

Late replicating bands of human chromosomes demonstrated by fluorochrome and Giemsa staining

The addition of thymidine (TdR) to cells growing in a medium containing 5-bromodeoxyuridine (BUdR) at the end of the first replication cycle results in the incorporation of TdR into the late replicating DNA regions. These sites can be visualized by staining the metaphase chromosomes with the fluorescent dye "33258 Hoechst" or a "33258 Hoechst" Giemsa procedure. A sequence of late replication patterns has been established in metaphase chromosomes of cultured human peripheral lymphocytes. The patterns are in agreement with those obtained by the standard autoradiographic procedures, but are more accurate. As is known from autoradiography, late replicating bands are in the position of G or Q bands. The "33258 Hoechst" Giemsa staining procedure of chromosomes which have replicated in the presence of BUdR first and in TdR for the last 2 hrs of the S phase is preferable to the currently used Giemsa banding techniques: the method yields very well banded metaphases in all preparations examined, as the chromosome structure is not disrupted by the pretreatment. The bands are very distinct, even in the "difficult" chromosomes (e.g. No. 4, 5, 8 and X). In female cells the late replicating X chromosome can be identified by its size and staining pattern. In addition to the replication asynchrony, the sequence of replication within both X chromosomes in female cells is not absolutely identical. The phenomenon of a phase difference in replication between the homologues is not a peculiarity of the X chromosome, but can be found in all autosomes as well as in homologous positions on the chromatids of individual chromosomes.

Fluorometrical detection of thymine base differences in complementary strands of satellite DNA in human metaphase chromosomes

Using the fluorochrome "Hoechst 33258", intensity of fluorescence was found to differ distinctly between the sister chromatids in the paracentric regions of chromosomes 1, 16, and 19, after one round of replication in medium containing BUdR. Thus the effect of fluorescence asymmetry is not limited to the part of the Y chromosomes that fluoresces intensely with quinacrine; it can also be determined in the weakly Q-fluorescent pericentric regions of chromosomes, which are known to be the sites where highly reiterated sequences of satellite DNA are located. However, an exception is the paracentric region of chromosome 9 which does not show the effect of lateral asymmetry. The difference of fluorescence intensity in the heterochromatic regions of the sister chromatids of human chromosome 1 is measured by densitometric tracement along the long axes of chromosomes; this is obtained from two individuals with an "uncoiler" heterchomatic block (type III) having a relative intensity of 1:1.93 in an average of the total measured blocks. This corresponds to the uneven distribution of thymine base of 22.8 and 43.2 in the two strands of the DNA double hexlix. A chromatid exchange rate of 9 in 100 metaphases per cell cycle was found within the uncoiler region of chromosome 1.

Giemsa staining of the sites replicating DNA early in human lymphocyte chromosomes

A timetable for the initiation of DNA replication in human lymphocyte chromosomes has been established by a technique which allows detection of areas of chromosomes replicating at a given interval of the S-phase. The resolution of the method, using 33258 Hoechst-Giemsa staining, is more refined than that obtained with 3H-thymidine autoradiography. Early replicating regions coincide with R-bands. The timetable is rather coarse since replication may start asynchronously in the same region of homologous autosomes of the same metaphase and since even the sequence of bands appearing on individual chromosomes sometimes deviates from the rule.

Correlation of light and electron micrographs of human metaphase chromosomes after incorporation of BUdR and staining with "33258 Hoechst" and Giemsa

Stained (Giemsa, "33258 Hoechst"1) and "33258 Hoechst" + Giemsa) and unstained metaphase chromosomes from human peripheral lymphocytes, after two rounds of replication in the presence of 5-bromodeoxyuridine (BUdR), have been prepared for electron microscopy. There is a positive correlation between light and electron micrographs. The same differential contrast on electron micrographs has been obtained whether the preparations have been stained or not. We attribute this differential contrast primarily to the lesser condensation of the bifilarly substituted chromatid.