Immunogenic Properties of Structurally Modified Human Tissue Plasminogen Activators in Chimpanzees and Mice

Immunogenic properties of second generation human tissue plasminogenactivator (tPA) derivatives were examined in chimpanzee andmouse systems. Five species of modified tPAs (mtPAs) (designated2660, 2663, 2810, 8000, and 9200), recombinant native tPA orbovine serum albumin (BSA) as a positive control were subcutaneouslyinjected nine times at suitable intervals into chimpanzees,genetically the closest species to man. These animals were testedfor antigen(Ag)-specific antibodies to the corresponding proteinsby means of enzyme-linked immunosorbent assay and Western blotanalysis. Neither 9200, one of the five mtPAs tested, nor tPAwas immunogenic, although BSA and the other four mtPAs wereimmunogenic under these conditions. Thus, an antigenic determinant was not exposed by the modification on 9200 and thismodified tPA is expected not to be immunogenic in humans. Inthe mouse studies, mice were immunized with mtPAs. Serum sam-piesfrom these animals were tested for antibodies to the mtPAs whichdid not concomitantly recognize native tPA by immune ad sorptionof the antibodies to tPA. The amount of such antibodies alterthe elimination of native tPA-reactive antibodies was littleor none when the serum samples from 9200 and from the othermtPAs, except 8000, were tested. Taking into consideration theresults of the chimpanzee studies, it can be concluded thatAg-specific antibodies are dominantly produced to unchangedepitopes present in modified proteins in the mouse system, inwhich the native protein is immunogenic. These results suggestthat the chimpanzee model should be useful to predict immunogenicityof second generation recombinant proteins in man, while themouse system adopted by us, which determines the newly generatedepitopes of the modified proteins, is not sufficient.     

Pharmacokinetics of antibiotics in neonates

The pharmacodynamics in neonates are different from those in adults and children because the absorption, distribution, metabolism and excretion of drugs in neonates are always changing for the following reasons. In neonates, the proportion of extracellular fluid is large; the amount of plasma protein is small; renal function is immature; and the hepatic enzyme system is immature. In addition, individual birthweights, gestational ages in weeks, cardiopulmonary functions and renal excretory functions vary. All of these factors should be considered when selecting the dose and administration method of a drug. In concrete terms the distribution volume is large, which causes a low maximum concentration. In addition neonate renal excretory function is low and the hepatic enzyme system is immature, thus the half-life of drugs is prolonged. Therefore, the same dose per unit time as that for children (including infants) needs to be administered to neonates at dosing intervals that may be prolonged according to renal function.     

Effects of glycyrrhizin on immune-mediated cytotoxicity

Intravenous administration of glycyrrhizin is known to decrease elevated plasma transaminase levels in patients with chronic viral hepatitis, in which immune-mediated cytotoxicity by cytotoxic T lymphocytes and tumour necrosis factor (TNF)-α is considered to play an important pathogenic role. However, the immunological interpretation of the transaminase-lowering action of glycyrrhizin is not known. Studies were performed to elucidate this action immunologically by assessing the effects of glycyrrhizin on immune-mediated cytotoxicity using an antigen-specific murine CD4⁺ T hybridoma line, which exhibits cytotoxicity against antigen-presenting cells after stimulation with specific antigen, and a murine TNF-α-sensitive fibroblast line. Glycyrrhizin inhibited the cytotoxic activity of the T cells against antigen-presenting cells and also suppressed TNF-α-induced cytotoxicity in the TNF-α-sensitive cell line in vitro. These results suggest that the decrease of elevated transaminase levels by glycyrrhizin in patients with chronic viral hepatitis is mediated in part by inhibition of immune-mediated cytotoxicity against hepatocytes.     

The influence of physical restraint or fasting on plaque-forming cell response in mice

Abstract This study was designed to investigate the effects of 1- and 3-day (16 h/day) physically restrained or fasting on immunological and endocrine responses in CBF1 mice. The influence of stressors on these responses was evaluated using anti-sheep red blood cell plaque-forming assay, and by examining T cell subsets, thymus weight and endocrine hormone levels. The results revealed that a significant elevation of the plaque-forming cells (PFC) was found in spleen cells in 1-day restrained mice, that the PFC were conversely suppressed following 3-day physically restrained stress, and that the PFC were not affected by 1- or 3-day fasting stress. Serum levels of norepinephrine were found to be significantly increased only in 1-day physically restrained mice. No change of T cell subsets and thymus weight was found in 1-day physically restrained mice. A significant increase in serum corticosterone levels was elicited in both 1- and 3-day physically restrained mice, and 3-day fasting mice, while increased Lyt2-positive T cells and thymic atrophy were found only in 3-day physically restrained mice. These findings suggest that immune function was differentially affected by the duration and types of stressors.     

Longitudinal Dissociation in the His Bundle: A Possible Mechanism of Two Distinct Cycle Lengths in Atrioventricular Reentrant Tachycardia

Two wide QRS tachycardias with identical morphology but different cycle lengths (CLs) developed in a 63-year-old man. Electrophysiological study demonstrated inducible atrioventricular reentrant tachycardia (AVRT) due to a concealed left posterior accessory pathway (AP), which was successfully ablated by radiofrequency application. Neither dual AV nodal pathways nor other APs were documented. Splitting of the His-bundle electrogram was shown, and programmed stimulation induced sudden prolongation of intra-hisian conduction time. These results suggest longitudinal dissociation in the His bundle may be responsible for two distinct CLs in AVRT without dualAV nodal physiology.     

Assessment of Angiographic Coronary Calcification and Plaque Composition in Virtual Histology Intravascular Ultrasound

Objectives

We assessed the relation between coronary plaque composition and angiographic calcification by using virtual histology intravascular ultrasound (VH‐IVUS).

Background

The plaque vulnerability according to angiographic calcification is unclear.

Methods

Subjects were 140 consecutive patients (145 lesions) undergoing VH‐IVUS before percutaneous coronary intervention. Subjects were divided into 4 groups: no calcification group (n = 27), spotty group (n = 65) that had calcium deposits under 90° in grayscale IVUS, intermediate group (n = 37) had calcium deposits with 90° or more and under 180°, and extensive group (n = 16) had calcium deposits with 180° or more.

Results

The number of VH thin‐cap fibroatheromas in spotty group was significantly larger than no calcification group, intermediate group, and extensive group (0.66 ± 0.71 vs 0.22 ± 0.42 [P < 0.01], 0.32 ± 0.48 [P < 0.05], 0.13 ± 0.34 [P < 0.01], respectively). Spotty group without angiographic calcification had significantly larger %necrotic core than with angiographic calcification (24.5 ± 6.7% vs 19.9 ± 7.2%, P < 0.05). Intermediate group without angiographic calcification had significantly larger necrotic core area than with angiographic calcification (2.5 ± 0.9 mm² vs 1.7 ± 0.9 mm², P < 0.05). Extensive group with angiographic calcification had significantly larger %dense calcium than without angiographic calcification (18.3 ± 4.0% vs 13.4 ± 4.4%, P < 0.05).

Conclusions

Lesions with spotty calcification was highly vulnerable in VH‐IVUS. Spotty or intermediate plaque calcification without angiographic calcification was more vulnerable than those with angiographic calcification. Extensive plaque calcification with angiographic calcification had more dense calcium than those without angiographic calcification.

     

Increased urinary excretion of human cytomegalovirus in children with malignancy: Detection by polymerase chain reaction

Human cytomegalovirus (HCMV) is one of the most important agents causing opportunistic infections in immunocompromised hosts. In this study, we examined the urinary excretion of HCMV in children with malignancy using polymerase chain reaction (PCR). Urine samples were collected from on-therapy, off-therapy patients with malignancy, and healthy controls. A simple DNA extraction method using glass powder was employed, and inhibitory effect of urine on PCR was prevented. For PCR, a pair of primers from the HCMV major immediate early gene sequence was used. Among patients who received intensive chemotherapy, 52.0% had urinary HCMV excretion after the chemotherapy course. In contrast, off-therapy patients and healthy controls showed a lower incidence of urinary HCMV excretion (20.4 and 8.7%, respectively). The incidence of HCMV urinary excretion in the on-therapy group was significantly higher than healthy controls (P < 0.05). In the on-therapy group, the total white blood cell count of the virus excreters was lower than that of non-excreters. The incidence of HCMV excretion was high in on-therapy patients. Most of the virus excreters were seropositive, so their viruria was thought to be caused by reactivation. Repeated monitoring of virus excretion by this rapid and simple method may be useful to detect HCMV infection early and to control it in such patients.     

Aldo-keto reductase family 1, member B10 in uterine carcinomas: a potential risk factor of recurrence after surgical therapy in cervical cancer

Aldo-keto reductase family 1, member B10 (AKR1B10), an enzyme that converts retinals into retinols is known to detect in non-small cell lung carcinoma (squamous cell- and adeno-carcinomas), but is barely expressed in normal tissues. Since these types of carcinoma occur frequently in the uterus (like in the lung), AKR1B10 may also be overexpressed in two major types of uterine cancer, cervical cancer (CC), and endometrial cancer (EMC). The objective of this study is to investigate AKR1B10 expression in uterine cancer and to analyze its clinical significance. In samples from uterine cancer patients, AKR1B10 was detected in 6 out of 30 (20.0%) CC cases and 6 out of 38 (15.8%) EMC cases. Statistical analysis indicated that AKR1B10 expression was associated with tumor recurrence after surgery and keratinization of squamous cell carcinoma only in CC. Although retinol (a metabolic product by AKR1B10) was observed in the normal epithelium, the molecule was not observed in cancer cells of AKR1B10-positive CC samples suggesting that the recurrence in CC may not depend on the convert of retinals into retinols via AKR1B10, a potential indicator in the management of patients with CC.     

Pyruvate dehydrogenase complex deficiency with multiple minor anomalies

Pyruvate dehydrogenase complex (PDHC) deficiency is known to cause congenital lactic acidosis. The case of a 9-month-old female infant with PDHC deficiency caused by a mutation in exon 11 of the pyruvate dehydrogenase (PDH) Elα gene is described. Her facial features were as follows: frontal bossing, upslanting palpebral fissures, a short upturned nose, a long philtrum and low set ears. These anomalies are characteristic not only of a malformation syndrome or chromosomal aberration, but also of PDHC deficiency. Because PDHC deficiency requires early treatment, metabolic disorders should be kept in mind in a patient with dysmorphic features. Further, she had multiple minor anomalies including bilateral inguinal herniae, an umbilical hernia and small hands and feet, which have not been described in previous reports.     

Potentiation of carbon tetrachloride-induced liver damage by dibutylyl-3',5'-cyclic AMP in unstarved rats

It has been reported that carbon tetrachloride-induced liver damage is potentiated by starvation partly due to fat accumulation in the liver and a decrease in hepatic reduced glutathione concentration and that dibutylyl-3′,5′-cyclic AMP (DBcAMP) affects fuel metabolism and decreases hepatic reduced glutathione. We investigated the effects of DBcAMP on carbon tetrachloride-induced liver damage both in unstarved and starved rats. In unstarved rats, intraperitoneal administration of DBcAMP potentiated an increase in serum alanine aminotransferase activity and fatty vacuolization in the liver, both of which were induced by carbon tetrachloride. Hepatic reduced glutathione concentration was also reduced by DBcAMP, although the change was not significant. In contrast, the administration of DBcAMP in starved rats did not affect carbon tetrachloride-induced changes in serum alanine aminotransferase activity, histological alterations and hepatic reduced glutathione concentration. Administration of DBcAMP to control rats induced different responses in unstarved control rats compared with starved control rats: in unstarved rats, blood glucose concentration decreased but serum free fatty acid concentration increased, whereas in starved rats, blood glucose concentration increased and serum free fatty acid concentration decreased. It was suggested that DBcAMP potentiated carbon tetrachloride-induced liver damage in unstarved rats, probably due to hepatic fat accumulation and a decreased hepatic reduced glutathione concentration. The former could increase the affinity of the liver for carbon tetrachloride and the latter could accelerate carbon tetrachloride-induced lipid peroxidation. It was also suggested that DBcAMP failed to affect carbon tetrachloride-induced liver damage in starved rats, probably because starvation had already decreased hepatic glutathione concentration and DBcAMP had different effects on fuel metabolism compared with effects observed in unstarved rats.