Impact of vaccination with SCB-2019 COVID-19 vaccine on transmission of SARS-CoV-2 infection: a household contact study in the Philippines

Background

An exploratory household transmission study was nested in SPECTRA, the phase 2/3 efficacy study of the adjuvanted recombinant protein-based COVID-19 vaccine SCB-2019. We compared occurrence of confirmed COVID-19 infections between households and household contacts of infected SPECTRA placebo or SCB-2019 recipients.

Methods

SPECTRA participants at eight study sites in the Philippines who developed rRT-PCR-confirmed COVID-19 were contacted by a study team blinded to assignment of index cases to vaccine or placebo groups to enroll in this household transmission study. Enrolled households and household contacts were monitored for three weeks using rRT-PCR and anti-SARS-CoV-2 N-antigen IgG/IgM testing to detect new COVID-19 infections.

Results

154 eligible COVID-19 index cases (51 vaccinees, 103 placebo) were included. The secondary attack rate per household for symptomatic COVID-19 infection was 0.76% (90% CI: 0.15–3.90) if the index case was a SCB-2019 vaccinee compared with 5.88% (90% CI: 3.20–10.8) for placebo index cases, a relative risk reduction (RRR) of 79% (90% CI: -28–97). The RRR of symptomatic COVID-19 per household member was similar: 84% (90% CI: 28–97). Impact on attack rates in household members if index cases were symptomatic (n = 130; RRR = 80%; 90% CI: 7–96) or asymptomatic (n = 24; RRR = 100%; 90% CI: -76–100) was measurable but the low numbers undermine the clinical significance.

Conclusions

In this prospective household contact study vaccination with SCB-2019 reduced SARS-CoV-2 transmission compared with placebo in households and in household members independently of whether index cases were symptomatic or not.

Surge of Typhoid Intestinal Perforations as Possible Result of COVID-19-Associated Delays in Seeking Care, Madagascar

During the coronavirus disease pandemic, we observed a 6.4-fold increase in typhoid intestinal perforation incidence in Antananarivo, Madagascar. Thirteen perforations occurred within 6 months (February 2020–July 2020), compared with 13 perforations during the previous 41 months (August 2016–January 2020). The increase may be attributable to delayed healthcare seeking during the pandemic.

Hospital Volume of Emergency General Surgery and its Impact on Inpatient Mortality for Geriatric Patients: Analysis From 3994 Hospitals

BACKGROUND

Previous investigations have shown a positive association between hospital volume of operations and clinical outcomes. However, it is unclear whether such relationships also apply to emergency surgery. We sought to examine the association between hospital case volume and inpatient mortality for 7 common emergency general surgery (EGS) operations among geriatric patients.

METHODS

This is a population based retrospective cohort study using the Centers of Medicare and Medicaid Services (CMS) Limited Dataset Files (LDS) from 2011 to 2013. The 7 most common emergency surgeries included (1) partial colectomy, (2) small-bowel resection (SBR), (3) cholecystectomy, (4) appendectomy, (5) lysis of adhesions (LOA), (6) operative management of peptic ulcer disease (PUD), and (7) laparotomy with the primary outcome being inpatient mortality. Risk-adjusted inpatient mortality was plotted against operative volume. Subsequently an operative volume threshold was calculated using a best fit regression method. Based on these estimates, high- and low-volume hospitals were compared to examine significance of outcomes. Significance was defined as P-value < .05.

RESULTS

The final cohort comprised of 414 779 patients from 3994 hospitals. The standardized mortality ratio (SMR) for high-volume centers were lower in 6 out of 8 surgeries examined. Small-bowel resection and partial colectomy operations had a significant decrease in mortality based on a volume threshold.

CONCLUSION

We observed decreased mortality with higher surgical volume for small-bowel resection and partial colectomy operations. Such differences may be related to practice patterns during the perioperative period, as complications related to the perioperative care were significantly lower for high-volume centers.

Networks of face-to-face social contacts in Niakhar, Senegal

We present the first analysis of face-to-face contact network data from Niakhar, Senegal. Participants in a cluster-randomized influenza vaccine trial were interviewed about their contact patterns when they reported symptoms during their weekly household surveillance visit. We employ a negative binomial model to estimate effects of covariates on contact degree. We estimate the mean contact degree for asymptomatic Niakhar residents to be 16.5 (95% C.I. 14.3, 18.7) in the morning and 14.8 in the afternoon (95% C.I. 12.7, 16.9). We estimate that symptomatic people make 10% fewer contacts than asymptomatic people (95% C.I. 5%, 16%; p = 0.006), and those aged 0-5 make 33% fewer contacts than adults (95% C.I. 29%, 37%; p < 0.001). By explicitly modelling the partial rounding pattern observed in our data, we make inference for both the underlying (true) distribution of contacts as well as for the reported distribution. We created an estimator for homophily by compound (household) membership and estimate that 48% of contacts by symptomatic people are made to their own compound members in the morning (95% CI, 45%, 52%) and 60% in the afternoon/evening (95% CI, 56%, 64%). We did not find a significant effect of symptom status on compound homophily. We compare our findings to those from other countries and make design recommendations for future surveys.

Effects of infection history on dengue virus infection and pathogenicity

The understanding of immunological interactions among the four dengue virus (DENV) serotypes and their epidemiological implications is often hampered by the lack of individual-level infection history. Using a statistical framework that infers full infection history, we analyze a prospective pediatric cohort in Nicaragua to characterize how infection history modulates the risks of DENV infection and subsequent clinical disease. After controlling for age, one prior infection is associated with 54% lower, while two or more are associated with 91% higher, risk of a new infection, compared to DENV-naive children. Children >8 years old have 55% and 120% higher risks of infection and subsequent disease, respectively, than their younger peers. Among children with ≥1 prior infection, intermediate antibody titers increase, whereas high titers lower, the risk of subsequent infection, compared with undetectable titers. Such complex dependency needs to be considered in the design of dengue vaccines and vaccination strategies.

Rice Fortification: An Emerging Opportunity to Contribute to the Elimination of Vitamin and Mineral Deficiency Worldwide

Vitamin and mineral deficiencies are ranked among the top causes of poor health and disability in the world. These deficiencies damage developing brains, impair learning ability, increase susceptibility to infections, and reduce the work productivity of nations. Food fortification is a sustainable, cost-effective approach to reducing vitamin and mineral deficiency. As the staple food for an estimated 3 billion people, rice has the potential to fill an obvious gap in current fortification programs. In recent years, new technologies have produced fortified rice kernels that are efficacious in reducing vitamin and mineral deficiency. There are opportunities to fortify a significant share of rice that comes from large mills supplying centralized markets and national welfare programs in major rice-growing countries. The rice export markets, which handle 30 million MT of rice annually, also present a key fortification opportunity. The cost of fortifying rice is only 1.5% to 3% of the current retail price of rice. Countries that mandate rice fortification have the strongest evidence for achieving wide coverage and impact. The Rice Fortification Resource Group (RiFoRG), a global network of public and private partners that offers technical and advocacy support for rice fortification, has a vision of promoting rice fortification worldwide. It has a targeted approach, engaging multisector partners in key countries where the opportunities are greatest and there is receptivity to early adoption of large-scale rice fortification. The challenges are real, the imperative to address them is powerful, and the opportunities to deliver the promise of rice fortification are clear.

Age related changes in 5-methylcytosine content in human peripheral leukocytes and placentas: an HPLC-based study

The goal of the present study was to investigate inter-individual and age-dependent variation of global DNA methylation in human tissues. In this work, we examined 5-methyldeoxycytidine ((met)C) content by HPLC in human peripheral blood leukocytes obtained from 76 healthy individuals of ages varying from 4 to 94 years (yr), and 39 human placentas from various gestational stages. The HPLC analysis revealed a significant variation of (met)C across individuals and is consistent with the previous findings of age-dependent decrease of global methylation levels in human tissues. The age-dependent decrease of (met)C was relatively small, but statistically highly significant (p= 0.0002) in the aged group (65.9 +/- 8.9 [mean age +/- SD] yr; n = 22) in comparison to the young adult group (19.3 +/- 1.4 yr; n = 21). Males showed a subtle but statistically significant higher mean (met)C content than females. In contrast to the peripheral blood samples, DNA extracted from placentas exhibited gestational stage-dependent increase of methylation levels that appeared to inversely correlate with the expression levels of human endogenous retroviruses. These data may be helpful in further studies of DNA methylation, such as inheritance of epigenetic patterns, environment-induced changes, and involvement of epigenetic changes in disease.

Efficient liquid-phase synthesis of short-length nucleotides via the phosphoramidite method using stoichiometric amounts of reactants

The condensation of a nucleoside phosphoramidite and a nucleoside by the aid of a suitable promoter in stoichiometric use is achieved in acetonitrile in the presence of molecular sieves 3A or 4A to give a desired coupling product in an excellent yield. This strategy is particularly useful for the large-scale synthesis of short nucleotides.

Medullary reticulospinal tract mediating the generalized motor inhibition in cats: II. Functional organization within the medullary reticular formation with respect to postsynaptic inhibition of forelimb and hindlimb motoneurons

We compared postsynaptic inhibitory effects on forelimb motoneurons and those on hindlimb motoneurons during generalized motor inhibition evoked by stimulating the medullary reticular formation in decerebrate cats. Here, we address two questions. First, whether the medullary inhibitory effects upon forelimb motoneurons are equivalent to those upon hindlimb motoneurons. Second, whether there is a somatotopographical organization within the medullary reticular formation in terms of inhibitory connections with motoneurons. Repetitive stimulation (20-50 microA, 50-100 Hz) delivered to the dorsomedial medullary reticular formation bilaterally suppressed muscle tone of both the forelimbs and hindlimbs. The medullary stimulation hyperpolarized the membrane potentials of the forelimb (5.4+/-1.8 mV, n=46) and hindlimb (5.4+/-2.0 mV, n=59) motoneurons together with a decrease in input resistance. The degree of membrane hyperpolarization and input resistance was not different in the forelimb and hindlimb motoneurons. The medullary stimulation also depressed the capability of generating antidromic and orthodromic spikes in the motoneurons. Stimuli with pulse trains (one to three pulses, 5-10-ms intervals, 20-50 microA) applied to the medullary inhibitory region induced a mixture of excitatory and inhibitory postsynaptic potentials in the motoneurons. The most noteworthy potentials were the inhibitory postsynaptic potentials with a late latency. They were observed in most forelimb (n=57/58, 98.3%) and hindlimb (n=63/64, 98.4%) motoneurons. The inhibitory potentials in forelimb motoneurons had a latency of 25-30 ms and a peak latency of 35-40 ms, and those in hindlimb motoneurons had a latency of 30-35 ms and a peak latency of 50-60 ms. A difference was not observed in the location of the effective sites for evoking the inhibitory effects in the forelimb and hindlimb motoneurons. These sites were homogeneously distributed in the dorsomedial part of the medullary reticular formation corresponding to the location of the nucleus reticularis gigantocellularis. From these findings we suggest that there is an equivalent amount of the postsynaptic inhibitory effects exerted on forelimb and hindlimb motoneurons during medullary-induced generalized motor inhibition. In addition, the medullary reticular formation may be functionally organized as a homogeneous or non-specific region in terms of the medullary reticulospinal inhibitory connections with forelimb and hindlimb motoneurons.

Search for active endogenous retroviruses: identification and characterization of a HERV-E gene that is expressed in the pancreas and thyroid

To elucidate possible physiological functions of human endogenous retroviruses (HERVs) and their role in the pathogenesis of human diseases, we have developed a strategy to identify transcriptionally active HERV genes. By this approach, we have identified and isolated an active HERV-E gene that was mapped to 17q11. Although the gene was predicted to produce no intact viral particles due to the presence of stop codons, long open reading frames were retained in each gag and pol region. Northern blot analyses revealed in the pancreas (and thyroid) two major transcripts, 3.3 and 4.1 kb in size, associated with 500- to 600-nucleotide-longer minor bands. Preferential expression in pancreas and thyroid gland tissues may suggest a role for this gene in physiological functions common to these tissues.

Identification of nonsynonymous polymorphisms in the superantigen-coding region of IDDMK1,2 22 and a pilot study on the association between IDDMK1,2 22 and type 1 diabetes

To investigate the possible involvement of IDDMK1,2 22/HERV-K18 in childhood type I diabetes mellitus, we identified two nonsynonymous A/G polymorphisms in the superantigen-coding region of IDDMK1,2 22 at the 290- and 461-nucleotide (nt) positions from the initial methionine codon and compared their frequencies in 74 Japanese patients with type 1 diabetes and in 54 nondiabetic controls. Although the G substitution was observed more frequently at either site in the patients than it was in the controls (7% vs. 4% at 290 nt, and 29% vs. 20% at 461 nt), the differences were not statistically significant. A weak significance of difference in the frequency of 461G was obtained only in an early-onset group of patients manifesting the disease at 5 years of age or less (n = 24) when compared with controls (38% vs. 20%; P = 0.03). However, in addition to the common absence of a particular allele among the expected four alleles, remarkable differences in allele frequencies were present between Japanese and European populations. This first trial investigating the association of IDDMK1,12 22 with type 1 diabetes presents intriguing suggestions for the role of this region in the etiology of autoimmune and infectious diseases.

Immunohistochemical characterization of hepatoblastomas in B6C3F1 mice treated with diethylnitrosamine and sodium phenobarbital

Hepatoblastomas (HBs) were induced in B6C3F1 male mice by diethylnitrosamine (DEN) and sodium phenobarbital (PB). Six-week-old mice received a single intraperitoneal dose of DEN followed by a continuous treatment with PB in diet at a concentration of 0 (group 1) or 500 (group 2) ppm for 50 weeks. HBs were observed in 13 of 21 (62%) group 2 mice, with typical histologic features as reported previously, while no such tumors were observed in group 1. Seven of 13 (54%) HBs were found in and/or adjacent to hepatocellular adenomas (HCAs) or hepatocellular carcinomas (HCCs). Immunohistochemically, all HBs were positive for S-100 protein but negative for keratin, alpha-fetoprotein (AFP), albumin (ALB) and vimentin, while HCC cells occasionally reacted positively for AFP with a mosaic pattern. HCC and HCA cells were occasionally positive for ALB. Non-neoplastic hepatocytes and normal bile ducts were positively stained for ALB and keratin/S-100 protein, respectively. S-100 protein is known to be expressed in many mesenchymal tissues and neoplasms including neuroectodermal elements but negative in cells of the hepatic lineage. Thus, the present immunohistochemical results suggested that mesenchymal differentiation occurs in mouse HB cells as observed in human HBs, one of the most frequent infant liver tumors in humans. Although the susceptibility of mouse HBs to PB-promotion suggests a hepatocytic histogenesis, the present immunohistochemical results support the hypothesis that the mouse HB is derived from pluripotent endodermal stem-like cells.

Glucose alters the susceptibility of mesangial cells to contrast media

RATIONALE AND OBJECTIVES

Diabetic patients frequently suffer contrast media-induced nephropathy. Hyperglycemia in diabetes mellitus causes gradual deterioration of glomerular mesangial cells (MCs) in the kidney. In this study, the authors investigated the response of rat MCs cultured in high-glucose medium to diatrizoate and iohexol, high- and low-osmolar contrast media, respectively.

METHODS

Isolated rat MCs were precultured under basal-glucose (5.5 mmol/L) and high-glucose (30 and 55 mmol/L) conditions for 24 hours to mimic hyperglycemia in diabetes mellitus and then were exposed to diatrizoate (40 and 80 mg I/mL) and iohexol (80, 120, 160 mg I/mL) for 2 hours. The cytotoxic effects of diatrizoate and iohexol were monitored by neutral red uptake in MCs. The protective effects of an antioxidant, d-alpha-tocopherol (Toc), on cytotoxicity of the contrast media were determined when MCs were precultured with Toc under high-glucose conditions or were exposed to the contrast media together with Toc. Peroxide levels in the cells exposed to the contrast media were analyzed by flow cytometry using dichlorofluorescin diacetate.

RESULTS

Exposure to both contrast media (diatrizoate and iohexol) induced a concentration-dependent decrease in viability of the cells precultured under basal-glucose conditions (5.5 mmol/L). Preculture under high-glucose conditions (30 and 55 mmol/L) augmented the cytotoxic effects of both contrast media. An increase in the intracellular peroxide level was detected after exposure to both contrast media. Preculture with Toc prevented augmentation of the cytotoxic effects of diatrizoate by the higher glucose concentration (55 mmol/L). The exposure to diatrizoate together with Toc also attenuated its cytotoxic effects. Toc showed no such protective effects against iohexol exposure.

CONCLUSIONS

These findings suggest that high-glucose conditions enhance the susceptibility of MCs to the cytotoxic effects of both contrast media; the enhanced susceptibility was in part attributable to oxidative stress caused by high-glucose conditions; diatrizoate exerted the cytotoxic effects by means of oxidative stress; and iohexol appeared to exert its cytotoxicity in a manner different from diatrizoate.

Greater expression of transforming growth factor alpha and proliferating cell nuclear antigen staining in mouse hepatoblastomas than hepatocellular carcinomas induced by a diethylnitrosamine-sodium phenobarbital regimen

Transforming growth factor alpha (TGF-alpha) is a potent stimulator of normal hepatocyte proliferation, considered to have relationship to the liver regeneration or carcinogenesis. In this study, we investigated immunohistochemically the association between expression of TGF-alpha and cell proliferation activity in mouse hepatoblastomas (HBs) and hepatocellular carcinomas (HCCs) induced in B6C3F1 mice by diethylnitrosamine and sodium phenobarbital. The TGF-alpha-positive rate in HBs (29.2%) was significantly higher than that in HCCs (12.7%). Likewise, the proliferating cell nuclear antigen-positive rate (22.2%) was higher than the HCC value (14.5%). On the individual data for both TGF-alpha and PCNA, most of the HBs showed higher positive rates than HCCs. In HBs, TGF-alpha was localized only in the nuclei, whereas some HCC cells stained positive both in their nuclei and cytoplasm (0.6%). These results suggest expression of TGF-alpha and its localization might be linked to cell proliferation and play a role in malignant progression of mouse HBs.

Tuberous sclerosis: epileptogenicity and multimodal presurgical evaluations

We report on a patient with tuberous sclerosis-related epilepsy who benefited from surgical treatment. Various presurgical evaluations, including positron emission tomography (PET), made it possible for us to localize the epileptic focus accurately. In this paper, we stress the importance of performing multimodal evaluations to determine which tubers really possess epileptogenicity. In addition, the implications of PET in tuberous sclerosis-related epilepsy are described.

N-phenylimidazolium triflate as a highly effective promoter for the interribonucleotide-bond formation via the phosphoramidite method

N-Phenylimidazolium triflate has been invented as an extremely effective promoter for the construction of interribonucleotide linkage according to the phosphoramidite strategy.

Transcriptionally active HERV-K genes: identification, isolation, and chromosomal mapping

Preceding the isolation of transcriptionally active HERV-K genes, expression status was examined by RT-PCR and sequence analysis of mRNA from various tissues. In addition to the detection of IDDMK(1,2)22/HERV-K18 expression in peripheral leukocytes, three novel members of the family, which are expressed in multiple tissues, were identified. The novel HERV-K genes (HGMW-approved symbols ERVK4 and ERVK5) were isolated from a BAC library using oligonucleotide probes and assigned by RH mapping to chromosomal regions 3q21-q25.2, 3cen-q13, and 1q21-q23. Although their expression could not be confirmed in any normal tissues by Northern blot analysis, substantial promoter activity of their 5' LTRs was demonstrated in luciferase assays using teratocarcinoma cell lines. Thus, they seem to have the potential to be actively transcribed. The results, combined with those of the expression analysis by RT-PCR and subsequent sequencing of cloned products, also suggest that LTR sequences with subtle base changes might play a role in gene regulation, such as tissue specificity of HERV-K expression.

Immunohistochemical localization of transforming growth factor alpha in chemically induced rat hepatocellular carcinomas with reference to differentiation and proliferation

Hepatocellular carcinomas (HCCs) were induced in male Fischer 344 rats with dietary 3'-methyl-4-(dimethylamino)-azobenzene treatment and were classified into solid, glandular (well- or poorly differentiated), and trabecular types. Investigation of cell proliferation kinetics and immunohistochemical localization of transforming growth factor alpha (TGF-alpha) demonstrated all solid (n = 24) and poorly differentiated glandular type (n = 6) HCCs to have TGF-alpha-positive nuclei. Nuclear staining of TGF-alpha was also observed in 13 of 28 (46%) trabecular-type HCCs, whereas 12 (43%) exhibited cytoplasmic staining, and 3 (11%) were negative. As for well-differentiated glandular HCCs, 7 of 20 (35%) were positively stained in their nucleus, another 7 (35%) demonstrated antibody binding in the cytoplasm, and 6 (30%) were negative. The order for growth rate evaluated by bromodeoxyuridine (BrdU) labeling was solid (38.22%), poorly differentiated glandular (26.82%), trabecular (7.98%), and well-differentiated glandular (2.57%) types. For trabecular HCCs with nuclear, cytoplasmic, or negative TGF reactions, values were 13.39% (n = 13), 3.61% (n = 12), and 2.01% (n = 3), respectively. Likewise, BrdU-labeling indices for the counterpart groups of well-differentiated glandular type HCCs were 4.53, 1.91, and 1.29%, respectively. The results indicate that TGF-alpha expression might be linked to histopathological differentiation and cell proliferation in rat HCCs.

Identification of the TCL6 genes within the breakpoint cluster region on chromosome 14q32 in T-cell leukemia

A region on chromosome 14q32.1 is often involved in chromosomal translocations and inversions with one of the T-cell receptor loci in T-cell lymphoproliferative diseases. The breakpoints of the different rearrangements segregate into two clusters; a cluster due to inversion on the centromeric side and a cluster due to simple balanced translocations on the telomeric side. If the target gene activated by these different types of chromosomal rearrangements is the same, the gene must be localized between the two clusters of breakpoints in a region of around 160 kb. Within this breakpoint cluster region, we isolated two genes; namely, TCL1 and TML1/TCL1b genes. In the course of characterizing the TML1 gene, we further identified a third novel gene, which we named TCL6 (T-cell leukemia/lymphoma 6), from a region 7 kb upstream of the TML1 locus. The TCL6 gene expressed at least 11 isoforms through very complex alternative-splicing, including splicing with the TML1 gene. Those isoforms encode at least five open reading frames (ORFs) with no homology to known sequences. The localization of the proteins corresponding to these ORF was determined by fusing green fluorescence protein at the carboxyl terminal of each ORF. ORF141 and ORF72 were observed in the cytoplasmic region, while ORF105, ORF119, and ORF163 were predominantly localized in the nuclear region. Since the TCL6 gene was expressed in T-cell leukemia carrying a t(14;14)(q11;q32.1) chromosome translocation and was not expressed in normal T-cells (just like the TML1 and TCL1 genes), it is also a candidate gene potentially involved in leukemogenesis. Oncogene (2000).

A patient with mitochondrial myopathy associated with isolated succinate dehydrogenase deficiency

We report on a boy with normal mental development who had muscle hypotonia and congenital dislocation of the hip and knee joints. Histochemical and biochemical examinations of his muscle specimen revealed no succinate dehydrogenase (SDH) activity. Since the NADH cytochrome c reductase and cytochrome c oxidase activities were normal, we concluded that he had an isolated SDH deficiency. Our patient provides further evidence for the clinical variability of this disorder.

The decrease in total collagen fibers in the liver by hepatocyte growth factor after formation of cirrhosis induced by thioacetamide

Liver cirrhosis is an inveterate disease accompanying fibrosis, hepatocyte damage, and liver dysfunction. In this study, the therapeutic effects of recombinant human hepatocyte growth factor (rhHGF) on liver cirrhosis were examined in rats administered thioacetamide (TAA). Repeated administration of TAA for 10 weeks to rats induced liver cirrhosis with collagen nodes and pseudo-lobe generation, a condition that was pathologically similar to that in humans. Administration of rhHGF after the formation of liver cirrhosis markedly decreased the incidence of pathological fibrosis and the degree of fibrosis as measured by a computed image analysis system. Continuous administration of rhHGF by infusion pump was more effective than bolus administration. Northern blotting analysis showed that rhHGF reduced mRNA levels of procollagen alpha2(I), alpha1(IV), and transforming growth factor-beta1 (TGF-beta1) that were stimulated in the TAA-treated liver. The labeling index of hepatocytes increased following administration of rhHGF in this model. These observations suggest that the pathological recession of liver fibrosis is the result of the reduction of TGF-beta1 and collagen synthesis and, in part, of the stimulation of mitosis of hepatocytes directly by rhHGF and indirectly by TGF-beta1 reduction in the cirrhotic liver. These results demonstrate the usefulness of rhHGF as a therapeutic agent in liver cirrhosis.

Establishment and characterization of a cell line from a chemically-induced mouse hepatoblastoma

We established a cell line (MHB-2) from a hepatoblastoma (HB) induced by diethylnitrosamine (DEN) and sodium phenobarbital (PB) in male B6C3F1 mice and examined the biological characteristics of MHB-2. MHB-2 cells grew as monolayers in culture and showed a spindle or polygonal shape. Immunohistochemically, the original tumor cells and MHB-2 cells were negative for keratin, alpha-fetoprotein and albumin. Electron microscopically, MHB-2 cells had irregular-shaped nuclei with prominent nucleoli, abundant free ribosomes, myelinosomes, desmosomes and surface microvilli. Growth of this cell line was significantly accelerated by hepatocyte growth factor (HGF) and expression of its receptor c-met was confirmed by the reverse transcription-polymerase chain reaction (RT-PCR). MHB-2, however, was not found to be tumorigenic when transplanted into the subcutaneous tissue of syngeneic, nude or scid mice. To our knowledge, this is the first report on the establishment of a cell line derived from a mouse HB. MHB-2 would be useful for further studies to clarify the biological characteristics of mouse HB.

Glomerulonephritis with fibrillary deposition in a transgenic mouse carrying the human prototype c-Ha-ras gene (rasH2 mouse)

Glomerulonephritis was observed in a 34-week-old transgenic CB6F1 mouse carrying the human prototype c-Ha-ras gene (rasH2 mouse) from a medium-term carcinogenicity study of N-methyl-N-nitrosourea (MNU). Lesions were characterized by severe diffuse enlargement and prominent hyalinization of glomeruli. The hyaline material was positive for periodic acid-Schiff but negative for amyloid by the Congo red method. Immunohistochemically, affected glomeruli were positive for polyclonal anti-mouse IgG. Ultrastructurally, there were characteristic subendothelial and mesangial deposits composed of fibrils showing a fingerprint pattern. Lamellae were 7.5-14.3 nm in diameter and formed multilayered structures. In addition to the renal lesions, a lymphoma was observed in the thymus, with metastasis to the spleen and some lymph nodes. However, there was no glomerulonephritis in 32 other mice bearing thymic lymphomas and in more than 40 males and females given MNU in the same study. Thus, the lesions in this mouse may have been spontaneous. Glomerulonephritis was not found in more than 120 other male and female rasH2 mice in our facility. This is the first report of glomerulonephritis in a rasH2 mouse, a promising candidate for medium-term carcinogenicity risk assessment.

COLLABORATIVE WORK TO EVALUATE TOXICITY ON MALE REPRODUCTIVE ORGANS BY REPEATED DOSE STUDIES IN RATS : 25)EFFECTS OF 2- AND 4- WEEK REPEATED-DOSING OF DIBROMOACETIC ACID

To assess the sensitivity of rats to a testicular toxicant, 2- and 4-week repeated-dose studies using dibromoacetic acid (DBAA) were performed. Four groups of 6- or 8-week old male SD rats were given DBAA at a daily dosage of 0, 5, 50 or 250 mg/kg. The highest dose was given for 2 weeks, and the others for 2 and 4 weeks. There were no effects on body or testicular weights in any of the DBAA-treated groups. However, the mean absolute epididymal weight in the 250 mg/kg group was significantly lower than that of the control group. Histopathologically, atypical residual bodies (ARBs) and retention of Step 19 spermatids were evident with this high dose. In the same group, ARBs in the epididymal ducts and narrowing of these lumina were also observed. Retention of Step 19 spermatids was similarly apparent in the testes of animals given 50 mg/kg for 2 or 4 weeks, and in one animal given 5 mg/kg for 4 weeks. Based on these data, DBAA testicular toxicity is histopathologically detectable within 2-weeks of repeated dosing at an appropriate dose.

Assignment of the human poly(A) polymerase (PAP) gene to chromosome 14q32.1-q32.2 and isolation of a polymorphic CA repeat sequence

We report the chromosomal localization of the gene for human poly(A) polymerase (PAP) and the characterization of a newly isolated CA repeat near the PAP locus. By fluorescence in situ hybridization and polymerase chain reaction (PCR)-based analysis with both a human/rodent monochromosomal hybrid cell panel and a radiation hybrid mapping panel, this gene was mapped on the q32.1-q32.2 region of chromosome 14. From a genomic clone containing the human PAP locus, we have isolated a polymorphic dinucleotide (CA) sequence. High heterozygosity (0.81) makes this polymorphism a useful marker in the genetic study of disorders localized at the 14q32 region, such as autosomal recessive congenital microphthalmia (CMIC).

REM sleep components predict the response to initial treatment of infantile spasms

PURPOSE

The phasic inhibition index (PII) is the rate of the simultaneous occurrence of rapid eye movement bursts (RBs) and phasic chin muscle activity (PCMA) during rapid eye movement sleep (REMS). PII is low insofar as physiologically occurring REM-related phasic inhibition acts on chin muscles. Previously we found that PII was significantly higher in patients with infantile spasms (ISs) who had a recurrence of convulsions than in patients with ISs who exhibited no recurrence. We aimed to predict the response of patients with ISs to conventional anticonvulsants (AEDs) by means of REMS components including PII, expecting to facilitate avoidance of potentially hazardous hormonal therapy.

METHODS

REMS, recorded before the beginning of any medication, was retrospectively examined in 15 patients with ISs. The patients were classified into two groups according to the response to initial treatment with conventional AEDs. Conventional AEDs were enough to control the spasms in six good responders (GRs), whereas further hormonal therapy was required in nine poor responders (PRs) to control the spasms.

RESULTS

The amount of REMS was significantly lower in patients with ISs than in controls. GRs had less REMS than did PRs, although no significant difference was observed. Although the frequencies of RB and PCMA showed no significant differences among GRs, PRs, and controls, the average PII value in PRs (12.6+/-3.4; mean+/-SD) was significantly (p < 0.001) higher than that in GRs (6.1+/-1.7).

CONCLUSIONS

PII is a useful parameter for differentiating GRs from PRs.

Identification of the TCL1/MTCP1-like 1 (TML1) gene from the region next to the TCL1 locus

The region on chromosome 14q32.1 is frequently involved in chromosomal translocations and inversions with one of the T-cell receptor loci in human T-cell leukemias and lymphomas. The breakpoints of the different rearrangements segregate into two clusters: inversion on the centromeric side and simple balanced translocations on the telomeric side. If the target gene activated by these different types of chromosomal rearrangements is the same, the gene must reside between the two clusters of breakpoints in a region of approximately 160 kb. By screening of a placenta cDNA library using genomic probes derived from the vicinity of TCL1 locus, we have identified a gene coding for a 1.7-kb transcript that is expressed in leukemic cells carrying a t(14;14)(q11;q32) chromosome translocation. The cognate cDNA sequence reveals an open reading frame of 384 nucleotides encoding a Mr 15,000 protein with approximately 30% of homology with both p14TCL1 and p13MTCP1 oncoproteins. The genomic organization of the TML1 locus was characterized, with three exons located 15 kb from and tail-to-tail in relation to TCL1 locus. Because of its location and sequence similarity with TCL1 and MTCP1 oncoproteins, this gene, named TML1 (TCL1/MTCP1-like 1) is a candidate gene that is potentially involved in leukemogenesis.

[Auditory brainstem responses in group A xeroderma pigmentosum]

Xeroderma pigmentosum has been known to result from disturbance in the repair of injured DNA caused by the ultra violet light. According to cell fusion studies, this disease is classified into 8 groups. Among these groups, group A (A-XP) shows the most severe type of neurological disturbance. Slowly progressive diffuse impairment both in the central and the peripheral nervous systems has been reported. Although hearing loss occurs in all the patients, few papers have described the chronological changes of this disability. This study aimed to clarify the development of audiological abnormalities in A-XP patients. We recorded auditory brainstem evoked responses (ABRs) in 20 Japanese children with A-XP. All patients had homozygous intron 3 splicing mutations of xeroderma pigmentosum group A complementing gene, the most common type mutations in Japan. ABR threshold, peak latency of 5th wave and the peak interval latency between the 1st and 5th waves (I-V interpeak latency) were measured, and were compared with those obtained from age-matched controls. ABRs were well detected in all patients examined under 4 years old. The I-V interpeak latencies became shorter with age as in the controls. In 3 ears, the 5th wave was recorded without 1st wave. In 4 ears which no ABRs were detected with 90 dBHL stimulation, the only 5th wave was detected. No waves were obtained from the patients aged over 10 years. The current study revealed that ABR disturbance in A-XP patients became obvious after 4 years of age. In addition, no ABR was found to be identified after 10 years of age. During 4 to 10 years of age, some patients showed the elevation of the threshold of the 5th wave. In A-XP patients, the peripheral nerve was hypothesized to be affected earlier than the central pathway involved in ABR.

Oxidative DNA damage induced by aminoacetone, an amino acid metabolite

We investigated DNA damage induced by aminoacetone, a metabolite of threonine and glycine. Pulsed-field gel electrophoresis revealed that aminoacetone caused cellular DNA cleavage. Aminoacetone increased the amount of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) in human cultured cells in a dose-dependent manner. The formation of 8-oxodG in calf thymus DNA increased due to aminoacetone only in the presence of Cu(II). DNA ladder formation was observed at higher concentrations of aminoacetone than those causing DNA cleavage. Flow cytometry showed that aminoacetone enhanced the generation of hydrogen peroxide (H2O2) in cultured cells. Aminoacetone caused damage to 32P-5'-end-labeled DNA fragments, obtained from the human c-Ha-ras-1 and p53 genes, at cytosine and thymine residues in the presence of Cu(II). Catalase and bathocuproine inhibited DNA damage, suggesting that H2O2 and Cu(I) were involved. Analysis of the products generated from aminoacetone revealed that aminoacetone underwent Cu(II)-mediated autoxidation in two different pathways: the major pathway in which methylglyoxal and NH+4 are generated and the minor pathway in which 2,5-dimethylpyrazine is formed through condensation of two molecules of aminoacetone. These findings suggest that H2O2 generated by the autoxidation of aminoacetone reacts with Cu(I) to form reactive species capable of causing oxidative DNA damage.

Isolation and mapping of a polymorphic CA repeat sequence at the human VRK1 locus

VRK1 is a novel human putative serine/threonine kinase, and is located on chromosome 14 at band q32 where an autosomal recessive congenital microphthalmia (CMIC) is mapped. We isolated a polymorphic dinucleotide CA repeat marker from a genomic clone containing the human VRK1 gene. This polymorphism will be useful in genetic studies of disorders localized at the 14q32 region, such as CMIC.

Isolation and mapping of a putative b subunit of human ATP synthase (ATP-BL) from human leukocytes

From a human-leukocyte cDNA library, we cloned cDNA encoding a novel protein, which has a significant homology with the b subunit of ATP synthase (proton-transporting ATPase, F1F0-ATPase; EC3.6.1.34) derived from Anabaena sp. strain PCC 7120. The cDNA has an open reading frame of 1314 nucleotides corresponding to 438 amino acids. The coding sequence was 37.9% identical over 57 amino acid with b subunit of ATP synthase. The 34-amino-acid region of the predicted peptide sequence displays a coiled-coil motif that could form a complex with some other protein(s). We designated this novel gene as ATP-BL because of its homology to the b subunit of ATP synthase. The ATP-BL locus was mapped by fluorescence in situ hybridization (FISH) and radiation hybrid mapping to the q24 region of chromosome 16.

Comparative toxic effects of iobitridol and iohexol on the kidney

RATIONALE AND OBJECTIVES

The authors compare the toxic effects of iobitridol and iohexol, which are nonionic contrast media with equivalent osmolalities and viscosities on the kidney.

METHODS

In a rat acute renal failure (ARF) model, iobitridol or iohexol (both at the dose of 2.87 g I/kg) were injected to rats after pretreatment with indomethacin and N omega-nitro-L-arginin methyl ester. The effects on histopathology, creatinine clearance, and urinary N-acethyl-beta-D-glucosaminidase (NAG) activity were assessed. In a rat renal slice system, the slices were exposed to iobitridol or iohexol (both at the concentration range of 17.5-70 mg iodine/mL) for 60 min. The accumulation of para-aminohippuric acid (PAH), an organic anion, and the intracellular potassium content as the indicators of renal tubular injury were measured to assess the direct effects of iobitridol and iohexol on renal tubules.

RESULTS

In the ARF model, no significant difference was detected between the effects of iobitridol and those of iohexol on the creatinine clearance and urinary NAG activity 24 hours after the injection. However, iobitridol produced a lower degree and incidence of renal tubular injury of renal proximal tubules (P < 0.001) and distal tubules (P < 0.05) compared with iohexol. In the rat renal slice system, the iobitridol treatment had significantly less effect on the PAH accumulation compared with iohexol (P < 0.001). There were no changes in the intracellular potassium content.

CONCLUSIONS

These findings suggest that iobitridol has significantly less toxic effects on the kidney compared with iohexol under the condition of our experiment.

Video analysis of gross body movements during sleep

Gross body movements (GM) during sleep, classified into four GM types by the involved parts of body, were evaluated using two-dimensional video analysis in five normal children aged 4-12 years. The rate of occurrence of all GM types showed apparent sleep stage dependency. Among four GM types, GM-1 (GM with axial rotation) was the most frequent. Averaged duration of GM-1 was the longest. A total of 77.2% of GM-1 started with the contraction of chin muscle and 35% of total sleep changes (tSC) were related to GM. A total of 5.6% of tSC following GM shifted to the deeper stage. Further evaluation is necessary in order to understand the physiological mechanism of GM.

Alteration of anionic sites in renal glomerular basement membrane of pigs

Ultrastructural alteration of anionic sites (ASs) in the glomerular basement membrane (GBM) was studied in 10 cases of swine mesangial proliferative glomerulonephritis using a cationic ultrastructural tracer, 0.5% polyethyleneimine (M.W. = 1,800). Glomerular ASs were seen as discrete electron-dense particles in the GBM, mesangial matrix and epithelial cell surfaces by electron microscopy. In the lamina rara externa (LRE) of the normal GBM, ASs were distributed regularly in a single layer. In those areas of the LRE that contained electron dense deposits or clusters of spherical microparticles (SMPs), however, a distinct reduction or loss of ASs was observed in all the pigs. Quantitative assessment of ASs in the LRE over 1,000 nm of the GBM revealed a significant reduction in ASs in one case with diffuse global thickening of the GBM as compared with the remaining nine pigs without GBM thickening (P < 0.001, Mann-Whitney's U-test). There were no ASs in the lamina densa (LD) of the normal GBM, but an irregular distribution of ASs was seen within the LD of the pig showing diffuse global thickening of the GBM. These results suggest that a disturbance of the charge-selective barrier in the GBM may be induced by electron-dense deposits or SMPs, in the LRE as well as thickening of the GBM in swine glomerulonephritis.

Alterations in glomerular anionic sites in the autologous phase of canine anti-glomerular basement membrane nephritis

There have been a few studies on canine nephrotoxic glomerulonephritis produced by anti-glomerular basement membrane serum (AGBM), but these reports have not focused on an alteration in the charge properties of glomerular basement membrane (GBM). In this study, rabbit AGBM or normal rabbit serum (NRS) was given intravenously (2 ml/kg body weight) to 16 male beagle dogs. An alteration of anionic sites (ASs) of GBM was studied quantitatively using polyethyleneimine as a cationic probe by electron microscopy at weeks 1, 2, 4, and 8 postinjection. In AGBM-treated dogs, severe or mild proteinuria continued until week 2. At weeks 4 and 8, there was no significant difference in the intensity of proteinuria between AGBM- and NRS-treated groups. Until week 2 postinjection, there were significantly fewer ASs of GBM in AGBM-treated dogs than in NRS-treated dogs. At week 8, however, there was no difference in ASs of GBM between AGBM- and NRS-treated dogs. The fact that a reduction of glomerular AS occurred in AGBM-treated dogs with severe or mild proteinuria and the recovery of AS in the GBM coincided with an improvement of proteinuria suggested that alteration of the glomerular ASs might play an important role in the pathogenesis of proteinuria in canine anti-GBM nephritis.

Effects of a thrombin inhibitor, argatroban, on ischemic brain damage in the rat distal middle cerebral artery occlusion model

To elucidate the role of thrombin in brain damage during focal cerebral ischemia, we investigated the effects of a selective thrombin inhibitor, argatroban, on microthrombi formation, regional cerebral blood flow (rCBF), infarct areas and neurological deficits using a rat thrombotic distal middle cerebral artery (dMCA) occlusion model. The rat dMCA was occluded by a platelet-rich thrombus formed after photochemical reaction between rose bengal and green light. One day after dMCA occlusion, the number of microthrombi were counted. In the separate animals, rCBF was measured by using the iodoantipyrine method 1 day after dMCA occlusion. Three days after dMCA occlusion, behavioral tests were performed and the size of the cerebral infarction was determined. In the present study, argatroban was administered i.p. by continuous infusion after dMCA occlusion. Argatroban (0.3 mg/h/rat) significantly (P < .05) decreased the number of microthrombi 1 day after dMCA occlusion. Argatroban (0.1 and 0.3 mg/h/rat) significantly (P < .01) reversed a decrease in rCBF 1 day after dMCA occlusion. Argatroban (0.3 mg/h/rat) also significantly (P < .01) reduced the size of the cerebral infarction. Administration of argatroban (0.1 and 0.3 mg/h/rat) resulted in a significant improvement in neurological deficits 3 days after dMCA occlusion (P < .01 and P < .05, respectively). Argatroban decreased the size of the cerebral infarction and improved neurological deficits in the rat thrombotic dMCA occlusion model. These effects were thought to be due to the improvement of rCBF and to the reduction in secondary thrombus formation after dMCA occlusion.

Motor disturbance during REM sleep in group A xeroderma pigmentosum

We investigated motor phenomena during rapid eye movement (REM) sleep in 13 patients with group A xeroderma pigmentosum aged from 11 to 39 months, and compared them with those obtained from 12 age-matched controls. At the time of sleep study, they had no abnormality on routine electrophysiological examinations. The amount of REM sleep and the incidence of motor phenomena during REM sleep in patients were similar to those in age-matched controls. However using the newly designated indices, we demonstrated disturbance on both the tonic motor inhibition occurring during the whole REM sleep period and the phasic one acting simultaneously with horizontal rapid eye movements in these patients. Since the motor inhibition during REM sleep is mediated by the subcortical structures, our study indicate that these structures are functionally impaired in group A xeroderma pigmentosum even during the early stage of the illness.

Effective production of the hepatitis C virus core antigen having high purity in Escherichia coli

The amino-terminal half of putative nucleocapsid (core) protein (amino acids 1-115) of hepatitis C virus (HCV) was directly overproduced in Escherichia coli under the control of the tac promoter. Overproduction of core antigen was achieved by inserting several target genes and by optimizing the culture conditions, whereas a large amount of directly expressed and purified core antigen has not yet been reported. Although the level of expression was comparable to that of the conventional E. coli fused expression system, our recombinant proteins contain only HCV amino acid sequence. Using recombinant E. coli, overproduced large-scale culture system was achieved in jar-fermenter. A highly purified sample of the expressed protein was obtained by ion-exchange and gel permeation column chromatography in the presence of 8 M urea. From a 3.5 l culture, approximately 440 mg of recombinant core protein was obtained after a two-step purification procedure. An enzyme-linked immunosorbent assay developed using the highly purified antigen satisfactorily diagnosed hepatitis C.

Alterations in glomerular anionic sites in canine anti-glomerular basement membrane nephritis with onset of severe proteinuria

Rabbit anti-glomerular basement membrane serum (AGBM) or normal rabbit serum (NRS) were given intravenously (2 ml/kg body weight) to 8 male beagle dogs. Light and transmission electron microscopy and immunofluorescence were performed on the kidneys on day 7 postinjection. Alterations of anionic sites (ASs) of glomerular basement membrane (GBM) in peripheral, proximal, and paramesangial portions were studied quantitatively by electron microscopy using polyethyleneimine (PEI; molecular weight = 1,800) as a cationic probe. Severe or mild proteinuria developed on day 1 and continued until day 6 postinjection. On day 7 after AGBM injection, the number of PEI granules per 1,000 nm length of the lamina rara externa of GBM in all portions was significantly less than that in NRS-treated dogs (10.48 +/- 1.78 versus 14.19 +/- 2.35 granules per 1,000 nm of GBM in peripheral portion, 10.81 +/- 1.91 versus 14.97 +/- 1.35 granules per 1,000 nm of GBM in proximal portion, 8.44 +/- 1.76 vs 13.43 +/- 2.10 granules per 1,000 nm of GBM in paramesangial portion; p < 0.001). These results indicate that a reduction glomerular AS occurs in AGBM-treated dogs in association with severe or mild proteinuria and alterations in glomerular ASs might play an important role in the pathogenesis of proteinuria in the canine anti-GBM nephritis in addition to morphological changes.