Norwalk virus infection of volunteers: new insights based on improved assays

Norwalk virus infection is a common cause of gastroenteritis in humans. The clinical features and virologic and immunologic responses following oral administration of Norwalk virus to 50 volunteers were monitored. New ELISAs using recombinant virus particles as the antigen source were used to assess the pattern of virus shedding and the specific immune responses. Forty-one subjects (82%) became infected; 68% were symptomatic and 32% were asymptomatic. The proportion of subjects infected was similar for those with and without preexisting antibody (82% vs. 60%; P > .2). The magnitude of seroconversion was highest in subjects who had vomiting. The peak of viral shedding was between 25 and 72 h, and virus first appeared in stool at 15 h. Specimens collected 7 days after inoculation remained positive. These results show a higher infection rate, more subclinical infections, and longer virus excretion following Norwalk virus inoculation than previously recognized.

[Analysis on refraction status of eyes with normal vision]

Refractive status of 1,324 eyes with normal vision of the juvenile students in four grades was analysed. It was raised that the meaning of refractive status was different between the medical physiological optics and the physical or geometrical optics. "Emmetropia" did not really mean "the normal eye" in refraction as viewed from normal physiology, and the problem about the physiological refractive status of eyes in the juvenile was discussed preliminarily.

Clinical observations on the use of the Chinese herb Tripterygium wilfordii Hook for the treatment of nephrotic syndrome

A preparation of extracts from the root of the Chinese medicinal herb Tripterygium wilfordii Hook was administered orally at a dose of 1 mg/kg body weight per day to 13 children with idiopathic nephrotic syndrome. Eight children, including 4 who were steroid resistant, went into remission which was maintained in 4 for up to 3 years after withdrawal of treatment. In 3 children the proteinuria lessened with the return of plasma protein concentration to normal, and in 1 child this improvement was maintained for 4 years after treatment ceased. No serious side-effects were noted, but a temporary anti-fertility activity has been noted in other studies of both men and women.

Detection of Norwalk virus or Norwalk-like virus infections in Finnish infants and young children

Norwalk virus (NV) and Norwalk-like viruses are important causes of epidemic nonbacterial gastroenteritis in older children and adults. Serologic responses to NV of 154 Finnish infants and young children participating in a rotavirus vaccine study were examined by ELISA with a recently available baculovirus-expressed recombinant NV capsid protein. In 4 serially collected sera (at the median ages of 3, 4, 14, and 23 months), 49% of children had at least one NV infection over the approximately 2-year study period. Children with low NV-specific IgG titers (< 1:50) at the median age of 4 or 14 months were significantly more likely to acquire an NV infection by the median age of 14 or 23 months, respectively, than children who had higher NV IgG titers (> 1:50) (P < .05). Thus, NV or Norwalk-like virus infections are more common in infants and young children than previously believed, and antibody to NV may be protective against such infections.

Epidemiology of early primary hypertension and implications for prevention: the Bogalusa Heart Study

Epidemiological studies of BPs in children and young adults over the past 20 years have contributed considerably to understanding the early onset of primary hypertension. Observations from autopsies and echocardiographic studies, together with long-term BP studies, of children clearly indicate that primary hypertension begins in early childhood. Although abnormal BP levels in children are much lower than the adult criteria used for clinical diagnosis of hypertension, essential hypertension is identifiable in early life. Complex haemodynamic and metabolic mechanisms related to essential hypertension are also being identified in childhood. The development of intervention programs in an attempt to prevent hypertension in its early phases suggests hypertensive cardiovascular disease is preventable. Environmental factors (improved dietary factors, altering electrolyte intake, prevention of obesity and increased activity levels) are critical elements to prevention. Children and young adults identified as high risk for hypertension need to be targeted for prevention of early cardiovascular renal disease. Also, as hypertension is so prevalent, attempts should be made to control environmental factors in the general public. Preventive programmes established by primary healthcare physicians, paediatricians and para-professionals can have a major impact on the reduction of hypertension and its complications of cardiovascular renal disease in the future.

Identification of minireovirus as a Norwalk-like virus in pediatric patients with gastroenteritis

In 1977, 30- to 32-nm virus-like particles, named minireovirus because of their unique morphologic appearance, were detected by electron microscopy in the stools of infants and young children with gastroenteritis. Sequence analysis of approximately 2,800 consecutive bases derived from overlapping PCR clones of a recent minireovirus clinical isolate showed 52% nucleotide sequence identity with the Norwalk virus sequence and, in addition, demonstrated that the genomic organizations of these two viruses were similar. Our data show that minireovirus is a Norwalk-like virus and should now also be included in the Caliciviridae family.

Developmental expression of the protein kinase C family in rat hippocampus

Protein kinase C (PKC) is a heterogeneous family of ten or more isoforms which plays an important role in neuronal signal transduction. Isoforms from all subclasses are prominently expressed in the rat hippocampus, as demonstrated by immunoblot with isozyme-specific antisera: Ca(2+)-dependent (alpha, beta I, beta II and gamma), Ca(2+)-independent (delta, epsilon and a newly characterized PKC related to eta) and atypical (zeta). In addition, the zeta isoform is also found as the free, constitutively active catalytic domain, protein kinase M zeta (PKM zeta). Two distinct patterns of expression of PKC isozymes in rat hippocampus are found during development from E18 to P28. PKC zeta, PKM zeta and PKC delta are present at birth and their expression does not increase postnatally. In contrast, the other isoforms are expressed only at low levels at birth and then increase in the first 4 weeks postnatally. These two patterns of expression suggest distinct functions for PKC isozymes during development.

Molecular characterization and expression of the capsid protein of a Norwalk-like virus recovered from a Desert Shield troop with gastroenteritis

Norwalk virus (NV) infection was recently found to be associated with gastroenteritis in U.S. military troops stationed in Saudi Arabia during the 1990 Desert Shield Operation. We identified a Norwalk-like virus in the stools of two military personnel with gastroenteritis by ELISA and IEM. By RT-PCR and sequence analysis, the nucleotide sequence of part of the polymerase region of each of these two "Desert Shield" strains (DSV275 and DSV395) was found to be 73% identical to the corresponding region of NV. In addition, one of the strains (DSV395), which underwent sequence analysis of approximately 2900 consecutive bases, had a genomic organization characteristic of the Caliciviridae. Comparison of the DSV395 amino acid sequence of the capsid region with that of three other viruses in the Norwalk group (Norwalk, Southampton, and Toronto viruses) showed amino acid identity of 47-68%. Consensus sequence analysis of these capsid proteins identified two regions of conserved amino acids that flanked an area of variable amino acids. In addition, the proteins corresponding to the capsid regions of DSV395 and NV were expressed in an in vitro translation system. Immunoprecipitation studies using the expressed capsid proteins and paired DSV395 or NV infection sera indicated the presence of shared antigenic sites between the capsid proteins of DSV395 and NV. However, hyperimmune sera specific for the self-assembled recombinant NV capsid protein did not react with DSV stool antigen in an ELISA, suggesting that there may also be unique antigenic sites not shared between DSV395 and NV.

Ventilatory responses to hypoxia in rats pretreated with nonpeptide NK1 receptor antagonist CP-96,345

This study reports experiments designed to evaluate the role of neurokinin-1 (NK1) receptors for substance P (SP) in the ventilatory response to acute hypoxia. Ventilation was measured by indirect plethysmography in eight unanesthetized unrestrained adult rats before and after bolus injection of 1, 5, or 10 mg/kg (ip) of CP-96,345 (Pfizer), a potent nonpeptide competitive antagonist of the SP NK1 receptor. Ventilation was measured while the rats breathed air or 8% O2-92% N2 with and without administration of SP antagonist. Pretreatment with CP-96,345 decreased the magnitude of the hypoxic response in a dose-dependent fashion. Minute ventilation in rats pretreated with CP-96,345 was reduced by 22.1% (P < 0.05) at the highest dose (10 mg/kg), largely because of an attenuation of the frequency component. Although both control and treated rats responded to hypoxia with a decrease in duration of inspiration and expiration rats pretreated with CP-96,345 displayed a smaller decrease in inspiration and expiration than control rats (P < 0.05). We have recently shown that neuropeptide-containing fibers are important for mediating the tachypnic response during acute isocapnic hypoxia in rats. The attenuation in minute ventilation at the highest dose (10 mg/kg) is comparable in magnitude to the attenuation observed with neonatal capsaicin treatment, which permanently ablates neuropeptide-containing unmyelinated fibers. Accordingly, this previously reported role of capsaicin-sensitive nerves in the hypoxic ventilatory response of rats is probably attributable to released SP acting at NK1 receptors. One of the likely sites of action of SP antagonists is the carotid body.(ABSTRACT TRUNCATED AT 250 WORDS)

Application of PCR to detect Norwalk virus in fecal specimens from outbreaks of gastroenteritis

Norwalk virus (NV) and other small round-structured viruses (SRSVs) are frequent causes of gastroenteritis outbreaks. The recent cloning and sequencing of the NV genome has made it possible to detect NV and Norwalk-related viruses from fecal specimens by reverse transcription (RT)-PCR. We applied this technique to the examination of a total of 139 fecal specimens from 19 outbreaks characterized by NV serology, including 56 samples from 7 NV outbreaks, 36 from 6 Norwalk-related virus outbreaks, and 47 from 6 outbreaks with SRSVs visualized by electron microscopy that were serologically unrelated to NV. Three primer pairs were evaluated: two pairs in the polymerase region of NV and one pair near the 3' end of the genome. When one set of primers (primer pair 51-3) from the polymerase region was used, 40% of all samples were positive by RT-PCR and specimens from the NV outbreaks were more likely to be positive (64%) than those from outbreaks associated with Norwalk-related viruses (44%) or SRSVs (8%). To determine the relationship of the outbreak strains to NV, we compared the sequences of a 145-base portion of the polymerase gene from 10 specimens obtained from five different outbreaks characterized as NV by serology. No two outbreak strains had the same sequence in this 145-base portion of the polymerase gene, and the identities of the nucleotide and amino acid sequences of these products compared with the sequences of the corresponding region of NV ranged from 62 to 79% and 69 to 90%, respectively. Because of sequence diversity in the polymerase region, the successful application of RT-PCR to investigations of outbreaks of suspected NV-associated gastroenteritis will depend on the use of either multiple primer pairs or primers made against regions of the genome that are more conserved.

Preliminary report of molecular detection of retinoblastoma gene mutations

To develop gene diagnosis for retinoblastoma predisposition, it is necessary to disclose the retinoblastoma gene mutations or deletions in detail. Genomic DNA from tumor and peripheral white blood cells in 33 patients with retinoblastoma was detected with 3.8kb probe derived from 3' end of retinoblastoma gene cDNA. The gene abnormalities, including deletion, partial deletion and rearrangement, were found in 18 patients. Further research will be aimed at microdeletions or mutations for those patients without detectable variations in Southern hybridization.

The Myb and Ahi-1 genes are physically very closely linked on mouse chromosome 10

Ahi-1 has previously been identified as a common helper provirus integration site on mouse Chromosome (Chr) 10 in 16% of Abelson pre-B-cell lymphomas and shown to be closely linked to the Myb protooncogene. By using long-range restriction mapping, we have mapped the Myb and Ahi-1 regions within a 120-kbp DNA fragment. The Ahi-1 region is located approximately 35 kbp downstream of the Myb gene. A further confirmation of this finding was obtained by screening a mouse YAC library. The three positive clones obtained contained both the Myb and Ahi-1 gene sequences. To test whether provirus integration in the Ahi-1 region enhances the expression of Myb by a cis-acting mechanism, we have also examined Myb gene expression in A-MuLV-induced pre-B-lymphomas. Our data have revealed that there is no clear evidence for such activation in the tumors we have tested, indicating that provirus insertion in the Ahi-1 region is activating a novel gene, apparently involved in tumor formation.

Norwalk virus-associated gastroenteritis traced to ice consumption aboard a cruise ship in Hawaii: comparison and application of molecular method-based assays

Investigation of an outbreak of acute nonbacterial gastroenteritis on a cruise ship provided an opportunity to assess new molecular method-based diagnostic methods for Norwalk virus (NV) and the antibody response to NV infection. The outbreak began within 36 h of embarkation and affected 30% of 672 passengers and crew. No single meal, seating, or food item was implicated in the transmission of NV, but a passenger's risk of illness was associated with the amount of ice (but not water) consumed (chi-square for trend, P = 0.009). Of 19 fecal specimens examined, 7 were found to contain 27-nm NV-like particles by electron microscopy and 16 were positive by PCR with very sensitive NV-specific primers, but only 5 were positive by a new highly specific antigen enzyme immunoassay for NV. Ten of 12 serum specimen pairs demonstrated a fourfold or greater rise in antibody titer to recombinant baculovirus-expressed NV antigen. The amplified PCR band shared only 81% nucleotide sequence homology with the reference NV strain, which may explain the lack of utility of the fecal specimen enzyme immunoassay. This report, the first to document the use of these molecular method-based assays for investigation of an outbreak, demonstrates the importance of highly sensitive viral diagnostics such as PCR and serodiagnosis for the epidemiologic investigation of NV gastroenteritis.

Epidemiological study of Norwalk virus infections in Japan and Southeast Asia by enzyme-linked immunosorbent assays with Norwalk virus capsid protein produced by the baculovirus expression system

In this study, we investigated Norwalk virus (NV) antigen and antibody to recombinant NV (rNV) in human populations in Japan and Southeast Asia by enzyme-linked immunosorbent assays (ELISAs). Baculovirus-expressed recombinant NV (rNV) capsid protein was used for preparing antisera to rNV or used as an antigen for detecting antibody to rNV. The ELISAs were specific for NV and had sensitivities equivalent to or higher than those of the previously developed radioimmunoassays. In 159 stool samples obtained from children, mainly younger than 10 years old, with acute gastroenteritis due to small round structured viruses in Japan, only 1 was positive for NV antigen. The pattern of acquisition of antibody to rNV was quite different from those of antibodies to group A rotavirus and human calicivirus Sapporo (HuCV-Sa) strain. The prevalence of antibody to rNV remained at a low level throughout childhood and then showed a steep rise during school age and early adulthood in Japan. A high prevalence of antibody was observed in samples collected from healthy adults in Japan and Southeast Asia. These results suggested that NV infection is common in adults in Japan and Southeast Asia but may be rare in infants in Japan. The HuCV-Sa strain was negative by the ELISA, and no serological relationship between NV and the HuCV-Sa strain was found. NV may be quite different from the HuCV-Sa strain, although both viruses are classified in the family Caliciviridae.

[Functional and pathohistologic changes in an ischemic model of rat inner ear]

We investigated functional and histopathological changes in the inner ear circulatory disorder caused by thrombosis of the anterior inferior cerebellar artery (AICA) in rats. The thrombosis was induced by a photochemical reaction between green light and systemic injection of Rose Bengal. During this experiment, auditory brainstem responses (ABR) were recorded and cochlear blood flow (CBF) was measured by a laser doppler flowmeter. Within 5 weeks after the procedure, histopathological changes were studied by light microscopy following the observation of equilibrium dysfunction and ABR recording. CBF was reduced from the baseline in 30.8 +/- 3.4% (mean +/- SE, n = 25) by occlusion of the AICA, ABR was altered in 96% of animals, and equilibrium dysfunction was observed in 77%. When the AICA was not reopened within a short time, severe histopathological changes were frequently observed. There was no significant correlation between equilibrium dysfunction and histopathological changes in the vestibule. It is concluded that this experimental model may be useful for investigating functional and histopathological changes in the ischemic inner ear.

Detection of antibody to recombinant Norwalk virus antigen in specimens from outbreaks of gastroenteritis

Norwalk virus and other small round-structured viruses are commonly associated with outbreaks of gastroenteritis. We used a recently described recombinant-expressed Norwalk virus (rNV) capsid protein in enzyme immunoassays to quantitatively measure immunoglobulin G (IgG) and IgA to Norwalk virus in serum pairs from patients involved in outbreaks of gastroenteritis. The outbreaks previously were classified, on the basis of the results of a blocking antibody assay, as Norwalk virus negative, serologically intermediate, or Norwalk virus positive. The rNV IgG assay was more sensitive than the blocking assay for detecting IgG to Norwalk virus in serum from patients in all outbreak classes. There was 79% concordance between seroconversions detected by the blocking antibody assay and those detected by the rNV IgG assay. The rNV IgA assay detected seroconversions to Norwalk virus primarily in patients involved in outbreaks previously classified as Norwalk virus positive.

Macrophage control of Brucella abortus: role of reactive oxygen intermediates and nitric oxide

Macrophages infected with Brucella abortus are able to kill intracellular brucellae over the first 12 to 24 hr following infection. Thereafter, the surviving brucellae replicate. We have shown previously that macrophages activated with interferon-gamma (IFN-gamma) have enhanced brucellacidal and brucellastatic activities. In studies reported here, treatment of macrophages with methylene blue, an electron carrier, enhanced the initial killing of intracellular brucellae, indicating their susceptibility to reactive oxygen intermediates. In addition, inhibitors of reactive oxygen intermediates partially blocked the antibrucella activities exhibited by both non-cytokine-treated and IFN-gamma-activated macrophages. In contrast, addition of up to 5 mM NG-monomethyl-L-arginine, to block generation of nitric oxide, resulted in minor but significant levels of blocking of macrophage antibrucella activities only when macrophages were not maximally activated even though maximally activated macrophages produced nitric oxide as indicated by accumulation of nitrite in culture supernatants. In addition, while the J774A.1 macrophage cell line had antibrucella activities which were enhanced by IFN-gamma activation, it did not produce nitric oxide when activated with IFN-gamma and infected with B. abortus. Finally, the IFN-gamma-induced enhancement of antibrucella activities by peritoneal macrophages was inhibited by addition of antitumor necrosis factor-alpha (TNF-alpha) antibodies to the cultures, indicating that TNF-alpha is necessary for full expression of the macrophage antibrucella activities.

Long-range mapping of Mis-2, a common provirus integration site identified in murine leukemia virus-induced thymomas and located 160 kilobase pairs downstream of Myb

The nondefective Moloney murine leukemia virus (MuLV) induces clonal or oligoclonal T-cell tumors in mice or rats. The proviruses of these nondefective MuLVs have been shown to act as insertion mutagens most frequently activating an adjacent cellular gene involved in cell growth control. Mutations by provirus insertions, recognized as common provirus integration sites, have been instrumental in identifying novel cellular genes involved in tumor formation. We have searched for new common provirus integration sites in Moloney MuLV-induced thymomas. Using cellular sequences flanking a provirus cloned from one of these tumors, we found one region, designated Mis-2, which was the target of provirus integration in a low (3%) percentage of these tumors. Mis-2 was mapped on mouse chromosome 10, approximately 160 kbp downstream of myb. The Mis-2 region may contain a novel gene involved in tumor development.

Visualization of dendritic morphology of cortical projection neurons by retrograde axonal tracing

Currently there is no reliable retrograde tracing technique for visualization of dendritic morphologies of projection neurons. Here we describe a simple and efficient method that can be used to label neurons in Golgi-like fashion. The approach relies on activity-dependent uptake of tracer. For this purpose we inject the glutamate receptor agonist N-methyl-D,L-aspartic acid (NMDA) at the tracer injection site to massively stimulate neurons and to thereby promote uptake of biocytin or biotinylated dextran amine (BDA) by axon terminals. The results show that co-injections of NMDA/biocytin and NMDA/BDA into the extrastriate lateromedial area (LM) of rat visual cortex labels large numbers of neurons in area 17 in Golgi-like fashion. Similarly injections of the lateral geniculate nucleus (LGN) lead to Golgi-like labeling of corticogeniculate neurons in area 17. The distribution of labeled neurons is highly topographic. In addition the method allows excellent preservation of ultrastructure, indicating that this approach is useful for determining the organization of neuronal circuits within the central nervous system.

Persistent activation of the zeta isoform of protein kinase C in the maintenance of long-term potentiation

Long-term potentiation in the CA1 region of the hippocampus, a model for memory formation in the brain, is divided into two phases. A transient process (induction) is initiated, which then generates a persistent mechanism (maintenance) for enhancing synaptic strength. Protein kinase C (PKC), a gene family of multiple isozymes, may play a role in both induction and maintenance. In region CA1 from rat hippocampal slices, most of the isozymes of PKC translocated to the particulate fraction 15 sec after a tetanus. The increase of PKC in the particulate fraction did not persist into the maintenance phase of long-term potentiation. In contrast, a constitutively active kinase, PKM, a form specific to a single isozyme (zeta), increased in the cytosol during the maintenance phase. The transition from translocation of PKC to formation of PKM may help to explain the molecular mechanisms of induction and maintenance of long-term potentiation.

Evidence for a new, high-molecular weight isoform of protein kinase C in rat hippocampus

We describe a new form of protein kinase C (PKC) with a molecular weight of 97 kDa, higher than the known forms of vertebrate PKC. This putative new high-molecular weight isoform, which we are calling PKC (HMW), is increased in the membrane fraction either upon application of phorbol esters or with afferent synaptic stimulation of Schaffer collaterals in hippocampal slices. The protein cross-reacts on immunoblot with affinity-purified polyclonal antiserum raised against a peptide derived from the carboxy-terminus of PKC eta; it does not cross-react, however, with antiserum against the amino-terminal region of PKC eta. In the tissues examined, PKC(HMW) is localized primarily in brain, in contrast to PKC eta, which is found predominantly in lung and skin.

Electromagnetic wave emitting products and "Kikoh" potentiate human leukocyte functions

Tourmaline (electric stone, a type of granite stone), common granite stone, ceramic disks, hot spring water and human palmar energy (called "Kikoh" in Japan and China), all which emit electromagnetic radiation in the far infrared region (wavelength 4-14 microns). These materials were thus examined for effects on human leukocyte activity and on lipid peroxidation of unsaturated fatty acids. It was revealed that these materials significantly increased intracellular calcium ion concentration, phagocytosis, and generation of reactive oxygen species in neutrophils, and the blastogenetic response of lymphocytes to mitogens. Chemotactic activity by neutrophils was also enhanced by exposure to tourmaline and the palm of "Kikohshi" i.e., a person who heals professionally by the laying on of hands. Despite the increase in reactive oxygen species generated by neutrophils, lipid peroxidation from unsaturated fatty acid was markedly inhibited by these four materials. The results suggest that materials emitting electromagnetic radiation in the far infrared range, which are widely used in Japan for cosmetic, therapeutic, and preservative purposes, appear capable of potentiating leukocyte functions without promoting oxidative injury.

Comparison of the reactivities of baculovirus-expressed recombinant Norwalk virus capsid antigen with those of the native Norwalk virus antigen in serologic assays and some epidemiologic observations

Since the discovery of the Norwalk virus (NV) by immune electron microscopy (IEM) in 1972, serologic studies with this virus have relied on particle-positive fecal material from infected volunteers as the source of antigen because it has not been possible to propagate this virus in cell culture. However, the recent cloning of the NV (strain 8FIIa) genome and expression of the capsid protein in a baculovirus system to form "virus-like particles" has provided a consistent source of antigen (designated rNV). The purpose of the present study was to compare the antigenicities of these rNV particles with those of native NV antigen derived from human fecal material by using well-characterized sera obtained from earlier studies. In IEM studies, the rNV antigen reacted with NV-specific antibodies in a manner similar to that observed previously when particle-positive fecal material was used as antigen. In addition, a direct enzyme-linked immunosorbent assay, in which the rNV antigen was used as antigen, proved efficient and specific for the detection of serologic responses to NV compared with the previously established techniques of IEM and blocking antibody immunoassays in which particle-positive fecal material was used as the antigen. The availability of an unlimited source of antigen will enable serologic studies that will greatly increase our understanding of the epidemiology of NV and its role in human enteric illness.

Sequence and genomic organization of Norwalk virus

A library of overlapping cDNAs obtained from Norwalk virus purified from stools of human volunteers (Jiang et al., 1990, Science 250, 1580-1583) was used to obtain the nucleotide sequence of the viral genome. The sequence has a total of 7642 nucleotides, excluding the 3' poly(A) tail, and has a base composition of 48% G + C. Three open reading frames (ORF) are predicted in the sequence. The longest ORF (ORF1, nucleotides (nt) 146 to 5359) is predicted to encode a polyprotein precursor to nonstructural proteins based on identification of sequences similar to the picornavirus 2C protein, 3C protease, and 3D RNA-dependent RNA polymerase. ORF2 (nt 5346 to 6935) is predicted to encode a polypeptide with a predicted molecular weight of 56,571 (56.6K, close to the expected size of the viral capsid protein), and it contains a short region of sequence similarity to the picornavirus structural protein VP3. A third potential ORF (nt 6938 to 7573) could encode a small polypeptide of 22.5K. The genomic organization found in Norwalk virus shares striking similarities with the genome of two caliciviruses, the feline calicivirus and the rabbit hemorrhagic disease virus. The morphology, size, polarity, and genomic organization of the Norwalk virus indicate it is a member of the Caliciviridae family.

Association of fasting insulin with longitudinal changes in blood pressure in children and adolescents. The Bogalusa Heart Study

A cohort of children and adolescents (n = 801) aged 5 to 11 years living in Bogalusa, Louisiana was examined in three consecutive cross-sectional surveys over a 6 year period. The relationship between fasting insulin and glucose at baseline and longitudinal changes in blood pressure were examined. Significantly positive correlations were observed between fasting insulin and glucose at baseline and systolic and diastolic blood pressure at follow-up in white boys and girls (r = 0.19 to 0.38, P < .01), but not in blacks. After adjustment for several covariates, the association still existed in whites. In multiple regression analysis, fasting plasma insulin was observed to be a major contributor of subsequent systolic blood pressure levels independent of age, sex, height, obesity, and glucose levels in white children. These data suggest that insulin can be a determinant of blood pressure levels in children as suggested in adults. The relationship of insulin to blood pressure differs between black and white children and is likely modulated by the multiple mechanisms active in maintenance of blood pressure.

Involvement of antioxidant enzymes in multiple-drug resistance in a human T-lymphoblastic leukemia-cell line which over-expresses p-glycoprotein

We have compared the specific activities of Cu/Zn superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) in a vinblastine sensitive human T-lymphoblastic cell line (CCRF-CEM) and its multiple drug resistant (MDR) counterpart cell line (CEM/VLB100), which over-expresses P-glycoprotein (PGP). We have found that the specific activity Cu/Zn SOD was consistently 38% increased in CEM/VLB100 cells compared with CCRF-CEM cells. In contrast, the activities of CAT and GSH-Px were similar in the two cell lines. These results suggest that MDR in CEM/VLB100 is a complicated phenotype which not only involves a PGP mechanism, but also a SOD protection mechanism against drug-mediated O2.- cytotoxicity.

Measurement of the micro-electroretinogram and component analysis

The authors propose a new technique for detecting micro-electroretinograms (muERG) which uses light-emitting diode (LED) stimulation and frequency analysis. The advantage of this method is the applicability of linear system analysis to a muERG obtained by partial stimulation of a computer-controlled waveform. The paper discusses two basic techniques for detecting the muERG. One is Fourier analysis of a synchronised ERG obtained by sine-wave stimulus, and the other is correlation analysis using a random stimulus. The results of the two methods are compared, and the usefulness of the proposed method is indicated; the muERG is analysed by means of a model consisting of five components of a second-order transfer function with delay. Functions of the central and peripheral areas of the retina could be analysed in more detail by this technique.

Detection of murine cytomegalovirus (MCMV) DNA in skin using the polymerase chain reaction (PCR)

We used the polymerase chain reaction (PCR) and primers for the immediate early gene of murine cytomegalovirus (MCMV) to detect MCMV DNA in skin harvested from mice during acute infection. MCMV DNA was also detected in DNA extracted from spleen and salivary gland of MCMV-infected mice, but not in the skin, salivary gland, or spleen of uninfected, seronegative mice. Detection of MCMV DNA in skin provides direct evidence that skin can serve as a vehicle for transmission of MCMV. This observation is relevant to humans, such as burn patients, who receive skin allografts that may be infected with cytomegalovirus.

Leflunomide, a novel immunosuppressive agent. The mechanism of inhibition of T cell proliferation

Leflunomide is a novel immunomodulating drug that has recently been demonstrated to prevent acute rejection and reverse ongoing rejection of kidney and cardiac allografts in rats. In vitro studies here demonstrate that leflunomide suppresses proliferation of human PBL stimulated with (1) allogeneic PBL in a one-way MLR (50% inhibition with 50-25 microM); (2) anti-CD3 mABs plus PMA (50% inhibition with 70 microM leflunomide); and (3) anti-CD28 mABs plus PMA (50% inhibition with 65 microM leflunomide). In contrast, CsA only inhibited T cell proliferation stimulated by anti-CD3 plus PMA. Leflunomide partially inhibited IL-2 production of T cells stimulated with anti-CD3 plus PMA or anti-CD28 plus PMA, whereas CsA completely inhibited IL-2 production by T cells stimulated by the CD3 pathway and only partially inhibited IL-2 production by T cells stimulated by the CD28 pathway. Because comparable levels of IL-2 were produced by CD28-stimulated T cells treated with either CsA or leflunomide, but no inhibition of proliferation was observed in the CsA-treated cultures, we hypothesized that the lowering of IL-2 levels was not the mechanism by which leflunomide inhibited T cell proliferation. This hypothesis was supported by the observations that exogenous IL-2 failed to restore the T cell proliferation in the presence of leflunomide. Loss of T cell responsiveness to IL-2 in the presence of leflunomide was not due loss of expression of IL-2 receptors. Collectively, our data suggest that inhibition of T cell proliferation by leflunomide occurs via inhibition of responsiveness to IL-2.

Subclass-specific serum antibody responses to recombinant Norwalk virus capsid antigen (rNV) in adults infected with Norwalk, Snow Mountain, or Hawaii virus

Subclass-specific antibody responses to the Norwalk virus capsid protein in adults challenged with Norwalk, Snow Mountain, or Hawaii virus were evaluated by solid-phase enzyme immunoassay using recombinant Norwalk virus capsid antigen (rNV). Fourfold or greater serum immunoglobulin G (IgG) antibody responses to rNV were detected in 15 of 20 volunteers challenged with Norwalk virus, and serum IgA and IgM antibody responses to rNV were seen in almost all subjects who had rNV IgG responses. Serum rNV IgG antibody responses also were detected in 6 of 15 volunteers challenged with Snow Mountain virus and 2 of 12 volunteers challenged with the Hawaii virus. However, the magnitude of antibody response and the geometric mean postchallenge rNV IgG antibody titers were lower in subjects challenged with Snow Mountain or Hawaii virus, and serum IgA and IgM responses generally did not occur.

Macrophage control of Brucella abortus: influence of cytokines and iron

Brucella abortus is a facultative intracellular bacterium that can infect and replicate in mononuclear phagocytes. Recent work has elucidated the role of cytokines in activating macrophages to inhibit the intracellular replication of brucellae, and in recruiting macrophages to the site of infection in vivo. There is also evidence that iron increases the ability of cytokine-activated macrophages to control intracellular brucellae by mechanisms involving reactive oxygen intermediates.

The Vin-1 gene, identified by provirus insertional mutagenesis, is the cyclin D2

The Vin-1 gene was initially identified as a gene whose expression is altered by the integration of proviruses in the Vin-1 common site of integration in retrovirus-induced rodent T-cell leukemias. We have now isolated the Vin-1 cDNA. Sequencing of the Vin-1 cDNA and Vin-1 exons revealed that the proviruses are integrated at the 5' end of the Vin-1 gene in an inverse transcriptional orientation. The sequence of the Vin-1 gene is identical to that of the recently identified G1-phase cyclin D2 gene. The human homolog of the Vin-1/cyclin D2 gene (CCND2) was mapped to chromosome 12, band p13.3, by in situ hybridization, confirming previous mapping data. Our results strongly support a role of the cyclin D2 gene in oncogenesis and thereby implicate altered cell cycle regulation in transformation.

Iron augments macrophage-mediated killing of Brucella abortus alone and in conjunction with interferon-gamma

Brucella abortus are Gram negative facultative intracellular bacteria, which survive and replicate in host macrophages. We have recently demonstrated that activation of macrophages with interferon-gamma increases their anti-brucella activities but does not result in elimination of intracellular brucellae. Here we demonstrate that iron-loaded macrophages have an enhanced capacity to kill or prevent replication of intracellular brucellae. Iron added bound to transferrin or as a salt, iron-nitrilotriacetate, can mediate the effect. Macrophages supplemented with iron-loaded transferrin in addition to activation with interferon-gamma can frequently eliminate the intracellular organisms by 48 hr after infection. The effect is apparent following phagocytosis of either nonopsonized or antibody-opsonized brucellae, and with both attenuated and virulent strains of B. abortus. The killing can be blocked by the hydroxyl radical scavengers mannitol and thiourea. This is consistent with the Haber-Weiss reaction, in which iron catalyzes the generation of hydroxyl radicals from hydrogen peroxide.

Molecular cloning of a mouse myosin I expressed in brain

We have isolated two cDNAs that encode putative myosin I heavy chains by polymerase chain reaction amplification of brain cDNA with degenerate oligodeoxynucleotide primers representing myosin I-specific conserved amino acid sequences. We report the complete deduced amino acid sequence of one of these cDNAs. The sequences is most similar to those of the avian and bovine brush border myosin Is, with five putative calmodulin-binding repeats at the head-tail junction. Northern analysis demonstrates that this myosin heavy chain, unlike the brush border myosins, is expressed in many tissues.

Prevalence of antibodies to Norwalk virus in England: detection by enzyme-linked immunosorbent assay using baculovirus-expressed Norwalk virus capsid antigen

A total of 3,250 serum specimens collected in England in 1991 and 1992 were tested by an indirect enzyme-linked immunosorbent assay for antibody to Norwalk virus using baculovirus-expressed capsid antigen, and 2,382 (73.3%) were positive. The prevalence of Norwalk virus antibody differed regionally. It was lowest (24.6%) in 6- to 11-month-old infants and increased to 89.7% in persons over 60 years old.

[Determination of glycyrrhizin in glycyrrhiza and it's preparations by ion-pair HPLC]

Glycyrrhizin is the main component of glycyrrhiza. In this article an Ion-pair high performance liquid chromatography (HPLC) method is described for the determination of glycyrrhizin in two kinds of glycyrrhiza from different origins and twelve kinds of Chinese traditional patent medicine containing glycyrrhiza. A reversed phase system was used, including an ODS column with water and methanol (36:64) as the mobile phase which contained 5mmol/L tetra-n-butyl ammonium hydroxide and was adjusted to pH 6.0 by phosphoric acid. The column temperature was 35 degrees C; the detection was performed at 254 nm. Under this condition glycyrrhizin could be separated from other components. The limit of detection was 13ng, and the average recovery was 99.85%. During the experiments, we studied the concentration of counter-ion, the mixing ratio of methanol to water, the pH of the mobile phase and column temperature and their effect on the capacity factor of compound and resolution. We also studied the method of pre-treatment for the samples. The determination method is simple and accurate.

Association of fasting insulin with blood pressure in young individuals. The Bogalusa Heart Study

BACKGROUND

The relationship between fasting plasma insulin and blood pressure was studied in a cross-sectional survey of children and young adults aged 5 to 26 years.

METHODS

Fasting plasma insulin, glucose, blood pressure, and anthropometric measurements were obtained on 3518 individuals.

RESULTS

When divided into four age groups, the analyses showed that fasting insulin was significantly and positively correlated to both systolic and diastolic blood pressure in individuals at all age groups, except at 13 to 17 years. In multivariate regression analyses, fasting insulin remained independently associated with blood pressure levels after controlling for glucose levels, body mass index (weight/height) and skinfold thickness in children (aged 5 to 12 years) and young adults (aged 18 to 26 years), although not in adolescents (aged 13 to 17 years). Moreover, fasting insulin was more strongly related to systolic than to diastolic blood pressure. The fasting blood glucose level did not contribute independently to multivariate prediction of blood pressure in young adults. When the children and young adults were divided into tertiles according to fasting insulin and body mass index, the independent effect of insulin and body mass index on systolic pressure was also seen in children and young adults.

CONCLUSIONS

The association between plasma insulin and blood pressure noted even in healthy children and young adults help target areas for cardiovascular risk prevention.

Effects of cytokines on intracellular growth of Brucella abortus

Interleukin 1 alpha (IL-1 alpha), IL-2, IL-4, IL-6, gamma interferon (IFN-gamma), tumor necrosis factor alpha (TNF-alpha), and granulocyte macrophage colony-stimulating factor (GM-CSF) were tested for their abilities to alter the growth of Brucella abortus in BALB/c J774A.1 murine macrophages. IL-1 alpha, IL-4, IL-6, tumor necrosis factor alpha, and granulocyte macrophage-colony-stimulating factor had no consistent or significant effect on the growth of the avirulent B. abortus strain 19. In contrast, the addition of either IFN-gamma or IL-2 at 100 U/ml to the macrophage cultures resulted in a significant reduction in the number of intracellular bacteria that was not attributable to decreased infection rates. With IL-2, the reduction was most often apparent only during the first 24 h after infection, while inhibition with IFN-gamma was apparent throughout the culture period of 48 h. The addition of either IL-2 or IFN-gamma to macrophage cultures also resulted in reduced intracellular CFU of the virulent B. abortus strain 2308 and the attenuated rough mutant B. abortus strain RB51. Inhibition of intracellular growth was not augmented by combinations of cytokines. Additional studies with IFN-gamma and IL-2 indicated that they could mediate the inhibition of intracellular growth of B. abortus in resident and thioglycolate broth-induced BALB/c peritoneal macrophages and in splenic macrophages. IFN-gamma also inhibited bacterial growth when added after infection of the macrophages, although the magnitude of the antibrucellae effects was less than that when it was added before infection. Furthermore, the maximal inhibitory effect was sustained only when IFN-gamma remained in the cultures after infection of the macrophages.

Expression of aminopeptidase N in fetal rat lung during development

The ectopeptidase, aminopeptidase N, serves as a cell surface marker of the apical surface of the alveolar type II epithelial cell in adult lung. It is also present in fetal lung before differentiation of morphologically mature type II alveolar epithelial cells, suggesting that it is expressed by precursors of the type II cells. We have examined the mRNA coding for the aminopeptidase in adult and fetal lung and in mature type II cells and determined levels of mRNA and immunoreactive protein during fetal lung development. Comparison of the temporal patterns of steady-state levels of aminopeptidase mRNA and immunoreactive protein during development show that the expression of the protein is developmentally regulated and that expression is regulated, at least in part, at a pretranslational level. Both mRNA and immunoreactive protein levels increase severalfold on the final gestational day, suggesting that the function of the aminopeptidase may be associated with air breathing.

Expression, self-assembly, and antigenicity of the Norwalk virus capsid protein

Norwalk virus capsid protein was produced by expression of the second and third open reading frames of the Norwalk virus genome, using a cell-free translation system and baculovirus recombinants. Analysis of the expressed products showed that the second open reading frame encodes a protein with an apparent molecular weight of 58,000 (58K protein) and that this protein self-assembles to form empty viruslike particles similar to native capsids in size and appearance. The antigenicity of these particles was demonstrated by immunoprecipitation and enzyme-linked immunosorbent assays of paired serum samples from volunteers who developed illness following Norwalk virus challenge. These particles also induced high levels of Norwalk virus-specific serum antibody in laboratory animals following parenteral inoculation. A minor 34K protein was also found in infected insect cells. Amino acid sequence analysis of the N terminus of the 34K protein indicated that the 34K protein was a cleavage product of the 58K protein. The availability of large amounts of recombinant Norwalk virus particles will allow the development of rapid, sensitive, and reliable tests for the diagnosis of Norwalk virus infection as well as the implementation of structural studies.

Detection of Norwalk virus in stool by polymerase chain reaction

A method of reverse transcription (RT) and polymerase chain reaction (PCR) for the detection of Norwalk virus in human stools was developed. A cationic detergent, cetyltrimethylammonium bromide, was found to effectively remove from stool extracts factors that inhibit the RT-PCR assay. The specificities of the tests were shown by hybridization of the amplified DNA with Norwalk virus-specific cDNA probes and a consistent correlation between virus detection in stools and infection of volunteers. RT-PCR detected virus in stool samples diluted 10(-4) and was about 100 times more sensitive than dot blot hybridization. In serial stool samples collected before and at different times after inoculation of 10 volunteers with Norwalk virus, 37 of 55 were positive by RT-PCR, but only 27 were positive by dot blot hybridization (chi 2 = 22.96; P less than 0.001). Further application of this method should allow detection of Norwalk virus in food or environmental samples such as shellfish and shellfish waters.

The effect of lipid peroxides and superoxide dismutase on systemic lupus erythematosus: a preliminary study

Serum lipid peroxide (LPO) levels, superoxide dismutase (SOD) activity in peripheral blood erythrocytes, serum ANA, anti-dsDNA, and C3 were measured in 83 patients with systemic lupus erythematosus (SLE) and in 29 healthy controls. Compared to the controls, LPO levels were significantly increased in active SLE patients while SOD activity was markedly decreased. From the active phase to the inactive phase, a gradual decline in LPO levels and an increase in SOD activity were observed. There was a close correlation between LPO levels and disease activity or the parameters including ANA titers, anti-DNA titers, and C3 levels; a significant negative correlation was found between SOD activity and LPO levels or these parameters. Further, a marked difference in SOD activity was found in untreated active cases with and without nephritis. As the SLE patients improved, LPO levels gradually declined and SOD activity increased. The present study indicates that free radicals and resultantly formed lipid peroxide levels are higher in patients with SLE than those in normal persons, probably contributing to the production of autoantibodies, nephritis, and vasculitis of other organs, and that excessively generated free radicals may play an important role in the pathogenesis of SLE, which is possibly due to diminished SOD activity.

Building protein backbones from C alpha coordinates

An automatic procedure for building polyalanine backbones from guiding alpha-carbon positions is presented. Polyalanine backbones are built based on the geometric restraints of angle N-C alpha-C and the knowledge of main-chain dihedral angle distributions. A building module constructs a list of polyalanine backbones that follow exactly the C alpha trace. Then a selection module selects one backbone with the largest portion of phi-psi pairs in favoured regions. Several test cases on C alpha coordinates from X-ray refined structures give acceptable results. Less than 10% of the peptide planes are incorrectly built, and the result is not sensitive to random shift up to 0.5 A of C alpha coordinates.