Viruses of hemorrhagic fever with renal syndrome (HFRS) grouped by immunoprecipitation and hemagglutination inhibition

Nine viruses antigenically related to Hantaan virus that were isolated from various rodents in several countries and from a patient were examined by immunoprecipitation and by hemagglutination inhibition (HI). The immunoprecipitation tests were done with a monoclonal antibody that reacted with glycoprotein G2 and an antibody against a nucleocapsid protein. The viruses were classified into four subtypes on the basis of the molecular weights of their precipitated polypeptides and the pattern of results of the HI tests.

Serological evidence of Hantaan-related viruses in Hong Kong

Sera from rats (Rattus norvegicus), domestic animals and man in Hong Kong were studied by immunofluorescent antibody assay and plaque reduction neutralization tests for evidence of infection by Hantaan-related viruses. Antibody probably arising from infection by Seoul or a Seoul-like virus was detected in rat and human sera (and one pig serum), highlighting the potential public health importance of this group of viruses in Hong Kong, and in the region.

A new HPLC analytical method for o-hydroxyhippuric acid in uremic serum

o-Hydroxyhippuric acid (HHA) is formed in liver during the process of detoxication of salicylic acid which arises from either salicylic-containing dietary vegetables or hydrolysis of aspirin. Recently, HHA has also been shown as one of the so-called 'uremic toxins'. By derivatization of HHA with o-phthaldialdehyde (OPA), the resulting fluorescent product can easily be measured with the limit of measurement somewhere below 3 pmol on high performance liquid chromatography. Using the method described, an approximately 85% recovery of added HHA in human sera was obtained. This analytical system is now being employed to determine the concentration of HHA in human sera of uremic patients. Determination of HHA content in human uremic patients is very important, since uremia is associated with defective binding of many acidic drugs to serum protein(s) and HHA replaces these drugs by tightly binding to these proteins. This could potentially affect the therapeutic effectiveness of various pharmacologic agents.

Studies on naturally occurring proteinous inhibitor for transmethylation reactions

An inhibitor for S-adenosyl-L-methionine (AdoMet)-dependent methyltransferases has been purified from rat liver particulate fraction to apparent homogeneity, as judged by high-performance liquid chromatography, two-dimensional paper electrophoresis and isoelectric focusing chromatography. This inhibitor molecule, which is composed of 27 amino acid residues with an additional fluorescent chromophore, is rich in glycine, contains no basic amino acid, and has an isoelectric point (pI) of 3.70. A single absorption peak was observed at 248 nm in acidic as well as in neutral media, while two peaks were detected in alkaline medium at 206 nm and 248 nm. The former peak was found to be quite labile. The fluorescent spectra with excitation peak at 285 nm and emission peak at 358 nm are greatly influenced by the pH, being the highest in alkaline medium. The purified inhibitor inhibits all the AdoMet-dependent methyltransferases examined.

Growth experiment of Hantaan virus in A549 cells: an attempt to improve the immunofluorescent antibody technique for hemorrhagic fever with renal syndrome

An assay method for the infectivity of Hantaan virus, a causative agent of HFRS (hemorrhagic fever with renal syndrome), was developed by the use of IFA (immunofluorescent antibody technique). With the aid of this method, the growth characteristics of Hantaan virus, 76-118 strain, were followed in A549 cells. At a maximal MOI (multiplicity of infection) of 1.6 VAIU (viral antigen-inducing units) per cell, the conventionally available value, plateau level potencies of the viral antigen and virus infectivity were attained at eight and ten days postinfection, respectively, and most of the infective virus produced accumulated in the culture fluids of infected cells. When infections were defined with MOI values in terms of VAIU per cell, development of the viral antigen was highly consistent and followed a given pattern of kinetics. Based on these findings, a protocol for preparation of the viral antigen in IFA was presented, wherein spot culture and FBS treatment were emphasized as effective procedures to minimize non-specific staining.

Antigenic and genetic properties of viruses linked to hemorrhagic fever with renal syndrome

Hemorrhagic fever with renal syndrome (HFRS) comprises a variety of clinically similar diseases of viral etiology that are endemic to and sporadically epidemic throughout the Eurasian continent and Japan. Although HFRS has not been reported in North America, viruses that are antigenically similar to HFRS agents were recently isolated from rodents in the United States. Examination and comparison of eight representative isolates from endemic disease areas and from regions with no known associated HFRS indicate that these viruses represent a new and unique group that constitutes a separate genus in the Bunyaviridae family of animal viruses.

Positive serological evidence that Hantaan virus, the etiologic agent of hemorrhagic fever with renal syndrome, is endemic in Canada

Hemorrhagic fever with renal syndrome is endemic in most parts of the world. The etiological agent in known as Hantaan virus. More than 2000 Canadian sera from all age groups and provinces were tested for the presence of antibody to this virus by the indirect immunofluorescent antibody technique. The frequency of seropositivity ranged from 0.3 to 4.0%, with the national average being 1.4%. Newfoundland and New Brunswick in the Atlantic region had the highest positivity, being higher than hyperendemic areas in Korea. The inland provinces of Ontario, Manitoba, and Alberta had only 0.5% positives to Hantaan virus. In contrast, approximately 1.5% of sera from Saskatchewan, Quebec, and British Columbia were positive. No correlation in positivity was found between geography or sex, but positivity did increase with age. The highest titres were found in the group aged 65 to 93 years.

Studies on compartmentation of S-adenosyl-L-methionine in Saccharomyces cerevisiae and isolated rat hepatocytes

The existence of metabolically distinct pools of S-adenosyl-L-methionine in Saccharomyces cerevisiae and isolated rat hepatocytes was investigated. Utilizing a relatively long labeling period with [methyl-14C]methionine, a metabolically 'stable' pool was labeled. A subsequent short labeling with [methyl-3H]methionine selectively labeled a putative metabolically 'labile' pool. The existence of these distinguishable pools was ascertained by following the 3H and 14C label disappearance in S-adenosyl-L-methionine during the chase-period in label-free media containing cycloleucine to prevent further synthesis of S-adenosyl-L-methionine. In both yeast and hepatocytes, the 3H/14C ratio in S-adenosyl-L-methionine decreased sharply. The individual 3H and 14C decrease in S-adenosyl-L-methionine showed t1/2 values of 3 and 8 min for yeast and 4 and 18 min for hepatocytes. The results strongly indicate that at least two metabolically distinct S-adenosyl-L-methionine pools actually do exist in both systems. Subcellular fractionation revealed that the 'labile' pool exist in the cytosol for both yeast and hepatocytes while the 'stable' pool exists in the vacuolar and the mitochondrial fraction for the yeast and hepatocytes respectively. The S-adenosyl-L-methionine pools were also studied in normal yeast under anaerobic chase condition and petite mutant yeast. Sharply contrasting with aerobically chased normal yeast, both showed closely parallel 3H and 14C decreases in S-adenosyl-L-methionine.

Isolation of Hantaan virus, the etiologic agent of Korean hemorrhagic fever, from wild urban rats

Urban rats captured in Seoul and four nearby Korean cities were found to have immunofluorescent antibodies reactive with Hantaan virus, the etiologic agent of Korean hemorrhagic fever (KHF). Serum antibodies were detected in 13% from 477 Rattus norvegicus and 11% of 47 Rattus rattus. Hantaan viral antigen was found in pulmonary tissues of 42 animals, and Hantaan virus was recovered from 23 rats, all but two of which were R. norvegicus. Wistar rats were qualitatively much more sensitive than Apodemus agrarius rodents for isolation of virus from tissues of wild rats. Wistar rats inoculated with one of these strains had virus in lung and spleen for at least 75 days. These results document the existence of an urban cycle for Hantaan virus, which had been suspected on the basis of the occurrence of sporadic urban cases in humans of KHF, and suggest that Rattus-borne Hantaan virus may be widely distributed in urban centers.

Laboratory-acquired infections with Hantaan virus, the etiologic agent of Korean hemorrhagic fever

Clinically apparent infections with Hantaan virus, the etiologic agent of Korean hemorrhagic fever, occurred in nine persons exposed to the virus at the Korea University Virus Institute (Seoul) between 1971 and 1979. All were directly related to trapping of wild rodents or work with naturally or experimentally infected wild and laboratory rodents in a designated animal suite. All infections were acquired during the months of November-April, and none was associated with accidental parenteral inoculations. These facts suggested that aerosols produced by chronically infected rodents were the infectious vehicles and that limited air circulation and lowered humidity in the animal rooms during winter months increased the probability of viral transmission. Four persons, including two casual visitors, became ill within four months after the initiation of experimental studies of infections in Wistar rats with Hantaan virus, an occurrence suggesting that this rodent may be a highly infectious host for Hantaan virus.

Hantaan virus, aetiological agent of Korean haemorrhagic fever, has Bunyaviridae-like morphology

Spherical to oval particles with a unit membrane and subunit surface structure were demonstrated by negative-contrast staining of supernatant fluids of A-549 cell cultures infected with strain 76-118 of Hantaan virus. The particles had an average diameter of about 95 nm, with a range of 80 to 110 nm. Similar particles were isolated by buoyant density fractionation in sucrose gradients. In four separate experiments, infectivity cosedimented with 95 nm particles at buoyant densities from 1.15 to 1.18 g/ml. Immunoaggregation of the virions was specifically produced by antisera obtained after Hantaan virus infection of man and rabbit. The known physicochemical and morphological properties of these particles are compatible with those generally reported for the Bunyaviridae family of viruses.

Korean hemorrhagic fever among rural residents in Japan

Naturally occurring infection with Korean hemorrhagic fever virus among four families living in rural areas of northern and central Japan was proved by the demonstration of antibody to the virus. Furthermore, Korean hemorrhagic fever virus antigen was detected in the lung tissues of wild rodents captured in the endemic area. These findings indicate the endemic presence of Korean hemorrhagic fever virus on Honshu Island, Japan.

Intraspecific transmission of Hantaan virus, etiologic agent of Korean hemorrhagic fever, in the rodent Apodemus agrarius

Experimental parameters of infection and intraspecific transmission of Hantaan virus, the etiologic agent of Korean hemorrhagic fever, in Apodemus agrarius rodents were determined. Mice inoculated by the intramuscular route experienced viremia for about 1 week beginning on day 7. After 3 weeks, immunofluorescent and neutralizing antibodies were present and no mouse ever developed signs of acute illness. Virus was recovered from lung, kidney, salivary gland, and liver, and virus excretion in urine, saliva, and feces occurred from about day 10 through day 360 (urine) post-inoculation. Antigen, but not infectious virus, was persistent in lung tissue for as long as 1 year. Horizontal contact infection occurred among cage-mates regardless of sexual pairing up to 360 days after infection and no evidence for participation of ectoparasitic arthropods in such transmission was obtained.

Electron microscope appearance of Hantaan virus, the causative agent of Korean haemorrhagic fever

The morphology and morphogenesis of three strains of Hantaan virus, which causes Korean haemorrhagic fever (KHF), were examined by thin-section and negative-contrast electron microscopy of infected A549 cell-culture specimens. In thin sections, virus was detected within cytoplasmic granular matrices (viroplasms) of the infected cells. Virus particles were spherical (diameter 73 +/- 5 nm), and had an extremely electron-dense core (diameter 47 +/- 6.5 nm). Replication and maturation of the virus seemed to occur in the viroplasm. As infection progressed, viral particles increased in number and were packed into the granular matrices as cytoplasmic crystalline arrays. Viruses seemed to be released from infected cells by cell dissolution. Negative-contrast staining showed that the virus had an icosahedral structure (diameter 80 +/- 2 nm) and annular surface capsomeres. Viruses clumped when exposed to anti-Hantaan virus serum from a convalescent patient. The morphology and morphogenesis of the virus were compatible with those of orbiviruses.

Korean hemorrhagic fever: propagation of the etiologic agent in a cell line of human origin

The etiologic agent of Korean hemorrhagic fever has been propagated in a human cultured cell line derived from a carcinoma of the lung. The cells, described as type II, alveolar epithelial, support replication of the agent and successive passages. Antigen of the Korean hemorrhagic fever agent is readily detected in infected cells by means of direct or indirect fluorescent antibody techniques. Previous attempts to propagate this agent in vitro had been unsuccessful.

Observations on natural and laboratory infection of rodents with the etiologic agent of Korean hemorrhagic fever

Studies were conducted to define the natural host range of the Korean hemorrhagic fever (KHF) agent in South Korea, and to identify colonized rodents susceptible to this infection. Eight species of field rodents were captured in areas of Korea endemic for KHF and their tissues were examined by immunofluorescence for the presence of KHF antigen. One hundred and fourteen of 817 Apodemus agrarius coreae captured between 1974 and 1978 had one or more positive organs. No positive organ was found in 239 rodents of the other seven species examined. Two hundred and thirty-eight specimens of Apodemus agrarius jejuensis captured on Jeju Island, an area thought to be free of disease, were also negative. Attempted laboratory infection of nine species of rodents captured in the field but maintained in the laboratory was successful only in the two subspecies of Apodemus. The 46 specimens of A. a. jejunesis tested in this manner were all uniformly susceptible to infection as determined by immunofluorescence. Serial sacrifice of experimentally infected A. a. jejuensis revealed viremia of short duration terminating on day 10 postinfection. In contrast, other tissues of this animal, including lung, kidney, liver and parotid gland were positive on day 10 and remained so through the 100-day observation period. When 12 species of colonized laboratory rodents were inoculated with KHF agent five were found to develop KHF antibody by indirect immunofluorescence and two, Calomys callosus and Apodemus agrarious ningpoensis, developed detectable KHF antigen in their tissues.

Propagation of Korean hemorrhagic fever virus in laboratory rats

Korean hemorrhagic fever virus (KHFV) has been adapted to the Wistar and Fisher strains of rats. Infection was detected by the appearance of specific antigen in the lung tissue of the infected rats at 14 to 64 days after inoculation and by the appearance of circulating antibodies in ther serum which reacted specifically with KHFV antigen in the lungs of infected Apodemus agrarius subsp. coreae 3 weeks after inoculation. Distribution of antigen in rat tissues as determined by immunofluorescent staining was the same as that in Apodemus mice except that antigen was present in the spleens of rats. Adaptation of KHFV to the laboratory rat provides an animal model that is free of wild rodent viruses and is readily available for use in studies on the characterization of KHFV.

Korean haemorrhagic fever in staff in an animal laboratory

In March, 1975, and January, 1978, there were outbreaks of Korean haemorrhagic fever (K.H.F.) among staff in the animal laboratory of the clinical research building of Tohoku University hospital. 13 doctors and 1 veterinarian had K.H.F., and all except 1 had a mild but typical clinical course. K.H.F. antibody titres were significantly raised in all 14 patients. 12 other doctors working in the same room had no symptoms and no K.H.F. antibody. K.H.F. antibody was also detected in 3 animal technicians who had not been ill, but who had worked in the same room. Antibody was not detected in any of the 4 technicians who worked in different animal rooms in another building. Epidemiological studies suggest that laboratory rats were the source of the infection. High titres of K.H.F. antibody were most common in rats reared in the animal laboratory associated with the outbreak.

Etiological relation between Korean hemorrhagic fever and epidemic hemorrhagic fever in Japan

The first case of epidemic hemorrhagic fever in Japan was seen in Osaka in 1960. The etiologic agent of this disease has not yet been isolated, but a close etiologic relation between Korean hemorrhagic fever and epidemic hemorrhagic fever in Japan has been suspected because of similarities in the clinical and pathological pictures of the two diseases. This relation has now been confirmed serologically by demonstrating specific immunofluorescent antibodies to Korean hemorrhagic fever virus in 19 of 20 sera obtained from subjects 7 to 17 years after an acute attack of epidemic hemorrhagic fever.

Aetiological relation between Korean haemorrhagic fever and nephropathia epidemica

A close aetiological relation between Korean haemorrhagic fever and nephropathia epidemica of Scandinavia has often been suggested because of similarities in their clinical picture and epidemiology. This relation has now been confirmed serologically; raised titres of antibody to Korean haemorrhagic fever agent and seroconversions have been found by the indirect fluorescent-antibody technique in 20 patients with nephropathia epidemica.

Isolation of the etiologic agent of Korean Hemorrhagic fever

Lung tissues from 73 rodents (Apodemus agrarius coreae) gave specific immunofluorescent reactions when they reacted with sera from patients convalescing from Korean hemorrhagic fever. Similar staaining was observed in the lungs of A. agrarius inoculated with acute-phase sera obtained from two patients with this disease. The unidentified agent was successfully propagated in adult A. agrarius through eight passages representing a cumulative dilution of greater than 10(-17). Experimentally inoculated rodents developed specific fluorescent antigen in the lung, kidney, liver, parotid glands, and bladder. Organs, especially lungs, were positive beginning 10 days and continuing through 69 days after inoculation. The agent could not be cultivated in several types of cell cultures nor in laboratory animals. No fluorescence was observed when infected A. agrarius lung tissues were reacted with antisera to Marburg virus, Ebola virus, and serval arenaviruses. Diagnostic increases in immunofluorescent antibodies occurred in 113 of 116 severe and 11 of 34 milder cases of clinically suspected Korean hemorrhagic fever. Antibodies were present during the first week of symptoms, reached a peak at the end of the second week, and persisted for up to 14 years. Convalescent-phase sera from four persons suffering a similar disease in the Soviet Union were also positive for antibodies.

Effect of hydrocortisone on ammonia intoxication in the adrenalectomized rat

Adrenalectomy induces a hypersensitivity in the rat to ammonia intoxication. Daily injection of hydrocortisone hydrochloride to adrenalectomized rats restored normal sensitivity to ammonia intoxication, with concomitant restoration of liver urea-synthesizing capacity to the normal value. When injected with a large dose of ammonium acetate, hydrocortisone-treated adrenalectomized rats were able to reduce the plasma ammonia concentration much more rapidly than the adrenalectomized control rats. However, neither the increase in liver urea synthesis nor the more rapid decrease in the plasma ammonia concentration were sufficient to explain the protective aciton of hydrocortisone against ammonia intoxication.

S-adenosylmethionine: protein-arginine methyltransferase. Purification and mechanism of the enzyme

Protein methylase I (S-adenosylmethionine: protein-arginine methyltransferase, EC 2.1.1.23) has been purified from calf brain approximately 120-fold with a 14% yield. The final preparation is completely free of any other protein-specific methyltransferases and endogenous substrate protein. The enzyme has an optimum pH of 7.2 and pI value of 5.1. The Km values for S-adenosyl-L-methionine, histone H4, and an ancephalitogenic basic protein are 7.6 X 10(-6), 2.5 X 10(-5), and 7.1 X 10(-5) M, respectively, and the Ki value for S-adenosyl-L-homocysteine is 2.62 X 10(-6) M. The enzyme is highly specific for the arginine residues of protein, and the end products after hydrolysis of the methylated protein are NG,NG-di(asymmetric), NG,N'G-di(symmetric), and NG-monomethylarginine. The ratio of [14C]methyl incorporation into these derivatives by enzyme preparation at varying stages of purification remains unchanged at 40:5:55, strongly indicating that a single enzyme is involved in the synthesis of the three arginine derivatives. The kinetic mechanism of the protein methylase I reaction was studied with the purified enzyme. Initial velocity patterns converging at a point on the extended axis of abscissas were obtained with either histone H4 or S-adenosyl-L-methionine as the varied substrate. Product inhibition by S-adenosyl-L-homocysteine with S-adenosyl-L-methionine as the varied substrate was competitive regardless of whether or not the enzyme was saturated with histone H4. On the other hand, when histone H4 is the variable substrate, noncompetitive inhibition was obtained with S-adenosyl-L-homocysteine under conditions where the enzyme is not saturated with the other substrate, S-adenosyl-L-methionine. These results suggest that the mechanism of the protein methylase I reaction is a Sequential Ordered Bi Bi mechanism with S-adenosyl-L-methionine as the first substrate, histone H4 as the second substrate, methylated histone H4 as the first product, and S-adenosyl-L-homocysteine as the second product released.

The influence of dietary nitrate on nitrate concentration in egg yolk and albumen

Sodium nitrate (from 0 to 2,000 p.p.m.) was added to the drinking water of 32-week old S.C. White Leghorn pullets. Eggs collected once a week for 8 weeks were analyzed for nitrate content. Increasing levels of nitrate in the drinking water resulted in increasing levels of nitrate in albumen and yolk. Higher levels of nitrate were found in the yolk than in the albumen. When birds were started on the experiment, nitrate in the drinking water was reflected by immediate increases in nitrate content of the eggs. The nitrate content of eggs from birds receiving 1,000 p.p.m. NaNO3 (728 p.p.m. NO3-) exceeded the 45 p.p.m. permissible level of nitrate in drinking water for human beings.

Possible associations of dietary residues with growth of the large gut

Diets containing 67% cornstarch, or 42% cornstarch plus 25% lactose, agar, cellulose or raw potato starch, were fed to rats. Dimensions of the cecum and colon plus rectum and many characteristics of large intestinal and fecal residues were recorded. Possible relationships of these dimensions and characteristics to the diet-produced differences in weights of the cleaned cecum and colon plus rectum were sought by correlation and covariance methods. The following possible associations were found. The cecal dry weight was possibly associated with the length and maximum width of the cecum (containing its fill) and also with the weights of cecal fill. The dry weight and the weight:length ratio of the colon plus rectum were possibly associated with the fresh weight/fecal pellet and with other weights and dimensions of colonic fill and of feces. Despite these findings, in most cases we could not decide what relationship the residues might have to large intestinal growth and function. Nor could we decide how certain diets stimulate cecal or colonic growth.