Effect of age on some aspects of sulfate metabolism in the rat

S³⁵-labelled sodium sulfate was administered to rats 10, 30, and 300 days old in an intraperitoneal dose of 0.3 µc. per gm. of body weight. Representative animals of each age were sacrificed 12, 24, 48, and 96 hours after injection. The concentration of sulfur-35 in the pooled sera of the 10-day-old rats was found to be strikingly higher than the level in the sera of the 30-day-old and the 300-day-old rats, while the levels of sulfur-35 in the sera of rats in the latter two age groups were similar. The difference was not explained by the differences in binding of sulfate by serum proteins. Although no binding could be detected when sulfate was added to serum in vitro, a substantial fraction, up to 80 per cent by the 96th hour, was observed to be bound after injection into the living rat. The 10-day-old rats differed from the older ones in having lower levels of serum proteins and lesser amounts of bound sulfate. The non-dialyzable sulfur-35 was associated to the largest extent with the albumin component in the sera. The age of the rats found expression in the specific activities of the sulfate-sulfur of mucopolysaccharides isolated from the skeletons, pelts, and viscera. The highest specific activities were observed in the mucopolysaccharides isolated from the tissues of the youngest rats; the lowest in those from the oldest rats. Though the maximum concentration was rapidly attained in the mucopolysaccharides from the various tissues in each of the age groups, the subsequent decreases in concentration were slow. Radiochemical analyses for sulfur-35 in ends and shafts of femurs and radioautographs of humeri supported the assumption that the labelled sulfate had been incorporated into the chondroitin sulfate of growing cartilage.     

Turnover of S35-sulfate in epiphyses and diaphyses of suckling rats; nature of the S35-labelled compounds

S(35)-sulfate was injected intraperitoneally- into 7-day-old rats and their long bones were removed after intervals of time. The epiphyses were separated from the diaphyses for analysis. From the diaphyses freed of bone marrow about 82 per cent of the S(35) which they contained was extracted with a 2.5 N solution of sodium hydroxide. More, about 91 per cent of the S(35), was thus extracted from the epiphyses. Dialysis of the extracts against water showed that the fraction of S(35) which was dialyzable decreased rapidly with time. After 1 hour about 80 per cent and 50 per cent of the S(35) in the extracts of diaphyses and epiphyses, respectively were found in the dialysates, after 24 hours about 20 per cent and 4 per cent, and after 120 hours 12 per cent and 1 per cent. Similar values for the S(35) in inorganic sulfate were found when the extracts were chromatographed on an anion exchange resin, dowex-2. The S(35), other than inorganic sulfate, was in the form of bound sulfate, which was released by acid hydrolysis. Uronic acid and hexosamines, primarily galactosamine, were associated with the S(35). Indeed, on paper electrophoretograms and paper chromatograms the major S(35)-labelled component which was seen resembled chondroitin sulfate in its mobility. On the paper chromatograms, also a second S(35)-labelled component with a mobility lower than that of chondroitin sulfate was found. It is unlikely that the latter is a breakdown product of chondroitin sulfate, produced in the course of extraction with the sodium hydroxide solution. In fact, both components were also found in sodium versenate homogenates which had been dialyzed extensively against water. On the basis of these results it is suggested that the greatest part of the S(35)-labelled materials previously demonstrated by autoradiography to be progressively deposited in the metaphyses after 24 hours,-as the concentration of S(35)-sulfate concurrently decreased in the epiphyseal cartilage plates,-are akin to the chondroitin sulfate of the epiphyseal cartilage plates and are derived from the latter.     

Vitamin D and endochondral ossification in the rat as indicated by the use of sulfur-35 and phosphorus-32

The concentration of inorganic sulfate-sulfur in the serum of vitamin D-deficient rats, 2.6 to 3.5 mg. per cent, was found to be higher than that in the serum of normal rats of the same age, 2.0 mg. per cent. No change was observed following the administration of 25 γ of vitamin D₂. In accord with the results of others, it was found that a definitely increased deposition of phosphorus in femurs and tibiae had occurred 36 to 48 hours after the administration of vitamin D₂ to vitamin D-deficient rats. An immediate increase in the uptake of sulfate by the skeleton was found using sodium sulfate-S³⁵. As measured by the specific activity of sulfate-sulfur in samples of chondroitin sulfate isolated from the skeletons of the vitamin D-deficient animals and from normal controls receiving equal doses of sulfur-35, the rate of synthesis of chondroitin sulfate in rachitic rats is similar to the rate in normal rats of the same age. Likewise, the incorporation of labelled sulfate into the sulfomuco-polysaccharides of the pelts was found to be equal at 12 hours to that in normal rats. Following the administration of vitamin D₂ to deficient animals an increase in the rate of synthesis of the chondroitin sulfate of the skeletons was noted. The radiochemical and radioautographic evidence suggest that there is in vitamin D-deficient rats an impaired utilization of chondroitin sulfate and that vitamin D₂ is able to accelerate this process.     

OCCURRENCE OF POLIOMYELITIS VIRUS IN AUTOPSIES,PATIENTS, AND CONTACTS

1. Poliomyelitis virus has been recovered in monkeys from 50 per cent of spinal cords, 10 per cent of olfactory bulbs, 50 per cent of tonsil-adenoid tissue, and from 26 per cent of the colon contents of autopsies; from the stools of 20 per cent of patients, and of 5 per cent of the contacts examined in this series. 2. Other materials as indicated in Table I were tested without success. 3. In autopsies with positive cords, tonsil-adenoid tissues, or colon contents were positive in 73 per cent. 4. 22 per cent of stools from patients with paralysis yielded virus and 19 per cent of the stools from patients without paralysis yielded virus. 5. 20 per cent of the stools from males and 22 per cent of the stools from females yielded virus. 6. 40 per cent of 35 stools from patients under 16 years yielded virus while 8 per cent of 38 stools from patients above the age of 15 yielded virus. 7. 71 per cent of the cords of 35 autopsies under 16 years yielded virus while 31 per cent 16 years and over yielded virus. 8. Repeat stools from 5 positive cases, 1 month after the first positive stool, were negative. The stool of one contact was positive the 2nd month after first recovery but was negative the 3rd month.     

HOMOGRAFT IMMUNITY IN PREGNANCY : THE PLACENTAL TRANSFER OF CYTOTOXIC ANTIBODY IN RABBITS

The mammalian fetus affixed to the uterine wall in some ways resembles a homograft, but maternal homograft immunity even when specifically directed against her fetuses fails to destroy them. The placental barrier appears to be critical in protecting the fetus against maternal immunologic attack. In order to evaluate the means by which it affords protection, we have measured in rabbits the transfer of cytotoxic antibody from mother to fetus. When the offspring were not the specific targets for maternal antibody, we found titers of cytotoxic antibody in the newborn animals at or near maternal levels in 16 of 18 cases (89 per cent), demonstrating the ability of this antibody to cross the rabbit placenta. When the offspring were appropriate targets for antibody, however, 11 of 18 newborn animals (61 per cent) had no demonstrable titer. We believe that in these latter cases, antibody had become fixed to antigenic sites and thereby had been removed from the fetal circulation. There was, however, no evidence of harm to any of the fetuses, either in survival (as demonstrated in a previous study) or in spleen or thymus weights or peripheral leukocyte and mononuclear cell counts. Cytotoxic antibody appears to reach the embryo early in gestation, since we found antibody in 8-day-old blastocyst fluid in each of 2 trials. We conclude that the fetus neither receives nor requires protection against cytotoxic antibody, and believe that fetal protection against maternal homograft immunity is afforded by a placental barrier to maternal mononuclear leukocytes.     

Synthesis of sulfomucopolysaccharides in thyroidectomized rats

The thyroid glands of rats were made non-functional by a single dose of iodine-131 on the 1st day after birth or by surgical removal on the 28th day. The incorporation of sulfate-sulfur into the sulfomucopolysaccharides of skeletons and pelts was found to be significantly depressed by thyroidectomy. Daily supplements of 5 or 10 gamma of L-thyroxine, started on the 28th day, increased the uptake of sulfur-35, although it did not reach normal in the 2 weeks of treatment. Autoradiograms of sections of tibiae and pelts confirmed the analytical data. The findings suggest that the synthesis of sulfomucopolysaccharides is depressed in thyroidectomized rats.     

THE INFLUENCE OF AGE OF HOST AND TEMPERATURE OF INCUBATION ON INFECTION OF THE CHICK EMBRYO WITH VESICULAR STOMATITIS VIRUS

Chick embryos after 7 days of incubation were found to be much more susceptible to infection with vesicular stomatitis virus than were 10 day embryos. They had a 100 per cent mortality and were very suitable for titrations of the virus. The rate of increase of virus in 7 and 10 day embryos was studied. Two different temperatures of incubation were employed, 35–36°C. and 39–40°C., and the growth curves for the virus under the different conditions are presented. 10 day embryos were highly resistant and at 39–40°C. more than half of them survived. At the lower temperature of incubation, 35–36°C., all 10 day embryos died, but they survived much longer than did 7 day embryos. In the 7 day embryos death occurred after about 12 hours at 39–40°C. and after about 16 hours at 35–36°C., or earlier at the higher temperature. In embryos of both ages the virus titer reached at the higher temperature was only about 1 per cent of that reached at 35–36°C., even in those that died.     

Gastrointestinal manifestations of systemic vasculitis

Systemic vasculitis is known to affect the gastrointestinal tract but the nature of the complication is poorly characterized. Out of 65 patients with systemic vasculitis, the majority of whom had renal disease, the intestine was found to be affected in 18. These comprised four of eight patients with polyarteritis nodosa, nine of seventeen with microscopic polyarteritis, four of thirty-six with Wegener's granulomatosis and one of four with Churg-Strauss syndrome. The features included abdominal pain (85 per cent), diarrhoea (50 per cent), gut haemorrhage (44 per cent) and abnormal liver function tests (50 per cent). Manifestations of gastrointestinal disease were evident at presentation in half the patients and led to a fetal outcome in five. Ileus, mucosal abnormalities, perforation and slow transit were evident radiographically, and selective visceral angiography showed aneurysms or organ infarcts in five patients. Histological assessment of gut biopsies (chiefly rectal) revealed non-specific inflammation or ulceration in nine patients and intramucosal haemorrhage in two. Focal areas of necrosis and ulceration in colonoscopic biopsies were highly suggestive of vasculitis whereas arteritis was only found in one full thickness biopsy. Hence the diagnosis of gastrointestinal complications depends largely on clinical evidence. In patients who survived, the gastrointestinal features remitted as the systemic illness improved following treatment with steroids, cyclophosphamide or plasma exchange.     

Fundamental signals that regulate eosinophil homing to the gastrointestinal tract

The histological identification of increased eosinophils in the gastrointestinal tract occurs in numerous clinical disorders; however, there is a limited understanding of the mechanisms regulating eosinophil trafficking into this mucosal surface. The results presented in this study characterize the processes regulating eosinophil homing into the gastrointestinal tract at baseline. Eosinophils were found to be present in the lamina propria of 19-day-old embryos and germ-free adult mice at concentrations comparable to those present in non-germ-free adult mice. Furthermore, eosinophil gastrointestinal levels were not altered by increasing circulating eosinophils after pulmonary allergen challenge. Gastrointestinal eosinophil levels were partially reduced in mice deficient in recombinase activating gene-1 (RAG-1), IL-5, or the beta common chain (betac), but these reductions paralleled reductions in circulating eosinophils. In contrast, mice deficient in eotaxin had a marked reduction in gastrointestinal eosinophils but normal levels of eosinophils in the hematopoietic compartments. Furthermore, eotaxin was important for regulating eosinophil levels, even in the presence of high levels of IL-5. These investigations demonstrate eosinophil homing into the gastrointestinal tract during embryonic development occurring independently of viable intestinal flora. Furthermore, eotaxin is identified as the primary regulator of eosinophil gastrointestinal homing under homeostatic states, and may therefore have a fundamental role in innate immune responses.     

MUCUS IN INTESTINAL CONTENTS OF GERMFREE RATS

The fecal excretion of total nitrogen and of total hexosamines has been determined in germfree and conventional rats. Germfree rats excreted more hexosamines than the conventional rats, while no difference in the nitrogen excretion was found. Infection of the germfree rats with a normal flora resulted in a temporarily increased excretion of hexosamines and nitrogen over a period of 2 to 3 days after which they reached the level of the conventional animals. The contents of the germfree cecum contained 65 to 137 mg of hexosamines and 57 to 127 mg of nitrogen as compared to 1.2 to 5.3 and 7.4 to 23 mg in conventional animals. The high figures for hexosamines were due to an increase in the total amount of contents in the cecum and to a fivefold increase in the concentration of hexosamine-containing material. Studies on the distribution of hexosamine-containing cecal contents between sediment and supernatant after centrifugation at 20,000 g for 2 hours demonstrated that 5 to 10 per cent of the hexosamines occurred in the sediment in the germfree rats, while 75 to 85 per cent was found in this fraction in the conventional rats. The soluble part of the cecal contents in germfree as well as in the conventional rats contained 70 per cent of hexosamines in molecules with a molecular weight above approximatively 100,000 as found by gel filtration experiments on sephadex gels. The higher weight of the germfree cecal wall was reflected in a high total amount of nitrogen and hexosamines. Isolated strains of bacteria capable of reducing the cecal size in vivo did not show any capacity to degrade the mucus in vitro in a test system, where a full intestinal flora was highly active.     

CELLULAR MECHANISMS OF PROTEIN METABOLISM IN THE NEPHRON : IV. THE PARTITION OF SUCCINOXIDASE AND CYTOCHROME OXIDASE ACTIVITIES IN THE CELLS OF THE PROXIMAL CONVOLUTION OF THE RAT AFTER INTRAPERITONEAL INJECTION OF EGG WHITE

1. Shifts of enzymatic activity have been followed during the formation and evolution of the droplets that form in the cells of the proximal convolution of the nephron of the rat after the injection of a 50 per cent solution of egg white in isotonic saline. 2. Twelve hours after injection there is a 35 to 40 per cent decrease in succinoxidase and cytochrome oxidase activities in the fraction containing the larger particles; i.e. mitochondria and droplets in equal concentration. Although after 30 hours the quantitative proportion of droplets and mitochondria is the same as previously, the activities of the fraction have returned to the normal observed originally in the uninjected rat in a corresponding fraction consisting of mitochondria only. 3. The microsome fraction shows an average increase of 35 per cent in oxidative enzyme activities during the early period following injection, and decreases to the original figure in the later period of droplet formation. 4. It is concluded from the shifting pattern of localization of oxidative enzyme activity within the cell particulates that the absorption droplets arise by the incorporation of the mitochondrial elements, which originally contain the highest enzyme activity, with absorbed protein through the intermediate stage of smaller (microsomal) particles.     

COMPARISON OF THE EFFECTS OF PAPAIN AND VITAMIN A ON CARTILAGE : I. THE EFFECTS IN RABBITS

The administration of large amounts of vitamin A to rabbits has been shown to result in depletion of cartilage matrix. The normal basophilic, metachromatic, and Alcian blue staining properties of the matrix are lost, especially in articular and epiphyseal cartilage. The cartilage cells remain intact, but are reduced in size. These changes sometimes appeared as early as 48 hours after the initiation of daily injection of 1 million units of vitamin A, and were usually well established by 5 days. Some rabbits failed to show changes in cartilage, even after 5 daily injections. Increased amounts of material presumed to be chondroitin sulfate were present in the sera of vitamin A-treated rabbits, usually by 72 hours after the first injection. This was demonstrated by a turbidimetric procedure using hexamminecobaltic chloride. In rabbits given sulfur-35 (Na₂S³⁵O₄) 5 days before the initiation of vitamin A treatment, it was shown that sulfur-35 was lost from articular and epiphyseal cartilage. This was associated with an increase in the non-dialyzable sulfur-35 in both serum and in the cobalt-precipitable material. These rabbits also excreted more sulfur-35 than rabbits not given vitamin A. There was a reduction in sulfur-35 activity in chondromucoprotein extracted from the ear cartilage of vitamin A-treated rabbits. The changes are interpreted as indicating that the administration of large amounts of vitamin A to rabbits results in removal of chondroitin sulfate from cartilage matrix. The administration of small amounts of crude papain causes histologic changes in cartilage that are remarkably similar to those seen in vitamin A-treated rabbits. The possibility is suggested that the changes in cartilage produced by administration of vitamin A to rabbits may be the result of activation of a proteolytic enzyme or enzymes, with properties similar to those of papain.     

Distribution of zinc in skeletal muscle and liver tissue in normal and dietary controlled alcoholic rats.

Zinc deficiency is a concomitant of both alcoholism and cirrhosis, as indicated by plasma and tissue measurements in man. The intracellular sites of zinc distribution, the site-specific nature of alcohol/cirrhosis-related depletion, and the alcohol exposure-zinc depletion time function have not been reported. Spague-Dawley rats (16) at 5 to 6 weeks were given normal chow and 20 per cent ethanol as sole water source. Control animals (14) had tap water. In rats killed at 2, 5, 9, and 14 weeks, zinc levels were measured by atomic absorption spectroscopy in plasma (p); muscle tissue (MT), cell sap (MCS) cell sap-free (MCSF), and mitochondria (MM); liver tissue (LT), cell sap (MCS), cell sap-free fraction (LCSF), And mitochondria (LM). Control zinc levels were stable in all tissues over the 14-week study; p = 108, plus or minus 10 mug per 100 ml., MT = 125 plus or minus 18, MCS = 30.3 plus or minus 3, MCSF = 70 plus or minus 6, MM = 209 plus or minus 17, LT = 198 plus or minus 29, LCS = 125 plus or minus 11.0, LCSF = 79.5 plus or minus 11.2, and LM = 291 plus or minus 30 mug per gram of dry tissue. Ethanol-fed rats showed marked decrease in all liver zinc fractions from the earliest (2 weeks) time, with the greatest depletion in LM to 35 per cent of control. MT and p zinc showed monotonic gradual declines at the rate of 3 per cent per week, becoming statistically different from control at 9 weeks in both tissues. Normal weight gain occurred in control animals: alcohol rats gained 52 per cent of control to 5 weeks, and showed no subsequent gain, weighing 62 per cent of control levels at 14 weeks. Liver mitochondria contain the highest zinc concentration, and are most rapidly depleted. MT and p declines follow hepatic zinc loss.     

THE PREPARATION OF HIGHLY PURIFIED PR8 INFLUENZA VIRUS FROM INFECTED MOUSE LUNGS

Highly purified preparations of PR8 influenza virus were obtained from perfused, infected mouse lungs by a combination of methods involving adsorption of the virus on and elution from chicken red cells and differential centrifugation. Such preparations were found to possess 50 per cent infectivity end-points at 10^–11 to 10^–11.8, and 10^–13 to 10^–14.3 gm. of nitrogen in mice and in chick embryos, respectively. A sedimentation constant of 683 S was obtained for the material and electron micrographs revealed essentially spherical particles about 100 mµ in diameter. The material was isoelectric at pH 5.4 and chemical analyses on several of the preparations indicated the presence of 10.1 per cent of nitrogen, 1.06 per cent of phosphorus, 6.2 per cent of carbohydrate and about 33 per cent of lipid. Positive tests were obtained for both ribonucleic and desoxyribonucleic acids. The virus was precipitated strongly by antisenim to purified PR8 virus obtained from the allantoic fluid of infected chick embryos and this serum inhibited the agglutination of red cells by the mouse virus to a dilution of about 40,000. In general, the properties of the virus isolated from infected mouse lungs were found to coincide with those of the virus obtained from the allantoic fluid of infected chick embryos.     

An analysis of community and hospital-acquired bacteraemia in a large teaching hospital in the United Kingdom

A total of 875 episodes of bacteraemia and fungaemia were analysed in patients admitted to University Hospital, Nottingham, and three smaller hospitals over a four-year period. In 814 episodes (93 per cent) a single organism was isolated, most commonly Escherichia coli (27.4 per cent), other enterobacteria (14.4 per cent), Staphylococcus aureus (11.2 per cent), Streptococcus pneumoniae (9.0 per cent), or Haemophilus influenzae (6.4 per cent). In 61 cases (7.0 per cent) bacteraemia was due to two or more species. In almost 60 per cent of cases, bacteraemia was considered to be community-acquired. The most common sources were the urinary (26.9 per cent), respiratory (14.6 per cent), gastrointestinal (11.6 per cent) and biliary (9.5 per cent) tracts, but in almost 10 per cent of cases the focus of infection was unknown. Polymicrobial bacteraemia was common when the biliary tract was the focus of infection. Shock was recorded in 19.5 per cent of cases, and was commoner in polymicrobial (42.9 per cent) than in monomicrobial (17.4 per cent) episodes. In monomicrobial episodes haemolytic streptococci were associated with the highest incidence of shock (30.0 per cent). Mortality directly related to bacteraemia (19.5 per cent) was higher with Gram-positive (23.5 per cent) than with Gram-negative (15.8 per cent) organisms; in polymicrobial (31.1 per cent) than in monomicrobial episodes (18.7 per cent); and in those who had multiple episodes (34.7 per cent) than in those who had a single episode of bacteraemia (20.3 per cent). Other factors influencing mortality included shock, failure to mount an adequate febrile response, leucopenia or granulocytopenia, and underlying disease. Mortality was markedly reduced by appropriate treatment; a single antimicrobial agent was as effective as combination therapy in bacteraemia caused by Gram-negative bacilli.     

Accumulation of sulfate-containing acid mucopolysaccharides in I-cell fibroblasts.

A rapid and sensitive papper electrophoretic assay for 35SO4-containing compounds was developed which allowed measurement of 35S-acid mucopolysaccharides synthesized by skin fibroblasts grown in the presence of inorganic 35S-sulfate. Fibroblasts from a skin explant of a patient with I-cell disease when grown in culture accumulated abnormal amounts of 35S-acid mucopolysaccharides and other, as yet unidentified, 35S-labeled compounds. Approximately 75% of the 35S-compounds accumulated by I-cell fibroblasts were not metabolized and remained in the cells after transfer to nonlabeled medium. I-cell fibroblasts differ from fibroblasts derived from classical mucopolysaccharidoses such as Hurler's and Hunter's syndromes in the amount and types of 35S-labeled acid mucopolysaccharides accumulated. I-cell fibroblasts accumulated chondroitin 4- and 6-sulfates (16 per cent), dermatan sulfate (32 per cent), heparan sulfate (32 per cent), and other unidentified 35S-compounds. The unidentified fraction was not hydrolyzed by microbial chondroitinase or heparinase. Attempts to correct the defect in I-cell fibroblasts by growth in the presence of extracts of normal cells resulted in release of only 10 per cent of the accumulated mucopolysaccharides. Under the same conditions, Hurler and Hunter fibroblasts lost over 90 per cent of accumulated mucopolysaccharides.     

THE ADAPTATION OF UNMODIFIED STRAINS OF YELLOW FEVER VIRUS TO CULTIVATION IN VITRO

1. In a search for suitable tissues for the cultivation of yellow fever virus in vitro, mouse embryos were inoculated with this virus in utero. A titration for virus content of the various organs of the embryos indicated that the virus was present in the brain in greatest concentration. 2. Unmodified strains of yellow fever virus were readily adapted to cultivation in vitro in a medium consisting of minced mouse embryo brain tissue and Tyrode solution containing 10 per cent normal monkey serum. 3. After a continued cultivation in mouse embryo brain tissue cultures for twenty to twenty-five subcultures, these strains were readily adapted to cultivation in whole mouse embryo tissue medium. 4. There is evidence to indicate that a prolonged cultivation of the virus in mouse embryo brain medium increases its neurotropic properties. 5. Attempts to employ monkey tissues for in vitro cultivation of yellow fever virus gave entirely negative results.     

Comparison of Inverted Centrifugation, Saline Washing, and Dextran Sedimentation in the Preparation of Leukocyte-Poor Red Cells

Three methods (inverted centrifugation; inverted centrifugation followed by continuous-flow washing in 5 per cent dextrose-saline; and dextran sedimentation followed by continuous-flow washing in 5 per cent dextrose-saline) were evaluated for the preparation of leukocyte-poor red blood cells. Residual leukocyte contents were 0.32, 0.40, and 0.16 billion per 100 g of erythrocytes and erythrocyte losses were 24, 42, and 35 per cent, respectively, for the three methods. The mean removal of leukocytes per unit after inverted centrifugation was 80 per cent. Continuous-flow washing after inverted centrifugation did not remove additional leukocytes. Dextran sedimentation removed a mean 92 per cent of leukocytes. Residual dextran was not detected in the terminal wash solution. These findings suggest dextran sedimentation may be useful for preparing leukocyte-poor red blood cells for preventing sensitization to leukocytes in high risk recipients such as transplantation candidates.     

STUDIES OF THE HEMOLYSIS OF RED BLOOD CELLS BY MUMPS VIRUS : I. THE DEVELOPMENT OF MUMPS VIRUS HEMOLYSIN AND ITS INACTIVATION BY CERTAIN PHYSICAL AND CHEMICAL AGENTS

The conditions for the production of extra-embryonic fluids with hemolytic activity from chick embryos infected with mumps virus have been investigated. Infected fluids with strong hemolytic activity can be obtained by harvesting the fluids of 6- to 8-day-old chick embryos inoculated by the amniotic route after 5 to 6 days' incubation at 35°C. Under such circumstances, the hemolytic capacity of amniotic fluids is usually much higher than that of the allantoic fluids. The hemolytic activity and infectivity of the virus have been found to be reduced or destroyed by heat, formaldehyde, and ultraviolet irradiation under conditions which leave the hemagglutinating capacity practically unchanged. Ultraviolet irradiation appeared to have a greater deleterious effect on the infectivity of the virus than on its hemolytic capacity. The marked reduction or destruction of hemolytic activity of the virus produced by certain treatments with these various agencies was not accompanied by loss of the ability of the virus to elute following its adsorption on red blood cells during the process of hemagglutination. This test for hemolytic activity, which measures a more labile property of the virus than do determinations of virus hemagglutination or virus elution, may be useful in detecting changes which occur early during degradation of the virus.     

Studies on primary atypical pneumonia. I. Localization,isolation, and cultivation of a virus in chick embryos

By means of fluorescein-labelled antibody, the primary atypical pneumonia virus was found to multiply exclusively in the cytoplasm of the epithelial cells lining the bronchioles and air sacs of developing chick embryos. When 13-day old embryos were inoculated intra-amniotically and incubated at 35°C. for 5 days or longer, over 90 per cent of the inoculated embryos became infected. Between 1954 and 1956, seven strains of PAP virus were isolated from sputums or nasopharyngeal washings in patients during the acute stage of the PAP infection. One strain of virus was isolated from the frozen lung of a patient who died at Boston in 1943. All eight recently isolated strains and the Mac strain isolated by Eaton et al. in California in 1944 were antigenically closely related if not identical. PAP virus is not related antigenically to agents of psittacosis, Q fever, adenovirus (Types 1 to 6), influenza A or B, or PVM.