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The propagation of feline infectious peritonitis virus (NW1-FIPV strain) in cell culture is described. Tissue culture-propagated virus was used to inoculate specific-pathogen-free kittens intraperitoneally, intratracheally, or orally. Intraperitoneal inoculation caused seroconversion and effusive peritonitis in 100% of the kittens. Intratracheal inoculation produced disease in 60% of the kittens, and oral inoculation in only 20%. Seroconversions without production of disease occurred in 10% of the kittens inoculated by either the intratracheal or the oral route. The remainder of the kittens inoculated by the intratracheal (30%) and oral (70%) routes did not develop serum antibodies or disease.

An enteric coronavirus that is antigenically closely related to feline infectious peritonitis virus (FIPV) is ubiquitous in the cat population. This virus has been designated feline enteric coronavirus to differentiate it from FIPV. The virus is shed in the feces by many seropositive cats; in catteries it is a cause of inapparent to mildly severe enteritis in kittens 6 to 12 weeks of age. The virus may produce a more severe enteritis in young specific-pathogen-free kittens. Feline enteric coronavirus selectively infects the apical columnar epithelium of the intestinal villi, from the caudal part of the duodenum to the cecum. In severe infections, there are sloughing of the tips of the villi and villous atrophy. Many cats recovering from the disease remain carriers of the virus. Recovered cats, observed for 3 to 24 months, remained healthy and did not develop peritonitis, pleuritis, or granulomatous disease. The relationship of feline enteric coronavirus and FIPV was studied. Although the viruses were antigenically similar, they were distinctly different in their pathogenicities. The enteric coronavirus did not cause feline infectious peritonitis in coronavirus antibody-negative cats inoculated orally or intraperitoneally nor in coronavirus antibody-positive cats inoculated intraperitoneally or intratracheally. Serologic tests, using FIPV, canine coronavirus, and transmissible gastroenteritis virus of swine as substrate antigens in fluorescent antibody procedures may not accurately identify FIPV infection. These tests do not appear to distinguish between FIPV and this feline enteric coronavirus.

Coronaviruses are being isolated with increasing frequency from cats. These various isolates can be divided into two major groups: 1) coronaviruses that induce a disease of cats known as feline infectious peritonitis (FIP), and 2) coronaviruses that cause a transient subclinical to severe enteritis1,2. The various isolates in each of these groups are morphologically and antigenically related, and probably represent strains of a common species of virus that infects cats, dogs (canine coronavirus or CCV), and swine3,4.

The effusive form of feline infectious peritonitis (FIP) was reproduced by injecting 12- to 16-week-old kittens intraperitoneally with a cell-free inoculum derived from the tissues of infected cats. The kittens used for the study were either positive for FIP virus-reacting antibodies before inoculation or they were seronegative. Seropositive kittens were obtained from a cattery where the natural infection was enzootic, and seronegative kittens were obtained from a specific-pathogen-free cattery. Only about half the kittens that were seronegative before inoculation developed disease or serum antibodies to the tissue-derived virus. Seronegative kittens that developed disease showed no signs of illness until 8 to 10 days after inoculation, and they lived for 7 to 14 days after clinical signs appeared. The onset of clinical disease coincided with the appearance of serum antibodies. In contrast, all of the seropositive kittens became ill within 36 to 48 hours after inoculation, and died within 5 to 7 days. If seronegative kittens were treated with immune serum or immunoglobulin (Ig)G, they developed disease with the same frequency, acuteness, and severity as seropositive kittens. Foci of hepatitis and serositis in seropositive kittens contained viral antigen, IgG bound to antigen, and complement. Serum complement activity also decreased several days before death in seropositive kittens inoculated with tissue-derived FIP virus. The temporal relationship of clinical disease and the appearance of serum antibodies, the more acute and severe nature of the disease produced in seropositive kittens, and the presence of antibody and complement in the lesions indicated that effusive FIP is immunologically mediated.

Two major bovine rotavirus proteins have RNA-binding activity as shown by an RNA overlay-protein blot assay. Of the six proteins in purified virions, only one showed RNA-binding activity. This 92,000-molecular-weight (92K) protein was present in both single- and double-shelled particles. Its RNA-binding activity was blocked by preincubation with monospecific antibody to VP2. Thus, the 92K RNA-binding protein in rotavirus virions is VP2, the second most abundant protein in single-shelled particles. In infected cell extracts, numerous cellular RNA-binding proteins and two virus-specific RNA-binding proteins were detected, VP2 and a 31K nonstructural (NS31) protein. VP2 bound single-stranded RNA in preference to double-stranded RNA, whereas NS31 bound both single- and double-stranded RNA equally well. Binding did not appear to be nucleotide sequence specific, because RNA from uninfected cells and an unrelated RNA virus bound to VP2 and to NS31 as did rotavirus RNA. This technique showed that both cellular and rotavirus RNA-binding proteins also bound DNA. VP2 interacted with rotavirus RNA over a broad pH range, with an optimum at pH 6.4 to 6.8, and at NaCl concentrations between 0 and 100 mM. The RNA-binding activity of NS31 exhibited similar pH and NaCl dependency. Sequence-specific nucleic acid binding could be detected by this method. When labeled synthetic oligodeoxyribonucleotides corresponding to the 3' and 5' plus-sense terminal sequences of rotavirus gene segments were used as probes, the 3' synthetic oligodeoxyribonucleotide bound to one 48K protein in control and infected cells. This suggests that there may be a specific functional interaction between the 48K cellular protein and this 3'-terminal noncoding region of the rotavirus genome or mRNA. These data show that the RNA overlay-protein blot assay is a useful test to identify some cellular and viral proteins with RNA-binding activity. For bovine rotavirus, the evidence suggests that, of all the virus-specific proteins, VP2 and NS31 are most likely to interact with RNA during transcription and replication or virus assembly or both.

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Attempts to propagate a laryngeal papilloma virus in cell culture by the establishment of tissue culture lines from 27 papilloma specimens which were removed endoscopically from the larynx of 19 patients of all age groups were unsuccessful. By light microscopy, all the lesions, with one exception, exhibited the usual features of a typical squamous papilloma. Laryngeal papillomas were removed endoscopically from an adult male Caucasian on three separate occasions with intervening intervals of 13 and seven months. Tissue removed at each procedure was submitted for study. Tumor obtained from the first two operative procedures exhibited the features of a benign squamous papilloma. Histologic diagnosis of the most recent excised laryngeal neoplasm was consistent with carcinoma. Two papillomas which contained papova-like virus when examined by electron microscopy were among the excised specimens cultured. Laryngeal papillomas were removed endoscopically on two occasions at an interval of five months from a 22-year-old Caucasian male who had a one-month history of hoarseness. Electron microscopic examination of the most recently excised tissue revealed intranuclear viral particles which were in the shape of an icosahedron and measured approximately 45 mμ in diameter. The particles contained a densely staining core and were generally scattered throughout the nucleus. Occasionally, they were seen in crystalline arrays. The nuclear site of replication, their size and shape fit the description of the agents belonging to the papova virus group. Papova-like viruses were also seen in laryngeal papillomas from an 18-month-old Negro child born of a mother with venereal warts. Although many attempts at propagating the human papilloma virus have been reported,1 the virus known to cause common warts has to date never been successfully grown for continuous passage in tissue culture. The difficulty in isolating the laryngeal papilloma virus in tissue culture is also apparent.2 Serial studies done on an adult laryngeal papilloma showed transition of the tumor from a benign to a malignant lesion. It is interesting to speculate on this possibly viral-induced laryngeal malignancy. That viruses can cause malignancy in non-human species is well known, and there is no reason to presume that man is different from such species in this respect. Clinical evidence of the transmissability of this disease from infected genital warts to the newborn was suggested by the development of laryngeal warts in the young child. The electron microscopic identification of virus in the laryngeal papilloma that is morphologically similar to the genital wart virus, supports this theory of transmissability. The ultrastructure of human laryngeal papilloma has been described previously3 and the presence of virus4 and virus-like particles suggested;5 however, the crystalline lattice assemblies, characteristic of the papova group, have never been described heretofore. The results of these studies add strong morphologic and clinical evidence of the viral etiology of laryngeal papilloma; however, the evidence is not conclusive. The ultimate aim of this project is to propagate the papilloma virus in tissue culture.

The general considerations that apply to using unstable isotopes as the absorbing nuclei for the Mossbauer effect are discussed. Preliminary results of various workers with the isotopes 2.6-year Pm147, 7.2-year Ba133, 87-year Sm151, and 47-hr Sm153 are discussed as examples of the techniques involved.

In an attempt to evaluate the possible beneficial effects of facial nerve decompression or steroid therapy in Bell's palsy, a vascular lesion, simulating Bell's palsy, was produced in the intratemporal facial nerve of monkeys with ultrasound irradiation. The influence of surgical decompression or steroid therapy on the recovery rate was studied. Facial nerve decompression had little effect on the rate of recovery of facial function. Dexamethasone did little to influence the eventual return of facial function. In a corticotropin-treated animal earlier clinical return of facial function was seen.

Few problems are more challenging than papilloma of the larynx. In a sense, there exists a great deal of information on the subject, and there certainly exists a vast array of treatment modalities. This paper is not only a brief review of the subject but also a report on recent experiences of the authors in the surgical treatment of this disease. Our experience indicates that repeated endoscopic excision of papillomas at four to six-week intervals offers the greatest opportunity for eradication of the disease.

Adenotonsillectomy is the most commonly performed childhood operation and is indicated in recurrent adenotonsillitis and other disease and obstructive states of the tonsils and adenoids. It is contraindicated in children with uncontrolled coagulation disorders and is deferred under certain other circumstances. Special problems must be considered before operation is undertaken, and the child's parents should be carefully briefed to obtain their full understanding and cooperation and that of the child.

The tuning curve has been measured, in vivo, at a point approximately 1.5 millimeters from the stapes in the first turn of the guinea pig cochlea. Curves for constant stapes movement and constant sound pressure were obtained over the range 350 hertz to 30 kilohertz, with an amplitude peak at about 18 kilohertz.

This report presents the results of a study conducted to determine the feasibility of effecting a simplification in the current specification system covering thermal insulating materials. The study presents a plan to reduce a large number of single specifications to a small group of generalized specifications by elimination of all but essential testing procedures and by the standardization of test requirements. A general specification covering insulation felts and blankets, with emphasis on performance characteristics, is presented as an illustration of the proposed format.

Non‐crystalline (nc) layers of the known antiferromagnets (TN) FeF2 (78 K), FeCl2 (24 K) and FeBr2 (11 K) have been studied from 3–350 K. In contrast to the crystalline (crys) ferrous halides we find a single well‐defined magnetic ordering temperature Tm≈21 K for all nc layers. Spectra below 21 K show a randomly oriented effective hyperfine field (Heff) and electric field gradient (efg) to be present. Heff is not sharply defined and shows a Gaussian distribution with a relative width of ∼ 25°. This width is smaller than assumed in most theories of amorphous magnets. The rise of Heff between 0.4·Tm and Tm is less steep than that calculated for any Brillouin function. The saturation values of Heff deviate significantly from those for the crys ferrous halides.

Additional file 1. Statistical Analysis Plan.

Additional file 1. Statistical Analysis Plan.

Renal transplantation in the rat can be performed by a simple technique utilising cuff anastomosis. This method is quick and reliable, and the results compare well with those achieved by standard microsurgical techniques.