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PubMed1980

Persistence of pneumonia virus of mice and Sendai virus in germ-free (nu/nu) mice.

The pathogenicity and persistence of pneumonia virus of mice (PVM) and Sendai virus has been studied using germ-free nu/nu mice. PVM was found to infect cells of the bronchial epithelium (and the alveolar wall) of the lungs of germ-free nu/nu mice using the immunoperoxidase technique. The virus was located in the bronchial epithelium for 11 days before elimination, but persisted in the alveolar wall for the duration of the experiment (20 days). After Day 10 a humoral antibody response to PVM was observed which persisted, although at a low level (1 in 40), by haemagglutination-inhibition (HI) testing. Sendai virus in nu/nu mice also infected cells of the bronchial epithelium and this persisted for the duration of the experiment (27 days). The persistence of virus in the bronchial epithelium in relation to lack of humoral antibody is discussed with reference to local secretory antibody production, especially since this does not occur with PVM.

Animals↗
PubMed1983

Role of defective simian virus 40 genomes in establishment and maintenance of persistently infected primate cell lines.

Studies are reported of persistent simian virus 40 (SV40) infections of fully permissive monkey (TC-7 and BSC-1) and human (A172) cell lines, with emphasis on the role of viral defectives in establishment and maintenance of persistence. The presence of defectives prevented complete cell killing and allowed the establishment of persistently infected cultures. Hirt supernate DNAs from these cultures showed the continuing presence of defective genomes. Restriction enzyme analysis demonstrated that altered defective genomes evolved during passage of the carrier cultures, but that they always reflected structures of the genomes used to established the cultures. There was some host cell specificity in the effectiveness of establishment of persistence, e.g., TC-7-derived defectives were more effective in preventing killing of TC-7 than of BSC-1 or A172 cells. Persistent infections of TC-7 cells could also be established in the absence of defectives, but in the presence of neutralizing anti-SV40 antiserum. In fact, defectives were eliminated from carrier cultures established in the presence of antiserum. When antiserum was withdrawn, the wild-type SV40 grew and destroyed the cells. Antiserum maintains a low level of infection by neutralizing viruses outside the cells, so that many cells do not become infected. Defectives are eliminated because spread of infection is effectively at very low multiplicity. Carrier cultures that are established and maintained by defectives result from intracellular interference by the defectives with the normal development of wild-type virus.

Animals↗
PubMed1978

The persistent PHA-responsive population in the mouse thymus. I. Characterization of the population.

Using an in vitro culture technique, mouse thymus graft cells were co-cultured with peripheral blood lymphocytes in the presence of phytohaemagglutinin (PHA). The persistent PHA-responsive thymus graft population (Elliott, 1973) was shown to be able to respond to other T-cell mitogens (Con A, pokeweed mitogen, staphylococcal enterotoxin B), but not to E. coli lipopolysaccharide a known B-cell mitogen. The percentage of persistent PHA-responsive cells did not alter during 5 days in culture and was relatively unaffected by either hydrocortisone or anti-lymphocyte serum treatment in vivo. In allogeneic thymus grafts (AKR leads to CBA), persistent PHA-responsive cells could be demonstrated, which were destroyed when incubated with CBA anti thetaAKR serum and complement. When thymus graft cells were allowed to sediment on a 0.2--2 per cent BSA gradient, it was seen that the PHA-responsive population sedimented faster than the bulk of thymus graft cells. Some separation could be obtained on this gradient between the persistent and non-persistent PHA-responsive cell populations.

Animals↗
PubMed1984

[Persistence of virus in swine stock and breeding farms following an outbreak of Aujeszky's disease].

On seven fattening farms and seven breeding farms, investigations were carried out to examine whether Aujeszky virus was capable of persisting in particular animal groups or units of the farm as a productive infection following a virologically verified outbreak. After an outbreak on fattening farms, virus persisted temporarily as newly arrived piglets became systematically infected. On the farms on which this could be accurately followed, virus persistence continued for at least 1 1/2 to 2 months. However, this cycle of infection was found to be interrupted on each farm within approximately three months after the outbreak, which resulted in a gradual return to a totally sensitive animal population, so that new outbreaks could occur. On the seven swine breeding farms, virus persistence in the farrowing house was examined by placing seronegative sentinel piglets with sows during the immediate post-partum period. Twelve sentinel piglets were placed in the various farrowing houses for a total period of sixty-seven weeks, during which time 172 sows farrowed. None of these piglets became seropositive during their stay on the breeding farms. The results of this study show that Aujeszky's disease virus did not persist on breeding farms and that the productive infection on fattening farms in only transient following an outbreak. Therefore, it is very likely that new outbreaks of the disease are due to reintroduction of Aujeszky's disease virus on the farm. Though the role of latent carrier animals cannot be totally disregarded, natural reactivation of latent virus is believed an exception rather than the general rule.

Animals↗
PubMed1984

Persistent neutrophilic meningitis. Report of four cases and review of the literature.

Persistent neutrophilic meningitis is a poorly described variant of chronic meningitis characterized by the persistence of neutrophils in the CSF over extended periods of time (greater than 1 wk) in association with ongoing signs of meningeal inflammation and negative CSF cultures for bacteria and other pathogens. Although the incidence of persistent neutrophilic meningitis is difficult to ascertain, a review of available literature on CNS infections suggests that this entity is not rare. Etiologies of this syndrome are both infectious and noninfectious. Among infectious causes, bacteria such as Nocardia and Actinomyces and systemic mycoses such as Aspergillus and the zygomycetes are the predominant pathogens. The pathogenesis of the persistent neutrophilic CSF response is unknown; with some infectious etiologies, there may be a correlation between neutrophil response and the morphology of the invading organism. Mycelial-like pathogens appear to be the primary stimulus for an ongoing neutrophilic inflammatory response. In cases of persistent neutrophilic meningitis, epidemiologic features and clinical setting frequently offer clues to the etiologic agent, especially in the immunocompromised host. Evaluation should include repetitive cultural and serologic studies of the CSF with special emphasis upon special cultural methods, antigen detection and detection of characteristic metabolic byproducts. Biopsy of extraneural sites of disease should be pursued whenever possible to provide data for an inferential diagnosis of CNS disease. CNS biopsies should be selectively performed in those patients undergoing craniotomy for evaluation of mass lesions. Therapy must be individualized. However, in the immunocompromised host, consideration should be given to the empiric use of amphotericin B with or without a sulfonamide in undiagnosed cases that manifest progressive clinical deterioration.

Actinomycosis↗
PubMedDate not supplied

[Persistence of Sindbis virus in cultures either non-producing or irregularly producing oncornavirus].

Persistence of Sindbis virus (SV) was studied for 9 months in two lines of mouse cell cultures (BALB/C) in one of which the genome of endogenous ecotropic oncornaviruses was repressed. The other lines was exogenously infected at the level of plimary culture with Rauscher leukemia virus (RLV) and SV and showed gradual inhibition of oncornavirus functions. The presence of oncornavirus type C was not the necessary condition for the development of persistent SV infection, however it influenced the character of persistence. In both systems, sequential loss of the hemagglutinating and interferon-inducing activities, then infectivity of SV (61--82 days), and persistence of the noninfectious antigen of the arbovirus for 9 months were observed. The differences consisted in the time of appearance of homologous interference to SV: in the presence of oncornavirus earlier (40 days), under conditions of repressed oncornavirus genome later (179 days). Electron microscopic examinations showed that in the system infected with RLV and SV there occurred in the course of persistence a sharp activation of phagosome-lysosome complex accompanied by incorporation into phagocytolysomes of numerous intact and partially destroyed virions of SV and RLV and their release from cell with cytoplasmic fragments. Possible mechanisms of inhibition of functions of the oncogenic and infectious viruses in the reported model of mixed chronic infection are discussed.

Animals↗
PubMedDate not supplied

[Alphavirus reproduction in cultures of transplantable human lymphoblastoid cells during persistent infections].

The results of virological investigations of alphavirus persistence in human B-cell lines Raji and L-101 are presented. The formation of persisting infection was shown to depend both on the cell line and on the virus type. Productive persistent infection of Raji cells with Venezuelan equine encephalitis virus was followed for 11 months. The presence of the virus was confirmed by electron microscopic and immunofluorescent examinations. Infectious virus production varied from 0.001 to dozens PFU/cell, and the content of viable cells from 100,000 to 300,000 in 1 ml of the culture fluid. Virus infectivity in the culture medium varied within the range of 5-7 lg PFU/ml. Human lymphoblastoid cells Raji persistently infected with Venezuelan equine encephalitis virus were examined cytologically, karyologically, and electron microscopically. The long-term presence of the virus resulted in profound alterations in the cell population. Morphology of the cells and processes of division were changed, the mitotic index decreased, the rate of 3H-thymidine incorporation into cellular DNA increased. The mechanisms of persistence are discussed.

B-Lymphocytes↗
PubMedDate not supplied

[Characteristics of the persistence of the tick-borne encephalitis virus against a background of experimentally induced allergic encephalomyelitis in M. rhesus monkeys].

Asymptomatic persistence of tick-borne encephalitis (TBE) virus was modeled by subcutaneous inoculation; the virus and the antigen were detected up to 307 days by the cell co-cultivation, tissue explants, and immunofluorescence methods. At early and late periods of the persistent infection (1 1/2, 8 1/2, or 10 1/2 months) for the purpose of its stimulation, an autoimmune disease, experimental allergic encephalomyelitis (EAE), running a course of the type of delayed hyperergic reaction was induced in the animals by inoculation of an encephalitogenic mixture (EM). After EM inoculation, a chronic demyelinating process developed in the CNS without the involvement of neurons; proliferation of immunocompetent cell elements was observed in the spleen and lymph nodes; a short-time or stable stimulation of TBE-specific humoral immunity was observed. Against the background of the development of chronic EAE and a short-time stimulation of humoral immunity, persistence of TBE virus was prolonged for over 2 years, its location being unchanged (different parts of the brain, spleen). Despite long-term persistence of TBE virus in the CNS, no clinical and morphological symptoms of chronic TBE were found. Possible mechanisms of the effect of this stimulating factor favouring the activation of the persisting TBE virus on the one hand and limiting this process on the other are discussed.

Animals↗
PubMed1981

[Persistent primitive hypoglossal artery associated with intracranial aneurysm (author's transl)].

A case of the persistent left primitive hypoglossal artery associated with an intracranial aneurysm was reported. The thirty-year-old man was admitted to hospital in the diagnosis of subarachnoid hemorrhage at seven days after the onset. Bilateral carotid angiograms revealed a saccular aneurysm at the right internal carotid-posterior communicating artery junction and a persistent left hypoglossal artery arising from the left internal carotid artery at the level of the C-1 vertebra. Retrograde vertebral angiograms revealed right hypoplastic vertebral artery (2mm in diameter) and markedly hypoplastic left vertebral artery, vanishing at the level of the C-3 vertebra. The axial view of the left carotid angiogram demonstrated the hypoglossal artery entered into the cranial cavity through the hypoglossal canal. Linear tomogram in the modified reversed Stenvers projection demonstrated the enlarged left hypoglossal canal measuring 9 X 10 mm. The normal right canal measured 5 X 6 mm. The right frontotemporal craniotomy was performed and the aneurysm was successfully clipped at its neck under an operative microscope. The patient discharged without any neurological deficit. The persistent hypoglossal artery is one of the persistent carotidbasilar anastomoses. Ninety-six cases of the hypoglossal arteries have been reported in literature. Twenty cases of them were associated with intracranial aneurysms. The authors reviewed these twenty cases and discussed the genesis of the intracranial congenital aneurysm in relation to the persistent artery.

Adult↗
PubMed1994

Persistent hepatomegaly: an index of severity in sickle cell anaemia.

Eighty sickle cell anaemia patients, 29 with persistent hepatomegaly and 51 without, were evaluated with respect to clinical severity score. Haemoglobin F (HbF) was also determined in 52 patients, 20 with persistent hepatomegaly and 32 without. The severity scores were computed from the steady state haematocrit, number of transfusions per year, and number of crises per year. The HbF level was determined by the alkali denaturation method. The patients with persistent hepatomegaly had significantly higher clinical severity scores (P < 0.001) and significantly lower levels of HbF (P < 0.0001). The implication of the finding is that patients with persistent hepatomegaly may have a more severe clinical course than those without, and clinicians managing them may have to pay more particular attention to them. In effect, persistent hepatomegaly may be a useful indicator of severity in sickle cell anaemia.

Adolescent↗
PubMed1995

Persistent spermatozoa after vasectomy: a survey of British urologists.

OBJECTIVES: To determine the rate of, and main indications for, repeat vasectomy in our department, and to assist in policy-making procedures by determining how urologists in England and Wales manage those men who show small but persistent quantities of motile or non-motile spermatozoa in their ejaculate after vasectomy. SUBJECTS AND METHODS: A retrospective review of all of the vasectomies and repeat vasectomies performed by the Urology Department at Southmead Hospital during a 14-month period was undertaken to determine the rate of and indications for repeat vasectomy. Subsequently, every consultant urologist in England and Wales was canvassed with a questionnaire to determine whether they repeated vasectomy in the presence of persistent motile or non-motile sperms and if so, after what time interval. Any experience of pregnancies arising from these groups was also assessed, and any relevant comments invited. RESULTS: The local review revealed that 5% of all vasectomies were repeated within 6-36 months. Of these, 87% were performed because of persistent sperms in post-vasectomy semen samples, the majority of which showed sperm concentrations of one in 50 to one in 100 high-power fields. A response of 56% was obtained to the questionnaire and of those responding, 23% never repeated a vasectomy where there were presistent non-motile sperms, but almost all urologists would eventually repeat vasectomy where motile sperms were present. The median interval between the first and second vasectomies was 6 months and 12 months for motile and non-motile sperm, respectively. Apart from those cases already published, there was little experience of pregnancy arising from men with persistently few motile or non-motile sperms. CONCLUSIONS: The risk of pregnancy occurring in the presence of non-motile sperms was estimated to be less than the established risk of late recanalization, and this survey provides both logical and medico-legal support for issuing a 'special clearance' to men with few persistent non-motile sperm after vasectomy, providing the risks of pregnancy are properly discussed and documented. For motile sperm, however, there appears to be a stronger precedent for repeating the vasectomy. The technique used for post-vasectomy semen analysis was also an important consideration when determining any policy regarding such cases.

Attitude of Health Personnel↗
PubMed1995

Persistent rat virus infection in juvenile athymic rats and its modulation by immune serum.

In contrast to euthymic juvenile rats, which develop acute, self-limiting infection with rat virus (RV), RV infection of juvenile athymic rats was persistent for up to 12 weeks as demonstrated by recovery of infective virus, transmission to cagemates, and detection of viral DNA in the lungs. Administration of RV antiserum at the time of virus inoculation prevented persistent infection in five of six rats. Among rats given RV antiserum 1 week after virus, the interval at which euthymic rats begin to seroconvert, RV was not detected 1 week later but was recovered from four of six rats 3 weeks later. Results of these studies confirm that T-cell deficiency facilitates persistent RV infection and indicate that antibody provides significant protection from persistent infection only if it is present at the time of virus inoculation. The results support the concept that factors which prevent persistent infection in euthymic rats act early after virus inoculation and may include cellular immunity.

Animals↗
PubMed1995

Persistent sciatic artery in association with varicosities and limb length discrepancy: an unrecognized entity?

The persistence of the sciatic artery is an unusual occurrence, with an angiographically demonstrated incidence of 0.06%. There have been 71 cases previously reported. We report an additional case in a 14-year-old boy who presented with a chief complaint of unsightly varices. The involved right limb was notably shorter than the uninvolved left lower extremity. Work-up included physical examination, duplex studies, venography, and angiography. Our patient was found to have a patent deep venous anatomy with valvular incompetency associated with complete persistence of the sciatic artery and a foreshortened right leg. He has done well with conservative treatment. The persistence of a sciatic artery has occasionally been associated with other anomalies including Mullerian and left renal agenesis, A-V fistula formation, hypertrophy or hypotrophy, multiple hemangiomata, neurofibromatosis, or anomalies of leg arteries. The literature describes three previous case reports in which patients presented with gross varicosities and were incidentally found to have persistent sciatic arteries as well as limb length discrepancies. Our patient is a fourth example of this syndrome. This pattern of physical attributes has not been previously described as a distinct entity. The association of venous incompetency, limb discrepancies, and persistence of the sciatic artery may be an incidental finding or may represent a related embryologic event. This relationship merits consideration in a young patient presenting with severe venous varicosities.

Adolescent↗
PubMed1994

Persistent light reaction with erythroderma caused by musk ambrette: a case report.

Persistent light reaction is an uncommon type of photodermatitis caused mainly by musk ambrette, a synthetic fragrance material commonly used in foods and cosmetics. Erythrodermic persistent light reaction is rare. We report a case of erythroderma with underlying persistent light reaction due to musk ambrette. A 71-year-old man showed a photodermatitis that waxed and waned for five years before it became more persistent and finally evolved into erythroderma. Positive results of a photopatch test to musk ambrette and a low minimal erythema dose to ultraviolet B were noted. A biopsy specimen of the erythrodermic lesion revealed spongiotic dermatitis. The erythroderma and photodermatitis responded to systemic steroids and psoralen/ultraviolet A therapy (total dose: 90 J/cm2). We suggest that persistent light reaction be included in the differential diagnosis of erythroderma.

Aged↗
PubMed1994

[Persistent müllerian duct syndrome (males with uterus): a pediatric problem].

BACKGROUND: The persistent müllerian duct syndrome (PMDS) is characterized by the persistence of the uterus and Fallopian tubes in otherwise normally virilized boys. Its diagnosis is usually made during a surgical procedure for inguinal hernia or cryptorchidism. We report six recent cases of PMDS, in which we have studied anti-Müllerian hormone (AMH) serum levels. CASE REPORTS AND METHODS: Six boys including three brothers were operated on for cryptorchidism or inguinal hernia. Surgical exploration showed persistence of the uterus and Fallopian tubes in patients having normal 46, XY karyotype and male gonads. The AMH serum levels were measured by Elisa and the AMH gene by single strand conformation polymorphism of PCR products. RESULTS: The three brothers showed a mutation in the AMH gene which leads to the replacement of leucine by proline at position 70 and to a defect in AMH production. In two other patients, serum AMH values were normal, no mutation on the AMH gene was found, and end-organ insensitivity was suggested to explain the persistence of müllerian derivatives. In the last patient, although AMH serum levels were very low due to a progressive degeneration of testicular tissue, molecular analysis of the AMH gene suggested that end-organ resistance might be the cause of the persistence of müllerian ducts. CONCLUSION: PMDS is not extremely rare. Many diagnostic mistakes are made which could be prevented by performing pelvic or inguinal ultrasonography before surgical treatment of bilateral cryptorchidism or irreducible inguinal hernia. Prognosis depends upon the integrity of the testicular tissue, sometimes compromised for yet unexplained reasons, and upon the successful correction of cryptorchidism, which is complicated by the close anatomical relationship between the vasa deferentia and the Müllerian derivatives.

Adolescent↗
PubMed1994

Persistent enhancement after treatment for cerebral toxoplasmosis in patients with AIDS: predictive value for subsequent recurrence.

PURPOSE: To determine the predictive imaging (CT and/or MR) features of brain toxoplasmosis recurrences in acquired immunodeficiency syndrome. METHODS: The imaging studies of patients with brain toxoplasmosis were retrospectively reviewed. Forty-three patients with significant decrease or disappearance of brain lesions under specific treatment on follow-up imaging examinations were included. MR examinations were performed using T2- and T1-weighted sequences, before and after intravenous administration of gadolinium-DOTA. RESULTS: A recurrence occurred in 11 (26%) of 43 cases. Ten (91%) of these 11 patients with recurrence showed focal persistent enhancement after the initial treatment of toxoplasmosis abscess. One of the 11 patients with recurrence showed no persistent enhancement; 3 patients showed persistent enhancement but had no recurrence. CONCLUSIONS: Recurrences of brain toxoplasmosis in our series correlated with persistent contrast enhancement. We hypothesize that demonstration of persistent areas of contrast enhancement after treatment for initial toxoplasmosis may be a valuable sign for identifying patients at risk for recurrence.

AIDS-Related Opportunistic Infections↗
PubMed1976

Persistent infection of BHK cells with herpes simplex virus types 1 and 2 in the absence of specific anti-herpetic antibody.

Persistent infection of BHK-21 cells with 5 strains of herpes simplex virus (HSV) type 1 and a 1 strain of HSV type 2 is described. Acute infection only was obtained with two strains of type 1 and one strain of type 2. Persistent infection could not be established in HeLa and rabbit lung cells. Persistent infection of BHK cells proceeded in the absence of specific antibody. Persistently infected cells were more resistant to superinfection with homologous or heterologous HSV as compared to infection of normal BHK cells. No interferon activity was demonstrated in persistently infected cell cultures. The results of virus titration were in accordance with the demonstration of fluorescent antigen of HSV.

Animals↗
PubMed1994

Persistent right umbilical vein: sonographic detection and subsequent neonatal outcome.

OBJECTIVE: To review our experience with antenatal detection and subsequent neonatal outcome of fetuses with a persistent right umbilical vein. METHODS: In a prospective observational study, 33 cases of persistent right umbilical vein were detected during 15,237 obstetric ultrasound examinations performed after 15 weeks' gestation. RESULTS: Persistent right umbilical vein was detected at a rate of one per 476 obstetric ultrasound examinations. Six of 33 (18.2%) fetuses with a persistent right umbilical vein had additional important congenital malformations. CONCLUSIONS: Careful second- and third-trimester ultrasound examinations can detect a persistent right umbilical vein. When this particular anomaly is detected, a thorough fetal anatomic survey, including echocardiography, should be performed to rule out more serious congenital malformations.

Abortion, Eugenic↗