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PubMed1988

Weight loss in obese mice persistently infected with lymphocytic choriomeningitis virus is not associated with elevated tumor necrosis factor/cachectin activity in peritoneal macrophages.

C57BL/6 ob/ob (C57 ob/ob) mice infected persistently with lymphocytic choriomeningitis virus (LCMV) show cachexia as judged by a weight loss of greater than 20%. Virus persists in a subset of macrophages. Because a cachexic state occurs in several chronic debilitating diseases of humans, often accompanied by persistent microbial infections with macrophage/monocytic involvement and tumor necrosis factor (TNF) cachectin production, the role of TNF in the weightloss of ob/ob mice infected persistently with LCMV was investigated. TNF mRNA expression was not increased in peritoneal cells from such persistently-infected mice, nor did their serum levels of TNF rise above those in uninfected litter-mates. Furthermore, in vitro LCMV infection of adherent peritoneal cells from these C57 ob/ob mice did not enhance TNF mRNA or protein expression. Therefore, the cachexia-like weight loss observed in C57 ob/ob mice during a persistent LCMV infection is apparently not associated with a measurable increase in TNF.

Animals↗

PubMed1987

Inheritance of susceptibility to phototumorigenesis and persistent hyperplasia in F1 hybrids between SENCAR mice and BALB/c or C57BL/6 mice.

SENCAR mice are selectively bred for hypersusceptibility to two-stage chemical skin carcinogenesis. They are also hypersusceptible to UV radiation tumorigenesis with single high-dose, but not chronic low-dose, exposures. In addition, SENCAR mice exhibit an exaggerated and persistent epidermal hyperplasia (due to sustained proliferation of the basal cells) in response to UV-induced tissue damage. In the present study, we have examined the inheritance of susceptibility to both phototumorigenesis and persistent hyperplasia in the F1 offspring of SENCAR mice crossed with either of two inbred strains (BALB/c or C57BL/6) which are relatively resistant to phototumorigenesis. A total of 428 mice from the parental strains and reciprocal F1 crosses were given a single high dose (8.64 x 10(4) J/m2) of UV radiation (FS40 sunlamps) which causes persistent hyperplasia and tumorigenesis in many SENCAR, but no BALB/c or C57BL/6, mice. F1 hybrids between SENCAR and C57BL/6 mice did not develop persistent hyperplasia or skin tumors, which indicates that susceptibility to both traits is completely recessive to the C57BL/6 genotype. In contrast, F1 hybrids between SENCAR and BALB/c mice developed both persistent hyperplasia and skin tumors, although at a much lower incidence than the SENCAR mice, indicating that susceptibility to both traits is only partially (incompletely) recessive to the BALB/c genotype. Thus, in either F1 cross, susceptibility to phototumorigenesis decreased in parallel with persistent hyperplasia. These results are consistent with the hypothesis that the two characteristics are mechanistically related.

Animals↗

PubMedDate not supplied

Videoanalysis of chemokinesis: characterization of speed, persistence and orientation in an agarose assay.

Time-lapse video recording and off-line computer analysis were used to characterize the chemokinetic behavior of individual human neutrophils migrating in an agarose assay. When neutrophils were stimulated with an isotropic concentration of formyl-methionyl-leucyl-phenylalanine (fMLP), they migrated with a mean speed of 9.6 micron per min and oriented at random. The ratio of net displacement to total distance travelled (persistence of locomotion) was 0.66, indicating that neutrophils maintained some directional persistence even in the absence of a gradient of fMLP. The speed and persistence of locomotion index were correlated because both faster and slower cells had high persistence, while only slower cells had low persistence. The orientation angle was independent of both speed and persistence of locomotion. These are the first reported direct measurements of the chemokinetic locomotion of neutrophils using the agarose assay.

Chemotaxis, Leukocyte↗

PubMed1986

Stability of rubella virus after long-term persistence in human cell line.

Primary infection of HEp-2 cells with rubella virus resulted in non-cytophatic long-term persistent infection. During four years of persistence the virus was produced in sufficient quantities (up to 6 logs PFU/ml) and did not differ from the parental variant in its pathogenicity for BHK-21 or RK-13 cells, or hemagglutinating activity, but formed smaller plaques. Persistent virus preserved the original antigenicity as judged from reciprocal hemagglutination-inhibition or plaque reduction-neutralization tests with polyclonal antisera. Both original and persistent rubella viruses were thermoresistant (T 56 degrees C) and slightly temperature-sensitive. Clonal analysis revealed presence of ts-mutants among both original and persistent virus clones with different degrees of plating efficiency at 40 degrees/34 degrees C. RNA fingerprinting showed only minor changes in persistent rubella virus.

Antigens, Viral↗

PubMed1985

Kinetics of formation and persistence of ethylguanines in DNA of rats and hamsters treated with diethylnitrosamine.

The kinetics of formation and persistence of 7-ethylguanine (e7Gua) and O6-ethylguanine (O6eGua) were determined in rat liver and kidney DNA following i.p. injection with 12.5, 50, 100, or 200 mg DENA per kg body weight. The rate of ethylguanine formation in hepatic DNA was independent of carcinogen dose; however, the maximum level of DNA ethylation reached was linearly related to DENA dose. Persistence of O6eGua but not e7Gua in rat liver DNA appeared to be dose-dependent; the rate of decline in O6eGua concentration slowed as the dose of DENA increased. Ethylation of rat kidney DNA was quantifiable only following treatment with 200 mg DENA per kg body weight, and maximum concentrations of e7Gua and O6eGua were approximately ten times less than those in hepatic DNA of these animals. Nevertheless, elimination of e7Gua and O6eGua from DNA occurred at similar rates in these tissues. Whereas lung DNA from DENA-treated rats contained no detectable ethylguanines, both e7Gua and O6eGua were detected in lung DNA from treated hamsters. The half-life of e7Gua in hamster lung DNA was 28 h, while O6eGua persisted longer, exhibiting a half-life of 91 h. Only trace quantities of e7Gua and O6eGua were detected in hamster kidney DNA, precluding an accurate estimation of the kinetics of DNA alkylation in this tissue. The rate of formation of ethylguanines in hepatic DNA was faster in hamster than in rat, while maximum levels of e7Gua and O6eGua were similar in these two species. Persistence of both e7Gua and O6eGua was markedly different in hepatic DNA of rats and hamsters. e7Gua was eliminated at a faster rate in the hamster (half-life of 20 h), as compared to the rat (half-life of 35 h). Conversely, O6eGua persisted longer in hamster than in rat liver DNA; a half-life of 34 h was found for the hamster, compared to a half-life of 14 h for the rat. The half-lives of e7Gua and O6eGua in hepatic DNA of DENA-treated rats and hamsters were similar to those reported previously for m7Gua and O6mGua in these species, suggesting that the same enzymatic DNA repair systems act upon these structurally related DNA adducts. The formation and prolonged persistence of O6eGua in lung DNA of DENA-treated hamsters may be related to the sensitivity of this species to the induction of respiratory tract neoplasms following exposure to DENA.

Alkylation↗

PubMed1980

[Studies on establishment and maintenance of persistent infection with measles virus in NC-37 cell. 1. Production of DNA-synthesis-suppressing factor (DSF) in NC-37 cell infected with measles virus].

Wild strains of measles virus, such as Edmonston, Toyoshima and freshly isolated KM strain which had not a capacity to establish a persistent infection in NC-37 cell inhibited 80-90 percent of host cellular DNA synthesis, while attenuated or subacute sclerosing panencephalitis (SSPE) viruses, such as Schwarz, Halle and Mantooth which had a capacity to establish persistent infection inhibited about 50 percent of host cellular DNA synthesis 6 or 7 days after infection of virus. However, inhibition of DNA synthesis in cells infected with attenuated or SSPE virus recovered gradually to the same level of control cell within two weeks after infection of virus, and persistently infected cells were not suppressed cellular DNA synthesis in synchronized cell culture. NC-37 cells infected with wild strain produced host cellular DNA-synthesis-suppressing factor (DSF) into culture fluid, but it could detect no such factor in culture fluid of cells infected with attenuated, SSPE virus, or carried virus and persistently infected cell. Furthermore, persistently infected cell treated wtih DSF caused the suppression of DNA synthesis, and so these cells died of metabolic inhibition within one week after inoculation of DSF. NC-37 cell infected with Mantooth strain was inhibited the establishment of persistent infection by the treatment of cell with DSF.

Cells, Cultured↗

PubMed1980

Persistence: the role of partial reinforcement in psychotherapy.

Persistence, which refers to the ability of a learned behavior to survive protracted nonreinforcement (extinction), has been an overlooked dimension of clinical intervention. While persistence of newly acquired coping behavior is desired (and possibly assumed) by all psychotherapeutic procedures, few treatment programs possess features that operate to sustain responding in the face of a nonsupportive, nonreinforcing environment. The present article presents a treatment strategy designed to foster persistence based on the laboratory findings that partial reinforcement schedules produce greater resistance to extinction than continuous reinforcement schedules--a phenomenon referred to as the partial reinforcement extinction effect. The two major theories of persistence (Amsel's general theory of persistence and Capaldi's sequential theory) are discussed, and the basic principles of these models are extended to a number of therapeutic modalities including depression therapies, systemic desensitization, assertiveness training, and aversion therapy. In addition, procedural considerations including generalized and discriminated persistence are discussed.

Adaptation, Psychological↗

PubMedDate not supplied

[The biomedical aspects of the persistence of bacteria].

A correlation between the structure and function of bacteria was analyzed in the process of their persistence in the host body. A variety of persistent forms of bacteria was shown to be based on the isolation of their morphological substrate, peptidoglycane, which a cell "masked" (screening by surface bacterial structures, antigenic mimicry), "lost" (L-forms of bacteria, mycoplasmas) or protected against the system of host immunity by secreted factors. A new group of secreted bacterial (antilysozyme, anti-interferon, anti-immunoglobulin, anticomplement) factors, permitting microbial persistence in the host body, was described. Different methodological approaches to their determination were developed on the basis of the principle of "delayed antagonism". Applied aspects of the problem of persistence of bacteria were reviewed. The efficacy of new methods developed for the isolation and identification of a causative agent under the control of persistence markers was demonstrated on facultative microflora in different surgical, obstetrical, gynecological, urological diseases and diseases of internal organs. The facts concerning the use of the factors of bacterial persistence were presented for the solution of therapeutic (selection of means for controlling cell parasites), prognostic (development of carrier state in convalescents) and ecological (microbiological monitoring of the environment) problems.

Animals↗

PubMed1994

Reproductive potential after treatment for persistent ectopic pregnancy.

We examined the success rate and reproductive outcome of 50 patients who had been treated for persistent EP after initial unsuccessful salpingostomy. All who underwent salpingectomy had successful treatment of their persistent EP. One treatment failure occurred after MTX. Of 50 women, 32 (61.5%) attempted conception after treatment for persistent EP. The cumulative clinical pregnancy rate after treatment for persistent EP was 59% at 36 months. There was a significant association between clinical pregnancy rate after persistent EP and those with normal contralateral fallopian tubes (P < 0.005). The relative risk of having a clinical pregnancy among those who attempted conception was 2.3 for those having a normal contralateral fallopian tube compared with those with a contralateral fallopian tube with obvious pathology. Intrauterine pregnancy rates after treatment of persistent EP were similar to those reported for primary treatment of EP.

Adult↗

PubMed1993

Local immune response in persistent cervical dysplasia.

OBJECTIVE: To investigate the differences in local immune response between persistent and regressive cervical dysplasia. METHODS: We conducted a quantitative study of Langerhans cells, pan-T cells, and helper-inducer T cells in the subepithelial connective tissue using immunohistochemical techniques with S-100 protein antibody, UCHL1, and OPD4, respectively, in 52 paraffin sections. The subjects were patients with persistent cervical dysplasia and a comparable control group of 46 patients with regressive dysplasia. RESULTS: In the subepithelial stroma, the mean (+/- standard deviation) numbers of S-100- and OPD4-positive cells in the persistent group were 8.6 +/- 8.1 and 84.6 +/- 66.3, respectively, compared with 15.1 +/- 9.4 and 147.0 +/- 67.7, respectively, in the regression group. These data demonstrate a significant reduction of Langerhans cells and helper-inducer T cells (P < .0002 and P < .0001, respectively) with persistent dysplasia. CONCLUSION: The decreased numbers of S-100-positive Langerhans cells and helper-inducer T cells in persistent dysplasia compared to those of regressive dysplasia strongly support a decreased local immune response in persistent cervical dysplasia.

Adult↗

PubMedDate not supplied

MRI of persistent trigeminal artery.

OBJECTIVE: To describe the classic appearance of persistent trigeminal artery on MR imaging with the typical MR appearance of the hypoplastic precommunal basilar artery. This finding may be used as an ancillary sign of this anomaly in subtle cases of persistent fetal carotid-basilar artery anastomoses. MATERIALS AND METHODS: Two women (46 and 19 years of age) with persistent trigeminal artery were examined. An MR imaging study using spin-echo sequences was performed. The findings were confirmed on conventional angiography. RESULTS: Two cases showed a hypoplastic basilar trunk flow void in the caudal posterior fossa that enlarged to a more normal caliber rostrally above the persistent trigeminal artery anastomosis. The actual anastomosis was also demonstrated in both cases, and in one of the cases the persistent trigeminal artery was shown to form a groove in the dorsum sellae. CONCLUSION: A proximal hypoplastic basilar trunk below the anastomosis that enlarges to a more normal caliber above the aberrant communication is an important ancillary sign of persistent trigeminal artery and should be searched for on routine MR studies in cases with suspected carotid-basilar anastomoses.

Adult↗

PubMedDate not supplied

[Persistent infection in murine L cells infected with the parainfluenza virus SV5].

Persistent infection of mouse L cells was achieved by serial passages of undiluted parainfluenza SV5 virus. At the level of the 10--12th passage a stationary noncytocidal type of persistent infection was established. A low level of the infectious virus produced by the persistently infected cells was observed; the number of cells synthesizing the virus-specific antigen detectable by immunofluorescence was high. Persistently infected cells were resistant to the infection with the homologous virus and sensitive to superinfection with heterologous viruses. The persisting virus had marked interfering activity. The possibility of participation of defective interfering particles and endogenous oncornavirus in the maintenance of the persistent infection is discussed.

Animals↗

PubMed1995

Risk factors of persistent diarrhoea in children below five years of age.

Persistent diarrhoea has been identified as a major source of morbidity in the developing world. This study was conducted to evaluate the risk factors of persistent diarrhoea in children below five years of age. The data used is from a prospective analytical case control study carried out in the Department of Paediatrics, Dow Medical College and Civil Hospital, Karachi, during 1993-94. A total of 50 cases of persistent diarrhoea and 50 acute diarrhoeal controls (matched for age and sex) under 5 comprised the study subjects in this analysis. The maximum incidence of persistent diarrhoeal episodes occurred in children below one year of age. Male to female ratio was 3:2. The seasonal variation showed a peak incidence in summer rainy season. Risk factors for persistent diarrhoea recorded were young age, poor nutritional status, irrational use of antibiotics during acute diarrhoea, lack of exclusive breast feeding, incomplete vaccination, lack of tap water supply and sanitation facility at home and income < Rupees 2000/month of the earning members of the family. Thus, it is concluded that discouraging the irrational use of antibiotics and other drugs for the treatment of diarrhoea, promotion of breast feeding and Expanded Programme of Immunization (EPI), Standard Diarrhoea Case Management courses for doctors, medical students and paramedical staff and provision of safe drinking water and sanitation facility are important for the prevention of persistent diarrhoea.

Case-Control Studies↗

PubMedDate not supplied

F-persistence studies in L5-S1 lumbosacral radiculopathies.

F-wave persistence of the deep peroneal nerve was studied in 41 patients with L5-S1 compressive root lesion (22 with radicular pain (RP) and 19 with motor and/or sensory (MS) signs), and in 26 normal control subjects. We used specific conditions, i.e., surface electrodes, stronger stimulus and facilitating maneuver in order to enhance the frequency of F-response appearance. EMG and nerve conduction studies were done F-latency was also measured on both sides of the patients. In the affected sides, both RP and MS, F-persistence's mean value was 56.1 and 31.0 respectively, which was significantly (p < 0.01) lower than controls (mean 83.2), and showed a significant correlation with the extensor digitorum brevis maximal interference pattern. These findings possibly reflect demyelination and/or axonal damage of lower motoneuron. Reduced F-persistence was found in 22 selected patient sides with unequivocal dorsal root damage only (mean 56.7, p < 0.01). This finding could be the result of a reduced lower motoneuron excitability because of the disruption of the circuit retaining the muscle tone. The diagnostic utility of F-persistence, F-latency and EMG was also tested. EMG and F-persistence were found statistically equal while F-persistence was found with a significant preponderance in comparison with F-latency. Finally, EMG was found more sensitive than F-latency in the patient sides with neurologic deficits.

Adult↗

PubMedDate not supplied

[Influence of classic enteropathogenic Escherichia coli on small bowel bacterial proliferation in infant's acute and persistent diarrhea].

UNLABELLED: Bacterial proliferation of the colonic microflora can occur in up to 50% of the infants with acute and persistent diarrhea. EPEC strains are frequently associated with bacterial proliferation in the small bowel lumen. The persistence of diarrhea might be due to the proliferation of EPEC in the intestinal lumen. PURPOSE: The present study was aimed at comparing the magnitude of the bacterial proliferation in the small bowel lumen in infants with acute and persistent diarrhea due to EPEC and other agents. PATIENTS AND METHODS: Fourty infants with diarrhea (23 with acute diarrhea and 17 with persistent diarrhea) underwent a naso-jejunal intubation for intestinal secretion culture of aerobes and anaerobes microorganisms. Stool samples were also collected for the investigation of enteropathogenic agents. RESULTS: Bacterial proliferation in the small bowel was detected in 32 (80%) infants; in 30 (75%) infants there was proliferation of aerobic microorganisms while in 17 (43%) infants there was proliferation of microorganisms belonging to the anaerobic microflora. There was no statistical difference in the bacterial proliferation between patients with acute and persistent diarrhea. In 16 patients EPEC strains were identified in the stool culture, and all of them showed bacterial overgrowth above 10(3) microorganisms/mL. In contrast in the 24 patients without EPEC in the stools only 16 (67%) showed bacterial overgrowth in the small bowel lumen (p < 0.01). The mean concentration of E. coli in the intestinal secretion was 8 x 10(5) microorganisms/mL among the patients with EPEC in the stools and 3 x 10(2) microorganisms/mL among the patients with no EPEC in the stools (p < 0.05). CONCLUSIONS: EPEC infection either acute or persistent induce favorable conditions for bacterial proliferation in the small bowel secretion in infants with diarrhea.

Acute Disease↗

PubMed1997

Establishment and characterisation of a porcine rubulavirus (LPMV) persistent infection in porcine kidney cells.

Porcine rubulavirus (LPMV) can establish persistent infections in porcine kidney cells. Cell cultures characterised at passages 25 and 65 demonstrated haemadsorption, formation of syncytia, and a slower growth rate. The nucleoprotein (NP) and haemagglutinin-neuraminidase (HN) protein were present in all cells, although not to the same extent as in wild type infected cells. Incubation of the cell cultures with virus neutralising antibodies could not cure them from the infection. The cells were resistant to LPMV high multiplicity superinfection, but lysed rapidly upon infection with VSV. These cells thus fulfilled the criteria of a true persistent infection. Viral particles were released into the medium from the persistently infected cells as measured by HA and infection of PK-15 cells with medium from the persistently infected cells. The infectious titer of the virus released from the persistently infected cells was 3 logs lower compared to wild type virus, the HN titer still being comparable. Virus released from the persistently infected cells was unable to cause a lytic infection in PK-15 cells, and showed a reduced ability to spread when compared to a LPMV lytic infection.

Animals↗

PubMed2026

Durable burden suppression and recurrence patterns after cryoablation in early persistent AF: 3-year results of COOL-PER trial.

BACKGROUND: Long-term rhythm outcomes following cryoballoon ablation (CBA) in early persistent atrial fibrillation (AF) remain incompletely characterized. OBJECTIVE: To evaluate 3-year atrial fibrillation (AF) burden trajectories, subsequent recurrence patterns detected by implantable loop recorder (ILR), and their association with healthcare resource utilization (HCRU). METHODS: The COOL-PER trial was a prospective, multicenter, single-arm study that enrolled patients with early persistent AF (duration ≤ 3 years). An ILR was implanted 7-90 days before CBA for continuous rhythm monitoring. RESULTS: Among 130 enrolled patients, 123 completed the 3-year follow-up (mean age, 60.5 ± 8.4 years; 25.2% women). Median AF burden decreased from 99.9% (interquartile range, 53.1-100.0) at baseline to 0.1% (0.0-4.2), 0.5% (0.0-9.1), and 0.7% (0.0-9.5) at 1, 2, and 3 years (all P < .001). Of 47 patients who were recurrence-free at 1 year, 25 (53.2%) developed subsequent recurrence, and 20 (80.0%) were detected by ILR alone. Compared with first-year recurrence, subsequent recurrence was less often persistent (4.0% vs 28.9%; P = .001) and was associated with a lower AF burden (0.1% [0.0-1.6] vs 2.8% [0.4-18.7]; P = .010). Both persistent-type recurrence and AF burden ≥ 10% were associated with more additional rhythm control interventions (78.3% vs 30.8% vs 0%; 78.6% vs 39.1% vs 0%; both P < .001) and cardiovascular hospitalization (17.4% vs 3.8% vs 0%, P = .045; 14.3% vs 4.3% vs 0%, P = .029). CONCLUSION: CBA achieved durable AF burden suppression over 3 years in early persistent AF. Subsequent recurrence after the first year was common and was predominantly detectable by ILR only. Subsequent recurrences were often paroxysmal, with a lower AF burden and associated with lower HCRU, supporting the value of continuous long-term rhythm monitoring for characterizing rhythm status beyond the first post-ablation year.

Cryoballoon ablation↗

PubMed1990

National survey of diagnosis and management of persistent pulmonary hypertension of the newborn.

The diagnosis and management of persistent pulmonary hypertension of the newborn remains controversial. A national survey was performed to analyze recent trends in the incidence, diagnosis, management, and survival of patients with persistent pulmonary hypertension of the neonate. Sixty-six institutions from all geographical regions responded. The overall admission incidence was 3.9% +/- 2.6%. Secondary persistent pulmonary hypertension of the neonate was more common than primary. Unexplained hypoxemia, ductal level right-to-left shunting, echocardiography, and a positive response to hyperventilation were all used frequently (in at least 79% of institutions) to diagnose persistent pulmonary hypertension of the neonate. The majority of institutions considered a positive response to hyperventilation to be determined by an increase of PaO2 by 30 mm Hg with a concomitant decrease in PaCO2 to 25 mm Hg. Approximately 70% of institutions use varying ventilator techniques (ie, with or without hyperventilation), but the majority use hyperventilation predominantly. Almost all (greater than 90%) institutions used muscle paralytic agents and pulmonary vasodilators. Tolazoline was the first choice of pulmonary vasodilator therapy. The overall survival rate of persistent pulmonary hypertension of the newborn was 77.4% +/- 13.4%. Survival rate did not differ between different geographic areas of the country. There was a trend noted for improved survival with less use of muscle paralyzing agents. Yet despite varying treatment protocols, survival rates are improving.

Carbon Dioxide↗