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PubMed1986

Persistent tardive dyskinesia in bipolar patients.

The prevalence and outcome of persistent tardive dyskinesia (TD) was studied in 131 bipolar patients. There were 34 cases of persistent TD in the subgroup (n = 96) with a history of neuroleptic treatment (prevalence, 35.4%; 95% confidence interval, 25% to 45%); there were no cases of persistent TD in the subgroup (n = 35) without such treatment history. Except in one patient, signs of TD persisted in spite of lithium carbonate treatment in 23 patients (median duration, 16 months; range, five to 24 months), of whom 15 remained off of a neuroleptic regimen during the study period for a median duration of 14 months (range, four to 24 months). Using multiple regression analysis, two variables were found to predict the presence of persistent TD and account for 36% of the variance: longer cumulative duration of maintenance neuroleptic treatment and shorter duration of previous lithium carbonate treatment. There appears to be a significant risk of persistent TD among neuroleptic-treated bipolar patients. High-risk subgroups within this category need to be identified.

Adult↗
PubMed1989

Genetic epidemiology of persistent islet cell antibodies among IDDM patients.

The persistence of cytoplasmic islet cell antibodies (ICA) more than a year after diagnosis of insulin-dependent diabetes mellitus (IDDM) was investigated in 43 families with at least two children with IDDM. The prevalence of persistent ICA among IDDM patients was 16%. Persistence of ICA appeared to be familial in that siblings with IDDM were significantly more concordant for the presence or for the absence of ICA than expected by chance (P = 0.04). Patients with persistent ICA were older on average at onset of IDDM than patients without persistent ICA after adjusting for duration of disease (P = 0.004). Persistence of ICA was not significantly associated with HLA DR type, immunoglobulin genotype, insulin allele class, sex, history of viral diseases, or prior vaccinations.

Autoantibodies↗
PubMed1977

A persistent infection of baby hamster kidney-21 cells with mumps virus and the role of temperature-sensitive variants.

A persistent infection of baby hamster kidney-21 (BHK-21) cells with mumps virus (BHKpi) was maintained for over 60 cell passages in the absence of antiserum. Viral persistence was demonstrated in the cultures by hemadsorption, immunofluorescence, multinucleate syncytia, and released mumps virus at the level of 10(2)--10(3) fluorescent focus-forming units/ml. No detectable levels of interferon were found in cultures persistently infected with mumps virus. Approximately 85--95% of the cells contained viral antigens. Nuclear fluorescence was observed in the persistently infected cells. Mumps virus from persistently infected clutures (MuVpi) was more heat-labile than wild-type mumps (MuVo) when subjected to 40 degrees C. BHKpi cells had a more rapid doubling time and a higher cloning efficiency in soft agar in comparison to BHK-21 cells. MuVpi was also found to be temperature-sensitive. The temperature-sensitivity of MuVpi was determined by the efficiency of plating at 33 degrees and 39 degrees C. MuVpi readily established a persistent infection in BHK-21 cells with less cytopathology than MuVo, and released temperature-sensitive virus.

Animals↗
PubMed1995

Effect of persistent mouse hepatitis virus infection on MHC class I expression in murine astrocytes.

Neurotropic strains of mouse hepatitis virus (MHV) have been used extensively for the study of viral pathogenesis in the central nervous system (CNS), serving as models for human neurological diseases such as multiple sclerosis (MS). MHV strains A59 and JHMV both cause acute and chronic encephalomyelitis and demyelination in susceptible strains of mice and rats. In acute disease, CNS damage is most likely the result of lytic infection in neurons and oligodendrocytes, and death can be prevented by the adoptive transfer of Class I-restricted CD8+ T cells. However, in later stages of the disease induced by some MHV strains, virus tends to be restricted to astrocytes in a nonlytic infection, and the immune response appears to contribute to CNS damage. These data lead us to suggest that the astrocyte may play a central role in the neuropathogenesis of MHV infection. Consistent with this possibility, A59 has been reported to induce the expression of Class I molecules of the major histocompatibility complex (MHC) in glial cells following infection in vivo and in vitro. In this communication, we have examined the influence of persistent infection by both A59 and JHMV on MHC Class I expression in primary murine astrocytes. Persistence was characterized by the presence of intracellular viral antigen and mRNA in the absence of detectable infectious virus particles. Under these conditions, JHMV, but not A59, inhibited constitutive expression of the H-2 Kb molecule, with the magnitude of inhibition increasing with postinfection time. A59 was not able to induce Class I during persistence, presumably due to the lack of infectious virus particles. Class I expression was restored by the addition of gamma-interferon (IFN-gamma) to astrocytes persistently infected with either A59 or JHMV. Thus, Class I inhibition is not a permanent consequence of JHMV persistence, and persistence does not interfere with normal signalling pathways for Class I induction.

Animals↗
PubMed1988

Suppression of neuroleptic-induced persistent abnormal movements in Cebus apella monkeys by enantiomers of 3-PPP.

Effects of the enantiomers of the dopamine (DA) autoreceptor agonist 3-PPP (0.5-8.0 mg/kg body weight, i.m.) were studied in three Cebus apella monkeys with persistent abnormal movements induced by prior long-term treatment with fluphenazine enanthate. In 2 of the animals, (-)-3-PPP abolished the abnormal movements while producing only negligible acute motor effects (trembling and stereotypy). (+)-3-PPP, administered to one of these monkeys, also produced a dose-dependent suppression of the persistent abnormal movements, along with the appearance of acute motor signs including tongue protrusions, hyperkinesia, and stereotypy; at the highest dose, there was a biphasic effect. In the first phase, there were pronounced acute motor signs but no persistent abnormal movements. In the second phase, there were neither acute nor persistent abnormal movements. One monkey was unaffected by (-)-3-PPP or low doses of (+)-3-PPP; a higher dose (4 mg/kg) produced hyperkinesia and increased persistent abnormal movements in one experimental setting. The suppression of neuroleptic-induced persistent abnormal movements by 3-PPP enantiomers may be related to their ability to act as autoreceptor agonists, while the acute motor signs produced by higher doses of (+)-3-PPP may be due to activation of postsynaptic DA receptors. The present findings suggest that (-)-3-PPP and drugs with a similar pharmacological profile might be effective as symptomatic treatments for tardive dyskinesia, with little chance of inducing acute extrapyramidal side-effects.

Animals↗
PubMed1983

Persistent baculovirus infections: Spodoptera frugiperda NPV and Autographa californica NPV in Spodoptera frugiperda cells.

Establishment of a persistent infection of Spodoptera frugiperda nuclear polyhedrosis virus (NPV) in Spodoptera frugiperda (S.f.) cells occurred in three phases: the first phase was characterised by high levels of cell infection and death, the second phase by decreasing cell infection levels leading to the final phase where less than one per cent of the cells were infected during any subculture. The virus persisted at this level of infection provided the cells were maintained by regular subculturing and incubated at the optimum growth temperature of 27 degrees C. Because of the low proportion of cells infected, cultures of virus-free cells could be selected ('cured') by dilution of the persistent infection without the use of viral antiserum. Unlike the parent S.f. cells, cultures of cured cells were partially resistant to infection with S. frugiperda NPV or infection with an unrelated baculovirus Autographa californica NPV. A. californica NPV, which is cytolytic for the parent S.f. cell line, established a persistent infection in the cured cells. The establishment pattern was similar to that previously found for S. frugiperda NPV and only one to five per cent of the cells were infected at equilibrium. Cured cells from the A. californica NPV persistent infection were highly resistant to infection with both S. frugiperda NPV and A. californica NPV. All attempts to find a viral interference phenomenon to explain the resistance of the cured cells were unsuccessful. All cell types adsorbed virus equally well. Slower growth of S.f. cells cured from the persistent A. californica NPV infection is the only difference so far observed between any of the S.f. cell types.

Animals↗
PubMed1988

A model virus-cell system to study the persistence of African swine fever virus.

The persistence of African swine fever virus (ASFV) on Vero cells was induced by using 5-iodo-2'-deoxyuridine (IDU). After the persistence was established, several cycles of decreasing virus production were observed with intervals in which no virus could be detected. These latency-like periods could last from 15 to 25 days. After three and a half months the cells appeared to be "cured" and no virus was detected during almost three years. These "cured" cells (Vero-L) were more resistant to superinfection with the wild type virus, and when infected they always established persistence without drug addition characterized by a continuous virus production. The persistent virus isolated at passage 23rd from ASFV persistently infected Vero-L cells was different from wild type in a) the morphology of the plaque, b) its ability to replicate in Vero-L cells, and c) greater resistance to be inhibited by IDU in normal Vero cells (Vero-N). These results suggest that both, Vero cells and ASFV have changed during persistent infection.

African Swine Fever Virus↗
PubMed1976

Persistent infection of tissue culture cells by RNA viruses.

In this paper, the characteristics of cultured cells persistently infected with RNA viruses, other than leuko viruses are described. The roles that the host cell, interferon, virus mutants and defective interfering particles may play in the establishment and maintenance of persistent infection are discussed. It is proposed that the interaction of viruses with certain types of host cells can lead to persistent infection. The differences in virus-host interactions may be attributable to differences in membrane properties of various cells. Defective interfering particles may play a role in the establishment of persistent infections in cells which normally undergo lytic virus development. Mutant types of virus appear to be prominent in the virus released from persistently infected cells, but the role that various mutants play in the maintenance of persistent infections remains unclear.

Antibodies, Viral↗
PubMed1976

Persistent infection with bovine herpesvirus-1 (infectious bovine rhinotracheitis virus) in cultured hamster cells.

Bovine herpesvirus-1 infection in hamster embryo cells was found to be dependent upon input multiplicity; productive infection was achieved at input multiplicities greater than one, while persistent infection was established when input multiplicities were about 0.5. This persistence was characterized by a noncyclic, minimal degree of cytopathic effect with a low level of released virus. Maintenance of the persistently infected cultures did not require external supportive measures. Subcultivation of the persistently infected cultures led to virus replication followed by CPE and then cell regrowth. With 3 to 4 weeks after subcultivation a persistent infection was re-established. The possible mechanism for the bovine herpesvirus persistence in hamster cells is discussed.

Animals↗
PubMed1988

Visible persistence in paranoid schizophrenics.

A visual temporal integration (i.e., visible persistence) task was performed by normal controls and paranoid schizophrenics. The task evaluated the critical duration (CD), which approximates the duration of peripheral persistence duration and post-CD persistence, which is possibly more associated with central processes. Subjects were required to report when temporally modulated spatial frequency patterns, which are known to have characteristic temporal processing rates, were pulsing "on-off" with a distinct "off" period. The dependent measure was the duration of visible persistence. An analysis of groups X spatial frequency duration (50, 75, 150, 300 msec) X spatial frequency (high, medium, low), with repeated measures on the last two variables, revealed that the second-order interaction was significant (p less than 0.05). Schizophrenics had shorter visible persistence only for the 300-msec presentation for the high spatial frequency pattern. Also, the CD of schizophrenics did not conform to the duration of normals on the high spatial frequency. The results are discussed in terms of the role high spatial frequencies plays in visual information processing and how shorter visible persistence by paranoid schizophrenics may reflect a premature termination of information necessary for synthesis into accurate percepts.

Adolescent↗
PubMed1984

Visible persistence as a function of spatial frequency, number of cycles and retinal area.

Using a variety of measures it has been shown that processing time increases with increasing spatial frequency. Long and Sakitt (1981) [Vision Res. 21, 1387-1393] investigated duration of visible persistence as a function of both spatial frequency and number of cycles present. They concluded that number of cycles and not spatial frequency is the crucial variable in determining duration of visible persistence. The present paper investigates this issue in three experiments. Experiments 1 and 2 determined duration of visible persistence with spatial frequencies of 2, 4, 8 and 10 c/deg while holding both number of cycles and grating area constant in a dark surround and in a light surround. Stimulus durations of 50 and 300 msec were used in Experiments 1 and 2 respectively. The results at each stimulus duration showed an increase in duration of visible persistence with increasing spatial frequency similar to that found in most previous reports. This increase was less with a 300 than with a 50 msec stimulus duration. Whether the gratings were presented in a light or a dark surround had no significant effect. Experiment 3 showed that at 2 c/deg duration of visible persistence increased with increasing size of the grating stimuli when all stimulus sizes fell within the area of spatial summation. This effect was greater in a dark than in light surround. It is concluded that visible persistence does increase with spatial frequency. Previous results inconsistent with this conclusion are explained in terms of spatial summation.

Afterimage↗
PubMed1985

Visual persistence from brief letters and pictures.

The visual persistence from briefly presented letters and pictures was assessed by the popular probe-matching procedure over a range of background and target luminance levels and for several color conditions. It was determined that the fading visible persistence measured in this way increased with increasing target luminance and with decreasing background luminance. For small foveal presentations, photopically-matched targets of differing wavelength produced equivalent persistences; but for larger, parafoveal presentations, scotopically-matched targets of differing wavelength produced equivalent persistences. This was true for both letter and picture targets. Results were discussed in terms of an early sensory locus to such persistence effects. The strong consistency of these findings to some previous work and the apparent inconsistency with other work were treated in terms of different kinds of visual persistence effects assessed by different experimental methods.

Afterimage↗
PubMed1994

Effect of the ISI on the visible persistence of a stimulus in apparent motion.

The persistence of briefly flashed stimuli undergoing a horizontal apparent motion is assessed as a function of the temporal interval (inter-stimulus interval or ISI) between successive locations. The main result is that the duration of persistence is increased when the ISI is reduced (within the range 1-15 msec). An increase of persistence also occurs when the spatial separation (delta chi) between successive presentations of the moving stimulus becomes larger, a well established result which is replicated here. In both cases, the elevation of persistence suggests that inhibitory processes, which are assumed to underlie the persistence-suppression, have become less efficient. According to the data, it seems that the spatio-temporal parameters of motion, and not the speed as such, are responsible for the strength of inhibition. Namely, optimal inhibition, and thus suppression, would need a minimum amount of time to take place, and would improve with proximity (i.e. with smaller delta chi). Finally, a persistence-suppression decrease is observed when the angular size of the flashed stimuli is reduced (i.e. when higher spatial frequencies become more predominant). A model of transient-on-sustained inhibition accounts well for these results.

Afterimage↗
PubMed1989

Persistent albuminuria as an index of diabetic nephropathy in type 2 diabetic patients in Osaka, Japan-incidence, risk factors, prognosis and causes of death.

A group of 1196 type 2 (non-insulin-dependent) diabetic patients was followed for a mean of 10 years to determine the incidence of persistent albuminuria, its associated risk factors and prognosis, as well as causes of death in patients. None of the patients studied had albuminuria on entry. The mean annual incidence rate of persistent albuminuria per 1000 person-years in the patients was higher in males than in females (18.42 and 12.57, respectively). Development of persistent albuminuria was associated with age at entry, duration of known diabetes, systolic blood pressure, fasting glucose level, presence of diabetic retinopathy and type of treatment. Among 193 patients who developed persistent albuminuria during the observation period, 66 (34.2%) died before the end of the observation period, with a mean survival period (+/- SD) of 3.0 +/- 3.1 years after the onset of persistent albuminuria, indicating an extremely poor prognosis. Renal disease was the predominant cause of death in patients who developed persistent albuminuria, followed by heart disease and cerebrovascular disease.

Adult↗
PubMed1991

Disturbed secretion of atrial natriuretic peptide in patients with persistent atrial standstill: endocrinologic silence.

Persistent atrial standstill is a very rare pathophysiologic condition whose diagnosis is established when both electrical and mechanical silence of the atria are confirmed. To test the hypothesis that secretion of atrial natriuretic peptide is disturbed in patients with persistent atrial standstill, the response of atrial natriuretic peptide secretion and other neurohormonal factors during exercise was investigated in three patients with a rate-responsive ventricular demand (VVI) pacemaker implanted for confirmed persistent atrial standstill. The results were compared with those observed in eight normal subjects and patients with a rate-responsive VVI (Group A) or atrial demand (AAI) (Group B) pacemaker implanted for confirmed sick sinus syndrome. Patients in Group A displayed significant elevation of alpha-human atrial natriuretic peptide secretion both before and during exercise (122.5 +/- 14.8 and 207.5 +/- 8.3 pg/ml, respectively) compared with those in Group B (55 +/- 14.1 and 116.4 +/- 51.5 pg/ml, respectively) and the normal subjects (18.9 +/- 9.8 and 30.8 +/- 19.2 pg/ml, respectively). This indicated development of a nonphysiologic increase in atrial volume or pressure overload, or both, in rate-responsive VVI pacing because of lack of atrioventricular synchrony. However, patients with persistent atrial standstill had undetectable (less than 10 pg/ml) or almost undetectable secretion of atrial natriuretic peptide as well as lower levels of cyclic guanosine monophosphate in the circulation both before and during exercise. Changes in plasma catecholamines during exercise were similar in patients with persistent atrial standstill compared with the other groups. This study indicates that "endocrinologic silence" accompanies electrical and mechanical silence of the atria, which may constitute a third diagnostic clue to persistent atrial standstill.

Adult↗
PubMed1995

Chronic fatigue: risk factors for symptom persistence in a 2 1/2-year follow-up study.

BACKGROUND: The prolonged disability of patients suffering from chronic fatigue may be due to sustaining factors that are independent of the cause and subject to intervention. This study reexamined a cohort of patients with chronic fatigue to define medical and psychiatric predictors of persistent symptoms. METHODS: Seventy-eight patients with chronic fatigue present for 6 months or more (not required to meet the Centers for Disease Control case definition for chronic fatigue syndrome [CFS]) completed a self-report, follow-up questionnaire to measure the overall improvement or worsening of their condition at a mean of 2.5 years after their initial examination. At the time of initial evaluation, patients underwent a structured psychiatric examination, physical examination, laboratory studies, and self-report measures of psychological distress and functional disability. The psychiatric examination queried the patient about 28 somatic symptoms that are separate from those associated with CFS. Discriminant analysis was used to determine which variables present at the initial examination were significant predictors of persistent symptoms and disability at 2.5 years. RESULTS: The factors most important at the time of initial presentation in predicting persistent illness were: (1) more than eight medically unexplained physical symptoms separate from those associated with CFS case definition; (2) lifetime history of dysthymia; (3) duration of chronic fatigue symptoms greater than 1.5 years; (4) less than 16 years of formal education; and (5) age older than 38 years. None of the results of the initial physical examination, or immunologic, general laboratory, or viral antibody measurements were significant in predicting persistence of symptoms. Recovery rates for those who met the criteria for CFS by either of two case definitions were lower than the rate of noncases, but the differences were not statistically significant. The five aforementioned variables formed a significant discriminative function, correctly classifying 78% of those who recovered and 74% of those with persistent symptoms. CONCLUSIONS: At initial examination, patients with chronic fatigue, more than eight medically unexplained physical symptoms (excluding symptoms in the case criteria for CFS), a lifetime history of dysthymic disorder, longer than 1.5 years of chronic fatigue, less than 16 years of formal education, and who were older than 38 years were the most likely to have persistence of symptoms of chronic fatigue at the 2.5-year follow-up.

Adult↗
PubMed1984

Visible persistence as a function of viewing condition and eye-handedness relationship.

Duration of visible persistence was investigated as a function of spatial frequency, orientation and viewing condition (binocular, dominant eye and non-dominant eye). Persistence increased with increasing spatial frequency and was longer for oblique than vertical gratings. Viewing condition also influenced visible persistence such that binocular persistence was significantly shorter than for either monocular condition. A post-hoc analysis indicated that this was only true with subjects who were right-handed and right-eyed. Subjects mixed on this relationship showed no differences in persistence across viewing conditions. A second experiment which selected subjects on the basis of this relationship confirmed the results of Experiment 1. The results for the right-right group broaden the generality of the rule showing an inverse relationship between response strength and persistence duration. The results for the Mixed group indicate a lack of binocular summation.

Dominance, Cerebral↗
PubMed1988

Persistent ovarian cysts following administration of human menopausal and chorionic gonadotropins: an attenuated form of ovarian hyperstimulation syndrome.

Ovarian cysts persisting after the onset of menses were demonstrated by ultrasound (US) in 40 of 71 (56%) nonconception cycles following ovulation induction with human menopausal gonadotropins (hMG) and human chorionic gonadotropin (hCG). Persistent cysts were self-limited and all resolved spontaneously within two cycles. They developed more frequently during stimulation cycles with (1) higher mean pre-hCG serum estradiol (E2), (2) a greater number of medium and large follicles at peak pre-hCG E2, and (3) a larger leading follicle diameter at peak pre-hCG E2. Persistent ovarian cysts frequently occurred despite a peak pre-hCG E2 lower than 1000 pg/ml. Although ovarian enlargement in the presence of cysts exceeded 5 X 5 cm in 25% of cases, no patient developed clinical symptoms of ovarian hyperstimulation syndrome (OHSS). Repeated induction of ovulation with hMG/hCG in the presence of nonfunctional, persistent cysts resulted in pregnancies in 6 of 15 cases (40%). Asymptomatic persistent ovarian cysts frequently follow an hMG/hCG regimen and, when nonfunctional, are not a contraindication to repeated ovarian stimulation. Persistent ovarian cysts appear to be an attenuated form of OHSS.

Adult↗