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Biomedical subjects

D Guthrie

Publications and source records attributed to D Guthrie.

At least 19 recordsLinked to original sources
PubMed1992

Differential effects of women's child sexual abuse and subsequent sexual revictimization.

This study examines the differential effects of sexual revictimization in a community sample of 248 African-American and White American women, ages 18 to 36. Two classifications of sexual revictimization over the life course were used to assess the effects on later sexual and psychological functioning. The findings suggest that unintended pregnancies and abortions were significantly associated with sexual revictimization. Women who reported more than one incident in both childhood and adulthood were also likely to have multiple partnerships and brief sexual relationships. The findings are discussed within the context of the dynamics of sexual revictimization and its effects. Suggestions are offered for therapeutic strategies with survivors in order to minimize the effects of sexual revictimization.

Adolescent↗
PubMed1992

Communication deficits and formal thought disorder in schizophrenic children.

This study examined 31 schizophrenic children to determine if they used discourse devices that make speech coherence differently from sex and mental age matched normal children. It also investigated whether the discourse deficits of the schizophrenic children were related to clinical measures of formal thought disorder. Using Halliday and Hassan's analysis of cohesion, the authors found that schizophrenic children underutilize some discourse devices and overutilize others. Several of their discourse deficits were similar to those described in schizophrenic adults. The schizophrenic children, however, also had additional discourse deficits, which probably reflect developmental delays. The authors also demonstrated that the schizophrenic children with loose associations had different discourse deficits and discourse/IQ correlates than schizophrenic children without loose associations. The schizophrenic children receiving neuroleptic medication had lower loose associations scores than the unmedicated subjects. The authors discuss the possible confounding effect of medication and loose associations, as well as the developmental, cognitive, and clinical implications of the study's findings.

Child↗
PubMed1992

Communication deficits in childhood schizotypal personality disorder.

This study examined the similarities and differences in the communication deficits of 13 schizotypal and 12 schizophrenic children matched by age and IQ. Like schizophrenic children, schizotypal children underutilize some discourse devices necessary for coherent speech and overutilize others. Schizotypal children, however, appear to display a more restricted range of discourse deficits than schizophrenic children. In addition, their discourse deficits do not appear to be associated with clinical measures of loose associations. The clinical implications and the potential use of discourse measures to differentiate schizophrenic and schizotypal children are discussed.

Child↗
PubMed1992

Formal thought disorder in pediatric complex partial seizure disorder.

We compared the formal thought disorder ratings of 27 children with complex partial seizure disorder, 31 schizophrenic children and 58 normal children. The epileptic children with fullscale IQ scores below 100 had significantly more formal thought disorder than normal children with a similar IQ. The severity of their formal thought disorder was related to the age of seizure onset, seizure control and a diagnosis of schizophrenia spectrum disorder. The schizophrenic children had thought disorder irrespective of IQ scores. The cognitive correlates of their formal thought disorder scores differed from those of the epileptic children. Possible anatomical substrates of thought disorder in childhood complex partial seizure disorder and schizophrenia are discussed.

Attention↗
PubMed1992

Non-verbal communication skills of surgically treated children with infantile spasms.

The authors present preliminary findings on the effects of surgery on the development of early non-verbal social communication skills in eight children with intractable infantile spasms. After a mean follow-up of 15.2 months, there was no statistically significant change in the post-surgical non-verbal communication behavior of these children beyond the expected developmental change. Implications of these findings for the developmental impairment associated with infantile spasms are discussed.

Cerebral Cortex↗
PubMed1992

Early onset intractable seizures: nonverbal communication after hemispherectomy.

The nonverbal communication skills of 10 children (mean age = 44.2 months) who underwent hemispherectomy for early onset intractable seizures were tested before and after surgery. A within-group analysis suggests that the 10 seizure-free children used more nonverbal communication after a mean follow-up period of 11.2 months than before surgery. Young normal language age matches were available for the 4 older and higher functioning subjects in the sample. Before surgery, the surgical subjects used less requesting gestures than did the normal children. After surgery, these differences were no longer apparent. The patients also employed more gestures to focus an adult's attention on objects and events than language-age-matched normal children. The children who underwent left or right hemispherectomy used similar nonverbal communication behaviors. The study's findings suggest that children with early onset intractable seizures have impaired early social communication that improves to some extent after hemispherectomy.

Child, Preschool↗
PubMed1992

Meta-analysis of the role of platinum compounds in advanced ovarian carcinoma. The Advanced Ovarian Cancer Trialists Group.

This paper presents a systematic overview or meta-analysis of 54 randomized clinical trials testing a variety of chemotherapeutic approaches in advanced ovarian carcinoma. Prolonged follow-up data are available for most patients and individual patient data were made available for all patients; analysis was made on the basis of "intention to treat." Our report concentrates on two comparisons: (1) platinum alone versus platinum in combination, which appears to show a long-term survival advantage for the combination (however, the platinum dose in the single-agent arm was relatively low); and (2) carboplatin versus cisplatin, which shows no obvious survival differences. It is striking that no single study to date has been large enough to detect the modest survival differences expected from current therapy. Consequently, a series of international studies have been initiated. The International Collaborative Ovarian Neoplasm (ICON) group will examine the role of adjuvant chemotherapy in early ovarian cancer (ICON 1) and will compare carboplatin with cisplatin, doxorubicin, and cyclophosphamide in more advanced disease (ICON 2).

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1991

Reduced attention-related negative potentials in schizophrenic children.

ERPs were recorded from normal and schizophrenic children during performance of a reaction time task (RT) followed by a complex visual discrimination, the span of apprehension task (Span), sensitive to vulnerability factors in schizophrenia. Subjects responded rapidly to the onset of the visual arrays in the RT condition and differentially to the presence of 1 of 2 target letters in the Span condition. The EEG was recorded at 19 scalp sites and ERPs included activity 1 sec before through 1 sec after Span array onset. Difference potentials (Span-RT) were computed to remove unvarying exogenous activity, thus isolating endogenous activity associated with the processing demands of the Span task. When RT and Span task ERPs are compared, schizophrenic children produced a significantly smaller than normal increment in endogenous negative activity. This endogenous negativity differed in its topography and time course from the exogenous components (P1, N1 and P2), and most likely reflects attentional effort associated with serial search, pattern recognition and stimulus identification. We believe that the current results support the position that schizophrenics are impaired in their ability to allocate adequate attentional resources for the processing of the Span stimuli. It is important to note that this deficit is apparent quite early in discriminative processing.

Analysis of Variance↗
PubMed1991

Sigma receptor ligands alter concentrations of corticosterone in plasma in the rat.

Both BMY-14802 (alpha-(4-fluorophenyl)-4-(5-fluoro-2-pyrimidinyl)-1-piperazine-butanol hydrochloride) and gevotroline (WY-47384; 8-fluoro-2,3,4,5-tetrahydro-2-[3-(3-pyridinyl)-propyl]-1H-pyrido[4,3-b] indole hydrochloride) are known to antagonize the psychotomimetic action of N-allyl-normetazocine (NAN; SKF-10047) and exhibit a high affinity for the sigma receptor. Unexpectedly, the putative antagonists BMY-14802 and gevotroline acted like the agonist NAN and increased activity in the hypothalamic-pituitary-adrenal axis to elevate levels of corticosterone in plasma. During the acrophase (peak) of the effects of the circadian rhythm on the hypothalamic-pituitary-adrenal axis, the ED50 was 6.5 mmol/kg for BMY-14802 and 9.6 mmol/kg for gevotroline. The ED50s for BMY-14802 and gevotroline during the low activity phase were 15.8 and 21.2 mmol/kg, respectively. The efficacies during both phases of the circadian rhythm were similar for each drug. Additive effects on the levels of corticosterone in plasma were observed when the animals were pretreated with doses above the respective ED50 values and then subjected to a rotational stress, but a small dose of BMY-14802 (0.5 mg/kg) had the opposite effect and completely inhibited the stress-related increases in corticosterone in plasma. Neither drug, at large doses, altered the increase in levels of corticosterone in plasma generated by the circadian rhythm, but at smaller doses BMY-14802 did lower circadian-related levels of corticosterone. Pretreatment with dexamethasone blocked the gevotroline-related increase in corticosterone in plasma, but not the BMY-14802-related increase. These data suggest that central sigma receptor mechanisms are involved in the regulation of the hypothalamic-pituitary-adrenal axis and that therapeutic agents that affect these receptors may alter the activity in this axis.

Animals↗
PubMed1991

Significance testing of difference potentials.

This note provides a statistical-graphical method for the evaluation of the statistical significance of difference potentials from a group of subjects, and for the comparison of difference potentials between two groups. A table of the lengths of statistically significant intervals for various sampling interval lengths, numbers of subjects, and autocorrelation parameters is presented.

Arousal↗
PubMed1991

Modulatory influence of continuous tone, tone offset, and tone onset on the human acoustic startle response.

Startle modulation in young adult men, by continuous background tone and its offset, a 2-s sustained tone and its offset, and the onset of a 25-ms tone pip were compared. Tone (75dB 1000 Hz) offset and onset occurred either 2000 ms or 100-120 ms before the startle stimuli (104dB (SPL), 50-ms white noise bursts). Blink amplitude and latency were unaffected by continuous background tone. Blink amplitude was reliably inhibited by 100-ms offset of both the continuous background tone and the 2-s sustained tone or 120-ms onset of the tone pip, whereas effects on latency were more variable. Facilitation of blink amplitude and latency was significant but weak and only following the 2-s sustained tone, and only with respect to one of two experimental contexts. These findings support those of others and suggest that startle inhibition results from activation of neurons responding to transient environmental changes. The degree of inhibition appears to be related to stimulus value. Startle amplitude facilitation following long sustained prestimulation intervals is dependent on experimental context. Overall latency and amplitude modulation tend to be concordant, leading to the conclusion that the mechanism(s) underlying both are context dependent and linked in the adult human.

Acoustic Stimulation↗
PubMed1991

Maturation of prestimulation-induced startle modulation in girls.

This study of the maturation of prestimulation-induced modulation of startle in 4- to 8-year-old girls and young women demonstrated significant effects of age on both startle amplitude and onset latency modulation. Prestimulation with nonstartling tones resulted in strong inhibition of both amplitude and latency of the startle blink reflex in adults when 25-ms tones preceded the startling stimuli by 120 ms or 250 ms. Following sustained prestimulation for 2000 ms, the adults showed weak nonsignificant response facilitation. Eight-year-old girls showed mature inhibitory startle amplitude modulation, but significantly less inhibition of onset latency compared to adults. Preschool girls showed significantly less amplitude and latency inhibition and more facilitation than 8-year-olds and adult women. These findings in female subjects were very similar to those obtained by Ornitz, Guthrie, Kaplan, Lane, and Norman (1986) in male subjects. Gender differences were limited to the 8-year-old age group. The 8-year-old girls showed significantly less startle amplitude inhibition than 8-year-old boys following the 120-ms and 250-ms prestimulation intervals and less latency facilitation following 2000 ms of sustained prestimulation. In general, these findings suggest that brainstem mechanisms that mediate startle response modulation undergo development during early childhood and do not mature until about 8 years of age in both male and female subjects. The results are discussed in relation to studies of gender effects on development of other neurophysiological variables and to maturation of the nervous system.

Acoustic Stimulation↗
PubMed1990

Event-related potential correlates of impaired attention in schizophrenic children.

Electrophysiological correlates of focused attention were studied in 13 schizophrenic and 19 age- and gender-matched children. Subjects performed a version of the Continuous Performance Task (CPT) in which a target was designated as any digit from 0 through 9 occurring on two successive stimulus presentations. Signal digits were surrounded by distractor digits which varied in position, value, and number. Event-related potentials (ERPs) elicited by each stimulus of a target pair were recorded from midline and homologous parietal, temporal, and occipital electrode placements. Schizophrenic children made significantly more errors of omission and commission than normal children. The amplitude and time course of the intertrial CNV was the same for both groups. There was a circumscribed amplitude asymmetry, left smaller than right, for the P1/N1 and P2 measures which was greater in normal than in schizophrenic children. The P3 component was significantly larger to the second stimulus of the target pair than to the first for both groups, and larger for the normal than the schizophrenic children to both stimuli.

Arousal↗
PubMed1990

Symptom beliefs and actual blood glucose in type II diabetes.

The relationships of blood glucose levels to symptoms and symptom beliefs were examined in this study of persons (N = 51) with Type II diabetes. Analyses revealed that 88% of the subjects had at least one symptom that was substantially correlated with blood glucose levels. However, subjects' symptom beliefs (symptoms subjects believe are the best indicators of high or low blood glucose levels) were largely unrelated to actual blood glucose levels. Thus, subjects were often mistaken about which of their symptoms were accurate indicators of blood glucose levels. Analyses also showed that the accuracy of symptom beliefs for low blood glucose was positively related to metabolic control.

Adult↗
PubMed1990

Effects of hap mutations on heme and cytochrome formation in yeast.

Simultaneous effects of mutations in the transcriptional regulatory genes, HAP1, HAP2 and HAP3, on all respiratory cytochromes of Saccharomyces cerevisiae were determined. Cytochrome behavior in hap mutants and in cyc4 and rhm1 mutants, altered in regulation of 5-aminolevulinate synthase, was compared. Although hap mutants were isolated as trans-acting, transcriptional regulators of the CYC1 (iso-1-cytochrome c) gene, each mutant exhibits partial deficiencies in all cytochrome types. In hap2 and hap3 strains all cytochromes were decreased proportionally to about 40-50% of wild type values. In contrast, hap1 caused a decrease in all cytochromes and an accumulation of a pigment, probably Zn porphyrin. Apparently apocytochrome and heme biosynthesis retain coordination in hap2 and hap3, but not in hap1, mutants. Unlike cyc4 and rhm1 mutants, hap mutants do not exhibit 5-aminolevulinate-dependent restoration of cytochromes. The hap1 mutant grew at near-normal rates on glycerol, whereas hap2 and hap3 mutants grew very slowly. The frequency of [rho-] was high (16-18%) in hap2 and hap3 strains. Results are consistent with generalized control of mitochondrial replication directed by the HAP1-HAP2 system and heme-directed control of formation of all apocytochromes mediated by HAP1. Neither system exerts all-or-nothing control.

5-Aminolevulinate Synthetase↗