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Biomedical subjects

D Schnur

Publications and source records attributed to D Schnur.

6 recordsLinked to original sources
PubMed1998

Hillside study of risk and early detection in schizophrenia.

BACKGROUND: The Hillside Study of Risk and Early Detection in Schizophrenia is a prospective study of young probands (ages 14-28) and their at-risk siblings (ages 14-24). A major goal is the identification of early predictors of illness that will facilitate intervention. The project design and pilot study are discussed. METHOD: Fifteen adolescents were compared to 14 typical age-of-onset adults, all undergoing their first hospitalisation for schizophrenia. RESULTS: There were no differences between adolescents and adults on any of the measures administered (i.e. attention, eye tracking, neurocognitive or clinical). In addition, for the sample overall, no association was found between neurocognitive functions and clinical state, either at admission or after treatment. CONCLUSIONS: Individuals with adolescent onset of schizophrenia are considered to be representative of schizophrenia in general. Furthermore, neurocognitive deficits and clinical symptoms are concluded to be two independent classes of risk indicators.

Adolescent↗
PubMed1993

Computer-assisted molecular modeling: indispensable tools for molecular pharmacology.

Ball-and-stick mechanical models, typically associated with chemists, have been helpful in understanding structural problems and the relationship between structure and biologic activity. With progress in computer speed, graphics performance, and software innovation, molecules of biological interest can be subjected to rigorous calculations. Computational chemistry and biology are rooted in the belief that theoretical physics can be used to calculate accurate molecular structures. Although in its infancy, computer-assisted molecular modeling is gaining attention and acceptability as an increasing number of researchers turn their attention toward rational molecular design. The trend to use theoretical methods can be traced to the greater availability of computer graphics work-stations, decreasing computer costs, faster central processing units, more robust algorithms, and "user-friendly" software codes. Every major pharmaceutical company has invested in these resources to reduce the time it takes to design and develop pharmaceutical agents. Because of the vast financial and manpower investments needed to introduce a single drug, medicinal chemists and pharmacologists are interested in understanding and predicting drug action at the molecular level. Although drug action is still poorly understood, molecular modeling should reduce some of the labor in the development of pharmaceutical agents.

Computer Graphics↗
PubMed1991

Specificity of smooth pursuit eye movement and visual fixation abnormalities in schizophrenia. Comparison to mania and normal controls.

Smooth pursuit eye movements (SPEM) were assessed in 30 schizophrenic patients, 12 lithium-free manic patients, and 20 normal controls. Compared to schizophrenic patients, manic patients evidenced less SPEM impairment in an attention enhancing, sinusoidal target motion condition and had superior performance during a visual fixation condition. SPEM and visual fixation dysfunctions may be more common in schizophrenic than in acutely manic patients, even when the latter are characterized by marked attentional dysfunction, poor interepisode psychosocial functioning, and psychosis.

Adult↗
PubMed1990

Antitumor agents. 113. New 4 beta-arylamino derivatives of 4'-O-demethylepipodophyllotoxin and related compounds as potent inhibitors of human DNA topoisomerase II.

A number of 4'-O-demethylepipodophyllotoxin derivatives possessing various 4 beta-N-, 4 beta-O- or 4 beta-S-aromatic rings have been synthesized and evaluated for their inhibitory activity against the human DNA topoisomerase II as well as for their activity in causing cellular protein-linked DNA breakage. The results indicated, that for DNA topoisomerase II, a basic unsubstituted 4 beta-anilino moiety is structurally required for the enhanced activity. Substitution on this moiety with CN, COOCH3, COOC2H5, OH and COOCH3, OCH3, COCH3, CH2OH, OCH2O, OCH2CH2O, phenoxy, morpholino, NO2, and NH2 either at the para and/or the meta position yielded compounds which are as potent or more potent than etoposide. Substitution with COOC2H5 and OH at the ortho position afforded inactive compounds. Replacement of the aryl nitrogen with oxygen or sulfur gave compounds which are much less active or inactive. However, replacement of the phenyl ring with a pyridine nucleus furnished compounds which are as active or slightly more active than etoposide. There is a lack of correlation between the ability of these compounds in inhibiting DNA topoisomerase II and in causing protein-linked DNA breaks.

Antineoplastic Agents↗
PubMed1985

A limiting factor in the "normalization" of schizophrenic orienting response dysfunction.

Forty schizophrenic patients, 40 non-schizophrenic patients, and 40 normal subjects were given 60 each alternating 1000- and 2000-Hz, 1-second tones at 60 dB. Half of each sample, the Press Group (PG), had to press a pedal to the high (low) target tone, ignoring the nontarget tone. The other half, the Nonpress Groups (NPGs), were given no reason to attend. Skin conductance response (SCR), finger pulse volume (FPV), and electroencephalographic (EEG) activity were recorded. NPG schizophrenic subjects were more often nonresponsive in both SCR and FPV than other samples, but less often responsive in EEG only when a 20 percent criterion of alpha blockade was used. Schizophrenic subjects showed greater consistency of OR nonresponsiveness in SCR and FPV, and nonsignificantly greater consistency in criterion alpha block, pointing to a deficit in orienting response (OR) rather than in peripheral response. When the targeted signal was given, schizophrenic subjects showed the same response as other groups in all systems. This was not due to an indiscriminate increase in reactivity, since response increase centered on the targeted signal itself in all groups. As the target signal was repeated, autonomic OR in schizophrenics declined sharply so that they again became underresponsive. Thus, OR "normalization" achieved by targeting significant signals is restricted to relatively early responsiveness. The rapid decline in autonomic OR may help explain differences in schizophrenic subjects between P300 and autonomic ORs to significant stimuli. Schizophrenic subjects were no different from controls in bilateral SCR or FPV asymmetry, but displayed less frequent criterion alpha blockade and reduced background alpha power in the left hemisphere. Each system showed a different pattern of bilateral asymmetry, reflecting complex, not well understood relations among these responses. This was further emphasized by the fact that skin conductance level (SCL) incremented over trials in PG subjects, reflecting sustained activation, while EEG background showed an increase in slower wave power, consistent with reports of increased drowsiness. The only drug effect seen was a lowering of SCL. Neuroleptics were associated with a flexible inhibitory control of SCL, permitting normal-like increment when circumstances required. Depressed patients' data suggested they might show heightened OR nonresponsiveness to innocuous stimuli which might not be subject to "normalization" by manipulation of stimulus significance; hence OR deficit might still differentiate schizophrenic from depressive patients.

Adult↗