Showing papers by "University of Texas Medical Branch published in 1990"

Violence and Psychiatric Disorder in the Community: Evidence From the Epidemiologic Catchment Area Surveys

Abstract: Data from the Epidemiologic Catchment Area survey were used to examine the relationship between violence and psychiatric disorders among adults living in the community. Psychiatric assessment of survey respondents was based on the Diagnostic Interview Schedule, which also provided self-report information about violent behavior. Those who reported violent behavior within the preceding year tended to be young, male, and of low socioeconomic status, and more than half met DSM-III criteria for one or more psychiatric disorders. Subjects with alcohol or drug use disorders were more than twice as likely as those with schizophrenia to report violent behavior. In a multivariate model of the predictors of violence, a significant interaction effect was found between major mental illness and substance abuse. The risk of violent behavior increased with the number of psychiatric diagnoses for which respondents met DSM-III criteria.

Mild head injury classification.

Abstract: Inconsistencies across studies concerning outcome after mild head injury may reflect differences in the diagnostic criteria used for selection of patients Consequently, we compared the neurobehavioral outcome in three groups of consecutively hospitalized patients (aged 16 to 50 years) who sustained a closed head injury (CHI) and had a Glasgow Coma Scale (GCS) score in the 9 to 15 range These groups included patients with uncomplicated CHI with mild impairment of consciousness as reflected by a GCS score in the 13 to 15 range (n = 78), patients with initially mild impairment of consciousness complicated by brain lesion or depressed skull fracture (n = 77), and patients with moderate CHI (n = 60) Tests of memory, information processing, and verbal fluency were administered within 1 to 3 months after injury, and the Glasgow Outcome Scale was completed at 6 months Neurobehavioral functioning was impaired in the groups with complicated mild CHI and moderate CHI as compared to the group with uncomplicated mild CHI Although moderate CHI produced longer durations of impaired consciousness and posttraumatic amnesia than complicated mild head injury, patients in these groups did not differ in neurobehavioral performance Global outcome at 6 months was better in the patients with mild CHI than in patients with complicated mild and moderate injuries Analysis of the various complications of mild CHI revealed that the presence of an intracranial lesion was related to more severe neurobehavioral sequelae than injuries complicated by a depressed fracture

Initial CT findings in 753 patients with severe head injury. A report from the NIH Traumatic Coma Data Bank

Abstract: In this prospective multicenter study, the authors have examined data derived from the initial computerized tomography (CT) scans of 753 patients with severe head injury. When the CT findings were related to abnormal intracranial pressure and to death, the most important characteristics of the scans were: midline shift: compression or obliteration of the mesencephalic cisterns: and the presence of subarachnoid blood. Diffuse hemispheric swelling was also found to be associated with an early episode of either hypoxia or hypotension.

Effects of recombinant human growth hormone on donor-site healing in severely burned children.

Abstract: The beneficial effects of growth hormone on wound healing in severely burned children were studied. Forty patients who were 2 to 18 years old, with 40% or more total body surface area (TBSA) and 20% or more TBSA full-thickness flame or scald burns, were randomized in a double-blind study to receive placebo or 0.1 mg/kg/day recombinant human growth hormone (rHGH) until the first donor site healed or to receive 0.2 mg/kg/day rHGH or placebo from admission throughout hospitalization. Patients receiving 0.2 mg/kg/day rHGH demonstrated significantly higher serum IGF-1 levels at 4.8 +/- 1.7 U/mL compared to placebos at 1.6 +/- 0.4 U/mL (p less than 0.05) and a significant decrease in donor-site healing times compared to placebo (p less than 0.05). Length of hospital stay (LOS/%TBSA) was decreased from 0.80 +/- 0.10 days/%TBSA burned in the placebo group to 0.54 +/- 0.04 days/%TBSA burned in the 0.2 mg/kg/day treatment group (p less than 0.05). This translates, for the average 60% TBSA burned patient, to a decrease in LOS from 46 to 32 days.

After Reaching Retirement Age Physical Activity Sustains Cerebral Perfusion and Cognition

Abstract: Among neurologically normal volunteers approaching age 65 with an option for retirement, a four-year prospective longitudinal study was designed to examine effects of different levels of physical activity on cerebral perfusion by between-group comparisons. After the fourth year, cognitive performance was also tested. Three groups were compared, each composed of 30 elderly volunteers, assigned as follows: Group 1, who continued to work; Group 2, who retired but participated in regular physical activities; and Group 3, who retired but did not participate in regular, planned physical activities. Retirees who elected to become physically inactive exhibited significant declines in cerebral blood flow (CBF) throughout four years of follow-up. Those who continued to work or retirees who elected to participate in regular activities sustained more constant CBF levels. Active retirees and those who continued to work also scored better on cognitive testing after the fourth year of follow-up compared to inactive retirees.

Human cytomegalovirus - Stimulation of [3H] release from [3H]-arachidonic acid prelabelled cells

Abstract: Exposure of human lung fibroblasts to human cytomegalovirus (HCMV) stimulated a rapid increase in the release of [3H] from cells prelabelled with radiolabelled arachidonic acid ([3H]AA). Maximum stimulation of [3H] release was observed at 20 min postinfection and was quantitatively similar to that induced by the tumor promoter 12-O-tetradecanoylphorbol 13-acetate (TPA: 10 nM) or fetal calf serum (5%). The level of [3H] release was dependent on the multiplicity of infection, and appeared to be mediated by a component(s) of the virion, since the findings from three series of experiments suggested that neither infectious virus, nor HCMV-specific macromolecular synthesis was required for stimulation of [3H] release. (1) Inactivation of HCMV infectivity with ultra-violet (UV) light (approximately 254 nm, 4.80 x 10(4) ergs/mm2) did not diminish the stimulation of [3H] release. (2) Significant reduction in the level of [3H] release was not observed when infected cells were maintained in the presence of a protein synthesis inhibitor, cycloheximide (50 micrograms/ml), or an inhibitor of mRNA synthesis, 3'-deoxyadenosine (cordycepin, 50 micrograms/ml). (3) No correlation was established between the expression of HCMV immediate early (IE) antigens and the induction of [3H] release, since there was little, if any, synthesis of HCMV IE antigen detectable by anticomplement immunofluorescence through the first 30 min postinfection. These findings suggesting that the HCMV particle rapidly stimulates AA metabolism are consistent with the view that the interaction of a HCMV virion component(s) with the cell surface may initiate membrane-associated events similar to those induced by growth factors.

Neurobehavioral outcome 1 year after severe head injury. Experience of the Traumatic Coma Data Bank.

Abstract: ✓ The outcome 1 year after they had sustained a severe head injury was investigated in patients who were admitted to the neurosurgery service at one of four centers participating in the Traumatic Coma Data Bank (TCDB). Of 300 eligible survivors, the quality of recovery 1 year after injury was assessed by at least the Glasgow Outcome Scale (GOS) in 263 patients (87%), whereas complete neuropsychological assessment was performed in 127 (42%) of the eligible survivors. The capacity of the patients to undergo neuropsychological testing 1 year after injury was a criterion of recovery as reflected by a significant relationship to neurological indices of acute injury and the GOS score at the time of hospital discharge. The neurobehavioral data at 1 year after injury were generally comparable across the four samples of patients and characterized by impairment of memory and slowed information processing. In contrast, language and visuospatial ability recovered to within the normal range. The lowest postresuscitati...

Neuropsychology of early-treated phenylketonuria: specific executive function deficits.

Abstract: This study explored the hypothesis that children with early-treated phenylketonuria (PKU) are selectively impaired on executive function measures, even when still on diet. The rationale for this hypothesis is that even mild elevations in phenylalanine (Phe) can lead to lower central levels of biogenic amines, including dopamine (DA). We hypothesize that this mild DA depletion causes subtle prefrontal dysfunction, which in turn affects executive functions such as set maintenance, planning, and organized search. 11 preschool early-treated PKU children (M age = 4.64) and a sample of age- and IQ-matched unaffected peers (n = 11) were evaluated on a battery of executive function (EF) measures. In addition, a "non-executive function" task, recognition memory, was administered to all subjects. Group comparisons demonstrated that PKU children were significantly impaired on an executive function composite score; there were no group differences, however, in recognition memory. These results supported the hypothesized specific deficit in executive function. Furthermore, within the PKU group the executive function composite score was significantly negatively correlated with concurrent phenylalanine levels, even after controlling for the correlation between IQ and executive function skills. This second finding provides support for the proposed biochemical mechanism underlying the specific cognitive deficits.

Effects of distal radius fracture malunion on wrist joint mechanics

Abstract: An experimental model using a static positioning frame, pressure-sensitive film (Fuji), and a microcomputer-based videodigitizing system was used to measure contact areas and pressures in the wrist. Contact areas and pressures were compared in a group of wrists between the normal state and with simulated distal radius fracture malunions of varying degrees. In simulated malunions, radial shortening to any degree slightly increased the total contact area in the lunate fossa, and was significant at 2 mm of shortening. By angulating the distal radius more than 20 degrees either palmar or dorsal, there was a dorsal shift in the scaphoid and lunate high pressure areas, and the loads were more concentrated, but there was no change in the load distribution between the scaphoid and lunate. Decreasing the radial inclination shifted the load distribution so that there was more load in the lunate fossa and less load in the scaphoid fossa.

Erythropoietin for the treatment of porphyria cutanea tarda in a patient on long-term hemodialysis.

Abstract: PORPHYRIA cutanea tarda, which is the most common and readily treated form of porphyria in humans, results from a deficiency of uroporphyrinogen decarboxylase in the liver.1 2 3 It is characterized by cutaneous photosensitivity. The disease is usually classified as sporadic if uroporphyrinogen decarboxylase is deficient only in the liver, and as familial (autosomal dominant) if the enzyme is also deficient in nonhepatic tissues such as erythrocytes.3 4 5 There is also a familial form in which only the hepatic enzyme is deficient.6 Increased iron content in the liver is a major contributing factor in both sporadic and familial porphyria cutanea tarda,7 as are . . .

Topographic organization of the ventral striatal efferent projections in the rhesus monkey: an anterograde tracing study.

Abstract: The ventral striatum is considered to be that portion of the striatum associated with the limbic system by virtue of its afferent connections from allocortical and mesolimbic areas as well as from the amygdala. The efferent projections from this striatal region in the primate were traced by using 3H amino acids and Phaseolus vulgaris-leucoagglutinin (PHA-L). Particular attention was paid to the topographic organization of terminal fields in the globus pallidus and substantia nigra, the projections to non-extrapyramidal areas, the relationship between projections from the nucleus accumbens and the other parts of the ventral striatum, and the comparison between ventral and dorsal striatal projections. This study demonstrates that in monkeys a circumscribed region of the globus pallidus receives topographically organized efferent fibers from the ventral striatum. The ventral striatal fibers terminate in the ventral pallidum, the subcommissural part of the globus pallidus, the rostral pole of the external segment, and the rostromedial portion of the internal segment. The more central and caudal portions of the globus pallidus do not receive this input. This striatal output appears to remain segregated from the dorsal striatal efferent projections to pallidal structures. Fibers from the ventral striatum projecting to the substantia nigra are not as confined to a specific region as those projecting to the globus pallidus. Although the densest terminal fields occur in the medial portion, numerous fibers also extend laterally to innervate the dorsal stratum of dopaminergic neurons of the substantia nigra and the retrorubral area. Furthermore, they project throughout the rostral-caudal extent of the substantia nigra. Projections from the medial part of the ventral striatum reach the more caudally located pedunculopontine tegmental nucleus. Thus unlike the above described terminals in the globus pallidus, the ventral striatum project widely throughout the substantia nigra, a fact that indicates that they may contribute to the integration between limbic and other output systems of the striatum. Finally, the ventral striatum projects to non-extrapyramidal regions including the bed nucleus of the stria terminals, the nucleus basalis magnocellularis, the lateral hypothalamus, and the medial thalamus.

Behavioral changes after closed head injury in children.

Abstract: This study provides a longitudinal follow-up of the behavioral adjustment of 45 children with mild, moderate, and severe closed head injuries. Two measures of behavioral adjustment, the Child Behavior Checklist (CBCL) and the Vineland Adaptive Behavior Scales (VABS), were obtained from a parent at the time of injury and at 6 and 12 months postinjury. The severely injured children obtained significantly poorer VABS scores than children with mild and moderate injuries over the year-long follow-up. In addition, on the CBCL, severely injured children had more school problems and engaged in fewer social activities than mild and moderately injured children. These results show that severe head injury in children was associated with declines in adaptive functioning, whereas scores for children with mild and moderate injuries did not differ, nor did they deviate from average levels at any follow-up interval. Language: en

Measuring social support among older adults.

Abstract: The purpose of this study is to introduce a measure of natural supportive behaviors for use in studies that examine the relationship between stress, social support, and health among older adults. The index improves on existing measures in three ways: it avoids problems arising from confounding potentially supportive relationships with support that is actually received; the scale also assesses variations in individual support needs; and it measures four distinct dimensions of social support (informational support, tangible help, emotional support, and integration). Based on data from a random community survey of 351 older adults, the basic psychometric properties and the factor structure of the scale are explored. The predictive validity of the scale is demonstrated by showing that the dimensions of support buffer the stressful effects of bereavement on depressive symptoms.

Children's Activity Rating Scale (CARS): Description and Calibration

Abstract: A five-level Children's Activity Rating Scale (CARS) was designed to categorize the intensity of physical activities and discriminate between levels of energy expenditure in young children. The CARS was used by trained observers over a 12-month period to assess physical activities of 3-4 year-old children during field observations. Agreement among observers using the CARS was 84.1% for 389 paired observation periods. The energy expenditure for each level was assessed by measuring VO2s and heart rates of 5-6 year-old children (12 boys, 13 girls) while they performed eight activities representing the CARS levels. Mean VO2s for the eight activities in Levels 1-5 ranged from 7.1 to 37.5 ml kg BW−1 min−1 (1 to 5.42 METS; 145% to 80.6% of VO2max). Mean heart rates ranged from 89 to 183 b min−1 for activities in Levels 1-5. VO2s and heart rates at each level were significantly different from all other levels. These data demonstrate that the CARS encompasses a wide range of energy expenditures, discrimin...

Genotoxic effects of estrogens.

Abstract: Estrogens are associated with several cancers in humans and are known to induce tumors in rodents. In this review a mechanism of carcinogenesis by estrogens is discussed which features the following key events: (1) Steroid estrogens are metabolized by estrogen 2- and 4-hydroxylases to catecholestrogens. Target organs of estrogen-induced carcinogenesis, hamster kidney or mouse uterus, contain high levels of estrogen 4-hydroxylase activity. Since the methylation of 4-hydroxyestradiol by catechol-O-methyltransferase is inhibited by 2-hydroxyestradiol, it is proposed that a build up of 4-hydroxyestrogens precedes estrogen-induced cancer. (2) The catecholestrogen or diethylstilbestrol (DES) are oxidized to semiquinones and quinones by the peroxidatic activity of cytochrome P-450. The quinones are proposed to be (the) reactive intermediates of estrogen metabolism. (3) The quinones may be reduced to catecholestrogens and DES and redox cycling may ensue. Redox cycling of estrogens has been shown to generate free radicals which may react to form the organic hydroperoxides needed as cofactors for oxidation to quinones. (4) The quinone metabolites of catechol estrogens and of DES bind covalently to DNA in vitro whereas DNA binding in vivo has only been examined for DES. When DES is administered to hamsters, the resulting DES-DNA adduct profile in liver, kidney, or other organs closely matches that of DES quinone-DNA adducts in vitro. In vitro, DES-DNA adducts are chemically unstable and are generated in incubations with organic hydroperoxide as cofactor. It is proposed that the instability of adducts and the lower sensitivity of previous assay methods contributed to the reported failures to detect adducts. Steroid estrogen-DNA adducts in vivo are currently under investigation. (5) Tumors are postulated to arise in cells rapidly proliferating due to the growth stimulus provided by the estrogenic activity of the primary estrogen or of hormonally potent metabolites such as 4-hydroxyestradiol. The covalent modification of DNA in these cells is temporary because of the chemical instability of adducts and will result in altered genetic messages in daughter cells, whereas in non-proliferating cells there may be no lasting genetic damage. The sequence of events described above is a plausible mechanism for tumor initiation by estrogens and is partially substantiated by experimental evidence obtained in vitro and/or in vivo.

Medial (hamate) facet of the lunate

Abstract: One hundred sixty-five cadaveric wrists were dissected to assess the incidence of a medial (hamate) facet on the lunate and any associated pathologic conditions. Forty-seven of these specimens and 137 clinical patients' radiographs were reviewed to attempt to recognize and further assess the incidence of a medial (hamate) facet on the lunate. Two types of lunate were identified. Type I, in which there was no medial facet, was evident in 34.5% of the dissected specimens and type H, in which there was a medial facet, was evident in 65.5% of the dissected specimens. The medial facets in the type II lunates ranged from a shallow 1 mm facet to a deep 6 mm facet. Significant cartilage erosion with exposed subchondral bone at the proximal pole of the hamate, which was not identifiable by radiograph, was evident at dissection in 44.4%) of the type II lunates, while none (0%) of the type I lunates had such associated hamate pathologic conditions. This type II lunate, with the high incidence of associated hamate pathology, may be an unidentified cause of wrist pain on the ulnar side.

Frontal lobe dysfunction following closed head injury : a review of the literature

Abstract: This review of the relationship between frontal lobe pathology and sequelae of closed head injury (CHI) emphasizes the variety of neuropsychological disturbances that may be present and factors that influence symptom presentation. First, the mechanisms of injury in CHI are briefly summarized with an

Non-NMDA receptors mediate sensory afferent synaptic transmission in medial nucleus tractus solitarius.

Abstract: Indirect evidence suggests that excitatory amino acids (EAA) are involved in synaptic transmission of visceral afferents at their synapses within the nucleus tractus solitarius (NTS). Little is known about the identity of the postsynaptic receptors or response mechanisms. Here we report results from a longitudinal brain slice of the rat medulla. Intracellular recordings were made from neurons in delimited portions of the dorsal medial NTS (mNTS) known to receive baroreceptor inputs. Stimulation of the solitary tract 1-3 mm from the mNTS recording site evoked short (2 ms) latency excitatory postsynaptic potentials (EPSPs), which had durations of 40-50 ms. Addition of the non-N-methyl-D-aspartate (non-NMDA) selective antagonist 6-cyano-7-nitro-quinoxaline-2,3-dione (CNQX) to the slice surface near the recording electrode resulted in a rapid (within 30-45 s) suppression of the EPSP. Complete EPSP blockade was only slowly reversed by drug-free saline. Concentration-response relations (n = 14) showed 50% depression of EPSPs by surface concentrations of 1-10 microM CNQX. EPSP amplitude was resistant to the selective NMDA antagonist 2-amino-5-phosphonovalerate (AP 5) and, on average, was reduced less than 20% at 100 microM AP 5, an effect that was not statistically significant (n = 10; P greater than 0.05). In conclusion, this study offers the first direct evidence that EAAs mediate the primary events of afferent synaptic transmission in NTS. The experiments suggest that excitatory sensory afferent synaptic transmission to mNTS neurons is mediated by an EAA transmitter acting at non-NMDA receptors, but NMDA receptors may have a modulatory role.

Kinetics of activation and inactivation of swelling-stimulated K+/Cl- transport. The volume-sensitive parameter is the rate constant for inactivation.

Abstract: Red blood cells of several species are known to exhibit a ouabain-insensitive, anion-dependent K+ (Rb+) flux that is stimulated by cell swelling We have used rabbit red cells to study the kinetics of activation and inactivation of the flux upon step changes in tonicity Sudden hypotonic swelling (210 mosmol) activates the flux after a lag period of 10 min at 37 degrees C and 30-50 min at 25 degrees C In cells that were preswollen to activate the transporter, sudden shrinkage (by addition of hypertonic NaCl) causes a rapid inactivation of the flux; the time lag for inactivation is less than 2 min at 37 degrees C A minimal model of the volume-sensitive KCl transport system requires two states of the transporter The activated (A) state catalyzes transport at some finite rate (turnover number unknown because the number of transporters is unknown) The resting (R) state has a much lower or possibly zero transport rate The interconversion between the states is characterized by unimolecular rate constants R k12 in equilibrium with k21 A The rate of relaxation to any new steady state is equal to the sum of the rate constants k12 + k21 Because the rate of transport activation in a hypotonic medium is lower than the rate of inactivation in an isotonic medium, we conclude that the volume-sensitive rate process is inactivation (the A to R transition); that is, cell swelling activates transport by lowering k21 Three phosphatase inhibitors (fluoride, orthovanadate, and inorganic phosphate) all inhibit the swelling-activated flux and also slow down the rate of approach to the swollen steady state This finding suggests that a net dephosphorylation is necessary for activation of the flux and that the net dephosphorylation takes place as a result of swelling-induced inhibition of a kinase rather than stimulation of a phosphatase

Hepatocarcinogenesis due to chronic liver cell injury in hepatitis B virus transgenic mice.

Abstract: Fifty-nine transgenic mice from a lineage that overproduces the hepatitis B virus large envelope polypeptide and accumulates high intrahepatic concentrations of hepatitis B surface antigen were followed for evidence of liver disease throughout their 24-month life span. By 4 months of age all mice displayed biochemical and histological evidence of moderately severe chronic hepatitis which was followed sequentially by the development of regenerative nodules and oval cell hyperplasia (by 6 months), liver cell adenomas (by 8 months), and hepatocellular carcinomas (by 12 months of age). One hundred % of mice in this lineage developed hepatocellular carcinoma by 20 months of age, whereas no histopathological changes were observed in age- and sex-matched nontransgenic littermate controls over the same period of observation. These results indicate that overproduction of the hepatitis B virus large envelope polypeptide initiates a process characterized by liver cell injury, inflammation, and regenerative hyperplasia, which places large numbers of hepatocytes at risk for the development of transforming mutations, and inexorably progresses to hepatocellular carcinoma. We suggest that this is a general mechanism of hepatocarcinogenesis that may be operative in human hepatitis B virus infection and other necroinflammatory liver diseases as well.

Early burn wound excision significantly reduces blood loss.

Abstract: The hypothesis that near-total early excision of large burns in children can be performed safely with a reduction in blood loss was tested. Of 1662 acutely burned patients admitted to this institution between 1982 and 1989, 594 underwent near-total excision of cutaneous flame or scald burn injuries in a single procedure. Operations took less than 3 hours and there were no operative deaths. Blood losses in burns of more than 30% total body surface area (TBSA) were significantly less at 0.40 +/- 0.06 mL/cm2 and 0.49 +/- 0.49 mL/cm2 excised when surgery was performed within the first 24 hours or after the 16th day after burn, respectively, when compared to 0.75 +/- 0.02 mL/cm2 for those excised between 2 and 16 days after burn (p less than 0.05). Blood loss for burns of less than 30% TBSA was of 1.19 +/- 0.13 mL/cm2. Early excision did not increase mortality rate when compared to later excision times. We suggest that near-total excision of large burns within the first 24 hours reduces blood requirements and morbidity without adversely altering hemodynamic stability or increasing mortality risks.

Ulnar-sided perilunate instability: An anatomic and biomechanic study

Abstract: A staging system for ulnar-sided perilunate instability is presented based on a series of cadaver dissections and load studies. Stage I: partial or complete disruption of the lunotriquetral interosseous ligament, without clinical and/or radiographic evidence of dynamic or static volar intercalated segment instability deformity; stage II: complete disruption of the lunotriquetral interosseous ligament and disruption of the palmar lunotriquetral ligament, with clinical and/or radiographic evidence of dynamic volar intercalated segment instability deformity; and stage III: complete disruption of the lunotriquetral interosseous and the palmar lunotriquetral ligaments, attenuation or disruption of the dorsal radiocarpal ligament, with clinical and/or radiographic evidence of static volar intercalated segment instability deformity.

The children's orientation and amnesia test: Relationship to severity of acute head injury and to recovery of memory

Abstract: The Children's Orientation and Amnesia Test (COAT) was developed to assess cognition serially during the early stage of recovery from traumatic brain injury in children and adolescents. The norms for the COAT, which is composed of 16 items evaluating general orientation, temporal orientation, and memory, were defined from data obtained from 146 children aged 3 to 15 years. In 37 patients with head injuries, the duration of posttraumatic amnesia, as indicated by the number of days COAT scores were in the impaired range, was significantly related to both verbal and nonverbal memory at the baseline and 6 and 12 months after injury. COAT scores were a better predictor of verbal and nonverbal memory performance than the Glasgow Coma Scale score at 6 and 12 months after the injury. This study shows that the COAT has adequate reliability and validity as a measure of the duration of posttraumatic amnesia in children and adolescents.

Activation of proto-oncogenes: an immediate early event in human cytomegalovirus infection

Abstract: A rapid increase in the RNA levels of the proto-oncogenes c-fos, c-jun, and c-myc was detected after human cytomegalovirus infection. Neither inactivation of viral infectivity with ultraviolet irradiation (with or without psoralen), nor inhibition of translation with cycloheximide or anisomycin adversely affected the enhanced expression of proto-oncogenes, even though these treatments substantially reduced or eliminated the detection of immediate early viral antigens. The increase in the RNA levels of the proto-oncogenes was prevented in the presence of alpha-amanitin or actinomycin D. Thus, expression of these oncogenes appears to be induced by events occurring before the onset of viral protein synthesis, perhaps by the interaction of viral particles with the cell surface.

Memory deficit after closed-head injury

Abstract: This paper reviews research concerning impairment of memory during the early and late stages of recovery from closed-head injury (CHI). Posttraumatic and retrograde amnesia are discussed, including direct measurement, rate of forgetting and evoked potential correlates. Studies of residual memory deficit in survivors of CHI are reviewed, including the effects of severity and chronicity of injury and features such as utilization of semantic features to guide recall. The evidence for relatively preserved motor and pattern analyzing skills after severe CHI is presented and the implications for rehabilitation are discussed.

Role of nerve growth factor in oxidant-antioxidant balance and neuronal injury. I. Stimulation of hydrogen peroxide resistance.

Abstract: The nerve growth factor protein (NGF) regulates neuronal cell death during the development of embryonic sensory and sympathetic neurons in the peripheral nervous system (PNS). NGF protects the rat pheochromocytoma line PC12, a useful model of NGF responsive peripheral neurons, from hydrogen peroxide, which interacts with ferrous iron to generate hydroxyl radicals. Exogenous catalase provides protection, whereas superoxide dismutase (SOD) has no effect on neuronal survival when PC12 cells are challenged with hydrogen peroxide. NGF treatment of PC12 cells increases the activity of catalase. NGF protection from hydrogen peroxide is partially abolished by aminotriazole (Az), a low molecular weight catalase inhibitor. Taken together, these data are consistent with the hypothesis that NGF protects from peroxidative events and consequent cell death via an induction of free radical detoxifying mechanisms, such as catalase activity.