Expression of neuronal intermediate filament proteins ON1 and ON2 during goldfish optic nerve regeneration: effect of tectal ablation

Goldfish retinal explants were used to study optic tectum participation in the regulation of intermediate filament protein synthesis in retinal ganglion cells during optic nerve regeneration. Retinas were explanted at various times after removal of the contralateral optic tectum. The synthesis of the intermediate filament proteins ON1 and ON2 in the cultures was quantitated by labeling with [35S]methionine, followed by two-dimensional gel electrophoresis, autoradiography, and densitometry. Neuritic growth from the explants was quantitated based on fiber length and density. In retinal explants placed in culture after 23 days of optic nerve regeneration, the synthesis of ON1 and ON2 was reduced when the tectum had been ablated. In contrast, synthesis of these proteins in explants placed in culture at an earlier stage of regeneration was not affected by tectal ablation. At all time points tested, neuritic outgrowth from retinal explants was stimulated by tectal ablation. These findings indicate that the synthesis of the ON1 and ON2 intermediate filament proteins during regeneration is not directly regulated by axonal volume. Further, our findings suggest that interaction between growing axons and tectum is important for sustained expression of these proteins during the later stages of optic nerve regeneration.     

Monoclonal antibody for avian thymic hormone.

Avian thymic hormone (ATH), a parvalbumin with immunomodulating properties, was used as antigen for development of a hybridoma cell line. Hybridoma screening by enzyme-linked immunosorbent assay (ELISA) led to the culture, purification, and characterization of an hybridoma, designated 4A6, which secretes IgG1 that is specific for ATH. The monoclonal antibody (MAb) was characterized by techniques involving indirect competitive and non-competitive ELISA, Western Blot analysis, and immunohistological staining. The MAb was highly specific for ATH with no cross-reactivity to other chicken tissue extracts or commercially available parvalbumins.     

Symptomatic treatment in the fragile X-associated tremor/ataxia syndrome.

There is no established treatment for the neurological features of the recently discovered fragile X-associated tremor/ataxia syndrome (FXTAS). Fifty-six patients with FXTAS completed a questionnaire to determine whether any medications had been effective for neurological symptoms. Of 11 subjects with definite FXTAS, 8 (70%) were on medications for their neurological symptoms, whereas most subjects with possible or probable FXTAS, 31 (70%) of 45 subjects, were not on medications. Although no therapy was uniformly effective for intention tremor, ataxia, Parkinsonism, memory loss, or anxiety, some subjects with intention tremor or Parkinsonism reported improvement with medications frequently used in other movement disorders. Overall, all 22 subjects on medications reported improvement in one or more symptoms. Lack of insight, recall bias, and cognitive impairment may have resulted in an underestimation of the beneficial effect of medical therapy. This study suggests that patients with FXTAS can derive improvement from medication treatment for some of their symptoms.     

Diversity in Clinical Psychology

Clinical psychology is not as diverse as society, and the generalizability of clinical psychology to diverse groups has largely been untested. Some progress has been made in increasing the number of ethnic minorities receiving PhD degrees in clinical psychology and in increasing ethnic minority representation in clinical trials. Nevertheless, clinical psychologists and clinical psychology research are not diverse. A stages of change model may be useful in motivating clinical psychologists to diversify. A future scenario involving inertia and a second involving change are offered.     

Corrosion potential variation of aged dental amalgam restorations over time.

OBJECTIVE: The corrosion potential of a dental amalgam restoration is generally determined using a single measurement, even though environmental factors and abrasion can continuously alter the surface state and reactivity of this alloy. It was, therefore, the purpose of this study to determine the maximum variability of the corrosion potential of aged dental amalgam restorations, for 28 days. METHODS: The corrosion potentials of 148 aged dental amalgam restorations in 12 human subjects were measured at t = 0 and 4 h, and 4, 7, 14, 21 and 28 days. Measurements were made with a high impedance voltmeter and a Ag/AgCl micro-reference electrode. The subjects were instructed not to alter their usual eating and oral hygiene routines. RESULTS: Corrosion potential changes occurred throughout the 28 days. They were both positive and negative for the same restoration, and were sometimes very large. Only 4 h after the initial measurement, the absolute value of the corrosion potential changes ranged between 18 and 287 mV for 50% of the restorations. The largest maximum absolute corrosion potential change for each subject's restorations ranged between 85 and 329 mV. Statistical analysis showed that the overall mean maximum absolute corrosion potential change for the subjects' restorations was 74 mV. SIGNIFICANCE: It was shown that the corrosion potential of aged dental amalgam restorations varies substantially over time, and that a single measurement is not representative of short- or long-term electrochemical behavior. This finding has implications regarding the corrosion rate of dental amalgam restorations, particularly those that are part of a galvanic couple.     

Base deficit stratifies mortality and determines therapy.

OBJECTIVE: To determine the association of base deficit with mortality and other factors affecting mortality. DESIGN: Retrospective review. SETTING: Tertiary care center. PARTICIPANTS: Consecutive samples of 3791 trauma patients admitted with an arterial blood gas sample taken in the first 24 hours. MAIN OUTCOME MEASURES: Age, injury mechanism, head injury, shock (systolic blood pressure less than 90 mm Hg), Revised Trauma Score, TRISS probability of survival Ps, and mortality. RESULTS: Most (3038) patients (80.1%) exhibited a base deficit. Base deficit, age, injury mechanism, and head injury were associated with mortality using logistic regression. Age less than 55 years, no head injury, and a base deficit of -15 mmol/L were associated with 25% mortality. Age greater than or equal to 55 years with no head injury or age less than 55 years with a head injury and a base deficit of -8 mmol/L were associated with a 25% mortality. When shock was added to the model, all factors remained significant, and base deficit was supplemental to blood pressure. Base deficit also added significantly to the Revised Trauma Score and TRISS measurements. CONCLUSIONS: The base deficit is an expedient and sensitive measure of both the degree and the duration of inadequate perfusion. It is useful as a clinical tool and enhances the predictive ability of both the Revised Trauma Score and TRISS.     

Requirement for ICR-like sequences in the replication of brome mosaic virus genomic RNA.

Previous studies using a brome mosaic virus (BMV) RNA-2 deletion mutant (pRNA-2 M/S) and additional derivatives as reporters established that viral sequences resembling internal control regions (ICRs) 1 and 2 of tRNA gene promoters are vital to (+)-strand replication in protoplasts. Transfer of these mutations to genomic RNA-2 and functional analysis in protoplast, local lesion, and systemic infections revealed a sequence-specific requirement for bases within the ICR2-like motif. Despite the low (generally less than 20% of wild-type) and sometimes undetectable levels of replication of these RNA-2 mutants, sufficient p2a protein was produced to support at least modest levels of RNA-1, -3 and -4 replication in protoplasts. However, only those RNA-2 ICR2 mutants supporting substantial replication of the viral genome in protoplasts were capable of establishing local lesions in Chenopodium hybridum and systemic infections in barley, further establishing the essential role of the ICR-like sequences in viral infectivity. Upon passage through a second set of barley plants, accumulation patterns for progeny from inocula containing certain RNA-2 mutants paralleled those from wild-type inocula, indicating repair of the introduced mutations. RNA stability and translatability were shown to be unaffected by the introduced mutations. BMV RNA-3 contains several ICR-like sequences, each of which was individually deleted. Whereas deletion of the 5'-terminal ICR2-like motif had little effect on RNA-3 accumulation in protoplasts or local lesion formation, it debilitated systemic spread in barley. Deletion of an internal ICR2-like motif at position 1100 decreased (+):(-) strand asymmetry from greater than 100:1 to 14:1, reduced RNA-3 replication in protoplasts to less than 15% of wild-type, and abolished local lesion and systemic infectivity.