Impact of length of stay on functional outcomes of TBI patients.

The purpose of this study was to compare the functional outcomes of two groups of patients with traumatic brain injury (TBI) with attention to the impact of reduced length of stay (LOS) in the trauma center (TC) and rehabilitation hospital (RH). From 1991 to 1994, 55 patients, Group 1, with serious TBI (Abbreviated Injury Scale score > or = 3) were admitted to a level 1 TC and subsequently transferred to a comprehensive inpatient RH. These results have been previously published. From 1996 to 2002, 64 similarly injured patients, Group 2, received inpatient care at the same TC and RH. These patients had a marked decrease in length of stay. Functional Independence Measures (FIM) were obtained at admission (Adm), discharge (D/C), and at 1 year follow-up for both groups. The average length of stay at the TC dropped from 36 days in Group 1 to 26 days in Group 2. In addition, the average length of stay at the RH dropped from 46 days (Group 1) to 25 days (Group 2); overall, an average reduction of 31 days of inpatient care. Group 2 had significantly lower FIM scores at the time of RH discharge for self-care, locomotion, and mobility compared to Group 1. At the 1 year follow-up, however, there were no significant differences between Groups 1 and 2 in these FIM scores. FIM scores at 1 year were higher in Group 2 for communication (90% vs 71%) and social cognition (77% vs 49%) compared to Group 1. Over one-fourth of each group returned to work by the 1 year follow-up. Socially disruptive behavior occurred at least weekly in 28 per cent (Group 1) and 23 per cent (Group 2) of patients. The outcome for serious TBI is better than generally perceived. Reduction of inpatient LOS did not adversely affect the ultimate functional outcome. The decreased LOS placed a greater demand on outpatient rehabilitative services as well as a greater burden on the family of the brain-injured patient.

Temperature-dependent photochemistry of 1,3-diphenylpropenes. The di-pi-methane reaction revisited.

The temperature-dependent photochemical behavior of 1,3-diphenylpropene and several of its 3-substituted derivatives has been investigated over a wide temperature range. The singlet state is found to decay via two unactivated processes, fluorescence and intersystem crossing, and two activated processes, trans,cis isomerization and phenyl-vinyl bridging. The latter activated process yields a diradical intermediate which partitions between ground-state reactant and formation of the di-pi-methane rearrangement product. Kinetic modeling of temperature-dependent singlet decay times and quantum yields of fluorescence, isomerization, di-pi-methane rearrangement, and nonradiative decay provides rate constants and activation parameters for each of the primary and secondary processes. Substituents at the 3-position are found to have little effect on the electronic spectra or unactivated fluorescence and intersystem crossing pathways. However, they do effect the activated primary and secondary processes. Thus, the product ratios are highly temperature dependent.

Optically active BINOL core-based phenyleneethynylene dendrimers for the enantioselective fluorescent recognition of amino alcohols.

A dramatic enhancement in fluorescence intensity from 1,1'-bi-2-naphthol (BINOL) to dendritic phenyleneethynylenes containing the BINOL core was observed. The strong fluorescence of the dendrimers allows a very small amount of the chiral materials to be used for sensing. The light harvesting antennas of the dendrimer funnel energy to the center BINOL unit, whose hydroxyl groups upon interaction with a quencher molecule lead to fluorescence quenching. This mechanism makes the dendrimers have much more sensitive fluorescence responses than corresponding small molecule sensors. The fluorescence of these dendrimers can be enantioselectively quenched by chiral amino alcohols. It is observed that the fluorescence lifetime of the generation two dendrimer does not change in the presence of various concentrations of 2-amino-3-phenyl-1-propanol. This demonstrates that the fluorescence quenching is entirely due to static quenching. Thus, formation of nonfluorescent ground-state hydrogen-bond complexes between the dendrimers and amino alcohols is proposed to account for the fluorescent quenching. A linear relationship has been established between the Stern-Völmer constant of the generation two dendrimer and the enantiomeric composition of 2-amino-3-phenyl-1-propanol. Such enantioselective fluorescent sensors may allow a rapid determination of the enantiomeric composition of chiral molecules and are potentially useful in the combinatorial search of asymmetric catalysts and reagents.

Highly regioselective anaerobic photocyclization of 3-styrylpyridines.

The photochemical behavior of the cis isomers of the three isomeric styrylpyridines and two (aminostyryl)pyridines has been investigated under aerobic and anaerobic conditions. Both 3-styrylpyridine and its 3'-amino derivative undergo highly regioselective formation of 2-azaphenanthrene products under anaerobic conditions. In the presence of oxygen, mixtures of 4- and 2-azaphenanthrene products are obtained. The formation of 2-azaphenanthrenes in the absence of oxygen is attributed to conversion of the 4a,4b-dihydroazaphenanthrene primary photoproduct to a 1,4-dihydropyridine intermediate by means of a formal 1,7-hydrogen shift. This intermediate is moderately stable in the absence of oxygen and has been characterized by comparison of its (1)H NMR and electronic absorption spectra with calculated spectra. This intermediate is converted to the 2-azaphenanthrene in both the absence and presence of oxygen. The regioselectivity of photocyclization of 3-substituted stilbenes and related diarylethylenes is suggested to depend on the relative rate constants for ring opening and sigmatropic rearrangements of the dihydrophenanthrene intermediates as well as their rates of reaction with oxygen or other oxidants.

Dynamics of photoinduced charge transfer and hole transport in synthetic DNA hairpins.

The dynamics of photoinduced charge separation and charge recombination processes in synthetic DNA hairpins have been investigated by means of femtosecond transient absorption spectroscopy. The driving force and distance dependence of charge-transfer processes involving singlet acceptors and nucleobase donors are consistent with a single-step superexchange mechanism in which the electronic coupling between the donor and acceptor is strongly distance dependent. The dynamics of reversible hole transport between a primary guanine donor and nearby GG or GGG sequences has also been determined and establishes that these sequences are very shallow hole traps.

Direct measurement of hole transport dynamics in DNA.

Our understanding of oxidative damage to double helical DNA and the design of DNA-based devices for molecular electronics is crucially dependent upon elucidation of the mechanism and dynamics of electron and hole transport in DNA. Electrons and holes can migrate from the locus of formation to trap sites, and such migration can occur through either a single-step "superexchange" mechanism or a multistep charge transport "hopping" mechanism. The rates of single-step charge separation and charge recombination processes are found to decrease rapidly with increasing transfer distances, whereas multistep hole transport processes are only weakly distance dependent. However, the dynamics of hole transport has not yet been directly determined. Here we report spectroscopic measurements of photoinduced electron transfer in synthetic DNA that yield rate constants of approximately 5 x 10(7) s(-1) and 5 x 10(6) s(-1), respectively, for the forward and return hole transport from a single guanine base to a double guanine base step across a single adenine. These rates are faster than processes leading to strand cleavage, such as the reaction of guanine cation radical with water, thus permitting holes to migrate over long distances in DNA. However, they are too slow to compete with charge recombination in contact ion pairs, a process which protects DNA from photochemical damage.

Distance-dependent electron transfer in DNA hairpins.

The distance dependence of photoinduced electron transfer in duplex DNA was determined for a family of synthetic DNA hairpins in which a stilbene dicarboxamide forms a bridge connecting two oligonucleotide arms. Investigation of the fluorescence and transient absorption spectra of these hairpins established that no photoinduced electron transfer occurs for a hairpin that has six deoxyadenosine-deoxythymidine base pairs. However, the introduction of a single deoxyguanosine-deoxycytidine base pair resulted in distance-dependent fluorescence quenching and the formation of the stilbene anion radical. Kinetic analysis suggests that duplex DNA is somewhat more effective than proteins as a medium for electron transfer but that it does not function as a molecular wire.

Serious traumatic brain injury: an evaluation of functional outcomes.

OBJECTIVES: Evaluate independent living, productivity, and social outcomes of patients with serious traumatic brain injury (TBI) after inpatient rehabilitation. METHODS: Fifty-five adults with serious TBI (Abbreviated Injury Scale score > or = 3) were admitted to a Level I trauma center and subsequently transferred to a comprehensive inpatient rehabilitation hospital (Walton Rehabilitation Hospital). Functional Independence Measures were obtained at admission (Adm), discharge (D/C), and at 3- (n = 52) and 1-year (n = 51) follow-up. RESULTS: At 1 year, 90% of the patients were living at home. Eight (16%) required full-time supervision, while 41 (82%) were independent of supervision throughout most of the day. Thirteen (25%) patients had returned to work, eight full time and five with reduced responsibility and fewer hours than before injury. Nineteen shared household duties, while eight (16%) had primary responsibility. Fourteen (27%) patients demonstrated socially inappropriate or disruptive behavior at least weekly. [table: see text] CONCLUSION: Although cognitive skills were diminished for the majority of patients, many achieved a substantial reduction in disability within 18 months after TBI.

Outcomes of community re-entry programmes for brain injury survivors. Part 1: Independent living and productive activities.

This is a study of the multiple outcomes of residential community re-entry programmes for disabled survivors of brain injury. The sample consisted of 82 clients from nine facilities across the USA. The level of functioning of the client at and before admission was determined from clinical evaluations reported in programme records. Telephone interviews assessed outcomes 1 year after discharge. The participation in the re-entry programmes led to enduring improvements in independent living and productive activities. Total supervision requirements decreased substantially. Paid employment increased, but benefits went much beyond this to include improvements in educational activities, unpaid vocational activities, and especially household management. For the most part, these improvements cannot be attributed to chronicity or natural healing. The benefits of the re-entry programmes were clearly multiple. The results generally affirm the effectiveness and utility of community re-entry programmes.

Management of maladaptive social behavior of a brain injured adult.

This study examined the effectiveness of an individualized behavior point system for reducing the frequency of surplus maladaptive social behaviors of a severely brain injured adult. Treatment, given during meal periods, was applied in a multiple baseline design across three behaviors: loud verbal outburst, interruptions, and nonsensical talk. Generalization of treatment effects was assessed in informal community restaurants. The results revealed that each of the target behaviors declined with the introduction of the point system, although loud verbal outbursts and interruptions were more responsive to treatment than nonsensical talk. Some evidence was found for skill generalizations to untrained settings.