THC-induced place and taste aversions in Lewis and Sprague-Dawley rats.

The hedonic properties of delta-9-tetrahydrocannabinol (THC) were assessed in place and taste conditioning paradigms in both Lewis and Sprague-Dawley rat strains. THC produced place avoidance, taste avoidance, and aversive taste reactivity responses in both strains. The Lewis strain displayed more aversive taste reactions and a stronger taste avoidance when conditioned with lower doses of THC than did the Sprague-Dawley strain of rats. THC is an anomalous drug of abuse that appears to be aversive to rats when assessed by these measures. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Intermediate-term outcome of cervical spinal cord-injured patients older than 50 years of age

STUDY DESIGN: This study retrospectively reviewed the intermediate-term clinical outcome of patients who were 50 years of age or older at the time they experienced their cervical spinal cord injury. OBJECTIVES: To establish reasonable expectations for the functional outcome in the older patient with cervical spinal cord injury. BACKGROUND DATA: The long-term morbidity and mortality of large groups of patients with spinal cord injury have been reported. The specific functional ability, disposition, morbidity, and mortality of this group of older patients injured after 50 years of age, however, have been less well defined. METHODS: Forty-one consecutive patients older than 50 years of age at the time of cervical cord injury were studied, and functional abilities, independence, need for assistance in activities of daily living, disposition, morbidity, and mortality were assessed. All patients had more than 2 years of follow-up examinations (mean, 5.5 years) by the same spine injury service. RESULTS: There were 13 complete and 28 incomplete cervical cord lesions. The mean age of the patients at follow-up examination was 67.5 years. The average follow-up period was 5.5 years after injury. None of the patients with complete cord injury improved, and all required extensive care. Twenty-one (80%) of 26 of the patients with incomplete cord injury were able to ambulate with some assistance. Nineteen of 26 patients had independent or near-independent abilities with activities of daily living. Twenty (77%) of 26 were able to return home. All patients with complete cord injury (13 of 13) had died by the time of the follow-up visit. Seventy-seven percent (10 of 13) of this patient group had died within the first year. Those surviving lived an average of 3.5 years after their injury. Fourteen of 28 patients with incomplete cord injury (50%) had died by the time of the follow-up visit. Six (43%) of the 14 deaths were attributed to complications of their spinal cord injury. CONCLUSION: The functional outcome of the person older than 50 years with a complete cervical cord injury is poor. Of the 14% who survived the first year, all required extensive attendant care, and no neurologic improvement was seen. The patient with an incomplete cord injury has an overall good outcome regarding ambulation and returning to home.     

Symptomatic recurrent carotid stenosis and aneurysmal degeneration after endarterectomy

BACKGROUND: Aneurysmal degeneration of a carotid reconstruction was not recognized until the patient, who was known to have recurrent carotid artery stenosis, had a thromboembolic stroke. This sequelae of carotid endarterectomy is a serious complication, associated with a high morbidity and mortality rate. This review was conducted to establish the risk of transient ischemic attack and stroke for patients found to have recurrent carotid stenosis associated with aneurysmal degeneration of the carotid artery after endarterectomy. METHODS: A case is reported, and 100 literature references of aneurysmal degeneration of the carotid artery after endarterectomy were reviewed. RESULTS: False aneurysm from anastomotic disruption was the most common presentation identified in the cases reviewed. Nineteen of the patients had a significant neurologic event; however, three (50%) of six patients with aneurysm and recurrent carotid artery stenosis had a transient ischemic attack or stroke. CONCLUSIONS: The incidence of neurologic symptoms is markedly increased when recurrent carotid artery stenosis is associated with carotid aneurysm. During postoperative surveillance after endarterectomy, the identification of recurrent carotid artery stenosis requires evaluation for aneurysmal degeneration of the carotid artery with duplex scanning. These patients are at significant risk for transient ischemic attack and stroke. This rare complication merits operative repair.     

Dynamic digital holographic wavelength filtering

This paper describes the theory and results of a new generic technology for use in optical telecommunications and wavelength division multiplexing (WDM): dynamic digital holographic wavelength filtering. The enabling component is a polarization-insensitive ferroelectric liquid crystal (FLC) spatial light modulator (SLM) in conjunction with a highly wavelength-dispersive fixed diffractive element. The technology has been used to perform demultiplexing of single or multiple WDM signals, dynamic erbium doped fiber amplifier (EDFA) gain equalization and channel management, and used to tune an erbium-doped fiber laser (EDFL) functioning as a high power, very narrow linewidth WDM source     

Femorodistal vein grafts: the utility of graft surveillance criteria

PURPOSE: This retrospective review of femorodistal vein grafts was analyzed to determine the usefulness of various graft surveillance criteria. METHOD: The surveillance schedule involved evaluations at 1 month, every 3 months the first year, and then every 6 months. Salvage intervention or graft occlusion occurring within the next follow-up interval defined surveillance end points. One hundred two grafts (329 surveillance visits) had an ankle/brachial index (ABI). A duplex scanning-determined midgraft peak systolic flow velocity (PSFV) was available for 81 grafts (262 visits). Forty-eight grafts (137 visits) had both a PSFV and entire graft duplex scanning (EGDS) to determine stenosis greater than 50%, whereas 40 grafts (91 visits) had simultaneous ABI and EGDS. RESULTS: When a greater than 15% decrease in ABI denoted an abnormal surveillance study result, a positive predictive value (PPV) of 24.3% and negative predictive value of 94.5% were noted. Similarly, a PSFV cutoff of less than 35 cm/sec demonstrated values of 26.3% and 94.2%, respectively. When an EGDS of greater than 50% stenosis or a PSFV of less than 35 cm/sec were the cutoff criteria, the PPV was 36.7% and negative predictive value 99.1%, whereas characterizing abnormal results further with ABI (> 15% decreases) increased the PPV to 83.3%. CONCLUSION: The combination of an EGDS, midgraft PSFV, and ABI provides optimal follow-up for our patients with a femorodistal vein graft.     

DNA recognition by the EcoK methyltransferase. The influence of DNA methylation and the cofactor S-adenosyl-L-methionine

The methyltransferase of the EcoK type I restriction/modification system is trimeric, M2S1, where the S subunit determines the sequence specificity of the enzyme. The methyltransferase has a strong preference for hemimethylated substrate DNA and, therefore, we have investigated the effect of the methylation state of DNA on binding by the enzyme, together with the effects on binding of the cofactor S-adenosyl-L-methionine. Our results indicate that the methyltransferase has two non-interacting S-adenosyl-L-methionine binding sites, each with a dissociation constant of 3.60 (+/- 0.42) microM determined by equilibrium dialysis, or 2.21 (+/- 0.29) microM determined by the displacement of a fluorescent probe. Ultraviolet light-induced crosslinking showed that S-adenosyl-L-methionine binds strongly only to the modification (M) subunits. Changes in the sedimentation velocity of the methyltransferase imply a protein conformational change due to S-adenosyl-L-methionine binding. Gel retardation results show that the binding of S-adenosyl-L-methionine to the methyltransferase enhances binding to both specific and non-specific DNAs, but the enhancement is greater for the specific DNA. Differences in binding affinities contribute to the recognition of the specific nucleotide sequence AAC(N)6GTGC by the methyltransferase in preference to a non-specific sequence. In contrast, although the complexes of unmodified and hemimethylated DNAs with the methyltransferase have different mobilities in non-denaturing gels, there appears to be no contribution of binding affinity to the distinction between these two substrates. Therefore, the preference for a hemimethylated substrate must be due to a difference in catalysis.