Widespread correction of central nervous system disease after intracranial gene therapy in a feline model of Sandhoff disease.

Sandhoff disease (SD) is caused by deficiency of N-acetyl-ß-hexosaminidase (Hex) resulting in pathological accumulation of GM2 ganglioside in lysosomes of the central nervous system (CNS) and progressive neurodegeneration. Currently, there is no treatment for SD, which often results in death by the age of five years. Adeno-associated virus (AAV) gene therapy achieved global CNS Hex restoration and widespread normalization of storage in the SD mouse model. Using a similar treatment approach, we sought to translate the outcome in mice to the feline SD model as an important step toward human clinical trials. Sixteen weeks after four intracranial injections of AAVrh8 vectors, Hex activity was restored to above normal levels throughout the entire CNS and in cerebrospinal fluid, despite a humoral immune response to the vector. In accordance with significant normalization of a secondary lysosomal biomarker, ganglioside storage was substantially improved, but not completely cleared. At the study endpoint, 5-month-old AAV-treated SD cats had preserved neurological function and gait compared with untreated animals (humane endpoint, 4.4±0.6 months) demonstrating clinical benefit from AAV treatment. Translation of widespread biochemical disease correction from the mouse to the feline SD model provides optimism for treatment of the larger human CNS with minimal modification of approach.

The anti-tumor activity of anti-CTLA-4 is mediated through its induction of IFN gamma.

The T-cell-specific receptor, CTLA-4, has been demonstrated to be a potent negative regulator of lymphocyte activation, the functional significance of which has been demonstrated in murine tumor models using blocking antibodies. However, the mechanism(s) involved in enhancing tumor regression has not been identified. In this study, we determined whether IFN gamma was playing a role in this activity. In vitro, anti-CTLA-4 enhanced IFN gamma production by lymph node cells obtained from tumor-bearing mice (351 pg/ml vs 77 pg/ml). Additionally, fibrosarcoma-challenged animals treated with anti-CTLA-4 had elevated levels of the IFN-inducible enzyme 2-5-OAS in draining lymph nodes (850 pM vs 260 pM for controls) and an increased amount of IFN gamma in tumor lysates (at day 7, 620 pg/100 micrograms vs 160 pg/100 micrograms in controls). The importance of IFN gamma was demonstrated by the ability of neutralizing antibodies to completely abrogate the anti-tumor effects of anti-CTLA-4. Moreover, fibrosarcoma cells were shown to be exquisitely sensitive to IFN gamma-mediated class I upregulation and histological examination of tumors from anti-CTLA-4-treated mice revealed a trend toward increased tumor cell apoptosis and decreased angiogenesis. These studies have demonstrated that one mechanism for the anti-tumor effects of anti-CTLA-4 relates to its ability to augment IFN gamma production, resulting in an increased expression of class I on the tumor, enhanced apoptosis, and a decrease in blood vessel growth.

Venous hemodynamic changes during laparoscopic cholecystectomy.

Virchow's triad of venous stasis, vessel wall damage, and hypercoagulability cites three factors that predispose to the formation of venous thrombosis. The pneumoperitoneum created during laparoscopic surgery results in an intraabdominal pressure that exceeds the pressure of venous blood return from the legs. This may alter venous hemodynamics enough to result in venous stasis in the legs, thus increasing the risk of thrombus formation. Duplex ultrasound was used to measure the diameter and venous flow volume of the common femoral vein during laparoscopic cholecystectomy. Measurements were obtained at three different times: after induction of anesthesia but prior to creation of pneumoperitoneum, during pneumoperitoneum, and after abdominal deflation but prior to reversal of anesthesia. After insufflation of the abdomen, the mean cross-sectional area of the common femoral vein increased (0.83 to 1.15 cm2; p = 0.0024) and the venous flow decreased (11.00 to 6.06 cm3/sec; p = 0.0008). After deflation of the abdomen, there was no significant change in cross-sectional area of the common femoral vein, but there was an increase in venous flow (6.06 to 9.94 cm3/sec; p = 0.0005). Abdominal insufflation during laparoscopic cholecystectomy results in dilation of and decreased flow in the common femoral vein. After deflation of the abdomen, flow in the vein returns to baseline levels.

The type A coronary-prone behavior pattern and reactions to uncontrollable stress: an analysis of performance strategies, affect, and attributions during failure.

The present study examined the ongoing experience of Type A and Type B undergraduates during prolonged exposure to unsolvable discrimination problems in which the cue signaling failure was highly or moderately salient to subjects. Subjects were asked to think out loud while solving the problems that were presented in a manner to permit monitoring of their problem-solving strategies. Results revealed that the problem-solving strategies of high-salience A's deteriorated across failure trials. At the same time, they commented on their lack of ability and, to some extent, on the task's difficulty as accounting for their failure. They expressed annoyance and anger at themselves and at their circumstances. On the other hand, B's did not use ineffectual strategies; they continued to perform appropriately during failure. However, they did comment on task difficulty (during the experiment) as well as on chance and the experimenter (at the conclusion of the experiment) as playing critical roles in their failure to do well. The results suggest that deficits in performance of A's and of B's in previous investigations are the outcomes of different processes: A's may be helpless, whereas B's may be pseudohelpless. The findings support Pattern A as a specific coping style aimed at maintaining and asserting control over stressful aspects of the environment. Implications for the reformulated models of learned helplessness are discussed.

Attention, unpredictability, and reports of physical symptoms: eliminating the benefits of predictability.

Sometimes unpredictable aversive events have more adverse consequences than predictable aversive events and sometimes not. Three experiments were conducted to test an attentional explanation of the inconsistent effects of unpredictability. This explanation suggests that unpredictable events exert a deleterious influence because more attention is typically directed to them. If there were no difference in the amount of attention directed to unpredictable and predictable events, however, there should be no difference in their effects. The validity of these notions was assessed by applying them to one previously established finding from the unpredictability literature--the finding that exposure to unpredictable noise leads to reports of more severe physical symptoms than does exposure to predictable noise. In Experiment 1, subjects performed a reaction time task while they listened to loud bursts of either predictable or unpredictable noise. As expected, reaction times were slower when the noise was unpredictable than when it was not. This finding suggests that more attention had been directed to the unpredictable than the predictable noise. In Experiments 2 and 3, subjects were exposed to either predictable or unpredictable noise and were either instructed to attend to the noise or given no special instructions. In both cases, subjects not instructed to attend to the noise reported more severe symptoms when the noise was unpredictable than when it was not, thus replicating the previous finding. Of greater interest, however, was the fact that equating the amount of attention directed to the unpredictable and predictable noise (by asking subjects to attend to the noise) eliminated the apparent benefits of predictability. The discussion of the findings centers on their theoretical and practical significance.

Allocation of attention and the Type A coronary-prone behavior pattern.

Three studies were conducted to assess the attentional style of individuals with the Type A coronary-prone behavior pattern. Experiment 1, which made use of a dual-task paradigm, revealed that Type A's focus their attention on central tasks; thus, they attend less to peripheral tasks than do Type B's. Experiments 2 and 3, which used a single task performed in the presence of a distracting stimulus, indicated that Type A's actively inhibit or suppress their attention to task-irrelevant peripheral events that might distract them from task performance. These findings validated anecdotal observations that Type A's appear hyperalert (focused in their attention) but neglect task-irrelevant cues. Previous research has demonstrated that Type A's fail to report fatigue as well as a variety of other physical symptoms of illness during task performance. To the extent that symptoms are analogous to peripheral events that distract from task performance, the data suggest that Type A's suppress their attention to symptoms. Implications of the attentional style of Type A's for the pathogenesis of coronary artery and heart disease are discussed.