Transcatheter Vacuum-Assisted Mass Extraction Versus Surgical Debridement for Vegetations in Tricuspid Valve Infective Endocarditis: A Meta-Analysis of Observational Studies

Tricuspid valve infective endocarditis (TVIE), often associated with vegetation in people who inject drugs, has introduced a less invasive option for vegetation removal: transcatheter vacuum-assisted mass extraction (TVME). This technique is emerging as an alternative to standard surgical debridement (SD) and valve repair. However, the comparative effectiveness of TVME versus SD in treating TVIE has yet to be investigated. A comprehensive systematic literature search was performed on PubMed, Embase, and Cochrane to identify all relevant studies comparing TVME with SD in patients with TVIE. The search covered studies from inception up to August 15, 2023. For data analysis, Review Manager (RevMan) 5.4 software was employed, using a random-effects model to calculate risk ratios (RRs), mean differences, and 95% confidence intervals (CIs). Five studies included a total of 431 patients (244 in the TVME arm and 187 in the SD arm). In-hospital mortality (p = 0.72), procedural mortality (p = 0.77), 30-day mortality (p = 0.25), and 1-year mortality (p = 0.44) insignificantly favored SD over TVME. Overall mortality across the 5 studies insignificantly favored TVME over SD (RR = 0.66, 95% CI 0.31 to 1.39, p = 0.27, I2 = 57%). When addressing heterogeneity by excluding 1 study, no statistical significance in the difference between the 2 arms regarding overall mortality was observed (RR 0.99, 95% CI 0.60 to 1.63, p = 0.97, I2 = 0%). This meta-analysis of the 5 observational studies found no significant difference in overall mortality between TVME and SD for the treatment of TVIE. However, prospective randomized controlled trials are necessary to further understand and compare the outcomes of these 2 approaches.

Multi-organ dysfunction as a presentation of calcium channel blocker intoxication

SummaryWe report the case of a 73-year-old woman who intentionally ingested 400 mg of amlodipine in a suicidal attempt who initially presented with hypotension which persisted despite aggressive therapy with fluid resuscitation, multiple pressor support, high-dose insulin therapy and calcium infusion. Her haemodynamic instability evolved to include bradycardia requiring atropine and transcutaneous pacing. Eventually she required salvage therapy with intravenous lipid emulsion (ILE) therapy . Despite all aggressive therapy, she developed multi-organ failure resulting in death. The literature on high-dose insulin euglycaemic therapy (HIET) and ILE therapy shows mixed results with some showing significant improvement in haemodynamic status. In our case, it had no significant positive impact on the outcome.

Structured, Timely, and Individualized Patient Feedback to Residents and its Effect on HCAHPS Scores

Physician communication is integral for improving patients’ experience and clinical outcomes. Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) scores are used by the Centers for Medicare & Medicaid Services to assess the quality of care provided to the patients. We conducted a prospective pre–post-intervention study from March 2018 to March 2020 and included patients and residents of the community-based university-affiliated Internal Medicine Residency Program. Residents’ communication was evaluated through resident surveys and results were shared with them and attending physicians within 48 h. To correlate with the effect over a 4-year period, 839 HCAHPS surveys were obtained for attending physicians as an outcome measure. The mean overall HCAHPS score and doctor's communication scores increased by 8.52 and 6.06 points post-intervention. The doctor's performance score for respect increased by 6.18 points, listening increased by 3.12 points, and explanation increased by 8.23 points. This study demonstrates that timely, structured, and individualized resident feedback in an academic medicine service can result in a sustainable increase in the attendings’ overall HCAHPS and doctor's communication scores.

Bayesian network meta-analysis comparing cryoablation, radiofrequency ablation, and antiarrhythmic drugs as initial therapies for atrial fibrillation

BACKGROUND

Antiarrhythmic drugs (AADs) and catheter ablation are first line treatments of paroxysmal atrial fibrillation (PAF), however, there exists a paucity of data regarding the potential benefit of different catheter ablation technologies versus AADs as an early rhythm strategy.

OBJECTIVE

To assess the safety and efficacy of cryoablation versus radiofrequency ablation (RFA) versus AADs as a first line therapy of PAF.

METHODS

MEDLINE, Embase, Scopus and CENTRAL were searched to retrieve randomized clinical trials (RCTs) comparing cryoablation, RFA or AADs to one another as first line therapies for atrial fibrillation (AF). The primary outcome was overall freedom from arrhythmia recurrence (AF, atrial flutter [AFL], atrial tachycardia). Secondary outcomes included freedom from symptomatic arrhythmia recurrence, hospitalization, and serious adverse events. A random-effects Bayesian network meta-analysis was used to calculate odds ratios (OR) and 95% credible intervals (CrI).

RESULTS

Six RCTs (N = 1212) met the inclusion criteria (605 AADs, 365 Cryoablation, and 245 RFA). Compared with AADs, overall recurrence was reduced with RFA (OR: 0.31; 95% CrI: 0.10-0.71) and cryoablation (OR: 0.39; 95% CrI: 0.16-1.00). Comparing ablation (cryoablation and RFA) with AADs in respect to freedom from symptomatic AF recurrence, neither cryoablation (OR: 0.35; 95% CrI: 0.06-1.96) nor RFA (OR: 0.34; 95% CrI: 0.07-1.27) resulted in statistically significant reductions individually compared to AADs, though pooled ablation with both technologies showed lower odds of arrhythmia recurrence (OR: 0.35; 95% CrI: 0.13-0.79). In terms of serious adverse events rates, neither cryoablation (OR: 0.77; 95% CrI: 0.44-1.39) nor RFA (OR: 1.45; 95% CrI: 0.67-3.23) were significantly different to AADs. RFA resulted in a statistically significant reduction in hospitalizations compared to AAD (OR: 0.08; 95% CrI: 0.01-0.99), whereas cryoablation did not (OR: 0.77; 95% CrI: 0.44-1.39). The surface under the cumulative ranking curve showed RFA to be the most effective treatment at reducing overall rates of recurrence, symptomatic recurrence and hospitalizations; whereas cryoablation was most likely to reduce serious adverse events.

CONCLUSION

Cryoablation and RFA are both effective and safe first line therapies for AF compared to AADs, with RFA being the most effective at reducing recurrences.

Left atrial appendage closure during cardiac surgery for atrial fibrillation: A meta-analysis

BACKGROUND

Left atrial appendage closure (LAAC) during cardiac surgery in atrial fibrillation (AF) patients has been investigated in multiple studies with variable safety and efficacy results.

METHODS

A comprehensive review was performed of all studies comparing LAAC and placebo arm during cardiac surgery in AF patients. A random-effect model was used to calculate risk ratios, mean differences, and 95% confidence intervals.

RESULTS

Five randomized controlled trials and 22 observational studies were included with a total of 540,111 patients. The LAAC group had significantly decreased postoperative stroke/embolic events as compared to the no LAAC group with all cardiac surgeries (3.74% vs 4.88%, p = 0.0002), isolated valvular surgery (1.95% vs 4.48%, p = 0.002). However, CABG insignificantly favored the LAAC group for stroke/embolic events (6.72% vs 8.30%, p = 0.07). There was no difference between both groups in all-cause mortality in the perioperative period (p = 0.42), but was significantly lower in the LAAC arm after two years (14.1% vs 18.3%, p = 0.02). There was no difference in major bleeding, all-cause rehospitalizations, or cross-clamp time between both groups (p = 0.53 and p = 0.45). The bypass and the cross-clamp time were longer in the LAAC group (4 and 9 min, respectively).

CONCLUSION

In AF patients, LAAC during cardiac surgery had a decreased risk of stroke and long-term all-cause mortality. Additionally, there was no difference in major bleeding, all-cause rehospitalizations, or cross-clamp time.

Potential Role of Cardiopulmonary Exercise Testing as an Early Screening Tool for Patients With Suspected Pulmonary Hypertension Including Exercise-Induced Pulmonary Hypertension: Results From a Retrospective Analysis

OBJECTIVE

The primary goal of our retrospective case-control study was to evaluate the ability of cardiopulmonary exercise testing to screen for underlying exercise-induced pulmonary hypertension (EIPH) in symptomatic patients who had a negative stress test and elevated right ventricular systolic pressure on echocardiogram. We also evaluated long-acting nitrates and ranolazine as medication challenges.

SETTING

Performed at a single, tertiary-care medical center in the United States.

PARTICIPANTS

Based on the inclusion and exclusion criteria, 81 patients were included in this study. The primary outcome of the study was to measure mean pulmonary arterial pressure at rest and exertion, as well as Wasserman curves. We also recorded patient demographics and risk factors, left ventricular ejection fraction, and mean oxygen consumption. Additionally, patients were monitored symptomatically after receiving long-acting nitrates and ranolazine.

RESULTS

A total of 61 patients had resting pulmonary arterial hypertension, and 27 had EIPH. The EIPH group had a significantly higher mean age of 71.67 years. Wasserman curves calculated from the cardiopulmonary exercise testing data revealed 3 subgroups of EIPH patients: cardiac restriction, chronotropic incompetence, and combination of both patterns. The EIPH group showed significant improvement in symptoms after receiving long-acting nitrate therapy.

CONCLUSIONS

Many patients with symptoms of angina, dyspnea, and/or fatigue on exertion with negative cardiac stress testing may have underlying pulmonary arterial hypertension, including EIPH. Therefore, these patients require adequate treatment and follow-up to prevent worsening of symptoms and pathology.

The rare presentation of the de Winter's pattern: Case report and literature review

Although not classified as a ST elevated myocardial infarction (STEMI), the patterns known as equivalents also require prompt recognition and treatment. A 50-year-old male with no pertinent history presented to the emergency department for chest pain that radiated to his left shoulder. An electrocardiogram (EKG) revealed findings consistent with the de Winter's pattern, which were greater than 1 mm upsloping ST depressions at the J point in leads V3-V6 (maximally in leads V3-V5), tall, peaked T waves in leads II, III, and V3-V5, ST elevations in lead aVR, and 1 mm ST elevation in V1 and V2. The physical exam, troponins, and other laboratory investigations were unrevealing. Urgent, diagnostic coronary angiography revealed complete occlusion of the proximal left anterior descending (LAD) artery, which was successfully treated with percutaneous coronary intervention (PCI) and two drug-eluting stents. After the stent placement, arterial blood flow was re-established and the ECG normalized. The patient was started on guideline based treatment and discharged home once medically stable. The de Winter's pattern on electrocardiogram indicates a significant coronary artery disease. This pattern requires urgent intervention, typically percutaneous stent placement.

Scombroid pancreatitis from mahi-mahi consumption

A 61-year-old woman with no significant previous medical history presented to an urgent care facility with generalised rash, flushing and abdominal pain after eating mahi-mahi. She was diagnosed with an allergic reaction and discharged home. Later she experienced severe acute abdominal pain and multiple episodes of vomiting, which prompted her to go to the hospital. On admission, the patient had an elevated white count, lipase, amylase and C reactive protein with normal liver enzymes and bilirubin. Imaging showed acute pancreatitis that was suspected to be secondary to scombroid poisoning. This was confirmed by elevated immunoglobulin E and histamine levels. The acute pancreatitis was treated with pain management and supportive treatment. Scombroid poisoning is a well-recognised disease, however, acute pancreatitis secondary to this is rare as only two cases have been reported in the literature, one with codfish and the second an unknown type of fish.

Amphetamine affects the behavioral outcome of lateral fluid percussion brain injury in the rat

This study examined the effects of (D)-amphetamine, methoxamine (an al-adrenergic receptor agonist), and prazosin (an al-adrenergic receptor antagonist) on the behavioral outcome of lateral fluid percussion brain injury. Rats trained to perform a beam walking task were subjected to brain injury of moderate severity (2.1-2.2 atm). At 10 min after injury, rats were treated with amphetamine, methoxamine or prazosin at two different dose levels. Amphetamine-treated animals displayed significantly lower impairment in beam walking ability from days 1 to 5 after brain injury. Neither methoxamine nor prazosin significantly affected the impairment in beam walking ability from day 1 to day 7 after injury. However, prazosin treatment at both dose levels increased the post-injury mortality and the incidences of failure to recovery from hemiplegia. Amphetamine-treatment at 4 mg/kg, but not at 2 mg/kg, improved the spatial learning abilities of the injured animals. Neither methoxamine nor prazosin affected the spatial learning abilities. These results indicate that amphetamine facilitated beam walking recovery and improved cognitive function after concussive fluid percussion injury. Although the methoxamine experiments suggest that the norepinephrine-α1-adrenergic receptor system may not be involved in the pathophysiology of fluid percussion brain injury, our results with amphetamine (beneficial effects) and prazosin (deleterious effects) and the results observed in other models of brain injury point out that further investigations are necessary to understand the role of a1-adrenergic receptors in brain injury.

Effects of binge ethanol administration on the behavioral outcome of rats after lateral fluid percussion brain injury

This study examined the effects of 4 weeks of binge ethanol administration (BEAn) on the behavioral outcome in rats after lateral fluid percussion (FP) brain injury. Rats were intragastrically given 7.5 mL/kg of either 40% ethanol in 5% glucose solution (3 g ethanol/kg; binge ethanol group), or 5% glucose solution (vehicle group), twice on Thursday and Friday of 3 consecutive weeks. Then rats from both groups were subjected to either lateral FP brain injury of moderate severity (1.8 atm) or to sham operation. Postinjury behavioral measurements revealed that brain injury caused significant spatial learning disability in both groups. There were no significant differences in mean search latencies in the sham animals between the vehicle and binge ethanol groups. On the other hand, the mean search latency of the binge ethanol group was significantly higher than that of the vehicle group in trial blocks 2 and 4. There were no significant differences in the target visits (expressed as mean zone difference [MZD]) during the probe trial between the injured animals of binge ethanol and vehicle groups. However, there was only a minor trend towards worsened MZD score in the binge-injured animals. Histologic analysis of injured animals from both injured ethanol and vehicle groups revealed similar extents of ipsilateral cortical and observable hippocampal damage. These results suggest that 4 weeks of binge ethanol treatment followed by ethanol intoxication at the time of injury worsens some aspects of the spatial learning ability of rats. This worsening is probably caused by subtle, undetectable morphologic damage by binge ethanol administration.

Regional expression of Par-4 mRNA and protein after fluid percussion brain injury in the rat

Regional levels of prostate apoptosis response-4 (Par-4) protein and mRNA were measured after lateral fluid percussion (FP) brain injury in rats. Immunochemical studies indicated that Par-4 immunoreactivity (ir) is present in cortical neurons and hippocampal CA1-CA3 pyramidal neurons in uninjured rats. Increases of Par-4-ir were observed in the CA3 neurons of the ipsilateral hippocampus (IH), but not in injured left cortex (IC) at 48 h after FP brain injury. Levels of the Par-4 mRNA measured by RT-PCR assay and protein measured by Western blot procedure were significantly increased in the injured IC and IH, but not in the contralateral right cortex and hippocampus after brain injury. Levels of both Par-4 protein and mRNA were significantly increased in the IC and IH as early as 2 h and stayed elevated at 24 and 48 h after injury. These data show that the induction of proapoptotic Par-4 mRNA and protein occurs only in the IC and IH that have been observed to undergo apoptosis and neuronal cell loss after lateral FP brain injury. Because increased expression of Par-4 has been observed to contribute to apoptosis and cell death in cultured neurons, the present temporal pattern of Par-4 expression is consistent with a role for Par-4 in apoptosis and neuronal cell death after traumatic brain injury.

Regional expression of Bcl-2 mRNA and mitochondrial cytochrome c release after experimental brain injury in the rat

Regional levels of anti-apoptotic Bcl-2 mRNA and the cytosolic cytochrome c protein were measured after lateral fluid percussion (FP) brain injury in rats. Levels of Bcl-2 mRNA were significantly decreased in the injured left cortex (IC) and ipsilateral hippocampus (IH), but not in the contralateral right cortex (CC) and hippocampus (CH) after brain injury. Levels of Bcl-2 mRNA were significantly decreased as early as 2 h and stayed decreased as long as 48 h in the IC and IH after injury. Levels of the cytosolic cytochrome c protein were significantly increased in the IC and IH, but not in the CC and CH after brain injury. Levels of cytosolic cytochrome c were significantly increased in the IC at 30 min, 48 and 72 h, and in the IH at 2 h and as long as 72 h after injury. The increase of cytosolic cytochrome c suggests that the mitochondrial release of cytochrome is increased in the IC and IH after lateral FP brain injury. These data show that the reduction of anti-apoptotic Bcl-2 and increases of mitochondrial release of cytochrome c protein occur only in the IC and IH, regions which have been observed to undergo apoptosis and neuronal cell loss after lateral FP brain injury. Therefore, it is likely that the reduction of Bcl-2 and the increased cytochrome c protein in the cytosol contribute to the observed apoptosis and neuronal cell death in the IC and IH after lateral FP brain injury in rats.

Effects of chronic ethanol administration on expression of BDNF and trkB mRNAs in rat hippocampus after experimental brain injury

Previous evidence indicates that both chronic alcohol treatment and traumatic brain injury modulate expression of certain neurotrophins and neurotrophin receptors in cortical tissue. However, the combined effects of chronic alcohol and brain trauma on expression of neurotrophins and their receptors have not been investigated. In the present study, we examined the effects of 6 weeks of chronic ethanol administration on lateral fluid percussion (FP) brain injury-induced alterations in expression of mRNAs for the neurotrophin brain-derived neurotrophic factor (BDNF) and its high affinity receptor, trkB, in rat hippocampus. In both the control- (pair-fed isocaloric sucrose) diet and the chronic ethanol-diet groups, unilateral FP brain injury induced a bilateral increase in levels of both BDNF and trkB mRNAs in the dentate gyrus granule cell layer, and of BDNF mRNA in hippocampal region CA3. However, no significant differences in expression were found between the control-diet and ethanol-diet groups, in either the sham-injured or FP-injured animals. These findings suggest that 6 weeks of chronic ethanol administration does not alter the plasticity of hippocampal BDNF/trkB expression in response to experimental brain injury.

Three months of chronic ethanol administration and the behavioral outcome of rats after lateral fluid percussion brain injury

This study examined the effects of 3 months of chronic ethanol administration (CEAn) on the behavioral outcome in rats after lateral fluid percussion (FP) brain injury. Rats were given either an ethanol liquid diet (ethanol diet groups) or a pair-fed isocaloric sucrose control diet (control diet groups) for 3 months. Then, rats from both diet groups were subjected to either lateral FP brain injury of moderate severity (1.8 atm) or to sham operation. Postinjury behavioral measurements revealed that brain injury caused significant spatial learning disability in both diet groups. There were no significant differences in spatial learning ability in the sham or brain-injured animals between the control and ethanol diets. However, a trend towards cognitive impairment in the sham animals and a trend towards reduced deficits in the brain-injured animals were observed in the ethanol diet group. Histologic analysis of injured animals from both diet groups revealed similar extents of ipsilateral cortical and hippocampal CA3 damage. These results, in general, suggest that 3 months of CEAn does not significantly alter the behavioral and morphologic outcome of experimental brain injury.

Immunohistochemical detection of the lipid peroxidation product 4-hydroxynonenal after experimental brain injury in the rat

This study examined the accumulation of the cytotoxic lipid peroxidation product 4-hydroxynonenal (HNE) after lateral fluid percussion (FP) brain injury in rats. A diffuse distribution of HNE-immunoreactivity (HNE-ir) was observed in the cortex and hippocampus of the ipsilateral, but not of the contralateral, hemisphere at 30 min, 6 h, 24 h, and 48 h after brain injury. The HNE-ir was well-localized in cell bodies of the ipsilateral cortex and the CA3 pyramidal layer in the ipsilateral hippocampus. Because HNE's interaction with certain proteins causes protein dysfunction and HNE, in vitro, causes neuronal cell damage, the present results suggest that HNE's interaction with neuronal proteins may contribute to neuronal damage in the ipsilateral cortex and hippocampus after brain injury.

Kynurenate attenuates the accumulation of diacylglycerol and free fatty acids after experimental brain injury in the rat

This study examined the effects of the administration of kynurenate, a non-specific excitatory amino acid (EAA) receptor subtype antagonist, on the regional accumulation of diacylglycerol (DG) and free fatty acids (FFAs) after lateral fluid percussion (FP) brain injury in the rat. After brain injury of moderate severity (2.0 atm), rats were treated with either kynurenate (200 mg/kg, i.v.) or saline at 5 min after injury. In the saline-treated brain-injured rats, levels of all individual DG-fatty acids (palmitic, stearic, oleic and arachidonic acids) and total DG-fatty acids were increased in the ipsilateral left cortex and hippocampus at 30 min and 60 min after injury. Kynurenate administration attenuated increases of individual and total DG-fatty acids in the ipsilateral cortex at 30 and 60 min and in the ipsilateral hippocampus at 30 min after FP brain injury. At 30 and 60 min after FP brain injury, increases in the levels of individual FFAs (palmitic, stearic, oleic and arachidonic acids) and of total FFAs were also observed in the ipsilateral cortex and hippocampus of the saline-treated injured rats. Kynurenate administration attenuated increases of all individual and total FFAs in the ipsilateral cortex and hippocampus either at 30 min alone or at both 30 min and 60 min after FP brain injury. In the contralateral cortex, levels of both DG-fatty acids and FFAs were not increased in the saline-treated injured rats and were also not affected by the administration of kynurenate. These results support the role of EAA receptor subtypes in the phospholipases-catalyzed formation of DG and FFAs in the ipsilateral cortex and hippocampus after lateral FP brain injury.

Regional activities of phospholipase C after experimental brain injury in the rat

Regional activities of phosphoinositide-specific phospholipase C (PLC) were measured after lateral fluid percussion (FP) brain injury in rats. The activity of PLC on phosphatidylinositol 4,5-bisphosphate (PIP2) in the rat cortex required calcium, and at 45 microM concentration it increased PLC activity by about ten-fold. The activity of PLC was significantly increased in the cytosol fraction in the injured (left) cortex (IC) at 5 min, 30 min and 120 min after brain injury. However, in the same site, increases were observed in the membrane fraction only at 5 min after brain injury. In both the contralateral (right) cortex (CC) and ipsilateral hippocampus (IH), the activity of PLC was increased in the cytosol only at 5 min after brain injury. These results suggest that increased activity of PLC may contribute to increases in levels of cellular diacylglycerol and inositol trisphosphate in the IC (the greatest site of injury), and to a smaller extent in the IH and CC, after lateral FP brain injury. It is likely that this increased PLC activity is caused by alteration in either the levels or activities of one or more of its isozymes (PLCbeta, PLCgamma, and PLCdelta) after FP brain injury.

Effects of six weeks of chronic ethanol administration on the behavioral outcome of rats after lateral fluid percussion brain injury

This study examined the effects of 6 weeks of chronic ethanol administration on the behavioral outcome in rats after lateral fluid percussion (FP) brain injury. Rats were given either an ethanol liquid diet (ethanol diet-groups) or a pair-fed isocaloric sucrose control diet (control diet groups) for 6 weeks. After 6 weeks, the ethanol diet was discontinued for the ethanol diet rats and they were then given the control sucrose diet for 2 days. During those 2 days, the rats were trained to perform a beam-walking task and subjected to either lateral FP brain injury of low to moderate severity (1.8 atm) or to sham operation. In both the control diet and the ethanol diet groups, lateral FP brain injury caused beam-walking impairment on days 1 and 2 and spatial learning disability on days 7 and 8 after brain injury. There were no significant differences in beam-walking performance and spatial learning disability between brain injured animals from the control and ethanol diet groups. However, a trend towards greater behavioral deficits was observed in brain injured animals in the ethanol diet group. Histologic analysis of both diet groups after behavioral assessment revealed comparable ipsilateral cortical damage and observable CA3 neuronal loss in the ipsilateral hippocampus. These results only suggest that chronic ethanol administration, longer than six weeks of administration, may worsen behavioral outcome following lateral FP brain injury. For more significant behavioral and/or morphological change to occur, we would suggest that the duration of chronic ethanol administration must be increased.

Regional levels of phospholipase Cgamma after fluid percussion brain injury in the rat

Levels of PLCgamma, a phospholipase C (PLC) isozyme, were significantly increased in the cytosol in the injured left cortex (LC) at 5, 30 and 120 min after brain injury. In the same site, although levels of membrane PLCgamma did not alter at 5 and 30 min, they were found to be decreased at 2 h after brain injury. In general, the levels of both cytosolic and membrane PLCgamma were unaltered in the contralateral right cortex (RC), ipsilateral left hippocampus (LH) and contralateral right hippocampus (RH) between 5 and 120 min after brain injury. These results suggest that, in addition to well-proposed excitatory neurotransmitter-receptor systems, increased levels of PLCgamma may also contribute to alterations in PIP2 signal transduction pathway, particularly in the greatest injury site (LC) after lateral FP brain injury.

Amphetamine administration improves neurochemical outcome of lateral fluid percussion brain injury in the rat

This study examined the effects of the administration of D-amphetamine on the regional accumulation of lactate and free fatty acids (FFAs) after lateral fluid percussion (FP) brain injury in the rat. Rats were subjected to either FP brain injury of moderate severity (1.9 to 2.0 atm) or sham operation. At 5 min after injury, rats were treated with either d-amphetamine (4 mg/kg, i.p.) or saline. At 30 min and 60 min after brain injury, brains were frozen in situ, and cortices and hippocampi were excised at 0 degrees C. In the saline-treated brain injured rats, levels of lactate were increased in the ipsilateral left cortex and hippocampus at 30 min and 60 min after injury. These increases were attenuated by the administration of D-amphetamine at 5 min after lateral FP brain injury. At 30 and 60 min after FP brain injury, increases in the levels of all individual FFAs (palmitic, stearic, oleic and arachidonic acids) and of total FFAs were also observed in the ipsilateral cortex of the saline-treated injured rats. These increases in the ipsilateral cortex and hippocampus were also attenuated by the administration of d-amphetamine. Neither levels of lactate nor levels of FFAs were increased in the contralateral cortex in the saline-treated injured rats at 30 min or 60 min after FP brain injury. The levels of lactate and FFAs in the contralateral cortex were also unaffected by the administration of D-amphetamine. These results suggest that the attenuation of increases in the levels of lactate and FFAs in the ipsilateral cortex and hippocampus may be involved in the amphetamine-induced improvement in behavioral outcome after lateral FP brain injury.

Effects of six weeks of chronic ethanol administration on lactic acid accumulation and high energy phosphate levels after experimental brain injury in rats

The effects of 6 weeks of chronic ethanol administration on the lateral fluid percussion (FP) brain injury-induced regional accumulation of lactate and on the levels of total high-energy phosphates were examined in rats. In both the chronic ethanol diet (ethanol diet) and pair-fed isocaloric sucrose control diet (control diet) groups, tissue concentrations of lactate were elevated in the cortices and hippocampi of both the ipsilateral and contralateral hemispheres at 5 min after brain injury. In both diet groups, concentrations of lactate were elevated only in the injured left cortex and the ipsilateral hippocampus at 20 min after FP brain injury. No significant differences were found in the levels of lactate in the cortices and hippocampi of sham animals and brain-injured animals between the ethanol and control diet groups at 5 min and 20 min after injury. In the ethanol and control diet groups, tissue concentrations of total high-energy phosphates (ATP + PCr) were not affected in the cortices and hippocampi at 5 min and 20 min after lateral FP brain injury. No significant differences were found in the levels of total high-energy phosphates in the cortices and hippocampi of the sham and brain-injured animals between the ethanol and control diet groups at 5 min and 20 min after injury. Histologic studies revealed a similar extent of damage in the cortex and in the CA3 region of the ipsilateral hippocampus in both diet groups at 14 days after lateral FP brain injury. These findings suggest that 6 weeks of chronic ethanol administration does not alter brain injury-induced accumulation of lactate, levels of total high energy phosphates, and extent of morphological damage.

Lack of delayed effects of amphetamine, methoxamine, and prazosin (adrenergic drugs) on behavioral outcome after lateral fluid percussion brain injury in the rat

This study examined the delayed effects of the administration of d-amphetamine, methoxamine (an alpha1-adrenergic receptor agonist), and prazosin (an alpha1-adrenergic receptor antagonist) on the behavioral outcome of lateral fluid-percussion (FP) brain injury. Rats trained to perform a beam-walking task were subjected to brain injury of moderate severity (2.1 to 2.2 atm). Twenty-four hours after injury, rats were treated with amphetamine, methoxamine, or prazosin at two or three different dose levels. Amphetamine-treated animals displayed no significant improvement in beam-walking ability either during or after drug intoxication (from days 3 to 5 after brain injury). Similarly, neither methoxamine nor prazosin significantly affected beam-walking ability during or after drug intoxication. Neither amphetamine treatment at three different doses nor treatment with methoxamine or prazosin at two different doses affected the spatial learning disabilities of brain-injured animals. These results suggest that (1) unlike amphetamine administration after sensorimotor cortex (SMC) ablation or contusion brain injury models, amphetamine administration at 24 h after concussive FP brain injury does not improve beam-walking performance; (2) unlike amphetamine administration 10 min after concussive FP brain injury amphetamine administration 24 h after injury does not improve cognitive function; and (3) unlike prazosin administration after SMC ablation brain injury, prazosin administration 24 h after concussive FP brain injury does not effect beam-walking performance.