Cognitive outcomes following aneurysmal subarachnoid hemorrhage: Rehabilitation strategies

Despite decreases in mortality rate, the treatment of cognitive deficits following aneurysmal subarachnoid hemorrhage (aSAH) remains a serious challenge for clinicians and survivors alike. Deficits in executive function, language, and memory prevent more than half of survivors from returning to their previous level of work and put a tremendous amount of stress on the individual and their family. New therapies are needed for survivors of aSAH in order to improve cognitive outcomes and quality of life. The aim of this review is to discuss the prevalence and contributing factors of cognitive deficits following aSAH, as well as areas for therapeutic intervention. Due to the limited research on cognitive rehabilitative strategies for aSAH, a literature search of traumatic brain injury (TBI) was used to explore therapies with the potential to improve cognitive outcomes in aSAH. Across cognitive domains, existing rehabilitative and pharmacotherapeutic strategies for TBI show promise to be useful for survivors of aSAH. However, further study of these therapies in addition to consistent assessment of cognitive deficits are required to determine their efficacy in survivors of aSAH.

The preference for sugar over sweetener depends on a gut sensor cell

Guided by gut sensory cues, humans and animals prefer nutritive sugars over non-caloric sweeteners, but how the gut steers such preferences remains unknown. In the intestine, neuropod cells synapse with vagal neurons to convey sugar stimuli to the brain within seconds. Here, we found that cholecystokinin (CCK)-labeled duodenal neuropod cells differentiate and transduce luminal stimuli from sweeteners and sugars to the vagus nerve using sweet taste receptors and sodium glucose transporters. The two stimulus types elicited distinct neural pathways: while sweetener stimulated purinergic neurotransmission, sugar stimulated glutamatergic neurotransmission. To probe the contribution of these cells to behavior, we developed optogenetics for the gut lumen by engineering a flexible fiberoptic. We showed that preference for sugar over sweetener in mice depends on neuropod cell glutamatergic signaling. By swiftly discerning the precise identity of nutrient stimuli, gut neuropod cells serve as the entry point to guide nutritive choices.

Buchanan, Rupprecht, Kaelberer and colleagues show that the preference for sugar over sweetener in mice depends on gut neuropod cells. Akin to other sensor cells, neuropod cells swiftly communicate the precise identity of stimuli to drive food choices.

Haematologic determinants of left atrial spontaneous echo contrast in mitral stenosis

OBJECTIVES

To determine if a relationship exists in mitral stenosis, in patients with either sinus rhythm or atrial fibrillation, between left atrial spontaneous echo contrast and the haematologic indices haematocrit, red cell concentration, mean corpuscular volume, platelet count and volume.

METHODS

Left atrial spontaneous echo contrast severity was graded on a scale of 0-4 in 163 patients with symptomatic mitral stenosis (84 patients in sinus rhythm, 79 patients in atrial fibrillation) undergoing transesophageal echocardiography, cardiac catheterization and full blood examination as part of assessment prior to balloon mitral valvuloplasty.

RESULTS

In sinus rhythm, spontaneous echo contrast grade was negatively correlated with cardiac index (r=-0.33), mitral valve area (r=-0.25) and mitral regurgitation grade (r=-0.22) and positively correlated with haematocrit (r=0.24) and red cell concentration (r=0.25). Spontaneous echo contrast grade was not correlated with left atrial diameter or mean corpuscular volume. In atrial fibrillation, spontaneous echo contrast grade was also negatively correlated with mitral valve area (r=-0.25) and mitral regurgitation (r=-0.36) but was positively correlated with left atrial diameter (r=0.34) and was not correlated with cardiac index, haematocrit or red cell concentration. There was no correlation between spontaneous echo contrast grade and platelet variables in either group.

CONCLUSIONS

Natural variation in red cell concentration in patients with symptomatic mitral stenosis was an independent predictor of the severity of left atrial spontaneous echo contrast in sinus rhythm, but no relationship between red cell concentration and spontaneous echo contrast grade was evident in atrial fibrillation.

Echocardiographic aspects of percutaneous atrial septal defect closure in adults

Echocardiography plays an integral role in the diagnosis and management of atrial septal defects. With percutaneous closure of secundum defects becoming widespread, transoesophageal echocardiography in particular has assumed an important role in patient selection, as well as being central to the device deployment procedure, and an important tool in patient follow up.

Transforming growth factor-beta1 (TGF-beta1) in penile and prostate growth in the rat during sexual maturation

The goal of this study was to determine whether transforming growth factor-beta1 (TGF-beta1) may contribute to the arrest of penile growth and the down-regulation of androgen receptors (AR) that occur during sexual maturation in the rat penis. For this purpose, body, penis, and prostate weights were obtained from male rats of increasing ages, and penis and prostate TGF-beta1 concentrations were determined by a sandwich enzyme-linked immunosorbent assay. The cytosol fraction was obtained from the shafts and glandes of immature (19-day-old) and adult (90-day-old) rat penises, and ARs were measured by a western blot assay. The effect of exogenous TGF-beta1 on penile growth was examined in vivo in two groups of immature rats (21 and 27 days old) implanted with miniosmotic pumps delivering either human TGF-beta1 or vehicle only directly into the corpora cavernosa for 6 days. The penises, prostates, and testes were weighed, and the AR content was estimated by western blot. The growth rate of the penis declined after 8 weeks of age, whereas the ventral prostate growth rate increased until 14 weeks of age and then slowed down. The content of penile AR protein decreased seven-fold in the adult rats compared to the immature animals. Penile TGF-beta1 concentration increased nearly three-fold from the 19-day-old rats to a peak at 60 days of age and then decreased over the next 4 months to the initial levels. In contrast, TGF-beta1 concentration in the prostate was not significantly affected by age and remained below the lowest penile values in all age groups. Transforming growth factor-beta1 given locally to the penis reduced penile shaft weight by 38 and 22% in two groups of immature rats, while the weights of the penile glans, testis, and ventral prostate remained unaffected. Androgen receptor content was higher in the glans than in the shaft and was not changed by TGF-beta1 treatment. These results suggest that the increase of TGF-beta1 levels in the penis may reinforce growth arrest caused by the down-regulation of penile ARs, whereas the maintenance of a high content of ARs and a low TGF-beta1 concentration may allow prostate growth to continue.

Stability of left atrial spontaneous echo contrast at repeat transesophageal echocardiography in patients with mitral stenosis

We evaluated the stability of left atrial spontaneous echo contrast in 25 patients with mitral stenosis who underwent repeat transesophageal echocardiography over periods ranging from 1 month to 3 years. Left atrial spontaneous echo contrast did not disappear or decrease in severity in any patient and was unchanged in 88% of patients.

Effect of warfarin on regional left atrial coagulation activity in mitral stenosis

Increased regional left atrial (LA) coagulation activity has recently been implicated in the pathophysiology of LA thrombus and systemic embolism in mitral stenosis (MS). Anticoagulation with warfarin reduces the risk of such thromboembolism, but the effect of warfarin on LA coagulation activity is unknown. We have addressed this question in MS patients with normal or prolonged clotting times. Peripheral venous and LA coagulation activities were measured in MS patients on long-term oral anticoagulation, who were predisposed to increased LA coagulation activity because of the presence of LA spontaneous echo contrast. Patients ceased warfarin 4 days before percutaneous balloon mitral valvuloplasty, and had either a normal (n = 15) or prolonged (n = 8) International Normalized Ratio (INR) at valvuloplasty. Coagulation activity was assessed during the valvuloplasty procedure, but before valve dilation, by measuring levels of prothrombin fragment 1 + 2 (F1 + 2), a marker of thrombin generation. The LA F1 + 2 level exceeded the peripheral venous level in patients with a normal INR (p <0.001), but these levels were similar in patients with a prolonged INR (p = 0.16). Moreover, the LA (p <0.005) and peripheral venous (p <0.03) F1 + 2 levels, as well as the LA-peripheral venous F1 + 2 difference (p <0.03) were lower in patients with a prolonged INR. These results suggest that anticoagulation with warfarin in MS not only reduces systemic coagulation activity but is associated with a greater reduction in LA coagulation activity. The latter may contribute to the reduced risk of LA thrombus formation that accompanies warfarin therapy in MS.

Determinants of increased regional left atrial coagulation activity in patients with mitral stenosis

BACKGROUND

Recent evidence suggests that regional left atrial coagulation activity may be increased in mitral stenosis and perhaps contribute to the pathophysiology of left atrial thrombus. However, the relation of left atrial coagulation activity to factors that predispose to left atrial thrombus formation is unknown, and the relation between left atrial and systemic coagulation activities is unresolved.

METHODS AND RESULTS

Left atrial and peripheral venous levels of the coagulation marker prothrombin fragment 1 + 2 (F1 + 2) were measured in 32 patients with mitral stenosis with normal clotting times and no left atrial thrombus who were undergoing percutaneous balloon mitral valvuloplasty. Baseline peripheral venous F1 + 2 levels, measured at the beginning of the valvuloplasty procedure, did not differ from those of 30 age-matched control patients. Prevalvuloplasty left atrial F1 + 2 levels, obtained immediately after transseptal puncture, were similar to femoral venous levels in patients without left atrial spontaneous echo contrast (LASEC) (0.81 +/- 0.32 versus 0.81 +/- 0.27 nmol/L, n = 7) but greater than femoral venous levels in patients with LASEC and either sinus rhythm (1.57 +/- 0.86 versus 0.99 +/- 0.38 nmol/L, n = 16, P < .001) or atrial fibrillation (1.52 +/- 0.69 versus 0.85 +/- 0.33 nmol/L, n = 9, P < .003). Furthermore, LASEC emerged as the only significant predictor of increased regional left atrial coagulation activity (P = .005) on stepwise multivariate logistic regression analysis.

CONCLUSIONS

Increased regional left atrial coagulation activity in mitral stenosis occurs in the presence of LASEC, is evident in either sinus rhythm or atrial fibrillation, and is associated with normal systemic coagulation activity.

Extracorporeal methods of vascular control for difficult IVC procedures

Surgical procedures in the juxtaheptic and intrapericardial inferior vena cava (IVC) are difficult because of the complexity of achieving vascular control in the area. We describe 10 patients with a variety of pathologies in this region who underwent venovenous bypass (VVB) or cardiopulmonary bypass with hypothermic circulatory arrest (CBCA). Renal cell carcinoma with IVC extension was present in three patients (with tumor extension into the right atrium in two), adrenal adenocarcinoma in one, septic IVC thrombus in one, and blunt IVC/hepatic trauma in five. Those patients without atrial involvement underwent VVB with a mean bypass time of 40 minutes (range 12-144). Those patients with tumor extension into the right atrium underwent CBCA with systemic hypothermia to 18(0)C, total body exsanguination for a bloodless field, and removal of the tumor by cavotomy and right atriotomy. The mean bypass, aortic cross-clamp, and circulatory arrest times were 152, 92, and 36 minutes, respectively. Eight of the 10 patients did well and went home within 4 weeks of surgery. Two patients died, one from metabolic sequelae of exsanguinating IVC injury (VVB) and one from sepsis 2 weeks postoperatively (CBCA).

Modified venovenous bypass technique for resection of renal and adrenal carcinomas with involvement of the inferior vena cava

Peripheric tumours with extension into the inferior vena cava pose difficult management problems. Venovenous bypass using a centrifugal pump to decompress the inferior vena cava may be useful adjunct during vascular isolation of the tumour. We have modified the technique by adding portal decompression to avoid visceral accumulation of toxic metabolites. We have used this technique in two patients who had intracaval extension of tumours, one renal and one adrenal carcinoma.

Anatomic considerations in penetrating gluteal wounds

A retrospective study of 81 patients with penetrating gluteal wounds was performed to determine if the site of penetration was useful in predicting the likelihood of associated vascular or visceral injury. There were 53 gunshot wounds and 28 stab wounds, including one impalement. The gluteal region was divided into upper and lower zones by determining whether entry occurred above or below the greater trochanters. Sixty-six percent of all penetrating gluteal wounds entered the upper zone. Thirty-two percent of patients with upper zone penetration had associated vascular or visceral injury. Only one of 27 patients with lower zone penetration sustained major injury. The site of entry plays a critical role in determining the likelihood of serious injury associated with penetrating gluteal wounds. Wounds penetrating above the greater trochanters demand thorough evaluation, especially gunshot wounds.

Prospective trial of the six hour rule in stab wounds of the chest

Stab wounds of the chest may be associated with a spectrum of injuries ranging from the lethal to the insignificant. The management of asymptomatic patients with stab wounds of the chest is controversial. The results of previous reports have asserted that asymptomatic patients with stab wounds of the chest do not have delayed complications develop if roentgenograms of the chest taken six hours after the injury are normal. This "rule" has not been validated. A three year, prospective study of patients with stab wounds of the chest was done. Patients were excluded from the study if they had symptoms on arrival, evidence of physiologic derangement caused by intrathoracic injury, wounds near the subclavian vessels or precordial wounds. Patients with lower thoracic stab wounds were evaluated by diagnostic peritoneal lavage. If findings from lavage were negative, the patients were included in the study. One hundred and five patients met the criteria for inclusion in the study group. All of the patients were hospitalized and examined serially. All had roentgenograms of the chest performed at admission, at six hours and at 24 hours. Four patients had a pneumothorax or hemothorax develop between the time of admission and six hours of hospitalization. In the remaining 101 patients, none had a pneumothorax or hemothorax between six and 24 hours. No patient asymptomatic on admission had a tension pneumothorax develop later. No patient had delayed evidence of abdominal injury. An asymptomatic patient with a stab wound of the chest that is not precordial, not in proximity to the subclavian artery and not suspected of diaphragmatic penetration should be serially examined and have a follow-up roentgenogram of the chest at six hours. If the patient remains asymptomatic and the six hour film is normal, delayed complications are rarely, if ever, encountered and the patient does not require further studies or hospitalization. The six hour rule for stab wounds of the chest is valid.

Reduced cell death in skin flaps in rats treated with difluoromethylornithine

The beneficial effects of alpha-difluoromethylornithine (DFMO) were assessed in a model of peripheral ischemia. DFMO is an irreversible inhibitor of ornithine decarboxylase (ODC), the initial enzyme in the production of polyamines. A 7 x 7 cm rat abdominal skin flap was surgically raised based on two inferior epigastric nerve, artery, and vein pedicles. One of the pedicles was then ligated and the skin was sutured back in place. Necrosis of skin was assessed 2 and 7 days after surgery. The rats were divided into four groups: control, DFMO, DFMO + polyamines, and polyamines alone. DFMO was administered in drinking water at 0.2%. Polyamines (putrescine, spermidine, and spermine) were each administered by daily i.p. injection at a dose of 10 mg/kg. The percentage of necrosis of the area of skin at risk in controls was 65 +/- 2% (mean +/- SEM). Necrosis was significantly reduced with DFMO (19 +/- 1%), with DFMO plus polyamines (37 +/- 3%), or with polyamines alone (41 +/- 2%). Protein synthesis and ornithine decarboxylase activity in the skin were both significantly decreased by DFMO. These studies demonstrate that DFMO protects skin from ischemic damage at least in part through actions on polyamine metabolism.

Cataleptogenic potency of the antipsychotic drugs is inversely correlated with neuronal activity in the amygdaloid complex of the rat

At doses known to elicit catalepsy in rats, haloperidol (1.0 and 2.0 mg/kg) and pimozide (4.0 mg/kg), injected intraperitoneally, failed to alter the spontaneous activity of neurons in the amygdaloid complex of locally anesthetized, immobilized rats. In contrast, clozapine and thioridazine, which are devoid of cataleptic effects even at high doses (10.0 and 20.0 mg/kg), caused a dramatic and prolonged increase in firing rate, whereas chlorpromazine, which produces relatively mild catalepsy at doses of 5.0 and 10.0 mg/kg, produced an intermediate response. These results, which were obtained throughout the amygdaloid complex, indicate that the cataleptogenic potency of the antipsychotic drugs is inversely correlated with their ability to accelerate neuronal activity. This finding is discussed in relation to the known mechanisms of action of these drugs on various neurotransmitter systems in the amygdaloid complex.

Interaction of alpha-methyldopa with autonomic reflex tachycardia in man

Effects of alpha-methyldopa on cardiovascular reflexes were studied in normal healthy volunteers, and comparisons made with clonidine. Graded bicycle ergometer exercise and cumulative nitroprusside infusions were used as stimuli to autonomic reflexes. alpha-Methyldopa produced reduction in resting heart rate and a parallel shift in the stimulus-heart rate response relationship to nitroprusside and exercise 5 h after bolus intravenous dosing with 1,500 mg, but no effects at 0.5, 1.75, and 3 h during cumulative intravenous dosing with 1,875 mg. Clonidine produced a similar pattern of change in nitroprusside responses as early as 0.5 h after an intravenous dose of 300 micrograms. After atropine, alpha-methyldopa still produced a parallel shift in the nitroprusside stimulus-heart rate response relationship; however, clonidine reduced resting heart rate and abolished all increments in heart rate to nitroprusside infusion. Quantitative and qualitative differences in the effects of alpha-methyldopa and clonidine on autonomic reflexes in humans indicate differences in sites or mechanisms of action within the autonomic nervous system.