Clustering autism: using neuroanatomical differences in 26 mouse models to gain insight into the heterogeneity.

Autism is a heritable disorder, with over 250 associated genes identified to date, yet no single gene accounts for >1-2% of cases. The clinical presentation, behavioural symptoms, imaging and histopathology findings are strikingly heterogeneous. A more complete understanding of autism can be obtained by examining multiple genetic or behavioural mouse models of autism using magnetic resonance imaging (MRI)-based neuroanatomical phenotyping. Twenty-six different mouse models were examined and the consistently found abnormal brain regions across models were parieto-temporal lobe, cerebellar cortex, frontal lobe, hypothalamus and striatum. These models separated into three distinct clusters, two of which can be linked to the under and over-connectivity found in autism. These clusters also identified previously unknown connections between Nrxn1α, En2 and Fmr1; Nlgn3, BTBR and Slc6A4; and also between X monosomy and Mecp2. With no single treatment for autism found, clustering autism using neuroanatomy and identifying these strong connections may prove to be a crucial step in predicting treatment response.

Behavioral and neurochemical effects of 3-OH-pip-BTCP, an active metabolite of BTCP in rats.

The effects of N-[1-(2-benzo[b]thiophenyl)cyclohexyl]piperidin-3-ol (3-OH-pip-BTCP), an active metabolite of N-[1-(2-benzo[b]thiophenyl)cyclohexyl]piperidine (BTCP) was examined on locomotor activity and dopamine (DA) levels in the nucleus accumbens (NAcc) in rats. To study the stimulant action of 3-OH-pip-BTCP, rats were placed into activity chambers and injected with the compound (0-40 mg/kg, i.p.). To measure the effects of 3-OH-pip-BTCP on DA levels, rats were implanted with microdialysis probes into the NAcc and the same doses as used in the locomotor activity experiment were administered i.p. 3-OH-pip-BTCP dose-dependently increased locomotor activity and DA levels in the NAcc which lasted 4-5 h at 20 and 40 mg/kg. The results suggest that 3-OH-pip-BTCP exerts long lasting stimulating effects on locomotion and extracellular DA levels in the NAcc, suggesting that 3-OH-pip-BTCP contributes importantly to the pharmacological effects of its parent compound, BTCP.

Enduring resistance to extinction of cocaine-seeking behavior induced by drug-related cues.

The conditioning of cocaine's pharmacological actions with environmental stimuli is thought to be a critical factor in long-lasting relapse risk associated with cocaine addiction. To study the significance of environmental stimuli in enduring vulnerability to relapse, the resistance to extinction of drug-seeking behavior elicited by a cocaine-related stimulus was examined. Male Wistar rats were trained to associate discriminative stimuli (S(D)) with the availability of intravenous cocaine (S(+)) vs. the availability of non-rewarding (S(-)) saline solution, and then placed on extinction conditions during which intravenous solutions and S(D) were withheld. The rats were then presented with the S(+) or S(-) alone in 60-min reinstatement sessions conducted at 3-day intervals. To examine the long-term persistence of the motivating effects of the cocaine S(+), a subgroup of rats was re-tested following an additional three months of abstinence during which time the rats remained confined to their home cages. Re-exposure to the cocaine S(+) selectively elicited robust responding at the previously active lever. The efficacy and selectivity of this stimulus to elicit responding remained unaltered throughout a 34-day phase of repeated testing as well as following the additional extended abstinence period. In pharmacological tests, conducted in a separate group of rats, the dopamine (DA) D(1) antagonist SCH 39166 (10 microg/kg), the D(2/3) antagonist nafadotride (1 mg/kg), and the D(2/3) agonist PD 128907 (0.3 mg/kg) suppressed the cue-induced response reinstatement while the D(1) agonist SKF 81297 (1.0 mg/kg) produced a variable behavioral profile attenuating cue-induced responding in some rats while exacerbating this behavior in others. The results suggest that the motivating effects of cocaine-related stimuli are highly resistant to extinction. The undiminished efficacy of the cocaine S(+) to induce drug-seeking behavior both with repeated testing and following long-term abstinence parallels the long-lasting nature of conditioned cue reactivity and cue-induced cocaine craving in humans, and confirms a significant role of learning factors in long-lasting vulnerability to relapse associated with cocaine addiction. Finally, the results support a role of DA neurotransmission in cue-induced cocaine-seeking behavior.

5-HT(1A) receptor mutant mice exhibit enhanced tonic, stress-induced and fluoxetine-induced serotonergic neurotransmission.

Mutant mice that lack serotonin(1A) receptors exhibit enhanced anxiety-related behaviors, a phenotype that is hypothesized to result from impaired autoinhibitory control of midbrain serotonergic neuronal firing. Here we examined the impact of serotonin(1A) receptor deletion on forebrain serotonin neurotransmission using in vivo microdialysis in the frontal cortex and ventral hippocampus of serotonin(1A) receptor mutant and wild-type mice. Baseline dialysate serotonin levels were significantly elevated in mutant animals as compared with wild-types both in frontal cortex (mutant = 0.44 +/- 0.05 n M; wild-type = 0.28 +/- 0.03 n M) and hippocampus (mutant = 0.46 +/- 0.07 n M; wild-type = 0.27 +/- 0.04 n M). A stressor known to elicit enhanced anxiety-like behaviors in serotonin(1A) receptor mutants increased dialysate 5-HT levels in the frontal cortex of mutant mice by 144% while producing no alteration in cortical 5-HT in wild-type mice. There was no phenotypic difference in the effect of this stressor on serotonin levels in the hippocampus. Fluoxetine produced significantly greater increases in dialysate 5-HT content in serotonin(1A) receptor mutants as compared with wild-types, with two- and three-fold greater responses being observed in the hippocampus and frontal cortex, respectively. This phenotypic effect was mimicked in wild-types by pretreatment with the serotonin(1A) antagonist 4-iodo-N-[2-[4-(methoxyphenyl)-1-piperazinyl]ethyl]-N-2-pyridinyl-benzamide (p-MPPI). These results indicate that deletion of central serotonin(1A) receptors results in a tonic disinhibition of central serotonin neurotransmission, with a greater dysregulation of serotonin release in the frontal cortex than ventral hippocampus under conditions of stress or increased interstitial serotonin levels.

Control of cocaine-seeking behavior by drug-associated stimuli in rats: effects on recovery of extinguished operant-responding and extracellular dopamine levels in amygdala and nucleus accumbens.

The conditioning of the pharmacological actions of cocaine with environmental stimuli is thought to be a critical factor in the long-term addictive potential of this drug. Cocaine-related stimuli may increase the likelihood of relapse by evoking drug craving, and brain-imaging studies have identified the amygdala and nucleus accumbens (NAcc) as putative neuroanatomical substrates for these effects of cocaine cues. To study the significance of environmental stimuli in the recovery of extinguished cocaine-seeking behavior, male Wistar rats were trained to associate discriminative stimuli (SDeltas) with response-contingent availability of intravenous cocaine vs. saline. The rats then were subjected to repeated extinction sessions during which cocaine, saline, and the respective SDeltas were withheld until the animals reached an extinction criterion of

Dopamine activation of endogenous cannabinoid signaling in dorsal striatum.

We measured endogenous cannabinoid release in dorsal striatum of freely moving rats by microdialysis and gas chromatography/mass spectrometry. Neural activity stimulated the release of anandamide, but not of other endogenous cannabinoids such as 2-arachidonylglycerol. Moreover, anandamide release was increased eightfold over baseline after local administration of the D2-like (D2, D3, D4) dopamine receptor agonist quinpirole, a response that was prevented by the D2-like receptor antagonist raclopride. Administration of the D1-like (D1, D5) receptor agonist SKF38393 had no such effect. These results suggest that functional interactions between endocannabinoid and dopaminergic systems may contribute to striatal signaling. In agreement with this hypothesis, pretreatment with the cannabinoid antagonist SR141716A enhanced the stimulation of motor behavior elicited by systemic administration of quinpirole. The endocannabinoid system therefore may act as an inhibitory feedback mechanism countering dopamine-induced facilitation of motor activity.

Simple microbore high-performance liquid chromatographic method for the determination of dopamine and cocaine from a single in vivo brain microdialysis sample.

A microbore chromatographic method for the analysis of both dopamine and cocaine from in vivo brain microdialysis samples is described. To eliminate the need for separate chromatographic systems for each analyte, post-column electrochemical and ultraviolet detection systems were arranged in series. The limit of quantitation for dopamine (5 fmol) was well within range for detecting dialysate concentrations of this neurotransmitter in rats which were in a baseline, drug-free state. The limit of quantitation for cocaine (0.5 pmol) was sufficient to detect brain cocaine levels following the peripheral administration of a low dose of this psychostimulant (5 mg/kg, i.p.). Estimates of dialysate dopamine and cocaine concentrations after 5, 10 and 20 mg/kg cocaine (i.p.) were in agreement with reports which utilized separate HPLC analyses for each analyte.

Ethanol anticipation enhances dopamine efflux in the nucleus accumbens of alcohol-preferring (P) but not Wistar rats.

It has been argued that the anticipation of ethanol consumption can activate reinforcement substrates involved in alcohol-seeking behavior. To test this hypothesis nucleus accumbens (NAc) dopamine (DA) efflux was monitored in alcohol-preferring (P) and Wistar rats. Rats from each line were divided into two groups: one trained to self-administer 0.05% saccharin and the other trained to self-administer 10% (w/v) ethanol. On the test day dopamine efflux was monitored in all animals during saccharin self-administration. In ethanol-expecting P rats, self-administration of saccharin produced a significant elevation in extracellular DA (150% of baseline within the first 15-20min). In contrast, a significant increase in extracellular DA was only observed during the final 30min of the test session in ethanol-expecting Wistar rats self-administering saccharin. The self-administration of saccharin in animals expecting the sweetener failed to elevate extracellular DA in both strains. Overall, these results suggest that the mere expectation of ethanol availability enhances the efflux of DA in the NAc of the P, but not the Wistar rat, which may play a role in the initiation or maintenance of ethanol seeking behavior in the P line.

Venous and arterial anomalies of the lower extremities diagnosed by duplex scanning.

The complex embryologic development of the vascular system often results in a myriad of clinically relevant anomalies. It has been stated that the classic anatomic venous pattern in the lower extremity is found in only 16 percent of patients. Previous studies on this topic are limited to isolated venous dissections or phlebography that lack complete anatomic detail. The recent introduction of high resolution duplex scanners for the assessment of veins of the lower extremity provides a unique opportunity to determine the incidence of anatomic variation. The current prospective study was done to identify venous or arterial anomalies apparent during routine duplex scanning of the lower extremity performed to rule out deep venous thrombosis (DVT). Limbs that had evidence of acute or chronic extensive DVT were excluded. Of 1,600 consecutive extremity scans, 946 extremities (59 percent) had no evidence of DVT. Of these, there were 43 patients with 64 anomalies in 57 extremities. The mean age of the group was 53.4 years. There were 24 women (55.8 percent) and 19 men (44.2 percent). There were 59 (92.2 percent) venous and five (7.8 percent) arterial anomalies. Duplication of the superficial femoral vein was the most common anomaly noted. Duplication of the deep femoral and popliteal vein was also noted. Unilateral anomalies were more common than bilateral anomalies, namely 67.4 versus 32.6 percent, respectively. Pain and swelling, common complaints in the patients with an anomaly, were noted in 71.4 and 45.7 percent, respectively. The frequency of deep venous anomalies of the lower extremities may be less than previously reported. Knowledge concerning the incidence and distribution of venous anomalies may lead to improved assessment and treatment of venous disease.

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.

Lower extremity calf thrombosis: to treat or not to treat?

Seventy-five patients with isolated calf vein thrombi were prospectively monitored with sequential duplex scans at 3- to 4-day intervals. Twenty-four patients (32%) propagated and 11 of these 24 (46%) into the popliteal or larger veins of the thigh. Sex, age, obesity, trauma, estrogen use, malignancy, varicose veins, smoking, surgery, and activity level were not predictive for proximal propagation. Proximal soleal vein thrombi had the highest incidence in both propagating and non-propagating groups. Thrombus extent and bilateral involvement were not predictive of propagation. Five percent (4 of 75 patients) had highly probable ventilation perfusion scans as their initial indication for duplex scanning. Deep vein thrombosis isolated to the calf is not a benign problem. If anticoagulant therapy is contraindicated, the progress of the thrombus can be followed by duplex scanning.

Measurement of blood flow rates in the lower extremities with use of a nuclear magnetic resonance based instrument.

Direct, noninvasive measurement of pulsatile blood flow to the human extremity is now possible by means of a flow measurement instrument that is based on the principles of nuclear magnetic resonance. The instrument uses a physically independent calibration module as a primary calibration standard. Volumetric calibration of this module indicates that it is precise and accurate over the range of 0 to 100 ml/min. The calibration module is used, in turn, to calibrate an electromagnetic flow sensor that is incorporated into the instrumentation. The calibration module and the electromagnetic sensor were found to be linearly related over the range of 5 to 100 ml/min, with a regression correlation coefficient of 0.996. The calibrated electromagnetic flow sensor is used as a secondary standard for calibration of the nuclear magnetic resonance sensor. Blood flow measurements, obtained by use of this method, agree closely with those obtained by plethysmographic methods. They differ from the plethysmographic results in that magnetic resonance flows will distinguish between the at-rest blood flow in the normal extremity and the flows seen in the extremity (also at rest) with claudication. Based on the results obtained from studying a limited number of limbs with a high degree of ischemia, the method will not distinguish the limb with ischemia from the limb with claudication. Limitations of the method and refinements required to make the method clinically useful are discussed.

Superficial thrombophlebitis diagnosed by duplex scanning.

Since July 1982, this noninvasive vascular laboratory has performed 12,856 lower extermity venous duplex examinations. All cases of acute venous thrombosis have been categorized and entered into a computer data base. One thousand four hundred twelve examinations were positive for acute venous thrombosis. This report analyzes the laboratory's entire experience with superficial thrombophlebitis (SVT). One hundred eighty-six patients were diagnosed by duplex scanning to have SVT. Women outnumbered men 99 to 87. They were slightly older (average age 58.4 +/- 16.2 years) compared with the men (53.8 +/- 14.2 years). Men were more likely to have a complicated course of SVT (40% vs 22%; p less than 0.01). Complications included either radiographically documented pulmonary embolism or deep venous involvement. Fifty-seven (31%) patients had at least one complication of SVT. A series of predisposing factors was analyzed and six factors were associated with an increased risk of complications. They are bilateral SVT (p less than 0.01), age greater than 60 years (p less than 0.01), male sex (p less than 0.01), history of deep venous thrombosis (p less than 0.01), bed rest (p less than 0.02), and presence of infection (p less than 0.02). Location of thrombus within the greater saphenous vein (35%) was most likely to be associated with complications. Isolated varicosities (8%) were least likely to be associated with complications. Duplex scanning identifies a significant number of complications of patients with SVT and should be obtained in cases of saphenous vein involvement or in the presence of associated risk factors.

Analysis of 1084 consecutive lower extremities involved with acute venous thrombosis diagnosed by duplex scanning.

A retrospective analysis of 8658 consecutive lower extremity venous duplex scans performed between the years 1982 to 1988 revealed 953 patients with involvement of 1084 extremities with acute deep or superficial thrombi. Records of patients with acute thrombi were then evaluated for the incidence, location, and patterns of distribution. There were 485 women (50.9%) and 468 men (49.1%), with a mean age of 62.9 +/- 16.7 years and 58.8 +/- 15.2 years, respectively. There were 371 right-sided thrombi (180 women and 191 men), 451 left-sided thrombi (235 women and 216 men), and 131 (70 women and 61 men) patients with thrombi in both lower extremities. Women were found to be uniformly older, and the left leg was found to be involved more frequently (p less than 0.05). The overall distribution of the 3169 veins involved with acute thrombi in decreasing order were: popliteal, 16.1%; superficial femoral, 15.0%; posterior tibial, 13.4%; common femoral, 13.2%; greater saphenous, 9.9%; soleal, 9.1%; peroneal, 7.2%; deep femoral, 6.6%; lesser saphenous, 5.7%; anterior tibial, 2.0%; varicosities, 1.6%; and perforating, 0.3%. A different rank order was found in analysis of single thrombus patterns as follows: greater saphenous, 27.5%; soleal, 20.1%; lesser saphenous, 13.4%; varicosities, 8.8%; popliteal, 8.1%; posterior tibial, 9.1%; common femoral, 3.5%; superficial femoral, 4.9%; peroneal, 2.8%; deep femoral, 1.0%; anterior tibial, 0.3%; and perforating, 0.3%. In patients with multiple and bilateral thrombi there was a large number of unique patterns of thrombosis. Locations, patterns, and frequency of acute venous thrombi vary with age, sex, and leg involved. Patterns and statistical analyses of pertinent observations were performed.

Upper extremity venous thrombosis diagnosed by duplex scanning.

The incidence of axillary-subclavian venous thrombosis continues to rise, while reports of noninvasive methods to diagnose this condition have been sparse. A review of the records of 693 consecutive upper extremity duplex scans was performed, and a diagnosis of acute venous thrombosis was made in 123 of these patients. Of these, 85 involved the axillary or subclavian vein. Use of a central venous catheter was the most common risk factor for axillary-subclavian venous thrombosis. Within this group, 8% had a pulmonary embolism, of which 25% were fatal. Follow-up of patients with axillary-subclavian venous thrombosis at a mean of 2 years revealed that 49% of these patients had died. Of the remaining patients, more than one third had evidence of the post-thrombotic syndrome. Duplex scanning of the venous system provides a safe, reliable, and repeatable method of evaluating and following patients with suspected venous thrombosis of the upper extremity.

Hypotension and bleeding with various anatomic patterns of blunt splenic injury in adults.

A retrospective study of 112 consecutive adult patients with blunt splenic lacerations was performed. All of the patients had operative grading of the splenic injuries according to a prospective protocol. Data on preoperative hypotension (systolic blood pressure of less than 100) and intraoperative splenic bleeding were collected from hospital records. Patients with subcapsular hematomas were excluded. Over-all, 55.4 per cent of the patients with splenic lacerations were hypotensive preoperatively and 76.6 per cent were noted to be bleeding from the spleen at operation. For injuries not involving the hilum, seven of 22 of the patients with Grade I injuries were hypotensive preoperatively versus 19 of 29 of the patients with Grade IV injuries (p = 0.025). Fourteen of 21 patients with Grade I injuries were noted to be bleeding at operation. Seventeen of 23 with Grade IV injuries were noted to be bleeding. This difference was not significant. Of the patients with injuries involving the hilum, 25 of 38 were hypotensive preoperatively and 25 of 29 were noted to be bleeding at operation. No difference in the incidence of hypotension or bleeding was found between superficial and deep hilar injuries. No significant difference was found between the active bleeding with hilar and nonhilar injuries (p = 0.19). For isolated splenic injuries (N = 36), the incidence of hypotension was 39 per cent. However, 79 per cent of the patients with isolated splenic injuries were noted to be bleeding at operation. Of 49 patients with nonisolated splenic injuries who had been hypotensive preoperatively, 72.9 per cent were found to be bleeding at operation. Of the 27 patients never hypotensive preoperatively, 78 per cent were noted to be bleeding at operation (NS). For isolated splenic injury also, no relationship was found between preoperative hypotension and the presence of operative bleeding. No significant correlation was found between preoperative hypotension or the anatomic grade of splenic injury and the incidence of bleeding found at operation. Even if computed tomographic scans can reliably grade splenic injuries, anatomic grade may not be a predictor of clinical behavior. Hypotension also failed to predict the occurrence of continued splenic bleeding.

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.