Midline and intralaminar thalamic connections with the orbital and medial prefrontal networks in macaque monkeys

Although the midline and intralaminar thalamic nuclei (MITN) were long believed to project "nonspecifically," they are now known from rat studies to have restricted connections to the prefrontal cortex. This has not been studied thoroughly in primates, however, and it is not known how MITN are associated with the "orbital" and "medial" prefrontal networks. This study examined the connections of MITN in cynomolgus monkeys (Macaca fascicularis). Experiments with retrograde and anterograde tracer injections into the orbital and medial prefrontal cortex (OMPFC) showed that MITN are strongly connected with the medial prefrontal network. The dorsal nuclei of the midline thalamus, including the paraventricular (Pa) and parataenial nuclei (Pt), had heavy connections with medial network areas 25, 32, and 14c in the subgenual region. Areas 13a and 12o, which are associated with both networks, were strongly connected with the Pt and the central intermedial nucleus, respectively. Otherwise, orbital network areas had weak connections with MITN. Anterograde tracer injections into the dorsal midline thalamus resulted in heavy terminal labeling in the medial prefrontal network, most notably in areas ventral to the genu of the corpus callosum (25, 32, and 14c), but also in adjacent areas (13a and 13b). Retrograde tracer injection into the dorsal midline labeled similar areas. The medial network, particularly the subgenual region, is involved in visceral and emotional control and has been implicated in mood disorders. The strong connections between the subgenual cortex and the Pa provide a pathway through which stress signals from the Pa may influence these prefrontal circuits.

The effects of acute stress on the regulation of central and basolateral amygdala CRF-binding protein gene expression

Corticotropin-releasing factor (CRF) is a key mediator of the behavioral, autonomic, and endocrine responses to stress. CRF binds two receptors and a CRF-binding protein (CRF-BP), which may inactivate or modulate the actions of CRF at its receptors. The amygdala is an important anatomical substrate for CRF and contains CRF, its receptors, and CRF-BP. Few studies have examined the effects of acute stress on the regulation of amygdala CRF-BP with other CRF system genes. Therefore, we examined the time course of the effects of acute restraint stress on central (CeA) and basolateral (BLA) amygdala CRF system genes. Consistent with our previous study, acute stress increased BLA CRF-BP mRNA shortly after stress offset. Surprisingly, BLA CRF-BP mRNA remained elevated up to 21 h after the stressor. This effect was selective in the BLA as stress did not alter CeA CRF-BP mRNA, and there were no changes in CRF or CRF receptor mRNAs in either amygdala nucleus. These results suggest that alterations in BLA CRF-BP gene expression are a primary response of the BLA/CeA CRF system to acute stress. Because CRF-BP can modulate CRF action, changes in amygdala CRF-BP levels after stress exposure may affect the ability of an organism to adapt to future stressors.

Complete atresia of coronary ostia in pulmonary atresia and intact ventricular septum

We describe the clinical course, echocardiography, angiography, and histopathology of a female infant with pulmonary atresia and intact ventricular septum (PA/IVS) with complete coronary ostial atresia and right ventricle-dependent coronary circulation who survived for 7 weeks after palliative surgery. The patient expired from myocardial insufficiency while waiting for a donor heart. Postmortem examination demonstrated atretic coronary ostia, ventricular sinusoids, and myocardial infarctions of various ages. This report suggests that neonates with PA/IVS who have this extreme form of coronary abnormality may potentially be managed medically and surgically until cardiac transplantation is available.

Diurnal changes in corticotropin-releasing hormone messenger RNA in the rat thalamus

Corticotropin-releasing hormone (CRH) is critical for mediating the stress response. CRH messenger RNA (mRNA) is present in a variety of brain regions including the thalamus and thalamic CRH mRNA concentrations increase in response to stress exposure. The present study assessed changes in basal CRH mRNA concentrations in the rat thalamus during different times of the day. Using in situ hybridization, we demonstrated that thalamic CRH mRNA levels exhibited more than two-fold increases during the dark phase between 20:00 and 02:00 h, followed by a decrease at 08:00 and 14:00 h during the light phase. Dramatic changes in thalamic CRH mRNA levels may have important implications for the possible role of thalamic CRH systems in waking, arousal, and the stress response.

Acute stress-induced increases in thalamic CRH mRNA are blocked by repeated stress exposure

Corticotropin-releasing hormone (CRH) coordinates multiple aspects of the stress response. Recently, CRH mRNA has been identified in two regions of the thalamus: the posterior nuclear group (Po), and a region located at the interface of the central medial and ventral posteromedial nucleus (parvicellular part) (CM-VPMpc). Previous studies demonstrated that in both regions CRH mRNA increases following 1 h of restraint stress, suggesting involvement of thalamic CRH in processing somatosensory and visceral information related to stress. The current study was proposed to further understand the effects of repeated and acute restraint stress on levels of thalamic CRH mRNA. Adult male rats were assigned to one of four groups in a 2 (repeated stress, no repeated) x2 (acute, no acute) design. Brain sections were processed for CRH mRNA in situ hybridization. ANOVA revealed no main effects of acute or repeated stress in either thalamic region. However, significant interactions between acute and repeated stress for levels of CRH mRNA were found for both regions of the thalamus. Compared to the no stress condition, acute restraint significantly increased CRH mRNA in the Po (39%) and the CM-VPMpc (32%). Repeated restraint did not alter baseline CRH mRNA levels, but blocked the acute restraint-induced effects. Thus, while acute stress increases levels of thalamic CRH mRNA, repeated exposure to the same stressor is without effect and prevents the acute response. These findings add to data establishing a role for thalamic CRH in the stress response and suggest a mechanism that may underlie habituation to repeated stress exposure.

Ultrasound-assisted cannulation of the right internal jugular vein during electrophysiologic studies in children

Percutaneous access of the right internal jugular vein for coronary sinus cannulation in pediatric patients undergoing electrophysiologic studies may be technically difficult. We report the use of an ultrasound-guided technique for obtaining jugular venous access. Forty-five pediatric patients who underwent electrophysiologic study were analyzed. Access was obtained in 100 % of the patients using this technique with no major complications. Ultrasound guidance for access of the internal jugular vein for coronary sinus cannulation during electrophysiologic studies in pediatric patients, may increase the success rate and prevent the development of complications.

Effects of acute and repeated restraint stress on corticotropin-releasing hormone binding protein mRNA in rat amygdala and dorsal hippocampus

Corticotropin-releasing hormone (CRH) mediates endocrine, behavioral, and autonomic responses to stress. In addition to binding to two receptor subtypes, CRH binds to a CRH-binding protein (CRH-BP). While CRH-BP is hypothesized to play a role in regulating levels of free CRH and modulating the stress response, the effects of stressors on brain CRH-BP are relatively unexplored. The present study determined effects of acute and repeated restraint on CRH-BP mRNA in basolateral amygdala (BLA) and dorsal hippocampus (DH), brain regions involved in fear and motivation. Using in situ hybridization, we found that a single acute period of restraint significantly increased CRH-BP mRNA in BLA by 20% but had no effect in DH. Repeated restraint had no effect on basal levels of CRH-BP mRNA in BLA or DH. Importantly, repeated restraint blocked the effects of acute restraint in the BLA. These results demonstrate differential effects of acute and repeated restraint on CRH-BP mRNA.

Corticotropin-releasing hormone messenger RNA distribution and stress-induced activation in the thalamus

Corticotropin-releasing hormone plays a critical role in mediating the stress response. Brain circuits hypothesized to mediate stress include the thalamus, which plays a pivotal role in distributing sensory information to cortical and subcortical structures. In situ hybridization revealed neurons containing corticotropin-releasing hormone messenger RNA in the posterior thalamic nuclear group and the central medial nucleus of the thalamus, which interfaces with the ventral posteromedial nucleus (parvicellular part). These regions are of interest because they process somatosensory and visceral information. In the first experiment, the effect of acute stress on thalamic corticotropin-releasing hormone messenger RNA levels was assessed. Rats restrained for 1 h and killed 1 h later were found to have increased corticotropin-releasing hormone messenger RNA in the posterior thalamic nuclear group. The time course of these changes was examined in a second experiment in which rats were killed immediately or 3 h after restraint. While no changes occurred in the thalamus immediately after restraint, 3 h after restraint, increases in corticotropin-releasing hormone messenger RNA occurred in both the posterior thalamic nuclear group and the central medial-ventral posteromedial nucleus (parvicellular part) of the thalamus. A different pattern of activation was observed in the paraventricular nucleus of the hypothalamus with increased corticotropin-releasing hormone messenger RNA immediately after restraint, but not 1 or 3 h later. In addition to the stress-induced changes, a prominent decrease in baseline thalamic corticotropin-releasing hormone messenger RNA was observed from 1000 to 1300 h. These results show that the thalamus contains corticotropin-releasing hormone messenger RNA that increases after restraint stress, indicating a role for thalamic corticotropin-releasing hormone systems in the stress response. Stress-induced changes in thalamic corticotropin-releasing hormone messenger RNA expression appears to be regulated differently than that in the paraventricular nucleus of the hypothalamus, and may be influenced by diurnal mechanisms.

Outcomes of transcatheter balloon angioplasty of obstruction in the neo-aortic arch after the Norwood operation

Obstruction of the reconstructed aortic arch, or the neoaortic arch, is now known to be an important factor increasing mortality after the Norwood operation for hypoplastic left heart syndrome. Transcatheter balloon angioplasty has been shown to provide effective relief of both native aortic coarctation and obstructions of the aortic arch occurring subsequent to therapeutic intervention. We sought to determine the outcomes of balloon angioplasty used as an initial treatment for obstruction of the neoaortic arch occurring after the Norwood operation. We gathered the characteristics of 58 patients with such obstruction from 8 institutions, noting procedural factors and outcomes of initial balloon dilation. Obstruction occurred at a median interval of 4 months, with a range from 1.5 months to 6.3 years, after a Norwood operation. Ventricular dysfunction was present before dilation in 13 patients. Mean peak to peak systolic pressure gradients were acutely reduced from 31+/-20 mm Hg to 6+/-9 mmHg (p<0.001), with outcome subjectively judged to be successful in 89%. Three patients with pre-existing ventricular dysfunction died within 48 hours of dilation. There were 10 additional deaths during the period of follow-up, with Kaplan Meier estimates of survival after intervention of 87% at 1 month, 77% at 12 months, and 72% after 15 months. In addition, 9 patients required re-intervention during the period of follow-up, with Kaplan Meier estimates of freedom from re-intervention after dilation of 87% at 6 months, 78% at 12 months and 74% after 18 months. Although transcatheter dilation of neoaortic arch obstructions after Norwood operation is successful, there is a high risk of re-intervention and ongoing mortality in this subgroup of patients. Close follow-up is recommended.

Regression of pulmonary arteriovenous malformations following heart transplantation

Pulmonary arteriovenous malformations (PAVMs) can occur following caval to pulmonary artery connection, Glenn and/or Fontan procedure, leading to severe cyanosis and exercise intolerance. It is unknown whether these abnormalities regress or persist following heart transplantation (HTx). Twenty patients with failed Fontan or Glenn procedures were screened for PAVMs prior to HTx by contrast echocardiography, selective pulmonary angiography, and pulmonary venous desaturation. Age at transplant, diagnosis, previous operations, time from Glenn to transplant, systemic oxygenation, hemoglobin level, and ventricular function were determined. The clinical course after HTx was characterized in three patients with significant PAVMs. Indications for HTx were exercise intolerance and severe cyanosis in one patient, and cyanosis and ventricular dysfunction in two. Pre-HTx, mean systemic saturation was 67%; mean pulmonary venous wedge saturation was 81%. Post-HTx, oxygen saturations were normal (> 96%) at 14, 40, and 180 days. Contrast echocardiography, performed 1 month to 3.3 yrs after HTx, showed no intrapulmonary shunting in two patients and minimal shunting in one. One patient suffered an embolic stroke from right-to-left shunting post-HTx. All patients are alive and well 35, 71, and 73 months post-HTx. In patients with single ventricle physiology, PAVMs are not an absolute contraindication to HTx. Heart-lung transplant may not be required for these patients.

A new technique for endomyocardial biopsy in infants and small children

Endomyocardial biopsy (EMB) is usually performed from the femoral veins in infants and small children. This requires the use of a long vascular sheath to direct a bioptome to the ventricular septum. We describe a technique of EMB in this population that obviates the need for the use of a long vascular sheath. A 5 Fr 0.038" internal diameter, no-sideholes Cobra catheter (Cook, Bloomington, IN) introduced via a 5 Fr short sheath was used to direct a 3 Fr, 60-cm-length Cook bioptome to the ventricular septum. From January 1998 to August 1999, this technique was used 22 times in seven patients for EMB (median, age 13 months; range, 1-72 months). Indications for EMB in this group were posttransplantation surveillance (21 times) and evaluation for cardiomyopathy/myocarditis (1). Median number of EMB specimens obtained per procedure was 6 (range, 5-9). There was one pneumopericardium seen post-EMB with this technique without hemodynamic embarrassment. EMB in infants and small children can be performed successfully, safely, and repeatedly from the femoral veins without the need for a long sheath.

Improvement of rejection-induced diastolic abnormalities in rat cardiac allografts with inducible nitric oxide synthase inhibition

OBJECTIVE

Inhibition of inducible nitric oxide synthase (nitric oxide II) activity has been proposed as a method to attenuate capillary leak and edema during rejection of heterotopically transplanted rat hearts. Myocardial edema has previously been implicated in diastolic dysfunction during allograft rejection. Accordingly, we tested the hypothesis that inducible nitric oxide synthase inhibition with aminoguanidine would alleviate left ventricular stiffening and myocardial edema formation in 4-day heterotopic rat heart allografts.

METHODS

Passive left ventricular filling was studied in American Cancer Institute Lewis rats receiving heterotopic heart transplants receiving either aminoguanidine, a selective nitric oxide synthase inhibitor (n = 6); dexamethasone (1 mg. kg(-1). d(-1) administered subcutaneously) for 4 days after transplantation (n = 6); or intravenous saline solution (n = 6). American Cancer Institute-to-American Cancer Institute isografts (n = 6) were used as controls.

RESULTS

Serum nitrite/nitrate levels in the aminoguanidine group (18 +/- 3 mmol/L) and dexamethasone group (22 +/- 4 mmol/L) were reduced versus the intravenous saline group (144 +/- 36 mmol/L [SEM]) to levels seen in controls (25 +/- 9 mmol/L). Left ventricular volume at 15 mm Hg for the aminoguanidine group was increased versus that for the intravenous saline solution group, similar to that for controls, and reduced versus dexamethasone-treated animals. Myocardial water content for the aminoguanidine-treated animals (78.3% +/- 0.4%) was similar to those of intravenous saline-treated animals (78.0% +/- 0. 3%) but greater than those of controls (77.1% +/- 0.2%) and dexamethasone-treated animals (76.7% +/- 0.3%).

CONCLUSIONS

Nitric oxide II inhibition with aminoguanidine minimizes the reduction in left ventricular filling that is seen with allograft rejection through a mechanism that is not associated with attenuation of myocardial edema.

Serial echocardiographic measurements of the pulmonary autograft in the aortic valve position after the Ross operation in a pediatric population using normal pulmonary artery dimensions as the reference standard

Serial echocardiographic measurements of the annulus and sinus were obtained in children before the Ross operation, and early and late postoperatively. Values were compared with normal standards for the aorta and pulmonary artery (PA). There was no significant difference between PA annulus measurements before surgery and the corresponding autograft immediately afterward (1.73 +/- 0.60 cm preoperatively; 1. 63 +/- 0.58 cm postoperatively, p = NS). Late after surgery the mean annulus diameter was enlarged compared with the normal aorta (DeltaZ 1.9 +/- 2.4), but remained relatively unchanged compared with the normal PA (DeltaZ 0.7 +/- 1.1, p <0.01). In contrast, the autograft sinus was dilated early after surgery (1.83 +/- 0.58 cm preoperatively; 2.18 +/- 0.73 cm postoperatively, p <0.01). Mean sinus Z score further increased compared with both the aorta (DeltaZ 1.3 +/- 1.7) and PA (DeltaZ 1.3 +/- 1.6). Use of standard PA measurements may be important in the assessment of autograft enlargement. Minimal change in autograft Z scores over time suggests that annulus enlargement is mainly due to somatic growth. In contrast, the autograft sinus showed an immediate and continued disproportionate increase in size over time, suggesting that sinus enlargement is largely due to passive dilation.

Outcome after orthotopic cardiac transplantation in adults with congenital heart disease

BACKGROUND

Advances in surgical and medical management have greatly improved long-term survival rates in patients with congenital heart disease (CHD). As these patients reach adulthood, myocardial dysfunction can occur, leading to cardiac transplantation.

METHODS AND RESULTS

We reviewed the pretransplantation and posttransplantation courses of 24 patients >18 years old (mean age, 26 years; range, 18 to 56 years) with CHD who received a transplant between January 1985 and September 1998. The relation between preoperative and perioperative risk factors for complications and death was assessed. Single ventricle was the pretransplantation diagnosis for 12 patients (50%), and d-transposition of the great vessels was the diagnosis for 4 patients (16%). Twenty-two patients had a mean of 2 previous operations. At cardiac transplantation, additional surgical procedures were required to correct extracardiac lesions in 18 patients (75%). Refractory heart failure was present in 22 patients, significant cyanosis was present in 7, and protein-losing enteropathy was present in 4. There were 5 early deaths due to bleeding (n=3) and infection (n=2). The Kaplan-Meier survival rate after cardiac transplantation was 79% at 1 year and 60% at 5 years. No anatomic or surgical risk factor was predictive of death. The outcome of patients with CHD who received a transplant was compared with that for patients without CHD (n=788). Mean bypass and ischemic times were significantly longer in patients with CHD than in patients without CHD. Survival rates after transplantation did not differ significantly between patients with and those without CHD (P=0.83).

CONCLUSIONS

Successful cardiac transplantation is obtainable in adults with complex CHD, with an outcome similar to that of patients without CHD. A detailed assessment of cardiac anatomy and careful surgical planning are essential to the pretransplantation and posttransplantation management of these patients.

Coronary perfusate composition influences diastolic properties, myocardial water content, and histologic characteristics of the rat left ventricle

BACKGROUND

Recent studies found that edema, histology, and left ventricular diastolic compliance exhibit quantitative relationships in rats. Edema due to low osmolarity coronary perfusates increases myocardial water content and histologic edema score and decreases left ventricular filling. The present study examined effects of perfusate osmolarity and chemical composition on rat hearts.

METHODS

Arrested American Cancer Institute (ACI) rat hearts (4 degrees C) were perfused with different cardioplegia solutions, including Plegisol (289 mOsm/L), dilute Plegisol (172 mOsm/L), Stanford solution (409 mOsm/L), and University of Wisconsin solution (315 mOsm/L). Controls had blood perfusion (310 mOsm/L). Postmortem left ventricular pressure-volume curves and myocardial water content were measured. After glutaraldehyde or formalin fixation, dehydration, and paraffin embedding, edema was graded subjectively.

RESULTS

Myocardial water content reflected perfusate osmolarity, being lowest in Stanford and University of Wisconsin solutions (p<0.05 versus other groups) and highest in dilute Plegisol (p<0.05). Left ventricular filling volumes were smallest in dilute Plegisol and Plegisol (p<0.05). Osmolarity was not a major determinant of myocardial edema grade, which was highest with University of Wisconsin solution and dilute Plegisol (p<0.05 versus other groups).

CONCLUSIONS

Perfusate osmolarity determined myocardial water content and left ventricular filling volume. However, perfusate chemical composition influenced the histologic appearance of edema. Pathologic grading of edema can be influenced by factors other than osmolarity alone.

Pressure volume curves in arrested heterotopic rat heart isografts: role of improved myocardial protection

BACKGROUND

To minimize decreases in left ventricular (LV) compliance immediately after rat heart transplantation, we tested several different methods of myocardial protection.

MATERIALS AND METHODS

Five groups of ACI rat hearts (n = 6 each) were arrested by coronary perfusion with 5 ml of UW (University of Wisconsin), UW-BDM (UW with 2,3-butanedione monoxime), CU (Columbia University), or CU-BDM solution or by LV injection of potassium chloride and Ringer's lactate immersion (KCl/RL). After abdominal isografting and blood reperfusion for 15 min, transplanted hearts (TxH) were arrested and excised. Diastolic LV pressure-volume curves (LVPVCs) were correlated with myocardial water content (MWC). Native hearts (NH) were arrested identically to TxH and maintained at 4 degrees C by immersion. LVPVCs were measured at 15-min intervals for 90 min.

RESULTS

In three of four pressure intervals at Time 0, normalized LV volume (LVV) was smaller (P < 0.05, ANOVA) in KCl/RL native hearts than in the four perfusion groups. LVV decreased significantly in NH after 45-75 min; LVV decreased similarly with time in all groups. In TxH, postarrest LVVs were higher with UW-BDM, CU-BDM, and CU than with UW or KCl/RL (P < 0.05, ANOVA). Expressing LVV of TxH as a percentage of NH, UW-BDM, CU, and CU-BDM provided qualitatively better diastolic properties than KCl/RL and UW.

CONCLUSIONS

Thus rat LVPVCs can be improved after heart transplantation with alternative strategies of myocardial protection. KCl arrest decreases LV filling volume in this model and should be avoided.

Incidence and outcome of primary Epstein-Barr virus infection and lymphoproliferative disease in pediatric heart transplant recipients

BACKGROUND

The objective of this study was to assess the relationship between Epstein-Barr virus (EBV) infection and posttransplantation lymphoproliferative disease (PTLD) in pediatric heart transplant recipients. EBV is implicated in the development of PTLD. However, the relationship between primary EBV infection and PTLD is not well understood.

METHODS

Serial EBV titers were determined prospectively in 50 children before and after heart transplantation. Results were correlated with the development of PTLD. The clinical presentation, management, and outcome of PTLD were characterized.

RESULTS

Before transplantation, EBV titers were positive in 19 and negative in 31 patients. After transplantation, all EBV-positive patients remained positive; 1 developed PTLD. Among EBV-negative patients, 12 of 31 remained negative; none developed PTLD. Nineteen patients demonstrated serologic evidence of primary EBV infection after heart transplantation; 12 developed PTLD. Mean follow-up after heart transplantation was 3.3 years (range 0.4 to 8.4 years). Mean time from heart transplantation to histologic confirmation of PTLD was 29 months (range 3 to 72 months). Survival with PTLD was 92%.

CONCLUSIONS

Twelve of 13 pediatric heart transplant recipients who developed PTLD had evidence of primary EBV infection. Serial monitoring of EBV titers may lead to earlier identification and improved treatment of PTLD.

Effect of improved myocardial protection on edema and diastolic properties of the rat left ventricle during acute allograft rejection

BACKGROUND

Studies of myocardial edema and diastolic dysfunction in rat heart transplantation have been flawed by ischemic injury. This study uses improved methods to prevent ischemic contracture.

METHODS

Hearts of 30 ACI rats were transplanted into the abdomen of Lewis rats by use of cold University of Wisconsin solution for improved preservation. Left ventricular diastolic properties were expressed as volume at standardized pressure intervals.

RESULTS

On posttransplantation day 3, mean left ventricular volume at 15 mm Hg in allografts (290 +/- 9 microl, SEM) was not significantly different vs isografts (299 +/- 32 microl), allografts on day 0 (337 +/- 28 ml) or day 1 (324 +/- 20 microl), or native hearts (334 +/- 19 microl). However, volume was reduced to 173 +/- 17 microl on day 4 and to 70 +/- 23 microl on day 5 (p < 0.05). Similar findings were obtained for volume at 5 and 10 mm Hg. Allograft myocardial water content on day 3, 76.3% +/- 5%, similar to allografts on day 0 and 1 and to isografts on day 3, increased to 77.6% +/- 8% on day 4 (NS) and 79.4% +/- 6% on day 5 (p < 0.05 vs day 0). Histologically, rejection in allografts was mild on day 3, moderate on day 4, and severe on day 5.

CONCLUSIONS

Reduced left ventricular filling volume during rejection is only partially explained by edema. Abnormalities of diastolic properties previously attributed to the unloaded state of nonworking heart models may actually reflect inadequate peritransplantation myocardial protection.

The morphologic and molecular genetic categories of posttransplantation lymphoproliferative disorders are clinically relevant

BACKGROUND

Posttransplantation lymphoproliferative disorders (PT-LPDs) are a well-known complication of immunosuppression associated with solid organ transplantation. The clinical course of PT-LPDs is unpredictable; some patients experience regression of all lesions with a reduction in immunosuppression, whereas other patients, despite chemotherapy, radiation therapy, or surgery, rapidly die of their disease. In this study, the authors attempted to establish whether the previously described morphologic and molecular genetic categories of PT-LPD--plasmacytic hyperplasia (PH), polymorphic PT-LPD (polymorphic), and malignant lymphoma/multiple myeloma (ML/MM)--are clinically relevant and helpful in predicting the clinical outcome of patients who develop these lesions.

METHODS

To determine the clinical significance of the morphologic and molecular genetic categories of PT-LPDs, the clinical characteristics of 32 solid organ transplant recipients (26 heart, 5 kidney, and 1 lung), including age, time from transplantation to development of PT-LPD, stage of disease, and clinical outcome, were compared with the morphologic and molecular genetic features of the 41 PT-LPDs that they developed (15 PH in 12 patients, 19 polymorphic in 16 patients, and 7 ML/MM in 6 patients). Clinical outcome was defined by the following categories: 1) regression (after a reduction in immunosuppression) and surgical resolution (by surgical excision, with or without a reduction in immunosuppression); 2) medical resolution (by chemotherapy and/or radiation therapy); and 3) no response.

RESULTS

Although there was no difference in the time from transplantation to PT-LPD development among patients belonging to the three morphologic and molecular genetic categories, there was a significant difference in patient age at the time of PT-LPD development (P < 0.0098). Younger patients developed PH (mean age of 19 years), whereas older patients developed polymorphic PT-LPD (mean age of 35 years) and ML/MM (mean age of 56 years). Patients with PH presented with lower stages of disease (Stages I-II) than patients with ML/MM (P < 0.0004). Furthermore, there was a statistically significant trend between morphologic and molecular genetic category and clinical outcome, with decreased likelihood that lesions categorized as PH, polymorphic, or ML/MM would regress with a reduction in immunosuppression or be resolved by surgery, whereas those classified as ML/MM were more likely to exhibit no response to aggressive clinical intervention (P < 0.00006). Furthermore, no patients with PH died, whereas 20% with polymorphic PT-LPD and 67% with ML/MM died as a direct result of their PT-LPDs.

CONCLUSIONS

This study strongly suggests that classification of PT-LPDs into the morphologic and molecular genetic categories PH, polymorphic, PT-LPD and ML/MM is clinically relevant.

Rapid stress-induced elevations in corticotropin-releasing hormone mRNA in rat central amygdala nucleus and hypothalamic paraventricular nucleus: an in situ hybridization analysis

High densities of nerve cells containing corticotropin-releasing hormone (CRH) are located in the central nucleus of the amygdala (CeA) and paraventricular nucleus (PVN) of the hypothalamus. These brain regions play an important role in activating autonomic, behavioral, and endocrine responses to stress. This study was conducted to provide needed information concerning the acute effects of stress on CeA and PVN CRH mRNA expression. Rats were exposed to restraint stress for 1 h and brains collected after a 1-h post-stress interval. CRH mRNA expression occurring in the CeA and PVN was examined using in situ hybridization techniques. Densitometric analysis revealed that acute restraint stress produced significant increases in CRH mRNA levels in the PVN and in the rostral CeA region. In addition, the area in the rostral CeA encompassing high CRH mRNA signals increased significantly after stress. Results provide clear evidence that CRH neurons in the CeA and PVN exhibit rapid increases in CRH mRNA expression after exposure to stress.

Diastolic properties, myocardial water content, and histologic condition of the rat left ventricle: effect of varied osmolarity of a coronary perfusate

BACKGROUND

Although myocardial edema is known to impair diastolic filling of the left ventricle, the interrelation of edema, histologic condition, and function has not been quantitated sufficiently for extrapolation to studies of multifactorial influences on diastolic properties.

METHODS

Accordingly, ACI rat hearts arrested at 4 degrees C underwent coronary artery perfusion with a cardioplegia solution that was either unaltered (288 mOsm/L, P288 group, n = 6), diluted (144 mOsm/L, P144 group, n = 6), or concentrated (380 mOsm/L, P380 group, n = 6). Postmortem left ventricular pressure-volume curves and myocardial water content were measured. Myocardial samples were fixed in varying dilutions of glutaraldehyde. After dehydration and paraffin embedding, edema was graded subjectively (0 to 5), and myocardial interstitial spaces were determined by use of a semiquantitative method.

RESULTS

Mean normalized left ventricular filling volume at 20 mm Hg filling pressure in the P144 group, 189 +/- 16 microliters (SEM), was reduced versus both the P288 (278 +/- 26 microliters) and the P380 (332 +/- 18 microliters) groups (p < 0.05, ANOVA). Mean myocardial water content in the P144 group, 80.7% +/- 1%, was increased versus the P380 (76.7% +/- 0.4%, p < 0.05) but not versus the P288 group (78.4% +/- 0.8%). In hearts preserved with 2.5% glutaraldehyde, mean edema grade and interstitial space in the P144 group (4.0 +/- 0.3) were increased versus the P380 (1.8 +/- 0.3, p < 0.05) but not the P288 group (2.7 +/- 0.5). Derived linear regressions relate water content to filling volume and histologic condition.

CONCLUSIONS

Coronary perfusate osmolarity is thus associated with predictable changes in myocardial water content, left ventricular filling volume, and edema. These correlations allow definition of new hypotheses for the study of cardiac allograft rejection in patients and experimental animals.

Outcome after the single-stage, nonfenestrated Fontan procedure

BACKGROUND

A completed Fontan circulation is the goal in the management of patients with single-ventricle physiology. To achieve this end, a two-stage rather than a single-stage approach is carried out routinely at many centers. Some groups have advocated baffle fenestration for virtually all patients to minimize post-Fontan complications. Other centers perform single-stage Fontan operations and do not fenestrate. Thus controversies have arisen regarding the indications for the staged procedure versus single stage and for fenestration versus no fenestration.

METHODS AND RESULTS

The preoperative risk factors and postoperative course were characterized in 61 consecutive patients (median age, 3.3 years) undergoing a single-stage, nonfenestrated Fontan. The patients were followed for 3.5+/-1.9 years. The relationship between preoperative risk factors and mortality and morbidity was assessed. Preoperative risk factors assessed included age <2 years (n=18), branch pulmonary artery stenosis (n=20), elevated mean pulmonary artery pressure >15 mm Hg (n=16), atrioventricular valve regurgitation (n=5), and decreased ventricular function (n=2). Total caval pulmonary anastomosis was performed in 53 patients. Additional surgery was required at the time of the Fontan in 25 patients (41%). The median duration of mechanical ventilation was 1 day; median chest tube drainage was 5.5 days (range, 1 to 35). Oxygen saturation rose significantly postoperatively, from 83% to 95%. Early mortality was 4.9%; one patient died from pacemaker failure 9 months postoperatively, and one patient underwent successful heart transplant 4 months post-Fontan. One- and 5-year actuarial survival was 93%. No preoperative risk factor was associated with a failed Fontan or significant effusions.

CONCLUSIONS

A single-stage, nonfenestrated Fontan was performed in a large group of patients with excellent surgical results and intermediate outcome. There is no evidence that a two-stage approach and/or baffle fenestration is required for a large cohort of patients who are candidates for a Fontan operation.

Long-term survivors of pediatric heart transplantation: a multicenter report of sixty-eight children who have survived longer than five years

OBJECTIVE

Short-term survival after pediatric heart transplantation is now excellent, but ultimately the efficacy of this procedure will depend on duration and quality of survival. We sought to evaluate the clinical course of long-term survivors of heart transplantation in childhood.

METHODS

Patients who had undergone heart transplantation at the university hospitals of Stanford, Columbia, and Pittsburgh between 1975 and 1989 and survived longer than 5 years from transplantation were identified and their clinical courses retrospectively reviewed.

RESULTS

Sixty eight children have survived more than 5 years from transplantation, and 60 (88%) are currently alive with a median follow-up of 6.8 years (5 to 17.9 years). Thirteen have survived more than 10 years from transplantation. Renal dysfunction caused by immunosuppressive agents was common, and two patients required late renal transplantation. Lymphoproliferative disease or other neoplasm occurred in 12 patients, but none resulted in death. Coronary artery disease was diagnosed in 13 patients (19%), leading to retransplantation in eight. Death after 5 years was related to acute or chronic rejection in 5 of 8 cases. Two of the deaths were directly related to noncompliance with immunosuppressive medication. All survivors are in New York Heart Association class 1.

CONCLUSIONS

Long-term survival with good quality of life can be achieved after heart transplantation in childhood, though complications of immunosuppression remain common. Posttransplantation coronary artery disease is emerging as the main factor limiting long term graft and patient survival.