Double-outlet right ventricle and double septal defects in a Rhesus macaque (Macaca mulatta)

Double-outlet right ventricle (DORV) is a rare form of congenital heart defect, in which both great arteries (aorta and pulmonary trunk) arise from the right ventricle. The defect affects 1-1.5% of patients with congenital heart disease with a frequency of 1 in 10,000 live births in human beings. A 6-year-old male India-origin Rhesus macaque (Macaca mulatta) with no history of illness or trauma presented for project pre-assignment physical examination from the outdoor breeding colony at the Tulane National Primate Research Center (Covington, Louisiana). Upon physical examination, the animal was found to have poor body condition with a body condition score of 1 out of 5. Thoracic auscultation revealed caudal displacement of the heart with a grade VI/VI pansystolic murmur bilaterally. Thoracic radiographs showed a globoid heart with significant enlargement of the left atrium, left auricle, and both ventricles. The aortic shadow was not prominent, but the pulmonary artery trunk was enlarged ( Grossly, the animal was severely emaciated and dehydrated with diffuse muscular atrophy. The skin and external mucosa were moderately cyanotic. The heart was markedly enlarged and globoid with severe dilation of the left atrium and auricle and marked enlargement of both ventricles. Externally, the ascending aorta lay nearly parallel, right, and slightly posterior to the dilated and thin-walled pulmonary trun

Longitudinal evaluation of the functional connectivity changes in the secondary somatosensory cortex (S2) of the monkey brain during acute stroke

Background: Somatosensory deficits are frequently seen in acute stroke patients and may recover over time and affect functional outcome. However, the underlying mechanism of function recovery remains poorly understood. In the present study, progressive function alteration of the secondary somatosensory cortex (S2) and its relationship with regional perfusion and neurological outcome were examined using a monkey model of stroke. Methods and materials: Rhesus monkeys (n = 4) were induced with permanent middle cerebral artery occlusion (pMCAo). Resting-state functional MRI, dynamic susceptibility contrast perfusion MRI, diffusion-weighted, T1 and T2 weighted images were collected before surgery and at 4–6, 48, and 96 h post stroke on a 3T scanner. Progressive changes of relative functional connectivity (FC), cerebral blood flow (CBF), and CBF/Tmax (Time to Maximum) of affected S2 regions were evaluated. Neurological deficits were assessed using the Spetzler approach. Results: Ischemic lesion was evidently seen in the MCA territory including S2 in each monkey. Relative FC of injured S2 regions decreased substantially following stroke. Spetzler scores dropped substantially at 24 h post stroke but slightly recovered from Day 2 to Day 4. Relative FC progressively increased from 6 to 48 and 96 h post stroke and correlated significantly with relative CBFand CBF/Tmax changes. Conclusion: The present study revealed the progressive alteration of function connectivity in S2 during acute stroke. The preliminary results suggested the function recovery might start couple days post occlusion and collateral circulation might play a key role in the recovery of somatosensory function after stroke insult. The relative function connectivity in S2 may provide additional information for prediction of functional outcome in stroke patients

Temporal evolution of ischemic lesions in nonhuman primates: a diffusion and perfusion MRI study.

BACKGROUND AND PURPOSE:Diffusion-weighted imaging (DWI) and perfusion MRI were used to examine the spatiotemporal evolution of stroke lesions in adult macaques with ischemic occlusion. METHODS:Permanent MCA occlusion was induced with silk sutures through an interventional approach via the femoral artery in adult rhesus monkeys (n = 8, 10-21 years old). The stroke lesions were examined with high-resolution DWI and perfusion MRI, and T2-weighted imaging (T2W) on a clinical 3T scanner at 1-6, 48, and 96 hours post occlusion and validated with H&E staining. RESULTS:The stroke infarct evolved via a natural logarithmic pattern with the mean infarct growth rate = 1.38 ± 1.32 ml per logarithmic time scale (hours) (n = 7) in the hyperacute phase (1-6 hours). The mean infarct volume after 6 hours post occlusion was 3.6±2.8 ml (n = 7, by DWI) and increased to 3.9±2.9 ml (n = 5, by T2W) after 48 hours, and to 4.7±2.2ml (n = 3, by T2W) after 96 hours post occlusion. The infarct volumes predicted by the natural logarithmic function were correlated significantly with the T2W-derived lesion volumes (n = 5, r = 0.92, p = 0.01) at 48 hours post occlusion. The final infarct volumes derived from T2W were correlated significantly with those from H&E staining (r = 0.999, p < 0.0001, n = 4). In addition, the diffusion-perfusion mismatch was visible generally at 6 hours but nearly diminished at 48 hours post occlusion. CONCLUSION:The infarct evolution follows a natural logarithmic pattern in the hyperacute phase of stroke. The logarithmic pattern of evolution could last up to 48 hours after stroke onset and may be used to predict the infarct volume growth during the acute phase of ischemic stroke. The nonhuman primate model, MRI protocols, and post data processing strategy may provide an excellent platform for characterizing the evolution of acute stroke lesion in mechanistic studies and therapeutic interventions of stroke disease

Longitudinal MRI Evaluation of Ischemic Stroke in the Basal Ganglia of a Rhesus Macaque (Macaca mulatta) with Seizures.

An adult rhesus macaque developed seizures after the induction of ischemic stroke. Initially, on the day of surgery, a focal ischemic lesion was present exclusively in the right caudate nucleus. By 48 h after stroke induction, the lesion had extended into the putamen, when a seizure was observed. Our report highlights the temporal changes in infarction of unilateral basal ganglia after acute stroke and the accompanying clinical symptoms. This unusual case may provide additional information regarding the involvement of the basal ganglia in seizures, given that prior case reports and studies usually have not described the temporal and spatial evolution of the lesion before clinical symptoms emerge

Longitudinal MRI Evaluation of Ischemic Stroke in the Basal Ganglia of a Rhesus Macaque (Macaca mulatta) with Seizures.

An adult rhesus macaque developed seizures after the induction of ischemic stroke. Initially, on the day of surgery, a focal ischemic lesion was present exclusively in the right caudate nucleus. By 48 h after stroke induction, the lesion had extended into the putamen, when a seizure was observed. Our report highlights the temporal changes in infarction of unilateral basal ganglia after acute stroke and the accompanying clinical symptoms. This unusual case may provide additional information regarding the involvement of the basal ganglia in seizures, given that prior case reports and studies usually have not described the temporal and spatial evolution of the lesion before clinical symptoms emerge

Stroke lesion evolution.

<p>Top: Axial DWI images of Subject RJJ3 at 48 hours post stroke show the entire infarct territory. Bottom: representative DWI images of RJJ3 demonstrate the infarct evolution at different time point (in hours) post MCA occlusion.</p

Temporal volumetric changes of stroke infarct in each subject during the hyperacute phase (1–6 hours).

<p>A natural logarithmic fitting was performed for each data set. Y-axis: volume (ml); X-axis: hours post MCA occlusion.</p

Illustration of ischemic lesions on T2W images and histology sections.

<p>Top: Axial T2W images of Subject RVG4. Middle: Reconstructed coronal T2W images of the same stroke monkey. Bottom: H&E staining of this stroke monkey brain sample.</p