BACKGROUND:Perforator flaps of the upper thigh or buttock provide a valuable secondary choice in autologous breast reconstruction. The purpose of this study was to compare the vascular territories ...and supplying vessels of the transverse myocutaneous gracilis flap, the profunda artery perforator flap, and the fasciocutaneous infragluteal flap.
METHODS:In total, 26 lower limbs from 13 fresh specimens were investigated. All flap pedicles were selectively injected with methylene blue, eosin red, or green ink. The pedicle external diameters, lengths, and locations were measured. The dimensions of angiosomes, their intraindividual and interindividual correlations, and their relations to anatomical landmarks were analyzed.
RESULTS:The profunda artery perforator pedicle had the greatest mean external diameter with 3.6 ± 0.7 mm, followed by the transverse myocutaneous gracilis and fasciocutaneous infragluteal pedicles with 2.9 ± 0.6 mm and 2.9 ± 0.7 mm, respectively. The fasciocutaneous infragluteal pedicle was longest with a mean length of 12.5 ± 1.5 cm, whereas the profunda artery perforator and transverse myocutaneous gracilis pedicles had lengths of 8.8 ± 1.0 cm and 6.7 ± 1 cm on average. The profunda artery perforator angiosome provided the largest size, with a mean area of 98.5 ± 26.7 cm, followed by the fasciocutaneous infragluteal angiosome (77.2 ± 9.0 cm) and the transverse myocutaneous gracilis angiosome (74.1 ± 32.1 cm).
CONCLUSIONS:The authors’ anatomical findings about the transverse myocutaneous gracilis, profunda artery perforator, and fasciocutaneous infragluteal territories provide clinically valuable data for flap selection in breast reconstruction if an abdominal flap is not feasible.
This study investigated the postherpetic neuralgia pain-related brain regions and the underlying seed-based networks detected by arterial spin labeling.
This article investigates the effects of ...postherpetic neuralgia (PHN) on resting-state brain activity utilizing arterial spin labeling (ASL) techniques. Features of static and dynamic cerebral blood flow (CBF) were analyzed to reflect the specific brain response to PHN pain. Eleven consecutive patients suffering from PHN and 11 age- and gender-matched control subjects underwent perfusion functional magnetic resonance imaging brain scanning during the resting state. Group comparison was conducted to detect the regions with significant changes of CBF in PHN patients. Then we chose those regions that were highly correlated with the self-reported pain intensity as “seeds” to calculate the functional connectivity of both groups. Absolute CBF values of these regions were also compared across PHN patients and control subjects. Significant increases in CBF of the patient group were observed in left striatum, right thalamus, left primary somatosensory cortex (S1), left insula, left amygdala, left primary somatomotor cortex, and left inferior parietal lobule. Significant decreases in CBF were mainly located in the frontal cortex. Regional CBF in the left caudate, left insula, left S1, and right thalamus was highly correlated with the pain intensity, and further comparison showed that the regional CBF in these regions is significantly higher in PHN groups. Functional connectivity results demonstrated that the reward circuitry involved in striatum, prefrontal cortex, amygdala, and parahippocampal gyrus and the circuitry among striatum, thalamus, and insula were highly correlated with each element in PHN patients. In addition, noninvasive brain perfusion imaging at rest may provide novel insights into the central mechanisms underlying PHN pain.
The complex processing architecture underlying attentional control requires delineation of the functional role of different control-related brain networks. A key component is the cingulo-opercular ...(CO) network composed of anterior insula/operculum, dorsal anterior cingulate cortex, and thalamus. Its function has been particularly difficult to characterize due to the network's pervasive activity and frequent co-activation with other control-related networks. We previously suggested this network to underlie intrinsically maintained tonic alertness. Here, we tested this hypothesis by separately manipulating the demand for selective attention and for tonic alertness in a two-factorial, continuous pitch discrimination paradigm. The 2 factors had independent behavioral effects. Functional imaging revealed that activity as well as functional connectivity in the CO network increased when the task required more tonic alertness. Conversely, heightened selective attention to pitch increased activity in the dorsal attention (DAT) network but not in the CO network. Across participants, performance accuracy showed dissociable correlation patterns with activity in the CO, DAT, and fronto-parietal (FP) control networks. These results support tonic alertness as a fundamental function of the CO network. They further the characterization of this function as the effortful process of maintaining cognitive faculties available for current processing requirements.
Although cerebral blood flow (CBF) alterations are associated with Alzheimer’s disease (AD), CBF patterns across prodromal stages of AD remain unclear. Therefore, we investigated patterns of regional ...CBF in 162 Alzheimer’s Disease Neuroimaging Initiative participants characterized as cognitively unimpaired (CU; n = 80), objectively-defined subtle cognitive decline (Obj-SCD; n = 31), or mild cognitive impairment (MCI; n = 51). Arterial spin labeling MRI quantified regional CBF in a priori regions of interest: hippocampus, inferior temporal gyrus, inferior parietal lobe, medial orbitofrontal cortex, and rostral middle frontal gyrus. Obj-SCD participants had increased hippocampal and inferior parietal CBF relative to CU and MCI participants and increased inferior temporal CBF relative to MCI participants. CU and MCI groups did not differ in hippocampal or inferior parietal CBF, but CU participants had increased inferior temporal CBF relative to MCI participants. There were no CBF group differences in the two frontal regions. Thus, we found an inverted-U pattern of CBF signal across prodromal AD stages in regions susceptible to early AD pathology. Hippocampal and inferior parietal hyperperfusion in Obj-SCD may reflect early neurovascular dysregulation, whereby higher CBF is needed to maintain cognitive functioning relative to MCI participants, yet is also reflective of early cognitive inefficiencies that distinguish Obj-SCD from CU participants.
The goal of this study was the investigation of the arterial blood supply to the maxillary sinus to give clinicians the basis for a better understanding of the origin of vascular complications that ...can derive from surgical procedures at this level. The study consisted of 30 sinuses from 15 human cadavers with an age range of 59 to 90 years. To define the complex vascularization of the maxillary sinus, the afferent vascular network was injected with liquid latex mixed with red india ink through the external carotid arteries. An intraosseous anastomosis between the dental branch of the posterior superior alveolar artery, also known as alveolar antral artery, and the infraorbital artery was found in 100% of cases. Such an anastomosis seemed to guarantee the blood supply to the sinus membrane, to the periosteal tissues, and especially to the anterior lateral wall of the sinus. Moreover, the gingival branch of the posterior superior alveolar artery was found to anastomose an extraosseous branch of the infraorbital artery in 10 sinuses. The examination of the maxillary sinus also showed a close anatomic relationship among the sinus posterior wall, the descending palatine artery, and the sphenopalatine artery in all 30 sinuses. Small branches deriving from the posterior lateral nasal arteries have been found to perforate the nasal wall laterally and reach the mucosa of the maxillary sinus. A sound knowledge of the maxillary sinus vascularization is essential to prevent vascular complications during surgical operations involving this region.
Cerebral malaria is a severe complication of malaria. Sequestration of parasitized RBCs in brain microvasculature is associated with disease pathogenesis, but our understanding of this process is ...incomplete. In this study, we examined parasite tissue sequestration in an experimental model of cerebral malaria (ECM). We show that a rapid increase in parasite biomass is strongly associated with the induction of ECM, mediated by IFN-gamma and lymphotoxin alpha, whereas TNF and IL-10 limit this process. Crucially, we discovered that host CD4(+) and CD8(+) T cells promote parasite accumulation in vital organs, including the brain. Modulation of CD4(+) T cell responses by helminth coinfection amplified CD4(+) T cell-mediated parasite sequestration, whereas vaccination could generate CD4(+) T cells that reduced parasite biomass and prevented ECM. These findings provide novel insights into immune-mediated mechanisms of ECM pathogenesis and highlight the potential of T cells to both prevent and promote infectious diseases.
1 Department of Psychology and Center for Brain Science, Harvard University, Cambridge, Massachusetts; 2 Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, ...Charlestown, Massachusetts; 3 Howard Hughes Medical Institute, 4 Mallinckrodt Institute of Radiology and Department of Neurology Washington University School of Medicine, St. Louis, Missouri
Submitted 22 January 2008;
accepted in final form 27 March 2008
The hippocampus and adjacent cortical structures in the medial temporal lobe (MTL) contribute to memory through interactions with distributed brain areas. Studies of monkey and rodent anatomy suggest that parallel pathways converge on distinct subregions of the MTL. To explore the cortical areas linked to subregions of the MTL in humans, we examined cortico-cortical and hippocampal-cortical correlations using high-resolution, functional connectivity analysis in 100 individuals. MTL seed regions extended along the anterior to posterior axis and included hippocampus and adjacent structures. Results revealed two separate brain pathways that correlated with distinct subregions within the MTL. The body of the hippocampus and posterior parahippocampal cortex correlated with lateral parietal cortex, regions along the posterior midline including posterior cingulate and retrosplenial cortex, and ventral medial prefrontal cortex. By contrast, anterior hippocampus and the perirhinal/entorhinal cortices correlated with distinct regions in the lateral temporal cortex extending into the temporal pole. The present results are largely consistent with known connectivity in the monkey and provide a novel task-independent dissociation of the parallel pathways supporting the MTL memory system in humans. The cortical pathways include regions that have undergone considerable areal expansion in humans, providing insight into how the MTL memory system has evolved to support a diverse array of cognitive domains.
Address for reprint requests and other correspondence: I. Kahn, Howard Hughes Medical Institute at Harvard University, 33 Kirkland St., WJH 270, Cambridge, MA 02138 (E-mail: kahn{at}nmr.mgh.harvard.edu )
It is increasingly recognized that obesity is a risk factor for microvascular disease, involving both structural and functional changes in the microvasculature. This review aims to describe how ...obesity impacts the microvasculature of a variety of tissues, including visceral adipose tissue, skeletal muscle, heart, brain, kidneys, and lungs. These changes involve endothelial dysfunction, which in turn (i) impacts control of vascular tone, (ii) contributes to development of microvascular insulin resistance, (iii) alters secretion of paracrine factors like nitric oxide and endothelin, but (iv) also influences vascular structure and perivascular inflammation. In concert, these changes impair organ perfusion and organ function thereby contributing to altered release and clearance of neurohumoral factors, such as adipokines and inflammatory cytokines. Global microvascular dysfunction in obese subjects is therefore a common pathway that not only explains exercise-intolerance but also predisposes to development of chronic kidney disease, microvascular dementia, coronary microvascular angina, heart failure with preserved ejection fraction, chronic obstructive pulmonary disease, and pulmonary hypertension.
Dynamic exercise elicits fluctuations in blood pressure (BP) and cerebral blood flow (CBF). This study investigated responses in BP and CBF during cycling exercise and post-exercise hypotension (PEH) ...using positron emission tomography (PET). CBF was measured using oxygen-15-labeled water (H
O) and PET in 11 human subjects at rest (Rest), at the onset of exercise (Ex1), later in the exercise (Ex2), and during PEH. Global CBF significantly increased by 13% at Ex1 compared with Rest, but was unchanged at Ex2 and during PEH. Compared with at Rest, regional CBF (rCBF) increased at Ex1 (20~42%) in the cerebellar vermis, sensorimotor cortex for the bilateral legs (M1
and S1
), insular cortex and brain stem, but increased at Ex2 (28~31%) only in the vermis and M1
and S1
. During PEH, rCBF decreased compared with Rest (8~13%) in the cerebellum, temporal gyrus, piriform lobe, thalamus and pons. The areas showing correlations between rCBF and mean BP during exercise and PEH were consistent with the central autonomic network, including the brain stem, cerebellum, and hypothalamus (R
=0.25-0.64). The present study suggests that higher brain regions are coordinated through reflex centers in the brain stem in order to regulate the cardiovascular response to exercise.
The human brain vasculature is of great medical importance: its dysfunction causes disability and death
, and the specialized structure it forms-the blood-brain barrier-impedes the treatment of ...nearly all brain disorders
. Yet so far, we have no molecular map of the human brain vasculature. Here we develop vessel isolation and nuclei extraction for sequencing (VINE-seq) to profile the major vascular and perivascular cell types of the human brain through 143,793 single-nucleus transcriptomes from 25 hippocampus and cortex samples of 9 individuals with Alzheimer's disease and 8 individuals with no cognitive impairment. We identify brain-region- and species-enriched genes and pathways. We reveal molecular principles of human arteriovenous organization, recapitulating a gradual endothelial and punctuated mural cell continuum. We discover two subtypes of human pericytes, marked by solute transport and extracellular matrix (ECM) organization; and define perivascular versus meningeal fibroblast specialization. In Alzheimer's disease, we observe selective vulnerability of ECM-maintaining pericytes and gene expression patterns that implicate dysregulated blood flow. With an expanded survey of brain cell types, we find that 30 of the top 45 genes that have been linked to Alzheimer's disease risk by genome-wide association studies (GWASs) are expressed in the human brain vasculature, and we confirm this by immunostaining. Vascular GWAS genes map to endothelial protein transport, adaptive immune and ECM pathways. Many are microglia-specific in mice, suggesting a partial evolutionary transfer of Alzheimer's disease risk. Our work uncovers the molecular basis of the human brain vasculature, which will inform our understanding of overall brain health, disease and therapy.
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