Myofibroblast persistence and collagen type I accumulation in the human stenotic trachea.

BACKGROUND: Postintubation tracheal stenosis (PITS) is associated with an increased use of assisted ventilation in intensive care units. We investigated both collagen type I accumulation and myofibroblast localization in human PITS lesions excised for surgical therapeutic procedures, compared with normal tracheas. METHODS: We analyzed 2 segments of normal tracheas and 10 segments of PITS that were stained by hematoxylin-eosin and picrosirius red techniques and processed for immunohistochemistry using antibodies against both α-smooth muscle actin (α-sma) for myofibroblast detection, and collagen type I. RESULTS: We showed a significant increase in collagen deposition in PITS specimens compared with normal tracheas. We found spindle-shaped α-sma-positive cells (myofibroblasts) in the subepithelial layer of all pathologic tracheas, and the persistence of an intense myofibroblast network at PITS sites. CONCLUSIONS: Tracheal wall thickening in PITS is due to a deranged collagen remodeling that is related to myofibroblast activation.

Morphometrical analysis of the human mandibular canal: a CT investigation.

PURPOSE: This study aimed to clarify the correct localization of the mandibular canal (MC) that is essential in order to avoid injuries to the inferior alveolar neurovascular bundle during oral surgical procedures. METHODS: We have analyzed the position of the MC using computed tomography data bank examinations of the oral region from 50 partially dentulous Brazilian patients aging from 25 to 75 years old (mean ± SD values = 51.70 ± 4.50; females = 27; males = 23) that were obtained with the purpose of dental restoration and without any gross pathology of the mandible. Axial images were 1-mm-thick slices using bone regular algorithm, without intravenous contrast. RESULTS: We have measured (mean ± SD) the orthogonal distances between the MC and the following selected regions of the mandible: (a) the buccal cortical plate (6.10 ± 1.52 mm); (b) the inferior border of the mandible (10.55 ± 2.28 mm); (c) the lingual cortical plate (3.98 ± 1.14 mm); and (d) the superior border of the alveolar process (16.98 ± 2.85 mm). CONCLUSIONS: Our morphometric findings may help clarifying the detailed anatomy of the MC and its topographical relations for the planning of dental implantation.

The developmental anatomy of the human superior hypogastric plexus: A morphometrical investigation with clinical and surgical correlations.

The superior hypogastric plexus (SHP) is the part of the autonomic nervous system, which is responsible for the sympathetic innervation of pelvic organs and extrapelvic genitals in humans of both sexes. The SHP also functions as the anatomic pathway for the major part of visceral sensitive fibers originating from pelvic viscera. In this study, the morphology of the SHP was analyzed through anatomical dissections performed both in human adult and fetal cadavers. A computerized morphometrical investigation of the SHP was also performed and the resulting quantitative data statistically assessed. The comparison between fetal and adult SHP revealed that in the male group there was a developmental increase of six times (in height) and of about five times (in width); while in the female group, there was a developmental increase of 3.5 times both in height and width values. In addition, the distance from the superior border of the SHP to the bifurcation of the common iliac arteries presented a developmental increase of about six times in the male group, and about four times in the female group. We propose an original morphological classification with six types, based upon the anatomical arrangement of the nervous fibers in this autonomic plexus.

Developmental steps of the human cervical spine: parameters for evaluation of skeletal maturation stages.

The central objective of this investigation was to focus on the development of the cervical spine observed by lateral cephalometric radiological images of children and adolescents (6-16 years old). A sample of 26 individuals (12 girls and 14 boys) was classified according to stages of cervical spine maturation in two subcategories: group I (initiation phase) and group II (acceleration phase). The morphology of the cervical spine was assessed by lateral cephalometric radiographs obtained in accordance with an innovative method for establishing a standardized head posture. A total of 29 linear variables and 5 angular variables were used to clarify the dimensions of the cervical vertebrae. The results suggest that a few measurements can be used as parameters of vertebral maturation both for males and females. The aforementioned measurements include the inferior depth of C2-C4, the inferior depth of C5, the anterior height of C4-C5, and the posterior height of C5. We propose original morphological parameters that may prove remarkably useful in the determination of bone maturational stages of the cervical spine in children and adolescents.

The human superior tarsal muscle (Müller's muscle): a morphological classification with surgical correlations.

The superior tarsal muscle (STM) is a smooth muscle that originates from the undersurface of the levator palpebrae superioris muscle (LPSM) and inserts onto the superior tarsal plate (STP) of the upper eyelid. We have performed a morphometrical investigation of the STM in 49 adult human cadavers (34 males, 15 females). Histological analysis has shown a transitional area between the skeletal striated muscle (LPSM) and the adjacent smooth muscle (STM). We propose an original morphological classification based upon the attachment of STM to the upper border of the STP. Accordingly, we describe four patterns of STM. Pattern 1 (P1) consists of STM attachment to the central portion of the STP. Pattern 2 consists of both medial (P2M) STM attachment to both the central and medial regions of the STP and lateral (P2L) STM attachment to both the central and lateral regions of the STP. Pattern 3 (P3) consists of STM attachment along the whole extent of the STP. Pattern 3 was the most frequently observed pattern (63.27%) followed by patterns P2M (24.49%), P2L (8.16%) and P1 (4.08%). P3 was the predominant pattern in males (73.52%), while in females, both patterns P2M (46.66%) and P3 (40.00%) were equally prevalent. The analysis of paired specimens revealed a symmetrical arrangement in 72.20% of all cases, with the remaining cases (27.80%) displaying left-right STM asymmetries. To the best of our knowledge, this is the first description of the STM asymmetries in the medical literature. This innovative classification provides anatomical parameters for interpreting morphological variations of the STM with relevant applications in both plastic surgery and ophthalmology.

A radiological investigation of the hepatorenal space: the importance of the ventral decubitus for safer percutaneous right renal access.

We investigated anatomical and radiological morphometric parameters, aiming to minimize the risk of hepatic and colonic injuries during right percutaneous kidney access under either ventral or dorsal decubitus of patients. Prone and supine abdominal computerized tomographic examinations from 31 normal adult volunteers (men = 12; women = 19; without history of abdominal pathology) were analyzed morphometrically in order to study the dynamic anatomical relations between the liver and the right kidney. The age of the volunteers ranged from 22 to 64 years old (mean +/- SD = 42.77 +/- 2.10). We observed a significantly greater distance between the liver and the right kidney (hepatorenal space) when the examinee is positioned in ventral decubitus (3.93 +/- 0.37 cm) in comparison with dorsal decubitus (1.98 +/- 0.20 cm). Accordingly, we conclude that right percutaneous access to the inferior right renal pole implies a significantly lower risk (P < 0.01) of both hepatic and biliary injuries when performed in ventral decubitus, comparatively to dorsal decubitus.

Strapping the spinal cord: an innovative experimental model of CNS injury in rats.

Experimental models of spinal cord (SC) lesion are essential for understanding a few of the primary and secondary mechanisms of injury and functional recovery of the central nervous system (CNS). We have developed an experimental model of SC injury in adult rats (n=32), that involves the use of a device (SC-STRAPPER) that straps the SC and promotes gradual and controlled SC injury similar to clinical compressive SC injuries. SC strapping is a less-invasive procedure in comparison to other SC injury models, and it performs compression with smaller infection risk and undetectable paravertebral or vertebral lesions. The survival of the rats was 100%, minimizing the suffering of the animals. We have analyzed the histopathological changes that occur during experimental SC compression, as well as the immunohistochemical labeling for glial fibrillary acidic protein (GFAP). Animals survived for 21 days being thereafter anesthetized and perfused with aldehydes. SC lesions were associated with motor deficits and local increase in GFAP immunolabeling proportionate to the severity of the compression. This experimental model represents a potential contribution for neuroscientific research, providing a low-cost and rather simple system of controllable and reproducible SC experimental damage.

Axonal and extracellular matrix responses to experimental chronic nerve entrapment.

We have analyzed the ultrastructural and histopathological changes that occur during experimental chronic nerve entrapment, as well as the immunohistochemical expression of chondroitin sulfate proteoglycan (CSPG). Adult hamsters (n = 30) were anesthetized and received a cuff around the right sciatic nerve. Animals survived for varying times (5 to 15 weeks) being thereafter perfused transcardially with fixative solutions either for immunohistochemical or electron microscopic procedures. Experimental nerves were dissected based upon the site of compression (proximal, entrapment and distal). CSPG overexpression was detected in the compressed nerve segment and associated with an increase in perineurial and endoneurial cells. Ultrastructural changes and data from semithin sections were analyzed both in control and compressed nerves. We have observed endoneurial edema, perineurial and endoneurial thickening, and whorled cell-sparse pathological structures (Renaut bodies) in the compressed nerves. Morphometrical analyses of myelinated axons at the compression sites revealed: (a) a reduction both in axon sectional area (up to 30%) and in myelin sectional area (up to 80%); (b) an increase in number of small axons (up to 60%) comparatively to the control group. Distal segment of compressed nerves presented: (a) a reduction in axon sectional area (up to 60%) and in myelin sectional area (up to 90%); (b) a decrease in axon number (up to 40%) comparatively to the control data. In conclusion, we have shown that nerve entrapment is associated with a local intraneural increase in CSPG expression, segmental demyelination, perineurial and endoneurial fibrosis, and other histopathological findings.

Anatomical investigation of the esophageal and aortic hiatuses: physiologic, clinical and surgical considerations.

Precise knowledge about the anatomical constitution of the diaphragmatic pillars is essential to understand the physiologic, clinical and surgical roles of the esophageal and aortic hiatuses. Because anatomical descriptions found in the literature are dubious, we have decided to investigate this subject. Anatomical dissections and histologic sections of the right and left diaphragmatic pillars (diaphragma crura) from 43 human bodies were analyzed, comprising both non-fixed and fixed specimens. We have described a classification of the diaphragmatic pillars and their muscular branches, forming two basic arrangements (patterns I and II) around the esophageal and aortic hiatuses. Such anatomical and functional relationships between the esophagus and its diaphragmatic hiatus help explain why, during normal inspiration, a hiatal enlargement is observed first but is followed, thereafter, during deep inspiration, by a hiatal narrowing exerted by the contraction of the diaphragmatic pillars. Our results also show that the aortic hiatus does not seem to constitute a rigid ventral tendinous arc around the aorta that could impose any considerable degree of vascular compression, as suggested by other investigators. The present study provides anatomical data useful for a better understanding of gastroesophageal reflux physiology, antireflux surgery and abdominal angina.