The venous system during pregnancy. Part 1: physiologic considerations

An essential contributor to the hemodynamic responses observed during pregnancy, the venous system is affected by hormones, blood volume, flow rates, and an enlarging uterus. The venous system is a dynamic reservoir for blood volume, within which a virtual point of conversion between unstressed volume (Vu) and stressed volume (Vs) exists. The physiologic importance of the venous system during pregnancy is best understood when the basic concepts, functional characteristics, and alterations in pregnancy are reviewed.     

The duodenum. Part 4: Surgery

This is the last part of our efforts to present, if possible, the duodenum in toto as an anatomical and surgical entity. For all practical purposes, Part 4 is a short presentation of the anatomy involved in mobilization and exposure of the duodenum from a surgical standpoint with specific applications. A table with most of the anatomical complications of duodenal surgery is also included.     

Adrenal myelolipoma: clinical, radiologic, and histologic features

The adrenal myelolipoma is a benign, endocrinologically inactive tumor whose histologic structure consists of mature adipose tissue with foci of hematopoietic cells. A case is presented of a seventy-one-year-old woman in whom the diagnosis was established preoperatively by means of sonography, computerized tomography, and magnetic resonance tomography. In a review of the literature, the radiologic profile is discussed, and based on the analysis of 59 surgically treated cases a therapy recommendation is given.     

The lung inflammatory response to thermal injury: relationship between physiologic and histologic changes

We studied the effect of a body burn on lung physiologic, biochemical, and histologic changes in a 2-day postburn period. A 15% of total-body-surface third-degree burn was produced in 24 adult sheep with lung and burn lymph fistulas. Eight sheep were killed at 12 hours and eight at 48 hours. At 12 hours we noted increased lung tissue lipid peroxidation, lung congestion, and neutrophil sequestration, in addition to a 30% decrease in lung compliance. Lung permeability and water content were not increased. Increased release of lipid peroxides and prostanoids were noted from burn tissue, as evidenced by increased plasma levels of malondialdehyde and conjugated dienes that remained elevated for about 8 hours and were decreased with wound removal. The lung inflammatory response was still present at 48 hours, the cells being primarily neutrophils. Nevertheless, the lipid peroxidation process, as measured by lung tissue malondialdehyde, had resolved. There was no evidence of burn tissue infection, measured by quantitative culture, to explain the persistent increase in lung inflammatory cells. Excision and closure of the burn wound at 3 hours postburn in eight sheep attenuated the lipid peroxidation and compliance changes but did not decrease the neutrophil sequestration. We conclude that burn injury results in a local wound oxidant release that leads to lipid peroxidation, both in wounds and in lung, as well as lung inflammation. The lipid peroxidation process may be attenuated by removal of the wound. The neutrophil sequestration is not altered, however, indicating this response occurs very early after injury, probably as a result of oxidant-initiated complement activation.     

Carcinoids of the duodenum. A histologic and immunohistochemical study of 65 tumors

The light-microscopic and immunohistochemical characteristics of 65 duodenal carcinoids are presented. Most tumors showed a mixture of cribriform, insular, glandular, solid, and trabecular growth patterns. Eighty-five percent of the tumors were argyrophil and 15% argentaffin. The nonspecific neuroendocrine markers chromogranin, Leu-7, and neuron-specific enolase were positive in 97, 91, and 83% of tumors, respectively. Immunoreactivity for specific hormones/amines were as follows (percent positive tumors): somatostatin, 47%; N-gastrin, 56%; serotonin, 39%; calcitonin, 19%; insulin, 5%; pancreatic polypeptide, 3%; adrenal corticotropic hormone, 0%; glucagon, 0%. Sixty-eight percent had gastrin/cholecystokinin-like reactivity. Ten psammomatous tumors were located near the ampulla; eight were somatostatin positive, including two in patients with neurofibromatosis. One additional tumor in a patient with neurofibromatosis lacked psammoma bodies but elaborated somatostatin. Eight additional tumors in nonneurofibromatosis patients produced solely somatostatin. Duodenal carcinoids often elaborate more than one polypeptide hormone; those in the ampulla often elaborate somatostatin and have psammoma bodies.     

Cytologic and histologic features of superficial bladder cancer.

Despite technologic advances in diagnostic skills, cytologic and histologic evaluation is still the standard for the identification of bladder cancer, and these two techniques are critical in therapy selection and post-treatment surveillance. The key to the proper interpretation of cytologic specimens lies in appropriate collection and handling of the sample. Because treatment differs according to the histologic type of a tumor, when a mixture of types is found, all should be listed with their relative proportions. Both pathologists and urologists must be aware of the importance of the muscularis mucosae; a transitional-cell carcinoma may invade this layer without extending into the true muscle.     

The periosteum. Part 1: Anatomy, histology and molecular biology

The periosteum is a thin layer of connective tissue that covers the outer surface of a bone in all places except at joints (which are protected by articular cartilage). As opposed to bone itself, it has nociceptive nerve endings, making it very sensitive to manipulation. It also provides nourishment in the form of blood supply to the bone. The periosteum is connected to the bone by strong collagenous fibres called Sharpey's fibres, which extend to the outer circumferential and interstitial lamellae of bone. The periosteum consists of an outer "fibrous layer" and inner "cambium layer". The fibrous layer contains fibroblasts while the cambium layer contains progenitor cells which develop into osteoblasts that are responsible for increasing bone width. After a bone fracture the progenitor cells develop into osteoblasts and chondroblasts which are essential to the healing process. This review discusses the anatomy, histology and molecular biology of the periosteum in detail.     

The cubital tunnel: anatomic, histologic, and biomechanical study.

The anatomy of the cubital tunnel was examined in 19 human cadaveric elbows. Pressure measurements within the cubital tunnel were recorded at the medial epicondyle level and 3 cm distal to the epicondyle in various positions of elbow flexion. Histologic examination of the ulnar nerve was carried out at different levels. A common flexor aponeurosis (CFA) was consistently present in all specimens between the flexor carpi ulnaris and the flexor digitorum superficialis. Pressure measurements were greater distally at the CFA level than proximally in the fibrosseous tunnel. The pressure inside the cubital tunnel increased with increasing flexion at the 3 levels examined. Releasing the arcuate ligament decreased the pressure in the fibrosseous tunnel but not distally at the level of the CFA. An oligofascicular pattern of the ulnar nerve was observed at the level of the medial epicondyle and CFA. This finding was in contrast to the polyfascicular pattern present both proximal and distal to these structures. The findings of our study have shown that an intimate anatomic relationship exists between the ulnar nerve and the CFA. This proximity appears to affect the biomechanics of the cubital tunnel and to contribute to nerve compression by the CFA in the distal tunnel. We also found that elbow flexion increases the pressure in the distal tunnel and that releasing the arcuate ligament alone does not decompress the ulnar nerve in the distal tunnel.     

Intraoperative physiologic variables and outcome in cardiac surgery: Part II. Neurologic outcome

BACKGROUND: The impact of alterable physiologic variables on neurologic outcome after coronary artery bypass grafting procedures is unknown. The purpose of this study was to determine whether minimum intraoperative hematocrit, maximum glucose concentration, or mean arterial pressure during cardiopulmonary bypass influences risk-adjusted neurologic outcome after coronary artery bypass grafting. METHODS: Outcome data from 2,862 patients undergoing coronary artery bypass grafting were merged with intraoperative physiologic data. A preoperative stroke risk index was calculated for each patient. Variables found significant by univariate logistic regression were tested in a multivariable model to determine association with outcome. RESULTS: The incidence of stroke or coma in the study population was 1.3%. After controlling for stroke risk and bypass time, only an index of low mean arterial pressure during bypass retained a significant inverse association with outcome (p = 0.0304). CONCLUSIONS: This study found no evidence that glucose concentration or minimum hematocrit are associated with major adverse neurologic outcome. The association between lower pressure during bypass and decreased incidence of stroke or coma persisted in all risk groups. This points to mechanisms other than hypoperfusion as the primary cause of neurologic injury associated with cardiac surgery.     

Adenomas in glycogen storage disease type 1. Two cases with unusual histologic features

Two cases of hepatic adenomas arising in patients with glycogen storage disease type I are presented. In both cases, the adenomas showed unusual histological features including marked fatty change, a polymorphonuclear infiltrate, Mallory hyalin, and lamellar fibrosis. In addition, one case was associated with amyloidosis. Such features have only recently been described in adenomas and have not been reported previously in association with glycogen storage disease type I.     

Tribute to a Triad: History of Splenic Anatomy, Physiology, and Surgery—Part 1

Talmud, the Midrash, and the writings of Hippocrates, Plato, Aristotle, Galen, and several other giants of the past, one can find a lot of Delphian and Byzantine ambiguities. At that time, splenectomy was the art of surgery for many splenic diseases. From antiquity to the Renaissance, efforts were made to study the structure, functions, and anatomy of the spleen. Vesalius questioned Galen; and Malpighi, the founder of microscopic anatomy, gave a sound account of the histology and the physiologic destiny of the spleen. Surgical inquiry gradually became a focal point, yet it was still not clear what purpose the spleen served. It has been within the past 50 years that the most significant advances in the knowledge of the spleen and splenic surgery have been made. The work of Campos Christo in 1962 about the segmental anatomy of the spleen helped surgeons perform a partial splenectomy, thereby avoiding complications of postsplenectomy infection. With the recent successes of laparoscopic splenectomy in selected cases, the future of splenic surgery will undoubtedly bring many more changes.     

The infected implant. Part 1: bacteriology

Periprosthetic infection is a significant complication in joint replacement surgery and develops in 0.5-2% of cases. Staphylococcus aureus and commensal microorganisms of the skin, especially coagulase-negative staphylococci, as well as a broad spectrum of other potential pathogens typically already colonize the surface of the foreign body at the time of implantation. Specific mechanisms such as bacterial adhesion to host factors absorbed in the material, biofilm formation, and a metabolic adaptation of adherent microorganisms play a particularly important role in the pathogenesis and course of the disease. Microbiological diagnosis requires to some extent complex culture procedures of puncture specimens or tissue removed during surgery; this can be supplemented by modern molecular testing. Antimicrobial treatment must be conceived as a synopsis of clinical picture, confirmed pathogen, and the intended surgical procedure on an individual basis and is routinely administered as combination therapy for several weeks, sometimes also as sequential therapy. Validated preventive measures in joint replacement surgery include mandatory perioperative antibiotic prophylaxis and other additional measures.     

Anatomy, histologic features, and vascularity of the adult acetabular labrum

Acetabular labrum tears have been implicated as a cause of hip pain in adult patients. Few studies describe the anatomy, histologic features, and microvasculature of the acetabular labrum and labral tears. Fifty-five embalmed and 12 fresh-frozen adult hips with a mean age of 78 years (range, 61-98 years) were studied. Of these, 96 % (53 of 55) of the hips had labral tears, with 74% of the tears located in the anterosuperior quadrant. Histologically, the fibrocartilaginous labrum was contiguous with the acetabular articular cartilage through a 1- to 2-mm zone of transition. A consistent projection of bone extends from the bony acetabulum into the substance of the labrum that is attached via a zone of calcified cartilage with a well-defined tidemark. Two distinct types of tears of the labrum were identified histologically. The first consisted of a detachment of the fibrocartilaginous labrum from the articular hyaline cartilage at the transition zone. The second consisted of one or more cleavage planes of variable depth within the substance of the labrum. Both types of labral tears were associated with increased microvessel formation seen within the tear. The acetabular labrum tear appears to be an acquired condition that is highly prevalent in aging adult hips. Labral tears occur early in the arthritic process of the hip and may be one of the causes of degenerative hip disease.     

A microvascular anastomotic device: Part II. A histologic study in arteries and veins

This study analyzes the histology associated with the polyethylene ring-pin device. The device was placed in 20 rabbit femoral arteries and 20 femoral veins. Specimens were harvested at 24-hour and 3-week postoperative intervals and were analyzed using light, scanning electron, and transmission electron microscopy. Generally, the reparative process in the arteries and veins was similar. In 24-hour artery and vein specimens, the endothelial cells were absent, the media tapered within the device, but smooth muscle cells (SMC) remained partially viable. In 3-week specimens, the device junction was well healed and reendothelialized. Subintimal hyperplasia was present, the internal elastic lamina was not reconstituted, and the SMCs were partially viable. Small vascular channels formed at the device junction, and small venous valves were noted near the device. Macrophages lined the margins of the device. The early reparative process proceeds favorably, by histologic criteria, after vessel repair with the polyethylene ring-pin device.     

Effect of a body burn on endotoxin-induced lipid peroxidation: comparison with physiologic and histologic changes

We determined the effect of a 15% total body surface (TBS), full-thickness burn on the physiologic, histologic, and oxidant-induced lipid peroxidation changes produced by endotoxin. The endotoxin-burn response was compared with that of endotoxin alone. Twenty-two adult sheep with chronic lung and flank lymph fistulas were studied. In 11 sheep a burn was produced under anesthesia and 3 days later they were given 2 micrograms/kg of endotoxin. Data were also compared with those of control sheep and those that were given burns alone. Circulating conjugated dienes increased with endotoxin alone but remained at baseline with endotoxin and burn injury. The lung lymph flow response was increased significantly in the endotoxin-burn group (sixfold) compared with that of endotoxin alone (fourfold). Histologic quantitation of lung neutrophil count was comparable in both groups 6 hours after injury, although mononuclear cells were much more evident in lungs in the endotoxin-burn group. Lipid peroxidation measured by malondialdehyde was significantly increased in the endotoxin group compared with the endotoxin-burn group, despite the greater increase in lymph flow and lung water in the burned group. Oxygen consumption (VO2) remained constant after endotoxin alone compared with baseline. However, VO2 increased twofold immediately after endotoxin in the endotoxin-burn group. This marked increase was followed by a significant decrease in VO2 from baseline. Flank soft-tissue nonburned increased lung lymph flow twofold to threefold with endotoxin and burn, indicating increased soft-tissue permeability, whereas it remained unchanged with endotoxin alone. Liver malondialdehyde increased from a control of 110 +/- 20 to 210 +/- 80 mmol/gm tissue with endotoxin alone and to 450 +/- 54 nmol/gm tissue with endotoxin and burn. We can conclude that burn injury accentuates both the pulmonary and systemic physiologic response to endotoxin, possibly as a result of mediators released from mononuclear cells already activated in the presence of the burn. The increased lung physiologic response does not appear to be caused by greater oxidant-induced lipid peroxidation, as was seen in the liver with the combined injury.     

Fibronectin, MMP-1 and histologic changes in rotator cuff disease.

This study was designed to investigate human surgical specimens from patients with impingement (n = 16), ruptured supraspinatus tendons (n = 7), frozen shoulder (n = 2) and controls (n = 9) with respect to histological changes and the presence of fibronectin and Matrix metalloprotease-1 (MMP-1). The biopsy of the middle part of the supraspinatus tendons was analyzed microscopically after staining with hematoxyline eosin, Van Giesons hematoxyline and Phospho Tungstic Acid Hematoxyline for visualization of fibrin. Immunofluorescent stainings for fibronectin and MMP-1 were performed. Histology and immunofluorescence were assessed blindly. Necrotic tendinous tissue and fibrin were found only in some specimens from ruptures. The staining for fibronectin was significantly increased among patients with a rupture. MMP-1 was, however, only infrequently found in specimens from patients with impingement and ruptures. Fibrosis and thinning of fascicles seemed to be a more non-specific finding, appearing in control, impingement and rupture specimens. In conclusion, necrotic tendinous tissue, fibrin and fibronectin appear to be signs of tendon degeneration, whereas fibrosis and thinning of fascicles were found also in controls.     

The histologic features of the interfacial membrane of intramedullary nails

Thirty-six interfacial membranes collected at the time of removal of intramedullary L316 stainless steel nails were studied histologically. The membranes consisted of bland fibrous tissue in a minority of cases. Most often, the nails were enclosed within a synovial-like membrane. Palisading macrophages and fibroblasts abutted on the metallic surface of the nails. Foreign body giant-celled granulomas were scattered in the midzone of the membranes, mono- and polykaryonic macrophages having phagocytozed small metallic particles, necrotic bony debris, and, sometimes, lipidic compounds. Aggregates of hemosiderin-containing macrophages occasionally marked the sites of previous hemorrhages. When present in the retrieved specimen, the bone underlying the membrane was undergoing remodeling. Interfacial motion, consequent on dissimilar stiffness of the bone and nail, as well as deposition of metallic and bony debris, are likely responsible for the formation of the synovial-like interfacial membrane.