Heterotopic ossification

Acetyl-CoA carboxylase (ACC1) catalyzes the first and rate limiting step of de novo fatty acid synthesis. Defects in Acc1p were recently correlated with an altered structure/function of the nuclear envelope in yeast. The subcellular distribution of the enzyme was determined in wild-type and mutant cells by cell fractionation and confocal immunofluorescence microscopy. Even though fatty acid synthesis is generally considered to be a cytosolic reaction, we found that Acc1p cofractionated with nuclei and the ER (endoplasmic reticulum) marker BiP/Kar2p. Membrane-bound Acc1p was susceptible to proteinase K digestion and was solubilized by mild salt treatment indicating that it is loosely associated with the cytosolic surface of the nuclear ER membrane. Consistent with these observations, immunofluorescence analysis revealed that Acc1p was distributed in a gradient within the cytoplasm that had its highest concentration around the ER. Possible association of Acc1p with the nuclear pore complexes (NPCs) was investigated in strains that display NPC clustering. Results of these experiments suggest that Acc1p localization is independent of NPC distribution. We propose that association of Acc1p with the cytoplasmic surface of the ER membrane is physiologically relevant to "channel" the enzymatic product of Acc1p, malonyl-CoA, to a putative ER-localized fatty acid chain elongase complex.     

Heel replantation

Case report on a 44-year-old woman in good health with the symptoms of epiphora, a plump elastic, not distressing swelling under the medial canthal tendon of 1 cm size on the right side. In ultrasonography and intraoperatively a tumour of moderate reflectivity with infiltration of the lacrimal sac was found. The histological evaluation, including immunohistochemical studies of the removed lesion, revealed a malignant B-cell lymphoma.     

Heterotopic pharyngeal hypophyseal adenoma

Juvenile fibroma, carcinoma and sarcoma are the most frequent tumors of the nasopharynx. Ontogenetic tumors that originate from the base of the skull are found very rarely. The case reported deals with a heterotopic pharyngeal pituitary adenoma, that started growing from the epipharynx.     

Problems in replantation surgery

The development of replantation centres presents problems with respect to availability of operating rooms and staff. Attention must be paid to improving facilities at such centres but care is required in selecting cases suitable for replantation. This involves consideration of distance between the patient and the centre, the level of amputation and the condition of the patient and the amputated part. Furthermore, age, occupation, pre-existing disease and concomitant injury must be taken into account. This not only will make inappropriate replantation of a single digit because of resultant impairment of the entire hand seldom but the problems of staffing and accommodation will also be minimized by correct decision.     

Ear replantation without microsurgery

Reconstitution of the amputated ear remains a challenge to the plastic surgeon. Reattachment as a composite graft of the total or subtotal amputated ear is unreliable. Microsurgical replantation can be performed in a minority of cases; however, difficulty with adequate venous drainage complicates the technical complexity of these cases. To enhance survival of a reattached ear segment, Mladick et al. advocated use of the retroauricular pocket principle. This technique involves deepithelialization of the amputated part, followed by anatomic reattachment to the amputation stump and then burial in a retroauricular pocket. This simple technique increases the surface area of the avulsed segment in contact with surrounding nutrients, maximizing the probability of "take." The relationship between the dermis and cartilage is preserved, thus minimizing the deformity from cartilage warping. The undisturbed dermis on the involved segment can reepithelialize spontaneously, negating the need for a skin graft. We have used this technique successfully in five of six patients.     

Heterotopic ossification after femoral intramedullary rodding

Heterotopic ossification (HO) after femoral intramedullary rodding is a significant complication of the procedure. One hundred eighteen cases of femoral roddings performed on 113 patients were available for review. The data were computerized and evaluated using univariate analysis and multivariate regression analysis. A statistically significant increase of HO was found with male gender, increased delay to surgery, and in patients requiring prolonged intubation because of their multiple injuries. HO was classified using a modified version of the method of Brumback et al. (grades 0-IV). A strong correlation of HO with brain injury documented by computed tomography scan was also found to be statistically significant for the more severe grades of HO. This group of patients had not previously been identified as being at high risk for HO.     

Complete ear replantation without venous anastomosis

Bone metastasis in the hand is rare. The etiology is quite different from that of metastasis to other bones; bronchogenic carcinoma is by far the most frequent case. Distal phalanges are mainly involved with irregular osteolysis and cortical destruction. Differential diagnosis of phalangeal metastasis includes osteomyelitis, rheumatoid arthritis and gout. The prognosis is always that of metastatic bronchial cancer with an average survival of three months. Treatment may involve distal digital amputation or antalgic radiotherapy. A case of bronchogenic carcinoma with metastasis to the thumb is presented. The metastasis was located in the distal phalanx of the left thumb. The primary tumor was located in the lung. Treatment consisted of amputation. The overall survival was five months.     

Tooth replantation in germ-free and conventional rats

The purpose of the present study was to evaluate the influence of bacterial infection on the pulpal and periodontal tissues in replanted teeth using germ-free and conventional rats. Forty maxillary and mandibular first molars from ten 6-week-old germ-free male Wistar rats were used. The animals and all materials were maintained in a germ-free environment inside vinyl isolators throughout the experimental periods. Twenty conventional male Wistar rats served as controls. The first molars were intentionally replanted immediately after extraction. At 3 days, and 1, 2, 4 and 8 weeks after replantation, animals were sacrificed and the replanted teeth were histopathologically evaluated. Diversity of pulp tissue response was notable in conventional rats, which initially showed various degrees of neutrophil infiltration and then displayed different types of response, including revascularization with reparative dentin formation and complete necrosis. Pulpal responses of germ-free rats were less variable, being characterized by an almost complete lack of neutrophil infiltration and a high frequency of bone-like tissue ingrowth. Typical inflammatory resorption was detected only in conventional rats, whereas a higher incidence of ankylosis was notable in germ-free rats. The present results may corroborate the concept that bacterial infection is a major cause of serious healing complications following tooth replantation, such as pulp necrosis and inflammatory root resorption. The difficulty in optimally controlling bacterial infection seems to be highly relevant to the complexity and unpredictability of the outcome of this procedure. It should also be emphasized that extensive mechanical damage to the periodontal tissues may trigger the development of unfavorable healing complications as ankylosis, even under strictly aseptic conditions.     

Heterotopic periarticular ossification after total hip replacement]

Fractures of the proximal femur represent a significant health concern especially in the elderly. Fatigue damage and microfractures have been implicated in the etiology of hip fractures; however, the extent to which these factors are sufficient to bring about significant reductions in proximal femur strength and stiffness is unknown. This study examined the hypothesis that fatigue loading of the proximal femur results in highly correlated decreases in bone stiffness and strength through the accumulation of bone microdamage. One canine femur from each of 10 pairs was monotonically loaded to failure to determine the ultimate strength. The contralateral femur was then cyclically loaded at 50% of the ultimate load value for either 3600 cycles or until a 40% reduction in stiffness was achieved. This femur was then monotonically loaded to failure. For two additional femur pairs, the fatigued femur was histologically processed to reveal bone microdamage. In support of the hypothesis, the data demonstrated a linear relationship between strength loss and stiffness loss (Adj. R2 = 0.79, p < 0.0004) with significant decreases in residual whole bone strength (p < 0.004) following cyclic loading. In addition, damage (microcracks) in the cortical bone and broken trabeculae were observed in the neck and head region of the femur fatigued until its stiffness was reduced by 40% but not fractured subsequent to cyclic loading.     

Late occlusion of microvascular vein grafts in replantation

Two cases are described in which patients presented 16 and 17 years, respectively, after complete or incomplete amputation/replantation of the arm. In case 1, the patient complained of coldness, pain, and tingling in the replanted arm in the previous 24 hours and noticed that his fingers had gone white. Arteriography and subsequent surgery revealed obliteration of the vein graft (inserted in the distal brachial artery) by neointimal thickening and atherosclerotic plaque, which was confirmed in a subsequent morphologic examination. In case 2, the patient presented with discomfort and a pulsatile swelling on the inner aspect of his upper arm. Arteriography and surgery revealed an aneurysm in the previously inserted vein graft in the brachial artery, with some atherosclerotic degeneration. Both vein grafts were successfully replaced with a fresh autologous vein graft and the patients remain well several years later. The 2 cases suggest that as part of replantation surgery of a limb, it is essential to maintain postoperative clinical monitoring for signs of graft degeneration in all patients with long-term vein graft insertion.     

History of replantation: from miracle to microsurgery

Severed body parts, from fingers to extremities, are now being routinely reattached at medical centers around the world. The dream of replantation traces its rich history from miracles and legends to early laboratory experiments and clinical attempts, culminating in today's commonplace procedure.     

Heterotopic ossification after cemented or uncemented bateman bipolar hemiarthroplasty

BACKGROUND: This is a retrospective study to evaluate the incidence of heterotopic ossification (HO) in cemented and uncemented femoral neck fractures treated with Bateman bipolar hemiarthroplasty. METHODS: From October 1985 to July 1990, there were 451 cases of displaced intracapsular fractures of the femoral neck treated with Bateman bipolar hemiarthroplasty (261 uncemented vs 190 cemented) at the Veterans General Hospital-Taipei. RESULTS: After an average follow-up of 46 months, there was more HO in the cemented group than in the uncemented group (p = 0.014, chi-squared test). The average surgical time was approximately 20 minutes longer and the average blood loss was approximately 160 ml more in the cemented Bateman bipolar hemiarthroplasty group. CONCLUSIONS: HO formation is more common in cemented Bateman bipolar hemiarthroplasty than in the uncemented procedure. The incidence of HO is not related to age or sex.     

Heterotopic pancreatic tissue in the wall of the gallbladder

The overall aim of the present study was to investigate a new method for the screening of taste function in a clinical context. Instead of dripping liquids onto the tongue, thin edible wavers were used. One-hundred healthy subjects participated in the study (41 male, 59 female; mean age: 52 years; age range: 20-89 years). Supra-threshold taste stimuli were presented as flavoured wavers made from flour and water. Sequential testing was performed regionally on the anterior one-third of the tongue and as whole mouth testing. When comparing ratings for the 5 different wavers separately for regional and whole mouth testing, differences between qualities only emerged for regional testing. Women were found to have less difficulty in taste identification which was most pronounced for regional testing. No effects of the subjects' age were observed. In conclusion, the wavers were found to be easy to use; they have a shelf-life of 2 to 3 years and can be carried in the pocket. The results indicate that the wavers may be suited for the screening of gustatory function, especially in a clinical setting.