The danger of using metallic plate and screw fixation in the young.
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Adolescent↗
Biomedical subjects
D J Dunaway
Publications and source records attributed to D J Dunaway.
Prediction of the position of the intraparotid portion of the facial nerve on MRI and CT.
Despite developments in imaging technology, visualisation of the intraparotid portion of the facial nerve is not possible. Three separate radiological techniques have been described to predict the position of the facial nerve: Conn's arc; a plane extending posteriorly from the outer surface of the mandibular ramus; and soft-tissue structures, including the posterior belly of the digastric muscle, the retromandibular vein and the lateral border of the masseter muscle. We investigated the reliability of these techniques in predicting the relationship of tumours to the facial nerve. Cross-sectional imaging of the parotid glands was performed prior to the removal of a parotid mass in 26 patients. Twenty patients underwent MRI, and six had CT scans. We removed 14 malignant neoplasms, nine benign lesions and three non-neoplastic lesions. The relationship of the tumour to the facial nerve was assessed radiologically by each of the three techniques, and compared with the findings at surgery. In 18 patients the tumour involved the parotid gland deep to the facial nerve. The above techniques predicted the position of the facial nerve in 69%, 58% and 46% of cases, respectively. When planning parotid surgery, it is important that the surgeon understands the advantages and limitations of the radiological assessment of the position of parotid tumours in relation to the facial nerve.
Adult↗
The accuracy of head and neck carcinoma sentinel lymph node biopsy in the clinically N0 neck.
BACKGROUND: Sentinel lymph node (SLN) biopsy originally was described as a means of identifying lymph node metastases in malignant melanoma and breast carcinoma. The use of SLN biopsy in patients with oral and oropharyngeal squamous cell carcinoma and clinically N0 necks was investigated to determine whether the pathology of the SLN reflected that of the neck. METHODS: Patients undergoing elective neck dissections for head and neck squamous cell carcinoma accessible to injection were enrolled into our study. Sentinel lymph node biopsy was performed after blue dye and radiocolloid injection. Preoperative lymphoscintigraphy and the perioperative use of a gamma probe identified radioactive SLNs; visualization of blue stained lymphatics identified blue SLNs. A neck dissection completed the surgical procedure, and the pathology of the SLN was compared with that of the remaining neck dissection. RESULTS: Sentinel lymph node biopsy was performed on 40 cases with clinically N0 necks. Twenty were pathologically clear of tumor and 20 contained subclinical metastases. SLNs were found in 17 necks with pathologic disease and contained metastases in 16. The sentinel lymph node was the only lymph node containing tumor in 12 of 16. CONCLUSIONS: The SLN, in head and neck carcinomas accessible to injection without anesthesia, is an accurate reflector of the status of the regional lymph nodes, when found in patients with early tumors. Sentinel lymph nodes may be found in clinically unpredictable sites, and SLN biopsy may aid in identifying the clinically N0 patient with early lymph node disease. If SLNs cannot be located in the neck, an elective lymph node dissection should be considered.
Adult↗
Endothelin ET(A) and ET(B) receptors in postnatal intestine.
We aimed to characterize endothelin (ET) receptors in the swine intestinal vasculature and to determine ischemia-reperfusion (I/R) effects on these receptors. Saturation and competitive binding assays were performed on mesenteric artery protein membranes from 1- and 40-day-old animals, both control and those subjected to 1 h of partial ischemia followed by 6 h of reperfusion in vivo. Scatchard analysis of saturation binding with (125)I-labeled ET-1 in membranes from endothelium-denuded (E(-)) vessels revealed that the maximum number of binding sites was greater in younger animals. Competitive (125)I-ET-1 binding was significant for a one-site model with ET-1, ET-3, and sarafotoxin S6c (S6c) in membranes from endothelium-intact (E(+)) and E(-) vessels in both age groups. The maximum number of ET-1 binding sites was significantly greater in younger animals. In the presence of the ET(A) receptor antagonist BQ-123, competitive (125)I-ET-1 binding was significant for a one-site model with ET-1 and S6c in membranes from E(+) vessels in both age groups. The maximum number of ET-1 binding sites was significantly greater in younger animals. After I/R, the maximum number of ET-1 binding sites was unchanged. In the presence of BQ-123, specific binding by ET-1 and S6c was eliminated in both age groups after I/R. These results suggest that both ET receptor populations are expressed to a greater degree in younger animals and I/R significantly affects the ET(B) receptor.
Animals↗
Determinants of terminal mesenteric artery resistance during the first postnatal month.
Experiments were conducted to delineate the vascular effector systems that contribute to setting mesenteric vascular tone in swine during the first postnatal month. Terminal mesenteric arteries (TMA), which function as resistance vessels, were studied in vitro with a microvascular perfusion system allowing independent pressure and flow manipulation. When pressure was varied 0-100 mmHg in the absence of flow, TMA from 1-day-old animals demonstrated myogenic vasoconstriction, whereas TMA from 40-day-old animals did not. In 1- but not 40-day-old TMA, the endothelin A (ET(A)) receptor antagonist BQ-610 shifted the pressure-diameter curve upward, whereas the ET(B) receptor antagonist BQ-788 and the L-arginine analog N(G)-monomethyl-L-arginine (L-NMMA) shifted the curve downward; in all instances, myogenic vasoconstriction was preserved. Flow eliminated myogenic vasoconstriction in 1-day-old TMA, i.e., diameter increased as a function of pressure. The effect of BQ-610 was lost under flow conditions; however, BQ-788 and N-acyl-L-Trp-3,5-bis-(trifluoromethyl) benzyl ester, an antagonist specific to the substance P neurokinin-1 (NK(1)) receptor, shifted the pressure-diameter curve downward in the presence of flow, whereas L-NMMA restored myogenic vasoconstriction. Adding flow had no effect on the pressure-diameter relationship in 40-day-old TMA. Other blocking agents, including prazosin, losartan, indomethacin, and charybdotoxin, had no effect on the pressure-diameter relationship in either age group under flow or no-flow conditions. Constitutive production of nitric oxide (NO) and endothelin-1 participates in setting resistance in 1-day-old TMA, and important stimulants to NO production include flow and activation of ET(B) and NK(1) receptors. In contrast, 40-day-old TMA act as passive conduits in which the elastic properties of the vessel are the primary determinant of diameter.
Aging↗
A suggested method for sentinel node biopsy in squamous cell carcinoma of the head and neck.
BACKGROUND: Debate continues over the management of the N0 neck in head and neck malignancy. Therefore, the possibility of performing sentinel node biopsy in these patients was investigated to formulate a method for the procedure. METHODS: Patients undergoing prophylactic or therapeutic neck dissections were injected with either Patent Blue V dye alone or with blue dye and 99m-Tc labeled Albures. The latter group underwent preoperative lymphoscintigraphy. During surgery, blue stained lymphatics were followed to blue nodes, and a neoprobe was used to identify radioactive nodes. RESULTS: In 5 of 13 patients receiving blue dye, a blue node was identified, but none contained tumor. Metastases were identified in other neck nodes in 3 of 5. Sentinel nodes were identified in 15 of 16 patients receiving dye, and Albures. Sentinel node biopsy was accurate in 7 of 7 necks containing impalpable metastases when all nodes had been evaluated after dissection. DISCUSSION: Sentinel node biopsy using blue dye and radiocolloid may prove to be a reliable technique in the N0 neck and warrants further investigation.
Biopsy↗
The influence of maxillary dentures on mid-facial fracture patterns.
The presence of upper arch dentures modifies fracture patterns occurring in mid-facial trauma. The fracture patterns of 16 upper denture wearers suffering maxillary fractures were retrospectively studied. Mid-facial fractures in this group were predominantly of the Le Fort I type and in 14 patients demonstrated an atypical fracture path with a vertical fracture passing from the main Le Fort I fracture to the inferior orbital rim. Full upper arch dentures generally protected the upper alveolus from fracture but, where there was discontinuity of the prosthesis, alveolar fractures mirroring the edge of the denture as it crossed the alveolar region were seen. These findings should alert the clinician to the possibility of unusual maxillary fractures in denture wearers and aid our understanding of fracture patterns in the mid-facial skeleton.
Adult↗
Gustatory sweating in a free flap.
A case of Frey's syndrome arising in a free radial forearm flap used to reconstruct a defect in the parotid region is reported. To our knowledge, Frey's syndrome, although common following parotidectomy, has not been reported in a free flap. It is possible that parasympathetic secretomotor fibres gained access to the fasciocutaneous flap via the cutaneous nerve stumps in its edge, resulting in gustatory sweating.
Carcinoma, Squamous Cell↗
Open reduction and internal fixation of condylar fractures via an extended bicoronal approach with a masseteric myotomy.
Although condylar fractures of the mandible may be treated by closed reduction and appropriate physiotherapy, open reduction and internal fixation is indicated in specific circumstances. We report 25 cases of a previously unreported method of exposure of condylar fractures using an extended bicoronal approach combined with myotomy of the masseter muscle. Acceptable reduction and fixation was achieved in all cases with an early return to function. The incidence of complications was low, with three mild temporary facial palsies which had resolved by the sixth postoperative week and one haematoma beneath the bicoronal scalp flap. A cosmetically acceptable scar was produced in all cases. The excellent surgical exposure and protection of the facial nerve, combined with cosmetically acceptable scars, commend the use of this technique.
Adolescent↗
Intraorbital tissue expansion in the management of congenital anophthalmos.
Seven cases of intraorbital tissue expansion for the treatment of congenital anophthalmos or microphthalmos are presented. The ages of the patients at insertion of the expander ranged from 4 months to 8 years. A 4 ml spherical tissue expander with a remote injection port was inserted into the affected orbit via a bicoronal approach. Expansion periods ranged between 4 months and 3 years and are continuing in 2 patients. Results were assessed by clinical examination, comparison of photographs, 3D CT scans and orbital measurements taken from axial CT scans which were compared with established normal values. Results confirmed enlargement of the orbit with expansion. Long-term expansion over several years established near normal bony growth patterns. Placement of the expander within the orbital soft tissue cone resulted in more symmetrical expansion than subperiosteal placement. An osteotomy releasing the lateral orbital wall in older children allows expansion of the orbit and may reduce the incidence of expander extrusion. Although intraorbital tissue expansion successfully induces orbital growth, improvement in the form and size of the congenitally deficient eyelids is less marked.
Anophthalmos↗
Accumulation of donor-specific cytotoxic T cells in intestinal lymphoid tissues following intestinal transplantation.
Utilizing a rat model of semiallogeneic intestinal transplantation, recipients were evaluated for accumulation of donor-specific cytotoxic T cells in spleen, mesenteric lymph nodes, Peyer's patches, lamina propria, and intraepithelial lymphocytes using limiting dilution analysis. Naive animals exhibited a low frequency of cytotoxic T cells in spleen and mesenteric lymph nodes with minimal activity detected in Peyer's patches and intraepithelial lymphocytes, but not detectable activity in lamina propria. Orthotopic intestinal transplantation resulted in significant increases in cytotoxic T-cell activity in recipient Peyer's patches as early as Day 6 and by Day 8 in spleen, mesenteric lymph nodes, lamina propria and intraepithelial lymphocyte populations. Graft lamina propria and intraepithelial lymphocytes exhibited significant cytotoxic T-cell activity as early as 4 days following transplant. The highest donor-specific cytotoxic T-cell activity was observed in graft intraepithelial lymphocytes on Day 8 posttransplant. These studies demonstrate rapid expansion of donor-specific cytotoxic T cells which migrate to the graft site within 4 days after semiallogeneic intestinal transplantation.
Animals↗
Rat jejunal absorptive function after intestinal transplantation. Effects of extrinsic denervation.
Jejunal absorptive function was evaluated following small intestinal transplantation to determine the effects of extrinsic denervation. In particular, water and sodium absorption were measured following transplantation (denervated) and compared to a control group (Thiry-Vella). Water flow was initially secretory two days after transplantation (-41 +/- 27 microliters/min/g dry tissue weight) but became absorptive at day 8 (25 +/- 25). Water flow in the Thiry-Vella group was not significantly different (P > 0.05) from the transplant group at days 8 (17 +/- 7) and 10 (47 +/- 42). Sodium flows were also initially secretory in the transplant group and became absorptive. This study refutes previous claims that small bowel transplants have a deficiency of water absorption due to extrinsic denervation of the bowel and suggests normal absorptive function of water, electrolytes, and protein.
Alanine↗
A cheap and efficacious intraoperative tissue expander.
The application of a mass produced antral balloon catheter for intraoperative tissue expansion in the head and neck is described. This balloon catheter has the advantage of being cheap and readily available.
Catheterization↗
Carcinoma arising in a diverticulum of sigmoid colon.
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Adenocarcinoma↗
Small-bowel transplantation following portal venous injection of donor strain spleen cells.
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Animals↗
Monitoring of intestinal transplant rejection.
Our results show that maltase, sucrase, and lactase activity are present at a normal level in nonrejecting small bowel transplants after an initial postoperative decline. This confirms that the disaccharide absorbing capacity of these grafts is intact. In allogeneic bowel, however, the levels of maltase and sucrase decline as histologic rejection occurs. These results suggest that serial maltase, sucrase, and possibly lactase levels in allogeneic intestinal transplants may serve as a useful adjunct in the monitoring of small bowel transplant rejection.
Animals↗
Small-bowel transplantation permits survival in rats with lethal short-gut syndrome.
The functional integrity of transplanted bowel would most convincingly be demonstrated if transplantation after an otherwise lethal intestinal resection permitted survival and growth. In this experiment, we proposed to define the extent of bowel resection necessary for lethality and to show that transplantation allows salvage of these animals. Adult Brown-Norway rats (250 g) underwent extensive small-bowel resection (SBR) (ligament of Treitz to ileocecal valve) (n = 5), cecectomy only (CEC) (n = 3), SBR plus CEC (n = 6), or SBR plus CEC and syngeneic transplantation of 25 cm of jejunum (n = 6). All animals with SBR or CEC alone survived and grew; all animals with SBR plus CEC died within 2 weeks (mean, 6.4 days); and 6 of 6 animals with SBR plus CEC and transplant survived and grew. The difference in survival between the lethally resected rats and those with an intestinal transplant was highly significant (P less than 0.01). Dietary intake was similar in all groups. We conclude that in the rat, extensive small-bowel resection alone is not sufficient to be lethal; most of the small bowel and the cecum must be resected to obtain a lethal model. We have also shown that transplantation of small bowel into rats with an otherwise lethal extent of bowel resection will allow the animals to survive and grow. These results suggest the need for caution in correlating survival after intestinal transplantation in the rat with transplant function, since the preservation of too much native gut might permit survival even if the transplant has no nutritional function.
Animals↗
Leakage of intraluminal low molecular weight polyethylene glycol as a marker of small bowel transplant rejection.
To facilitate early detection of small bowel allograft rejection, we correlated transluminal leakage of low molecular weight polyethylene glycol (PEG) with the development of allograft rejection. Vascularized allogeneic and syngeneic jejunal transplants were performed in rats, without immunosuppression. A control group underwent creation of jejunal Thiry-Vella fistulas of similar length. Jejunal segments were perfused with a physiologic solution containing [3H]-PEG-900. At the end of an equilibrium period, an urinary bladder aspirate was collected and [3H]-PEG-900 measured by scintillation counting. Results are expressed as disintegrations per minute per 100 microL urine. Histologic examinations were performed at all experimental time points. Two days following transplantation, urinary PEG levels were elevated in both allogeneic and syngeneic groups (3943 +/- 935 and 4007 +/- 1164, respectively). Four days after the transplant, syngeneic urine PEG levels decreased to 581 +/- 159, and were not significantly different (P greater than .05) from Thiry-Vella controls (635 +/- 145). Syngeneic levels remained at this low level for the rest of the experiment. The allogeneic group continued to show significantly higher levels (P less than .05) compared with syngeneic and Thiry-Vella groups from day 4 until the end of the experiment. These elevated levels most likely represented the development of rejection, preceding the first significant histologic signs of rejection, which were found at six days post-transplant. Detection of transluminal leakage of low molecular weight PEG may be a useful adjunct in monitoring for small bowel transplant rejection.
Animals↗