Radial forearm osteocutaneous free flap in maxillofacial and oromandibular reconstructions

OBJECTIVES/HYPOTHESIS

The radial forearm osteocutaneous free flap is an excellent reconstructive modality for oromandibular and maxillofacial reconstruction in certain well-defined circumstances. The initial concern over donor site morbidity and the ability of the bone to reconstruct mandibular defects have led to only a few published series.

STUDY DESIGN

Retrospective study of the experience of two tertiary medical centers with radial forearm osteocutaneous free flap.

METHODS

Retrospectively, 52 patients were studied who underwent radial forearm osteocutaneous free flap reconstruction for cancer (49 cases) and trauma (3 cases). Bone length and skin paddle harvested, general morbidity (hematoma, wound infection, and dehiscence), recipient site morbidity (nonunion of neomandible, flap failure, and bone or plate exposure), and donor site morbidity (radius bone fracture, plate exposure, and skin graft failure) were reviewed.

RESULTS

The average skin paddle size was 55.1 cm (range, 15-112 cm). The average radius bone harvest length was 6.3 cm (range, 2.5-11 cm). Donor site complications included tendon exposure (3 cases), radius bone fracture (1 case), and exposure of the plate (0). Recipient site complications included nonunion of the mandible (4), exposed mandible (1), exposed mandibular plates (2), exposed maxillary plates or bone (0), venous compromise (1), and flap failure (1). Two patients had perioperative deaths.

CONCLUSION

Radial forearm osteocutaneous free flap is a valuable and viable option for oromandibular and maxillofacial reconstruction.

The impact of a monthly rest day on avian influenza virus isolation rates in retail live poultry markets in Hong Kong

Retail live poultry markets (LPMs) may act as a reservoir of avian influenza viruses (AIV). In this study we test the hypothesis that a rest day in the LPMs where the stalls are completely emptied of poultry, cleansed, and restocked will reduce the isolation rates of avian influenza viruses. The isolation rate of H9N2 subtype viruses from chicken was significantly lower after the rest day than prior to it, indicating its impact in reducing transmission. In contrast, Newcastle disease virus (NDV) isolation rates appear unaffected by this intervention, possibly reflecting differences in herd immunity or virus transmission dynamics.

A NASBA method to detect high- and low-pathogenicity H5 avian influenza viruses

Nucleic acid sequence-based amplification (NASBA) allows the rapid amplification of specific regions of nucleic acid obtained from a diverse range of sources. It is especially suitable for amplifying RNA sequences. A NASBA technique was developed that allows the detection of avian influenza A subtype H5 from allantoic fluid harvested from inoculated chick embryos. The amplified viral RNA is detected by electrochemiluminescence. The described NASBA technique is a specific, rapid, and sensitive method of detection of influenza A subtype H5 viruses. More importantly, it can be used to distinguish high- and low-pathogenicity strains of the H5 subtype.

The acetabular blood supply: implications for periacetabular osteotomies

As the popularity of juxta-acetabular osteotomies in adults increases, concern arises that such a procedure will potentially cause avascular necrosis of the acetabular fragment. In order to verify the remaining vascularization after a Bernese periacetabular osteotomy, an injection study with colored latex was performed. The vascularity of the outside of the periacetabular bone was studied in 16 hips after injection of colored latex into the abdominal aorta and the inside in four hips. To confirm the conclusions drawn from the anatomic study, a Bernese periacetabular osteotomy was performed in two additional hips after latex injection. This study demonstrated that through a modified Smith-Peterson approach and with execution of the osteotomies from the inside of the pelvis the acetabular fragment remains vascularized by the supra-acetabular and acetabular branches of the superior gluteal artery, the obturator artery and the inferior gluteal artery. Some uncertainty remains about how much correction is tolerated by the smaller blood vessels.

Excision of laparoscopic port sites increases the likelihood of wound metastases in an experimental model

BACKGROUND

Case reports of patients developing tumor metastases at port sites following laparoscopic surgery have prompted the development of preventive strategies to address this potential problem, including local excision of the port sites. While it has been suggested that this strategy could be used clinically, its efficacy has not been established.

METHODS

Twenty four immune-competent Dark Agouti rats underwent laparoscopy and standardized intraperitoneal laceration of an implanted abdominal flank tumor, using an established laparoscopic cancer model. Rats were randomized to either control (n = 12) or wound excision (n = 12) groups. Both groups underwent laparoscopy using carbon dioxide (CO2) insufflation and two mini-laparoscopy ports. In the wound excision group, one of the port site wounds was excised following desufflation of the abdominal cavity. One week later, the port site wounds were excised for histological examination.

RESULTS

Wound involvement with tumor was significantly more common following wound excision than with untreated control wounds (nine of 12 vs two of 12, p = 0.002). In the wound excision group, tumor metastases arose preferentially in the excised port site wound.

CONCLUSION

This study suggests that excision of laparoscopy port site wounds following laparoscopic surgery for cancer does not prevent the subsequent development of port site tumors. Furthermore, the excision of port sites may actually increase the risk of tumor metastases arising in port sites, suggesting that the clinical application of this strategy should be avoided pending further evaluation.

Hematogenous spread as a mechanism for the generation of abdominal wound metastases following laparoscopy

BACKGROUND

We designed this study to determine whether hematogenous spread has a role in the etiology of port site metastases following laparoscopic surgery.

METHODS

The study design had two parts. In experiment 1, two groups (n = 30) of male Dark Agouti rats were studied. Under general anesthesia, the first group (20 rats) underwent 15 mins of laparoscopic insufflation, followed by an injection of a suspension of 105 Dark Agouti mammary adenocarcinoma (DAMA) cells into the internal jugular vein and a further 15-mins period of insufflation. The laparoscopic ports were then removed, and the wounds were closed and marked. In the second group (n = 10), the procedure was identical except that a 2.5-cm midline laparotomy was performed 15 mins after the commencement of anesthesia and insufflation was not used. The laparotomy was closed in two layers. In experiment 2, one group (n = 4) was studied. The study protocol was identical to the first laparoscopic group except that a larger number of 106 DAMA cells were injected. All rats in both experiments were killed 15 days later, and the injection site, laparoscopy wounds, and laparotomy wound were examined histologically by a blinded histopathologist.

RESULTS

In experiment 1, one port site tumor was detected in the laparoscopic group and no wound metastases were found in the laparotomy group. Postoperative weight loss was significantly less in the laparoscopic group (p < 0.001). In experiment 2, no port site metastases were detected.

CONCLUSION

Although hematogenous spread is a possible mechanism in the development of port site metastases, judging from the low number of port site metastases in this study as compared to previous reports using this tumor model, this mechanism is unlikely to be a major contributor to the problem of wound metastasis following laparoscopy.

The transcriptional repressor CDP (Cutl1) is essential for epithelial cell differentiation of the lung and the hair follicle

The mammalian Cutl1 gene codes for the CCAAT displacement protein (CDP), which has been implicated as a transcriptional repressor in diverse processes such as terminal differentiation, cell cycle progression, and the control of nuclear matrix attachment regions. To investigate the in vivo function of Cutl1, we have replaced the C-terminal Cut repeat 3 and homeodomain exons with an in-frame lacZ gene by targeted mutagenesis in the mouse. The CDP-lacZ fusion protein is retained in the cytoplasm and fails to repress gene transcription, indicating that the Cutl1(lacZ) allele corresponds to a null mutation. Cutl1 mutant mice on inbred genetic backgrounds are born at Mendelian frequency, but die shortly after birth because of retarded differentiation of the lung epithelia, which indicates an essential role of CDP in lung maturation. A less pronounced delay in lung development allows Cutl1 mutant mice on an outbred background to survive beyond birth. These mice are growth-retarded and develop an abnormal pelage because of disrupted hair follicle morphogenesis. The inner root sheath (IRS) is reduced, and the transcription of Sonic hedgehog and IRS-specific genes is deregulated in Cutl1 mutant hair follicles, consistent with the specific expression of Cutl1 in the progenitors and cell lineages of the IRS. These data implicate CDP in cell-lineage specification during hair follicle morphogenesis, which resembles the role of the related Cut protein in specifying cell fates during Drosophila development.

Metabolic and immunologic consequences of laparoscopy with helium or carbon dioxide insufflation: a randomized clinical study

BACKGROUND

Previous studies using animal models have demonstrated that carbon dioxide (CO2) pneumoperitoneum during laparoscopy is associated with adverse physiological, metabolic, immunological and oncological effects, and many of these problems can be avoided by the use of helium insufflation. The present study was performed in patients to compare the effect of helium and CO2 insufflation on intraperitoneal markers of immunological and metabolic function.

METHODS

Eighteen patients undergoing elective upper gastrointestinal laparoscopic surgery were randomized to have insufflation achieved by using either helium (n = 8) or CO2 (n = 10) gas. Intraperitoneal pH was monitored continuously during surgery, and peritoneal macrophage function was determined by harvesting peritoneal macrophages at 5 min and 30 min after commencing laparoscopy, and then assessing their ability to produce tumour necrosis factor-alpha (TNF-alpha), and their phagocytic function.

RESULTS

Carbon dioxide laparoscopy was associated with a lower intraperitoneal pH at the commencement of laparoscopy, although this difference disappeared as surgery progressed. The production of TNF-alpha was better preserved by CO2 laparoscopy, but the insufflation gas used did not affect macrophage phagocytosis. Patients undergoing helium laparoscopy required less postoperative analgesia.

CONCLUSION

The choice of insufflation gas can affect intraperitoneal macrophage function in the clinical setting, and possibly acid-base balance. The present study suggested no immunological advantages for the clinical use of helium as an insufflation gas. The outcomes of the present study, however, are different to those obtained from previous laboratory studies and further research is needed to confirm this outcome.

Stability boundaries and lateral postural control in parkinson's disease

Postural instability is a major problem in patients with Parkinson's disease (PD). We examined balance control in PD by using center of pressure (CP) variability and time-to-contact to investigate boundary relevant postural control behavior under quiet stance leaning conditions. Postural orientation was manipulated by having patients (n = 10) and healthy older controls (n = 7) lean forward and backward with varying degrees of lean on a force platform. The subjects were instructed to lean forward or backward (either halfway or as far as possible) without bending their hips or lifting their heels or toes off the ground. Time-to-contact of the CP with the geometric stability boundary defined by the feet as well as CP position and variability were analyzed. Medio-lateral CP variability was increased in the patients with PD. Medio-lateral average time-to-contact was decreased in the patients but not so in the anterior-posterior direction. In contrast to the CP variability, the medio-lateral variability of time-to-contact was lower in the patients. Patients as well as healthy older controls responded to lean manipulations with an increase in CP variability. Boundary relevant CP measures thus show clear changes in control strategies and confirm the role of lateral instability in PD.

A prospective randomized trial of laparoscopic Nissen fundoplication with anterior vs posterior hiatal repair

HYPOTHESIS

The technique used for repair of the esophageal hiatus during laparoscopic Nissen fundoplication can influence the likelihood of postoperative dysphagia.

DESIGN

A prospective double-blind randomized control trial.

SETTING

A university teaching hospital.

PARTICIPANTS

A total of 102 patients with proven gastroesophageal reflux disease, undergoing a laparoscopic Nissen fundoplication were randomized to undergo fundoplication with either anterior (47 patients) or posterior (55 patients) repair of the diaphragmatic hiatus. Patients were excluded for the following reasons: they had esophageal motility disorders, required a concurrent abdominal procedure, had undergone previous antireflux surgery, or had very large hiatus hernias.

INTERVENTIONS

Laparoscopic Nissen fundoplication with anterior vs posterior hiatal repair.

MAIN OUTCOME MEASURES

Independent assessment of dysphagia, heartburn, patient satisfaction, and other symptoms 1, 3, and 6 months following surgery, using multiple standardized clinical grading systems. Objective measurement of lower esophageal sphincter pressure, esophageal emptying time, distal esophageal acid exposure, and endoscopic assessment of postoperative anatomy and esophageal mucosa.

RESULTS

Symptoms of postoperative dysphagia, relief of heartburn, and overall satisfaction 6 months after surgery were not influenced by the hiatal repair technique. However, to achieve a similar incidence of dysphagia, more patients who initially underwent posterior hiatal repair required a second surgical procedure (6 vs 0 patients). The hiatal repair technique did not affect the likelihood of early postoperative paraesophageal herniation.

CONCLUSION

Anterior suturing of the hiatus appears to be at least as good in the short-term as posterior suturing as a method of narrowing the hiatus during laparoscopic Nissen fundoplication.

Screw position affects dynamic compression plate strain in an in vitro fracture model

OBJECTIVE

This investigation considers the effect of a variety of screw positions on plate strain in three fracture models.

DESIGN

Dynamic compression plate fixation of in vitro fracture models.

METHODS

To model a fracture, a plastic pipe was cut transversely and a twenty-hole dynamic compression plate was attached by screws. Eighteen stacked, rectangular, rosette strain gauges were installed on the plate to evaluate strain. Three models were evaluated: two constructs in which there was no contact between the cut ends of the pipe under the fixation plate (small-and large-gap models) and a construct in which there was direct apposition of the cut ends (no-gap model). The pattern and magnitude of strains were assessed as a function of varying combinations of screw position for each model.

RESULTS

Maximal plate strain in the gap models was lowest with screws placed closest to the gap, compared with screws placed away from the gap or spaced apart. The no-gap model showed significantly lower strains when screws were placed further from the osteotomy site than when screws were positioned close together or spaced apart. In all cases, maximal plate strain occurred adjacent to the most central screw holes and rapidly dissipated along the length of the plate.

CONCLUSION

In a model simulating a comminuted fracture (gap), this study found that screws should be placed as close to the fracture site as possible to minimize plate strain. In an anatomically reduced two-part fracture model (no gap), widely spaced screws or those placed away from the fracture resulted in lower strains.

Efficient ex vivo transduction of pancreatic islet cells with recombinant adeno-associated virus vectors

The ability to transfer immunoregulatory, cytoprotective, or antiapoptotic genes into pancreatic islet cells may allow enhanced posttransplantation survival of islet allografts and inhibition of recurrent autoimmune destruction of these cells in type 1 diabetes. However, transient transgene expression and the tendency to induce host inflammatory responses have limited previous gene delivery studies using viral transfer vectors. We demonstrate here that recombinant adeno-associated virus (rAAV) serotype 2, a vector that can overcome these limitations, effectively transduces both human and murine pancreatic islet cells with reporter genes as well as potentially important immunoregulatory cytokine genes (interleukin-4, interleukin-10), although a very high multiplicity of infection (10,000 infectious units/islet equivalent) was required. This requirement was alleviated by switching to rAAV serotype 5, which efficiently transduced islets at a multiplicity of infection of 100. Although adenovirus (Ad) coinfection was required for efficient ex vivo expression at early time points, islets transduced without Ad expressed efficiently when they were transplanted under the renal capsule and allowed to survive in vivo. The rAAV-delivered transgenes did not interfere with islet cell insulin production and were expressed in both beta- and non-beta-cells. We believe rAAV will provide a useful tool to deliver therapeutic genes for modulating immune responses against islet cells and markedly enhance longterm graft survival.

Nitric oxide production by coelomocytes of Asterias forbesi

Vertebrate mononuclear phagocytes produce a plethora of molecules involved in host defense. Among the most potent are the reactive oxygen and nitrogen intermediates. Coelomocytes from invertebrates subserve many of the same functions. In order to determine whether invertebrate phagocytes employ reactive nitrogen intermediates, we investigated the effect of various nonspecific stimulators and invertebrate interleukin (IL)-1alpha- and beta-like molecules on nitric oxide (NO) production. Elevated NO release by stimulated coelomocytes was seen after 24 h. Incubation of stimulated coelomocytes in the presence of arginine analogs inhibited NO release. When invertebrate IL-1-like molecules were added to the coelomocytes, they stimulated the release of NO. Western blot analysis using a polyclonal rabbit antiserum to murine NO synthase detected a band at approximately 125 kDa. These data indicate that coelomocytes are capable of producing and releasing NO and that NO is a chemical mediator that has been conserved as a host defense weapon of phagocytes through evolutionary time.

Clozapine and risperidone treatment of psychosis in Parkinson's disease

The authors compared efficacy and safety of risperidone and clozapine for the treatment of psychosis in a double-blind trial with 10 subjects with Parkinson's disease (PD) and psychosis. Mean improvement in the Brief Psychiatric Rating Scale psychosis score was similar in the clozapine and the risperidone groups (P=0.23). Although the mean motor Unified Parkinson's Disease Rating Scale score worsened in the risperidone group and improved in the clozapine group, this difference did not reach statistical significance. One subject on clozapine developed neutropenia. In subjects with PD, risperidone may be considered as an alternative to clozapine because it is as effective for the treatment of psychoses without the hematologic, antimuscarinic, and seizure side effects. However, risperidone may worsen extrapyramidal symptoms more than clozapine and therefore must be used with caution.

Influence of gases on intraperitoneal immunity during laparoscopy in tumor-bearing rats

Laparoscopy has been associated with metastases to abdominal wall wounds. In addition, many recent experimental studies suggest that laparoscopy is associated with increased tumor dissemination. It is possible that immune or metabolic disturbances due to the use of a pneumoperitoneum could contribute to this problem. To investigate this possibility, we studied the effect of two insufflation gases and gasless laparoscopy on in vivo peritoneal macrophage function and intraperitoneal pH in an experimental model. A carcinoma was implanted into the flank of 32 experimental rats that underwent laparoscopic surgery in one of four treatment groups: anesthesia alone, gasless laparoscopy, helium insufflation, and CO2 insufflation. Intraperitoneal pH was monitored during surgery, and peritoneal macrophage function was determined 3 days after surgery by harvesting peritoneal macrophages and then examining their ability to produce tumour necrosis factor-alpha (TNF-alpha). CO2 insufflation was associated with a consistent fall in intraperitoneal pH and a significant reduction in TNFalpha production. These findings did not occur in the other study groups. The results of this study demonstrate that CO2 insufflation results in depressed intraperitoneal macrophage activity. It is possible that it is mediated by pH changes. In addition, it could be a contributing factor to the development of port-site metastases. Further studies are needed to determine whether the factors identified act during clinical surgery.

The effect of immune enhancement and suppression on the development of laparoscopic port site metastases

BACKGROUND

Recent clinical case reports and experimental studies have suggested that laparoscopic cancer surgery is associated with an increased risk of tumor spread to abdominal wall wounds. While the etiology of this problem was initially believed to be related to mechanical contamination of wounds, it is now recognized that there are other contributory factors, including disturbed immune function within the peritoneal cavity. To investigate this question further, we evaluated the effect of immune modulation within an established laparoscopic cancer model.

METHODS

Eighteen immune-competent syngeneic rats underwent modulation of their immune system, followed 18 h later by laparoscopy with the introduction of a suspension of adenocarcinoma cells into the peritoneal cavity. Rats were randomly allocated to receive either systemic cyclosporin (immune suppressor), intraperitoneal endotoxin (immune enhancer), or no agent (controls). Seven days later, all rats were killed and their peritoneal cavity was inspected for tumor implantation and port site metastases.

RESULTS

Cyclosporin did not influence the study outcome, but tumor growth (p = 0.008) and port site metastases (p < 0.0001) were less common following the administration of intraperitoneal endotoxin.

CONCLUSION

The results of this study suggest that the immune system plays a role in the genesis of port site metastases. A preventive role for endotoxin in patients undergoing laparoscopic cancer surgery, however, remains speculative.

Glutamic acid decarboxylase and IA-2 autoantibodies in type 1 diabetes: comparing sample substrates for autoantibody determinations

Large-scale programs designed to assess risk for type 1 diabetes through serologic assessment of autoantibodies to recombinant beta-cell autoantigens are hampered by several limitations, including the methods for sample collection and assay performance, as well as the volume required for autoantibody determinations. The present study was designed to develop a low sample-volume, primary screening method for autoantibody detection of high specificity and sensitivity, and to determine the feasibility of dried blood spots collected on filter paper in serving as vehicles for such determinations. Autoantibodies to glutamic acid decarboxylase (GAD) and ICA512bdc (IA-2), both individually and in combination, were determined in persons with type 1 diabetes, healthy controls, or individuals with other autoimmune disorders. Autoantibody results for serum, plasma, and dried blood spots were compared. GAD, IA-2, and combined GAD/IA-2 autoantibodies were concordant in their measurement from minimal volumes of serum, plasma, and whole blood extracted from dried filter paper. The autoantibody levels from the dried blood spots were, however, lower than corresponding serum samples, and, as currently designed, failed to detect low-titer autoantibodies. Despite this limitation, screening for diabetes risk can be performed using small volumes of whole blood, serum, or plasma collected onto filter paper. These methodological improvements should simplify matters, reduce costs, and increase the efficacy of screening programs for type 1 diabetes. Further development of better substrates/methods for blood-specimen collection seems necessary to exploit the full potential of this and other autoantibody measurement strategies for screening large populations.

Bloodborne pathogens: toward safer needles

California leads the way in protecting workers with sharps injury prevention devices. This article discusses the state's legislation to prevent needlestick injuries among healthcare workers and its impact. A chart to be used as a sharps injury log is provided.

The pharmacokinetics and pharmaco-dynamics of Procysteine in amyotrophic lateral sclerosis

In 13 subjects with ALS, we studied the safety and pharmacokinetic properties of Procysteine, a cysteine prodrug that increases levels of intracellular glutathione. We found that oral administration of Procysteine was safe. Procysteine enters CSF after both IV and oral dosing and accumulates to significant levels in CSF. We also observed that CSF levels of glutathione fall dramatically with aging.

Comparison of serological tests and faecal culture for the detection of Mycobacterium avium subsp. paratuberculosis infection in cattle and analysis of the antigens involved

Three hundred and forty-one sera from cattle in Western Australia and 106 sera from Mycobacterium paratuberculosis faecal culture positive cattle were used to evaluate the performance of two absorbed enzyme-linked immunosorbent assays (ELISA) (one locally produced, the other a commercial test) and a complement fixation test (CFT) for the detection of Johne's disease in cattle. The diagnostic sensitivity (47.2%) of the local ELISA was significantly higher than that of the commercial ELISA (31.1%), and significantly higher than that for the complement fixation test (17.9%) and immunoblot (20.8%). Diagnostic specificity for the two ELISAs was 99.7% and 97.9% and similar for CFT and immunoblot (97.1% and 97.7%, respectively). The diagnostic sensitivity rose for both ELISAs and the CFT as the number of M. paratuberculosis isolated from the faeces increased. The ELISA antigen was characterised by polyacrylamide gel electrophoresis and electrophoretic immunoblotting and was found to consist mostly of a carbohydrate-type macromolecule of 32-42 kDa. This macromolecule was identified as lipoarabinomannan (LAM) by using a LAM-specific monoclonal antibody in immunoblots and purified LAM in absorption experiments. By applying more complex antigen preparations in immunoblots, serum antibodies against proteins of 47, 37, 30, 24 and 21 kDa, and against the 32-42 kDa carbohydrate component were frequently found in infected cattle, and of these the 47 kDa protein and the 32-42 kDa antigen were immuno-dominant. Pre-absorption of the sera with M. phlei sonicate indicated that the protein antigens contributed markedly to non-specific serological cross-reactions, while the 32-42 kDa non-protein macromolecule appeared to be specific.