[Lateral neck dissection of hypopharyngeal cancer with clinically regional metastasis]

OBJECTIVE

To assess whether lateral neck dissection can control the hypopharyngeal cancer with clinically regional metastasis.

METHODS

A retrospective review of medical chart from 1975 to 1992 was performed. Ninety-three hypopharyngeal squamous cell carcinoma patients who had performed RND were included. The distribution of metastatic neck lymph node was analyzed.

RESULTS

Submandibular triangle lymph node metastasis was occult in only 3 patients. Histological lymph node metastasis to the posterior triangle was found in 5.9% of patients with N0, 7.0% with N1, 37.5% with N2a and 36% with N2b-N3. Histological neck lymph node metastasis to the posterior triangle was found in 4.0% of patients without inferior jugular lymph node metastasis and 34.1% of patients with inferior jugular lymph node metastasis.

CONCLUSIONS

Lateral neck dissection was recommended to treat hypopharyngeal cancers of N0 and N1. N2 and N3 should be treated with neck dissection including II-V group lymph nodes. After lateral neck dissection, frozen section of the inferior jugular lymph node should be performed. If the result of the frozen section is positive, V group dissection should be performed.

General anesthetic binding to gramicidin A: the structural requirements

There is a distinct possibility that general anesthetics exert their action on the postsynaptic receptor channels. The structural requirements for anesthetic binding in transmembrane channels, however, are largely unknown. High-resolution (1)H nuclear magnetic resonance and direct photoaffinity labeling were used in this study to characterize the volatile anesthetic binding sites in gramicidin A (gA) incorporated into sodium dodecyl sulfate (SDS) micelles and into dimyristoylphosphatidylcholine (DMPC) bilayers, respectively. To confirm that the structural arrangement of the peptide side chains can affect anesthetic binding, gA in nonchannel forms in methanol was also analyzed. The addition of volatile anesthetic halothane to gA in SDS with a channel conformation caused a concentration-dependent change in resonant frequencies of the indole amide protons of W9, W11, W13, and W15, with the most profound changes in W9. These frequency changes were observed only for gA carefully prepared to ensure a channel conformation and were absent for gA in methanol. For gA in DMPC bilayers, direct [(14)C]halothane photolabeling and microsequencing demonstrated dominant labeling of W9, less labeling of W11 and W13, and no significant labeling of W15. In methanol, gA showed much less labeling of any residues. Inspection of the 3-D structure of gA suggests that the spatial arrangements of the tryptophan residues in the channel form of gA, combined with the amphiphilic regions of lipid, create a favorable anesthetic binding motif.

[Effects of methylmercury on intracellular free calcium content in cerebral cortical neurons]

OBJECTIVE

This study was conducted to explore effects and potential mechanism of methylmercury on concentration of intracellular free calcium (Ca(2+)) in the acutely isolated cerebral cortical neurons.

METHODS

Calcium ion indicator Fura-2 two wave-length fluorophotometry was used to measure concentration of Ca(2+).

RESULTS

(0.10 - 5.00) x 10(-6) mol/L of methylmercury could increase level of free intracellular Ca(2+) in cerebral cortical neurons significantly (P < 0.01), in a dose-response manner. Increase in intracellular free Ca(2+) of neurons caused by methylmercury associated with large influx of Ca(2+) outside cells and release of stored Ca(2+) inside cells, especially by influx of Ca(2+) outside cells. Influx of Ca(2+) outside cells associated with Ca(2+) channels regulated by receptor gate and potential gate, but not associated with sodium-dependent channel.

CONCLUSION

Methylmercury lead to abnormal increase of intracellular free Ca(2+) in neurons, which is closely related to Ca(2+) channel.

[Pedicled galeal flap in the reconstruction of head and neck tumor defects]

OBJECTIVE

To evaluate the advantage and applications of pedicled galeal flap in head and neck region.

METHODS

A consecutive series of 17 patients underwent surgical reconstruction with pedicled galeal flaps after head and neck tumor resection. The defects included nasopharynx, skull base, maxilla, orbital base, oropharynx and oral cavity and the size ranged from 5 cm x 5 cm to 10 cm x 10 cm. The technique for using this flap was described and application was illustrated with 3 case reports.

RESULTS

Complete success of galeal flaps for the reconstruction of head and neck defects was achieved in 13 of the 17 cases (76.5%) and partial necrosis was observed in the remaining 4 cases (23.4%). Immediate wound complications occurred in four cases, which resolved spontaneously. Four delayed complications were observed in 4 of 9 survival cases that included trismus (3) and alopecia (1).

CONCLUSION

Galeal flap is a thin, pliable and well vascularised reconstruction tissue and is highly reliable. The donor site morbidity is minor. We have found the flap to be useful in the reconstruction of a variety of defects in head and neck, especially in skull base, orbital base, nasopharynx and oropharynx.

NMR study of volatile anesthetic binding to nicotinic acetylcholine receptors

New lines of evidence suggest that volatile anesthetics interact specifically with proteins. Direct binding analysis, however, has been largely limited to soluble proteins. In this study, specific interaction was investigated between isoflurane, a clinically important volatile anesthetic, and membrane-bound nicotinic acetylcholine receptors (nAChRs) from Torpedo electroplax, using (19)F nuclear magnetic resonance spectroscopy and gas chromatography. The receptors were reconstituted into 1, 2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) lipid vesicles. After correcting for nonspecific partitioning into the lipid, the equilibrium dissociation constant, K(d), of isoflurane binding to nAChR at 15 degrees C was found to be 0.36 +/- 0.03 mM. This value is within the clinically relevant concentration range of the agent. Based on the receptor concentrations in the vesicle suspension assayed by the bicinchoninic acid method and the fraction of bound isoflurane, X(b), determined by gas chromatography, an estimate of an average of 9-10 specifically bound isoflurane molecules can be made for each receptor, or two for each subunit. Upon binding, the transverse relaxation time constant (T(2)) of (19)F resonance of isoflurane is decreased by nearly three orders of magnitude, indicating a dramatic reduction in the mobility of specifically bound isoflurane. Kinetic analysis reveals that the off rate of binding, k(-1), is 1.7 x 10(4) s(-1). The on rate, k(+1), can thus be calculated to be approximately 4.8 x 10(7) M(-1) s(-1), suggesting a nearly diffusion-limited association. This is in contrast to anesthetic binding to a soluble protein, bovine serum albumin (BSA), where k(+1) and k(-1) are at least an order of magnitude slower. It is concluded that the presence of lipids may be critical for the correct evaluation of binding kinetics between volatile anesthetics and neuronal receptors.

[The treatment of tongue squamous cell with N0]

OBJECTIVE

To evaluate the validity of selective surgery for the N(0) neck in squamous cell carcinoma of the mobile tongue.

METHODS

116 patients with N(0) neck of the mobile tongue cancer who underwent comprehensive RND and 5 patients who had a selective RND were reviewed retrospectively.

RESULTS

According to the suggestion of division of neck level, 7 patients had metastasis at level I; 21, level II; 10, level III, 1 case for level IV or V each. There were 5 cases with level III involvement as a first echelon of metastasis which was peculiar for the neck metastasis of mobile tongue.

CONCLUSIONS

For N(0) neck of the mobile tongue cancer, a neck dissection of level I-III or level I-IV is more than enough.

[Expression of human flt3 ligand and thrombopoietin genes in a bone marrow stromal cell line by internal ribosome entry site (IRES) sequence]

OBJECTIVE

To explore the feasibility of retroviral-mediated Flt 3 ligand (FL) and thrombopoietin (Tpo) genes transferred into and expressed in a bone marrow stromal cell line HFCL by internal ribosome entry site(IRES) sequence.

METHODS

IRES sequence, FL and Tpo cDNA were recombined with retroviral vector pLXSN by gene recombination technology. The recombinant plasmid was transferred into retrovirus packaging cell line PA317 by lipofectamine, and the resistant clones were selected by G418 selective medium. mRNA expression in HFCL cells and integration of genome DNA were assayed by RT-PCR and genomic DNA PCR. The biological activities of FL and Tpo in the culture were investigated by CFU-GM assay and Tpo dependent cell line TD-3, respectively.

RESULTS

The recombinant plasmid pLFTSN was successfully constructed. In the genome of these transfected target cells, Neo gene and FL and Tpo cDNA were integrated, the expression of FL and Tpo mRNA was detected in HFCL cells. The specific activities of FL and Tpo in the culture indicated that HFCL cells transfected with FL and Tpo cDNA could significantly express FL and Tpo in vitro.

CONCLUSION

FL gene and Tpo gene were simultaneously expressed in bone marrow stromal cell line by the regulation of IRES sequence. These results provide a basis for studies on hematopoietic regulation by gene transfected bone marrow stromal cells.

[The role of surgery in the management of thyroid lymphoma]

OBJECTIVE

To evaluate the role of surgery in the management of thyroid lymphoma.

METHODS

A retrospective analysis was performed of 14 patients with thyroid lymphoma treated at the Cancer Hospital, Peking Union Medical College, Chinese Academy Medical Science from 1964 to March 1998. There were 5 males and 9 females, with a median age of 54 years (range 15-75). There were 4 cases in stage IEA, 9 in stage IIEA, 1 in stage II EB. Fine needle aspiration biopsy was performed in 1 case, excision biopsy in 4, thyroid lobectomy in 8, and total thyroidectomy in 1. Radiotherapy was used alone in 4 patients, chemotherapy alone in 2, radiotherapy combined with chemotherapy in 7, no postoperative treatment in 1.

RESULTS

All but 1 patients were histopathologically diagnosed as non-Hodgkin's lymphoma. It was of B cell origin in 11 cases, T cell origin in 2. Seven patients were alive without evidence of recurrent disease at follow-up, ranging from 5 to 112 months. Three patients died of lymphoma, 1 died of treatment complication, 2 died of other diseases, and 1 lost from follow-up. The major surgical resection did not appreciably affect survival.

CONCLUSION

Radiotherapy or chemotherapy, alone or in combination, is the treatment of choice for thyroid lymphoma. Surgical resection combined with radiotherapy or chemotherapy may be beneficial to survival in patients with intrathyroid lymphoma. It is otherwise limited to make a tissue diagnosis.

Is end-to-side neurorrhaphy effective? A study of axonal sprouting stimulated from intact nerves

The purpose of this study was to determine if axonal sprouting across an end-to-side coaptation could be stimulated and if so, to identify the source of the regenerating axons. Mechanical trauma, the method used to stimulate axonal sprouting, was compared to a control group with coaptation only and an additional non-grafted control group. After a 20-week recovery period, electrical stimulation revealed that the target muscles had been reinnervated in all groups except the non-grafted control group. Axonal counting demonstrated a significant increase for the mechanical trauma group compared to the control group with coaptation only [ratio of the density of axons/microm2 of the experimental to the contralateral control side: 2.78+/-0.11 vs. 0.96+/-0.15, respectively, p<0.002). Tibialis anterior muscle weights were significantly increased for both groups vs. the non-grafted control group (ratio of experimental to the contralateral control side: coaptation-only control, 0.539+/-0.024; mechanical trauma, 0.538+/-0.036 vs. nongrafted control, 0.220+/-0.003, p<0.002). Of importance, this study provides evidence that the intact tibial nerve functions as a bridge for regenerating axons derived from the proximal peroneal stump. This suggests an alternative explanation to successful end-to-side axonal sprouting, and questions the clinical utility of end-to-side coaptation.

Using affinity capillary electrophoresis to evaluate average binding constant of 18-mer diphosphotyrosine peptide to antiphosphotyrosine Fab

We used affinity electrophoresis in capillaries to investigate the interaction between a monovalent antiphosphotyrosine antibody fragment, antigen-binding fragment (Fab), and a divalent antigen (dAg), an 18-mer diphosphopeptide phosphorylated on two-site tyrosine residues. The migration shift behavior of Fab in electrophoretic solution was observed and the quantitative expression was presented to estimate the arithmetical average value of the intrinsic affinities for two epitopes on the dAg with the Ag binding site on the Fab. In dAg excess, based on measurement of mobility changes of Fab analytes at different dAg concentrations, the experimental average dissociation constant (Kd = 27.7 microM) was calculated. It was also found that the structural variation of the two epitopes for binding specificity to the Ag-binding domain of Fab is not apparent. Moreover, the Kd values of Fab-dAg complexes were measured at higher electric fields and shown to be independent of changes in the electric field. Thus, under conditions where the total dAg concentration is in excess of the total Fab concentration, the method and quantitative expression which we developed is generally useful for the understanding of molecular interaction for an unlabeled monovalent receptor and its divalent ligand in free solution.

Once daily, high dose versus divided, low dose gentamicin for open fractures

A prospective, randomized study was performed on 75 Gustilo Grades II and III open fractures to determine the efficacy of once daily, high dose aminoglycoside therapy, compared with more conventional dosing, in reducing the infection rate when used in conjunction with an aggressive operative treatment protocol. All patients enrolled in the study were treated with immediate irrigation, debridement, operative stabilization of the fracture, and 1 g of cefazolin every 8 hours. At the time of admission patients were randomized to two groups. Patients in Group I received gentamicin 5 mg/kg divided into twice daily doses, and patients in Group II received gentamicin 6 mg/kg given once daily. All patients were monitored for renal toxicity and observed for radiographic and clinical signs of infection until fracture union. The results of the study revealed no statistically significant difference between once daily, high dose versus divided, low dose gentamicin in infection rates. Thus, daily dosing of gentamicin was found to be safe, effective, and cost efficient in the treatment of open fractures when combined with a cephalosporin and aggressive operative debridement and stabilization.

Squamous cell carcinoma of temporal bone: reported on 33 patients

BACKGROUND

This study assessed the treatment results of a series of 33 patients with squamous cell carcinoma (SCC) of the temporal bone and evaluated the efficacy of mastoidectomy combined with perioperative radiation therapy protocol.

METHODS

Thirty-three patients with biopsy-proven SCC invaded to the temporal bone were reviewed retrospectively and staged into three subgroups according to the University of Pittsburgh TNM Staging System. There were 3 patients with Stage I and II disease(tumor confined to auditory canal), 17 patients with Stage III (tumor involving the middle ear or mastoid), and 13 patients with Stage IV(more extensive disease). Two patients were treated by surgery alone. Eleven patients received irradiation only, and the remaining 20 patients underwent combined surgery and perioperative radiotherapy. The surgical intervention included sleeve resection for patients with Stage I and II lesions and mastoidectomy for all patients with Stage III and IV lesions except 1 who had subtotal temporal bone resection. The radiation dose delivered was in the range of 3500 approximately 10 000 cGy, with an average dose of 6560 cGy.

RESULTS

The five-year survival rate for the whole series was 51.7% by the life-table analysis. After being staged into three subgroups (ie, Stage I + II, Stage III, and Stage IV), the estimated five-year survival rates were 100%, 68. 8%, and 19.6%, respectively (p = 0.04). Radiation alone yielded a 28. 7% five-year survival, while combined surgery and irradiation gave a result of 59.6% (p = 0.80). For patients treated with planned combined therapy, the actuarial five-year survival rates were 72.7% (8/11) for Stage III disease and 12.5% (1/8) for Stage IV disease (p = 0.02). Twelve patients who died of disease did so of local recurrence (10 cases), cervical metastases (1 case), and liver metastases (1 case), with 70% of succumbing to their diseases within two years. Complications include osteonecrosis (n = 1), osteitis (n = 3), radiation dermatitis (n = 2), facial nerve palsy (n = 2), and delayed healing (n = 2). Data on clinical presentation and treatment modality were also analyzed.

CONCLUSION

The results of mastoidectomy with removal of all gross tumor, combined with planned perioperative irradiation therapy, seems to be a useful approach for SCC of the temporal bone. This gives at least as good, and possibly better, five-year survival than temporal bone resection. The mastoidectomy procedure creates less operative morbidity and mortality. To facilitate the development of more effective means of treating advanced disease, an accepted staging system and cooperative group investigation is necessary.

Distinctly different interactions of anesthetic and nonimmobilizer with transmembrane channel peptides

Although it plays no clinical role in general anesthesia, gramicidin A, a transmembrane channel peptide, provides an excellent model for studying the specific interaction between volatile anesthetics and membrane proteins at the molecular level. We show here that a pair of structurally similar volatile anesthetic and nonimmobilizer (nonanesthetic), 1-chloro-1,2,2-trifluorocyclobutane (F3) and 1, 2-dichlorohexafluorocyclobutane (F6), respectively, interacts differently with the transmembrane peptide. With 400 microM gramicidin A in a vesicle suspension of 60 mM phosphatidylcholine-phosphatidylglycerol (PC/PG), the intermolecular cross-relaxation rate constants between (19)F of F3 and (1)H in the chemical shift regions for the indole and backbone amide protons were 0.0106 +/- 0.0007 (n = 12) and 0.0105 +/- 0.0014 (n = 8) s(-1), respectively. No cross-relaxation was measurable between (19)F of F6 and protons in these regions. Sodium transport study showed that with 75 microM gramicidin A in a vesicle suspension of 66 mM PC/PG, F3 increased the (23)Na apparent efflux rate constant from 149.7 +/- 7.2 of control (n = 3) to 191.7 +/- 12.2 s(-1) (n = 3), and the apparent influx rate constant from 182.1 +/- 15.4 to 222.8 +/- 21.7 s(-1) (n = 3). In contrast, F6 had no effects on either influx or efflux rate. It is concluded that the ability of general anesthetics to interact with amphipathic residues near the peptide-lipid-water interface and the inability of nonimmobilizer to do the same may represent some characteristics of anesthetic-protein interaction that are of importance to general anesthesia.

[Cervical management in the N0 squamous cell carcinoma of the tongue]

OBJECTIVE

To assess whether the elective neck dissection would be beneficial as a routine management in the N0 squamous cell carcinoma of the tongue.

METHODS

Cox regression model was used for analysis of tongue cancer cases treated by our hospital in a period from 1958 to 1996.

RESULTS

Size of primary tumor and preoperative radiation showed significant difference in relation to cervical lymph node recurrence or metastasis. Neck dissection in the series was not a factor to influence the rate of cervical recurrence or survival. 5-years survival was 73.5% versus 69.3% in patients who underwent elective neck dissection and those without neck dissection (difference not statistically significant).

CONCLUSION

We suggest that elective neck dissection would be avoided in T1 or T2 patients who have no neck node metastases.

Topiramate pharmacokinetics in infants

PURPOSE

This study's goal was to provide preliminary data on the pharmacokinetics of topiramate (TPM) in a cohort of infants (younger than 4 years) participating in an open-label trial of TPM in refractory infantile spasms.

METHODS

The pharmacokinetics of TPM were assessed in infants receiving a stable TPM dose for >7 days during the extension phase of this trial. Blood samples were drawn just before and 0.5. 1, 1.5, 2, 4, 6, 8, and 12 h after the morning TPM dose. TPM plasma concentrations were determined by fluorescence polarization immunoassay. The noncompartmental analysis module of WinNonlin was used to calculate individual patient pharmacokinetics profiles.

RESULTS

Five infants (ages, 23.5-29.5 months) formed the study cohort. These infants had been given TPM for a median of 9 months (range, 6-11 months) and were currently receiving between 11 and 38.5 mg/kg/day TPM. One was receiving TPM monotherapy, whereas four were taking concomitant antiepileptic medications (AEDs; n = 2, enzyme-inducing agents; n = 2, non-enzyme-inducing drugs). TPM pharmacokinetics in infants appears to be linear. In this cohort, mean TPM plasma clearance (CL/F, 66.6+/-27.4 ml/h/kg) was slightly higher than that reported for children and adolescents and therefore substantially higher than that reported for adults. TPM CL/F was higher and the calculated half-life shorter in the infants receiving concomitant enzyme-inducing AEDs.

CONCLUSIONS

Based on this small cohort of patients, it appears that infants may require significantly larger TPM doses, based on weight, than children, adolescents, or adults. Titration to effect and not absolute TPM dose should guide therapy in this age group.

Transforming growth factor-alpha antisense vectors can inhibit glioma cell growth

The effects of transforming growth factor-alpha (TGF-alpha) on cell growth were studied in human glioma U251 cells transfected with antisense TGF-alpha vectors (pcDNAI.neo). Several antisense clones showed a marked decrease in growth rate in serum-free medium but not in medium containing 10% FBS, compared with those of parental cells and clones from sense or vector transfectants. Antisense clones also produced fewer and smaller colonies in anchorage-independent growth assays. Moreover, there was a reduction in TGF-alpha expression in these antisense clones at both the protein and mRNA levels, as determined by enzyme linked immuno-sorbent assay and reverse transcriptase polymerase chain reaction analysis. A U251 clone transfected by TGF-alpha antisense in a different vector (pMT/Ep) also showed a marked suppression in cell growth and TGF-alpha mRNA level. Finally, transfected clones with either vector system, showed decreased tumorigenicity in nude mice. In summary, a strong correlation between the inhibition of glioma cell growth and TGF-alpha expression was obtained from two different plasmid vectors, indicating that the expression of TGF-alpha could be specifically and effectively down-regulated by TGF-alpha antisense vector, which in turn led to growth inhibition. These studies suggests that TGF-alpha plays an essential role in controlling human glioma cell proliferation and may serve as a potential target for treatment of malignant glioma.

Structural consequences of anesthetic and nonimmobilizer interaction with gramicidin A channels

Although interactions of general anesthetics with soluble proteins have been studied, the specific interactions with membrane bound-proteins that characterize general anesthesia are largely unknown. The structural modulations of anesthetic interactions with synaptic ion channels have not been elucidated. Using gramicidin A as a simplified model for transmembrane ion channels, we have recently demonstrated that a pair of structurally similar volatile anesthetic and nonimmobilizer, 1-chloro-1,2,2-trifluorocyclobutane (F3) and 1,2-dichlorohexafluorocyclobutane (F6), respectively, have distinctly different effects on the channel function. Using high-resolution NMR structural analysis, we show here that neither F3 nor F6 at pharmacologically relevant concentrations can significantly affect the secondary structure of the gramicidin A channel. Although both the anesthetic F3 and the nonimmobilizer F6 can perturb residues at the middle section of the channel deep inside the hydrophobic region in the sodium dodecyl sulfate micelles, only F3, but not F6, can significantly alter the chemical shifts of the tryptophan indole N-H protons near the channel entrances. The results are consistent with the notion that anesthetics cause functional change of the channel by interacting with the amphipathic domains at the peptide-lipid-water interface.

[Treatment and outcome of cervical lymph nodal metastases of unknown primary sites]

OBJECTIVE

To ascertain the optimal management of cervical nodal metasta of unknown primary sites.

METHODS

The clinical data of 114 patients of cervical nodal metastases of unknown primary sites were retrospectively analyzed.

RESULTS

For metatic masses of the upper and/or middle part of the neck, the optimal approach varied depnding on the histologic type. Poorly-differentiated carcinoma was treated with radiotherapy, squamous-cell carcinoma was treated with radiotherapy plus surgery, while papillary adenocarcinoma was treated by combined radical thyroidectomy. Their 5-year survival rate was 45.2%, 53.8% and 62.5%, respectively. For metastatic masses in the supraclavicular region, chemotherapy was the first treatment of choice in all patients. In only 12 of the 114 patients (11.2%) the primary sites were found in the follow-up period.

CONCLUSION

For patients with cervical lymph node metastases from unknown primary sites, the management should be given according to the location of lymph node involved and histopathologic type of the tumor.

Concentration-dependent isoflurane effects on depolarization-evoked glutamate and GABA outflows from mouse brain slices

The synaptic concentrations of glutamate and gamma-aminobutyric acid (GABA) are modulated by their release and re-uptake. The effects of general anaesthetics on these two processes remain unclear. This study evaluates the effects of isoflurane, a clinically important anaesthetic, on glutamate and GABA release and re-uptake in superfused mouse cerebrocortical slices. Experiments consisted of two 1.5-min exposures to 40 mM KCl in 30 min intervals. During the second exposure, different concentrations of isoflurane with and without 0.3 mM L-transpyrrolidine-2,4-dicarboxylic acid (PDC, a competitive inhibitor of glutamate uptake transporter) or 1 mM nipecotic acid (a competitive inhibitor of GABA uptake transporter) were introduced. The ratios of the second to first KCl-evoked increases in glutamate and GABA were used to determine the isoflurane concentration-response curves. The results can be described as a sum of two independent processes, corresponding to the inhibitions of release and re-uptake, respectively. The EC50 values for the inhibitions of release and re-uptake were 295+/-16 and 805+/-43 microM for glutamate, and 229+/-13 and 520+/-25 microM for GABA, respectively. Addition of PDC did not significantly affect glutamate release but shifted the re-uptake curve to the left (EC50= 315+/-20 microM). Nipecotic acid completely blocked GABA uptake, rendering isoflurane inhibition of GABA re-uptake undetectable. Our data suggest that isoflurane inhibits both the release and re-uptake of neurotransmitters and that the inhibitions occur at different EC50's. For GABA, both EC50's are within the clinical concentration range. The net anaesthetic effect on extracellular concentrations of neurotransmitters, particularly GABA, depends on the competition between inhibition of release and that of re-uptake.

The radioulnar joints and forearm axis: surgeons' perspective

Forearm injuries are common and can vary in complexity. The fractures are easily diagnosed, but the associated soft tissue injuries may not be as obvious. Treatment results are dependent not only on the fracture healing but on the return of normal relationships about the distal radioulnar joint, the interosseous membrane, and the proximal radioulnar joint. Alteration in any of these elements can result in permanent loss of forearm rotation and stability. Recent anatomic and biomechanical studies have increased our knowledge of these structures and their role in forearm function. The findings from these studies may lead to earlier repair of soft tissue injuries about the radioulnar joints and the interosseous membrane. Further follow-up of these procedures will be needed to validate their indications.

Adenoviral transgene expression of MMAC/PTEN in human glioma cells inhibits Akt activation and induces anoikis

The MMAC/PTEN tumor suppressor gene encodes for a phosphatase that recently has been shown to have phosphotidylinositol phosphatase activity, implicating its possible involvement in phosphatidylinositol 3'-kinase-mediated signaling. To investigate possible alterations in growth factor-mediated signal transduction, an adenovirus containing MMAC/PTEN, Ad-MMAC, previously shown to inhibit growth and tumorigenicity in glioma cells, was used to acutely express the transgene. Human glioma cells infected with Ad-MMAC but not with control adenoviruses exhibited an inhibition of phosphorylation of both activating residues of Akt, Ser-473, and Thr-308, along with Akt's serine/threonine kinase activity, without significantly altering Akt expression. The effects of functional MMAC/PTEN expression were relatively specific, because members of several other growth factor-mediated signaling pathways showed no altered responses. The presence of MMAC/PTEN also inhibited phosphorylation of BAD, although no evidence of apoptosis in the in situ treated cells was observed. However, U251 glioma cells infected with Ad-MMAC were induced to undergo anoikis at a significantly higher rate than U251 cels treated with control viruses or mock infected with media. These results demonstrate that the acute administration of MMAC/PTEN results in the inhibition of Akt-mediated signaling, growth inhibition, and anoikis, implying that loss of MMAC/PTEN increases cellular proliferation and significantly augments a cell's survival potential during cellular processes that are associated with malignancy.

[Visceral voice training for laryngectomy after hypopharyngectomy and visceral transplant]

OBJECTIVE

To establish a way to visceral voice after stomach or colon transplantation for patients with hypopharyngeal or cervical esophageal cancer.

METHODS

Esophageal voice training was used and modified according to the compliance of the patients. Twenty laryngectomies with replacement of the hypopharynx and esophagus by stomach(13 cases), colon(6 cases) and jejunum (1 case) were trained for voice rehabilitation at the Department of Head and Neck Surgery.

RESULTS

The patients with an artificial esophagus from vicera were easy to gain an influx of certain volume of gas into their artificial esophagus (stomach or colon) and to learn to speak. But on the whole the quality of voice was not so satisfactory. In this series nineteen out of 20 patients (95%) could express their idea by speech after a training course of three weeks.

CONCLUSION

The literature has emphasized role of cricopharyngeus muscle in the training of esophageal voice. Owing to the fact that this series of patients who had had their cricopharyngeus removed, could easily get their voice rehabilitated, it seems this muscle played no major role in the voice rehabilitation.

[Preoperative radiation plus surgery vs. operation alone for laryngeal carcinoma]

OBJECTIVE

To study the validity of preoperative radiation in improving the survival rate of laryngocarcinoma.

METHODS

A prospective randomized clinical trial was conducted with preoperative radiation plus surgery (RS) as one group and surgery alone (SA) as the other group. The ages of the patients were less than 75 years, and the operative types were decided after clinical examination. The patients were divided into SA or RS group by random. Doses of preoperative irradiation was 40 Gy. Three hundred and seventy patients with laryngocarcinoma were treated, 215 in the SA group; 155 in the RS group. All patients were followed up over three years.

RESULTS

In SA group, 3 years survival rate was 83.3%, 5-year survival rate 82.6%, 10-year survival rate 80.3%. In RS group, 3-year survival rate was 78.9%, 5-year survival rate 76.4%, 10-year survival rate 68.6%. There is no statistically significant difference in survival rates between the groups (P = 0.1); but, the 10-year survival rate in SA group was better than that in RS group for the stage III and IV supraglottic carcinomas, the former was 73.6% and the latter 63.5% (P = 0.003). The 10-year survival rate for the patients with T3 and T4 supraglottic carcinomas who underwent total laryngectomy in SA group was better than that in RS group. The former was 68% and the latter 50% (P = 0.0001).

CONCLUSION

Preoperative radiotherapy with 40 Gy didn't increase the survival rate of laryngeal carcinoma. The 10-year survival of stages III and IV supraglottic carcinoma in combined treatment group was lower than that in the surgery alone group.