TGFβ3, dibutyryl cAMP and a notch inhibitor modulate phenotype late in stem cell-derived dopaminergic neuron maturation

The generation of midbrain dopaminergic neurons (mDAs) from pluripotent stem cells (hPSC) holds much promise for both disease modelling studies and as a cell therapy for Parkinson's disease (PD). Generally, dopaminergic neuron differentiation paradigms rely on inhibition of smad signalling for neural induction followed by hedgehog signalling and an elevation of β-catenin to drive dopaminergic differentiation. Post-patterning, differentiating dopaminergic neuron cultures are permitted time for maturation after which the success of these differentiation paradigms is usually defined by expression of tyrosine hydroxylase (TH), the rate limiting enzyme in the synthesis of dopamine. However, during maturation, culture media is often supplemented with additives to promote neuron survival and or promote cell differentiation. These additives include dibutyryl cyclic adenosine monophosphate (dbcAMP), transforming growth factor β3 (TGFβ3) and or the γ-secretase inhibitor (DAPT). While these factors are routinely added to cultures, their impact upon pluripotent stem cell-derived mDA phenotype is largely unclear. In this study, we differentiate pluripotent stem cells toward a dopaminergic phenotype and investigate how the omission of dbcAMP, TGFβ3 or DAPT, late in maturation, affects the regulation of multiple dopaminergic neuron phenotype markers. We now show that the removal of dbcAMP or TGFβ3 significantly and distinctly impacts multiple markers of the mDA phenotype (FOXA2, EN1, EN2, FOXA2, SOX6), while commonly increasing both MSX2 and NEUROD1 and reducing expression of both tyrosine hydroxylase and WNT5A. Removing DAPT significantly impacted MSX2, OTX2, EN1, and KCNJ6. In the absence of any stressful stimuli, we suggest that these culture additives should be viewed as mDA phenotype-modifying, rather than neuroprotective. We also suggest that their addition to cultures is likely to confound the interpretation of both transplantation and disease modelling studies.

Inhibition of β-catenin dependent WNT signalling upregulates the transcriptional repressor NR0B1 and downregulates markers of an A9 phenotype in human embryonic stem cell-derived dopaminergic neurons: Implications for Parkinson's disease

In this study we investigate how β-catenin-dependent WNT signalling impacts midbrain dopaminergic neuron (mDA) specification. mDA cultures at day 65 of differentiation responded to 25 days of the tankyrase inhibitor XAV969 (XAV, 100nM) with reduced expression of markers of an A9 mDA phenotype (KCNJ6, ALDH1A1 and TH) but increased expression of the transcriptional repressors NR0B1 and NR0B2. Overexpression of NR0B1 and or NR0B2 promoted a loss of A9 dopaminergic neuron phenotype markers (KCNJ6, ALDH1A1 and TH). Overexpression of NR0B1, but not NR0B2 promoted a reduction in expression of the β-catenin-dependent WNT signalling pathway activator RSPO2. Analysis of Parkinson’s disease (PD) transcriptomic databases shows a profound PD-associated elevation of NR0B1 as well as reduced transcript for RSPO2. We conclude that reduced β-catenin-dependent WNT signalling impacts dopaminergic neuron identity, in vitro, through increased expression of the transcriptional repressor, NR0B1. We also speculate that dopaminergic neuron regulatory mechanisms may be perturbed in PD and that this may have an impact upon both existing nigral neurons and also neural progenitors transplanted as PD therapy.

Induced Pluripotent Stem Cell-Derived Podocyte-Like Cells as Models for Assessing Mechanisms Underlying Heritable Disease Phenotype: Initial Studies Using Two Alport Syndrome Patient Lines Indicate Impaired Potassium Channel Activity

Renal podocyte survival depends upon the dynamic regulation of a complex cell architecture that links the glomerular basement membrane to integrins, ion channels, and receptors. Alport syndrome is a heritable chronic kidney disease where mutations in α3, α4, or α5 collagen genes promote podocyte death. In rodent models of renal failure, activation of the calcium-sensing receptor (CaSR) can protect podocytes from stress-related death. In this study, we assessed CaSR function in podocyte-like cells derived from induced-pluripotent stem cells from two patients with Alport Syndrome (AS1 & AS2) and a renal disease free individual [normal human mesangial cell (NHMC)], as well as a human immortalized podocyte-like (HIP) cell line. Extracellular calcium elicited concentration-dependent elevations of intracellular calcium in all podocyte-like cells. NHMC and HIP, but not AS1 or AS2 podocyte-like cells, also showed acute reductions in intracellular calcium prior to elevation. In NHMC podocyte-like cells this acute reduction was blocked by the large-conductance potassium channel (KCNMA1) inhibitors iberiotoxin (10 nM) and tetraethylammonium (5 mM), as well as the focal adhesion kinase inhibitor PF562271 (N-methyl-N-(3-((2-(2-oxo-2,3-dihydro-1H-indol-5-ylamino)-5-trifluoromethyl-pyrimidin-4-ylamino)-methyl)-pyridin-2-yl)-methanesulfonamide, 10 nM). Quantitative polymerase chain reaction (qPCR) and immunolabeling showed the presence of KCNMA1 transcript and protein in all podocyte-like cells tested. Cultivation of AS1 podocytes on decellularized plates of NHMC podocyte-like cells partially restored acute reductions in intracellular calcium in response to extracellular calcium. We conclude that the AS patient-derived podocyte-like cells used in this study showed dysfunctional integrin signaling and potassium channel function, which may contribute to podocyte death seen in Alport syndrome.

Self-Crosslinking Lipopeptide/DNA/PEGylated Particles: A New Platform for DNA Vaccination Designed for Assembly in Aqueous Solution

Delivery of plasmids for gene expression in vivo is an inefficient process that requires improvement and optimization to unlock the clinical potential of DNA vaccines. With ease of manufacture and biocompatibility in mind, we explored condensation of DNA in aqueous solution with a self-crosslinking, endosome-escaping lipopeptide (LP), stearoyl-Cys-His-His-Lys-Lys-Lys-amide (stearoyl-CH₂K₃), to produce cationic LP/DNA complexes. To test whether poly(ethylene glycol) (PEG)-ylation of these cationic complexes to neutralize the surface charge would improve the distribution, gene expression, and immune responses poly(ethylene glycol), these LP/DNA complexes were combined with 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000] (DSPE-PEG₂₀₀₀). Fluorescence imaging illustrated that the cationic complexes exhibited the highest degree of localization and lowest degree of dispersion throughout the injected muscle, suggesting impaired mobility of cationic particles upon administration. Nanoluciferase reporter assays over a 90-day period demonstrated that gene expression levels in muscle were highest for PEGylated particles, with over a 200-fold higher level of expression than the cationic particles observed at 30 days. Humoral and cell-mediated immune responses were evaluated in vivo after injection of an ovalbumin expression plasmid. PEGylation improved both immune responses to the DNA complexes in mice. Overall, this suggests that PEGylation of cationic lipopeptide complexes can significantly improve both the transgene expression and immunogenicity of intramuscular DNA vaccines.

A suicidal strain of Listeria monocytogenes is effective as a DNA vaccine delivery system for oral administration

In this study we determined the in vivo activity of model ovalbumin vaccines delivered by direct intramuscular delivery of plasmid DNA or oral delivery using a recombinant suicidal Listeria monocytogenes strain (rsΔ2). In a previous report we described how rsΔ2 is capable of delivering luciferase, as protein or DNA, in vitro, into non-dividing intestinal epithelial cells (Kuo et al., 2009). This is achieved by engineering a dual expression shuttle vector, pDuLX-Luc, that replicates in E. coli and rsΔ2 and drives gene expression from the Listeria promoter (Phly) as well as the eukaryotic cytomegalovirus promoter (CMV), thereby delivering both protein and plasmid DNA to the cell cytoplasm. For the current in vivo study rsΔ2 containing pDuLX-OVA was used to deliver both ovalbumin protein and the mammalian expression plasmid by the oral route. Controls were used to investigate the activity of this system versus positive and negative controls, as well as quantifying activity against direct intramuscular injection of expression plasmids. Oral administration of rsΔ2(pDuLX-OVA) produced significant titres of antibody and was effective at inducing targeted T-cell lysis (approximately 30% lysis relative to an experimental positive control, intravenous OVA-coated splenocytes+lipopolysaccharide). Intramuscular injection of plasmids pDuLX-OVA or p3L-OVA (which lacks the prokaryotic promoter) also produced significant CTL-mediated cell lysis. The delivery of the negative control rsΔ2 (pDuLX-Luc) confirmed that the observed activity was induced specifically by the ovalbumin vaccination. The data suggest that the oral activity of rsΔ2(pDuLX-OVA) is explained by delivery of OVA protein, expressed in rsΔ2 from the prokaryotic promoter present in pDuLX-OVA, but transfection of mammalian cells in vivo may also play a role. Antibody titres were also produced by oral delivery (in rsΔ2) of the p3L-OVA plasmid in which does not include a prokaryotic promoter.

Relaxant actions of nonprostanoid prostacyclin mimetics on human pulmonary artery

The specific prostacyclin (IP) receptor agonist cicaprost relaxed human pulmonary artery preparations precontracted with phenylephrine [50% inhibitory concentration (IC50) approximately 0.6 nM], U-46619 (IC50 approximately 0.9 nM), and K+ (approximately 40% maximal relaxation); endothelium removal had little effect on relaxant activity. Ranking of relaxant potencies for prostacyclin and five of its analogs was 17 alpha, 20-dimethyl-delta 6,6a-6a-carba PGI1 (TEI-9063) > or = cicaprost > iloprost > prostacyclin > taprostene > benzodioxane prostacyclin > 15-deoxy-16 alpha-hydroxy-16 beta,20-dimethyl-delta 6,6a-6a-carba PGI1 (TEI-3356). The potency of the isocarbacyclin TEI-3356 may have been under-estimated because of its contractile (EP3 receptor agonist) activity. The potency ranking of four nonprostanoid prostacyclin mimetics was 3-[4-(4,5-diphenyl-2-oxazolyl)-5-oxazolyl]phenoxy] acetic acid (BMY 45778; IC50 approximately 2.5 nM) > > 2-[3-[2-(4, 5-diphenyl-2-oxazolyl)ethyl]phenoxy]acetic acid (BMY 42393) > octimibate > CU 23 (a novel diphenylindole). From IP receptor binding affinities obtained on human platelet membranes, it is suggested that the slightly shallower log concentration-response curves for BMY 45778, BMY 42393, and CU 23 may reflect the near-maximal receptor occupancy required for complete relaxation. A fifth nonprostanoid, CU 602, had much shallower log concentration-response curves than cicaprost against phenylephrine tone but not against U-46619 tone; this may indicate IP receptor partial agonism coupled with TP receptor antagonism. The relaxant actions of the nonprostanoid mimetics were more persistent than those of the prostacyclin analogs on washout of the organ bath; by the inhalation route, this type of compound may be retained within pulmonary tissue and thus afford greater pulmonary/systemic selectivity than currently used pulmonary vasodilators.

Benign giant cell tumor of bone with osteosarcomatous transformation ("dedifferentiated" primary malignant GCT): report of two cases

It is not uncommon for sarcomatous transformation of giant cell tumor (GCT) of bone to occur after radiation, but rarely does malignant transformation occur spontaneously, with less than 15 cases reported up to 1995. Only four of these cases have been documented in detail. We report two additional cases of GCT of bone spontaneously transforming or "dedifferentiating" into osteosarcoma without radiation therapy. The first case is absolutely unique and most interesting in that the dedifferentiation process occurred in one of multiple GCT lung metastases 6 years after successful eradication of a primary tibial tumor. The right lung was resected due to development of a large tumor, and at pathologic examination, demonstrated several small nodules of conventional GCT and a much larger, 14-cm mass composed of a mixture of GCT and high-grade osteosarcoma. The second case involved a physician, who had a large tumor in the sacrum with vague symptoms for 8 years. Open biopsy revealed conventional, benign GCT of bone with a secondary aneurysmal bone cyst. Complete curettage 2 weeks later revealed, in addition to areas of conventional, benign GCT a second component of very high grade osteosarcoma. Both patients died less than 1.5 years from diagnosis. This report of osteosarcomatous transformation of a conventional GCT of bone strengthens the theory that there is a mesenchymal cell line in GCT that may spontaneously transform to sarcoma.

Thoracoscopic talc insufflation versus talc slurry for symptomatic malignant pleural effusion

BACKGROUND

Talc has been generally accepted to be the most effective sclerosant for chemical pleurodesis, although the optimal route of administration remains unclear.

METHODS

We designed a prospective, randomized study to compare video-assisted thoracoscopic talc insufflation with bedside talc slurry in the treatment of malignant pleural effusion. From September 1993 to November 1995, 57 patients were recruited and randomized to either video-assisted thoracoscopic talc insufflation under general anesthesia (n = 28) or talc slurry by the bedside (n = 29). Patients with poor general condition (Karnofsky score less than 30%), poor pulmonary function (forced expiratory volume in 1 second less than 0.5 L), or trapped lungs were excluded from this study. Five grams of purified talc was used for either video-assisted thoracoscopic talc insufflation or talc slurry.

RESULTS

There was no statistically significant difference between the two groups of patients with respect to age, sex ratio, chest drainage duration, postprocedural hospital stay, parenteral narcotics requirement, complications, or procedure failure (ie, recurrence).

CONCLUSIONS

Video-assisted thoracoscopic talc insufflation has not been shown to be a superior approach compared with talc slurry in our study. Because the former demands more resources, we advocate that talc slurry should be considered as the procedure of choice in the treatment of symptomatic malignant pleural effusion in patients who do not have trapped lungs.

The use of liver grafts infested with Clonorchis sinensis for orthotopic liver transplantation

In the Orient, millions are known to have Clonorchis sinensis (biliary trematodiasis) infestation. When these infested livers become available as donor organs, there are potentially serious implications that the transplant team would need to consider. We report the use of two such infested livers, one from a cadaveric donor and the other from a live related donor, for orthotopic liver transplantation. The parasite was encountered not only during organ procurement, but also caused early postoperative blockage of the hepatico-jejunostomy splintage tube and cessation of bile flow in the second recipient. Upon follow-up for four and two years, respectively, no other ill effect has been observed in either patient. Repeated examination of stool for ova of C sinensis in both patients during follow-up visits had been negative, indicating that all the parasites probably had been killed by the cold perfusion. In view of the severe shortage of liver grafts and the lack of serious morbidity associated with the use of these infested livers, we have adopted the policy to include these livers for future transplantation. Special considerations and precautions are, however, required during the perioperative period and on long-term follow-up.

A case report of a large thymic carcinoid

Thymic carcinoid is a rare tumour. A case of giant thymic carcinoid with extensive necrosis is reported in a 44-year-old Chinese male. Diagnosis was difficult to make before the operation and even intraoperatively. Subtotal excision was performed followed by adjuvant radiation therapy. The patient remained disease-free at the last follow-up 12 months after surgery. Complete excision remains the mainstay of treatment for this disease.

Video assisted thoracoscopic staple resection of a giant bulla

Video assisted thoracoscopic surgery (VATS) for spontaneous pneumothorax has been well described. However, there are few reports on the use of this technique on giant bullae. We report a 49 year old man with a symptomatic giant bulla who underwent a successful thoracoscopic staple resection. His chest drains were removed on the second postoperative day and he was discharged on the third postoperative day with virtually no discomfort. We conclude that thoracoscopic staple resection of a giant bulla is feasible technically and is an attractive alternative to the conventional open technique.

Immature mediastinal teratoma in a 2 1/2 year old Chinese girl

Teratoma is a rare tumour in children accounting for about 3% of all childhood malignancy. A case of immature mediastinal teratoma in a young Chinese girl is reported.

Thoracoscopic management of malignant pleural effusions

Malignant pleural effusion is a common condition and often presents a challenge for treatment. We report our experience from a single institution with the use of video-assisted thoracoscopic surgery (VATS) in the management of malignant effusions. From September 1992 to April 1995, 69 patients (31 men, 38 women; age range, 38 to 76 years) underwent diagnosis and/or treatment of malignant effusions; these included 46 pleural biopsies, 34 talc insufflations, and 16 limited decortications. There was no mortality and there were no intraoperative complications. Postoperative complications occurred in seven patients (10%). Specific histologic diagnoses were obtained in all but 6 patients (87%). Malignant effusion was confirmed in 25 of 46 cases (54%). Thoracoscopic talc insufflation with or without additional decortication was successful in 32 of 34 cases (94%) in controlling recurrence of effusion after a mean follow-up of 6 months among the survivors (22 patients died during the follow-up period without effusion reaccumulation). We conclude that VATS not only provides an accurate diagnosis but also allows effective therapeutic procedures to be performed for malignant effusions that are associated with an acceptable morbidity.

Thoracoscopic lobectomy for an infected intrapulmonary bronchogenic cyst

A 19-year-old male who presented with cough and fever was found to have an 8-cm cyst in his left lung. Video-assisted thoracoscopic left lower lobectomy was performed. The cyst had to be decompressed by needle aspiration prior to retrieval through a 5-cm minithoracotomy. The patient was discharged on postoperative day 4 in good condition. The technical aspects form the basis of this report.

Video-assisted thoracoscopic anatomic lung resections. The initial Hong Kong experience

We report our combined experience on video-assisted thoracoscopic (VAT) anatomic lung resections from two major hospitals in Hong Kong over a 17-month period. From August 1993 to December 1994, 82 cases of major lung resections were attempted using the VATS approach, of which 60 were successfully completed (55 lobectomies, 2 bilobectomies, 2 pneumonectomies, and 1 segmentectomy). Of these 60 cases, there were 43 men and 17 women with a mean age of 66 years (range, 37 to 85 years). The final pathologies were 52 primary lung cancers (37 adenocarcinoma, 11 squamous cell carcinoma, 2 bronchoalveolar carcinoma, 1 adenosquamous carcinoma, and 1 undifferentiated carcinoma); 1 pulmonary metastasis (from nasopharyngeal carcinoma); and 7 benign lesions (3 tuberculosis, 1 bronchiectasis, 1 sclerosing hemangioma, 2 organizing pneumonia). There was one postoperative death (mortality rate, 1.8%). Complications include persistent air leak over 10 days (four), wound infection (two), supraventricular tachycardia (three), and recurrence of tumor over the utility thoracotomy scar (one). All the patients were followed up from 8 weeks to 19 months (mean, 10 months). The mean duration of chest drainage was 5.4 days (range, 2 to 25 days). The mean hospital stay was 7.2 days (range, 4 to 35 days). The average postoperative parenteral narcotic (meperidine hydrochloride [Pethidine]) requirement by patient-controlled analgesia was 275 mg (range, 75 to 800 mg). This compared favorably with an age- and sex-matched historic group of patients who underwent posterolateral thoracotomy and had a hospital stay of 10.4 days (statistically non-significant) and narcotic requirement of 950 mg (statistically significant by paired t test). We conclude that VAT anatomic lung resection is technically feasible. However, there are some specific complications associated with major lung resection through minimal access. Refinement of our present technique and attention to details are important to improve our results.

Video-assisted thoracoscopic thymectomy for myasthenia gravis

Video-assisted thoracoscopic surgery (VATS) provides a new approach to thymectomy. From June 1993 to December 1994, we performed a total of eight thymectomies for myasthenia gravis (MG). There were four male and four female patients with ages ranging from 9 to 76 years. Three of the eight patients had associated thymoma. We believe that complete thymectomy was accomplished in all cases by examination of the thymic bed and resected specimen. There was no mortality or intraoperative complications. The median postoperative hospital stay was 5 days (range, 2 to 37 days). One patient required ventilatory support postoperatively. Clinical improvement was observed in all patients after a mean follow-up of 10 months (range, 2 to 21 months). Compared with a comparable historical group of patients with MG who underwent transsternal thymectomy, the VATS group was associated with significantly less analgesic requirement and shortened hospital stay. We conclude that VAT thymectomy is technically feasible and is associated with a favorable postoperative course compared with the transsternal approach. We believe that complete thymectomy can be achieved by this approach. Further investigation with long-term follow-up is needed to further clarify the role of VAT thymectomy in thoracic surgery.

Video-assisted thoracoscopic wedge resections of pulmonary metastatic osteosarcoma: should it be performed?

We studied the use of video-assisted thoracoscopic (VAT) surgery in the management of metastatic osteosarcoma. From September 1993 to March 1994, we performed a total of 11 VAT wedge resections of pulmonary metastatic osteosarcoma in seven patients (six males, one female, age 12 to 46 years). Three patients had bilateral procedures performed either under the same anaesthesia or in stages. One patient had two operations on the same side. The average number of nodules excised was three. Two patients subsequently required formal lobectomies when the metastatic tumours were either too big or too close to the hilum for safe wedge resections. There was one death on postoperative day 3 due to dysrhythmia. One patient died 5 months later from a progression of his underlying disease. Two patients remained disease free up to 8 and 12 months, respectively, from their first operations. The average postoperative chest drain duration was 1.4 +/- 0.7 days and hospital stay 2.3 +/- 1.1 days. The procedure was well tolerated and postoperative morbidity was minimal. We conclude that although VAT wedge resection of pulmonary metastatic osteosarcoma is feasible technically and is associated with a short hospital stay and minimal morbidity, this approach cannot be recommended when complete resection of all metastases is the goal as the technique relies heavily on computed tomographic scans to detect nodules. Recurrence of metastasis from 4 to 6 months in three of seven patients argues against VAT surgery being an adequate procedure. The high cost of the staplers, in addition, is a secondary consideration.

Interactions of a very long chain fatty acid with model membranes and serum albumin. Implications for the pathogenesis of adrenoleukodystrophy

Adrenoleukodystrophy (ALD) is an inherited disorder of fatty acid metabolism marked by accumulation of very long chain saturated fatty acids (VLCFA), especially the 26-carbon acid, hexacosanoic acid (HA), in membranes and tissues. We have studied interactions of 13C-enriched HA with model membranes (phospholipid bilayer vesicles) and bovine serum albumin (BSA) by 13C NMR spectroscopy to compare properties of HA with those of typical dietary fatty acids. In phospholipid bilayers the carboxyl group of HA is localized in the aqueous interface, with an apparent pKa (7.4) similar to other fatty acids; the acyl chain must then penetrate very deeply into the membrane. Desorption of HA from vesicles (t1+2 = 3 h) is orders of magnitude slower than shorter chain fatty acids. In mixtures of vesicles and BSA, HA partitions much more favorably to phospholipid bilayers than typical fatty acids. BSA binds a maximum of only 1 mole of HA at one binding site. Calorimetric experiments show strong perturbations of acyl chains of phospholipids by HA. We predict that disruptive effects of VLCFA on cell membrane structure and function may explain the neurological manifestations of ALD patients. These effects will be further amplified by slow desorption of VLCFA from membranes and by the ineffective binding to serum albumin.

Video-assisted subxiphoid pericardiectomy

We report a case of malignant pericardial effusion with chronic tamponade treated by video-assisted subxiphoid pericardiectomy in a 58-year-old female. The procedure was performed under local anesthesia through a 3.5-cm midline incision over the xiphoid process using a mediastinoscope, a 5-mm telescope connected to the video camera, and an endoscopic grasper and scissors. A large piece of pericardium (5 cm x 6 cm) over the right ventricle was excised. The patient obtained immediate relief and was discharged on the second postoperative day. Follow-up at 4 months showed no recurrence of effusion. Video assistance allows generous pericardiectomy, and as the rate of recurrence has been suggested to be directly related to the extent of resection, video-assisted subxiphoid pericardiectomy offers a theoretical advantage over the conventional approach, as more pericardium can be excised. We recommend that this technique receive further investigation.

Video-assisted thoracoscopic surgery in the paediatric population

OBJECTIVE

Video-assisted thoracoscopic surgery (VATS) is now widely practised in adults but there are few publications on its application in the paediatric population.

METHODOLOGY

Retrospective review of the authors' experience with VATS in children under 16 years old during an 18 month period in a university teaching hospital.

RESULTS

From September 1993 to March 1994, VATS was attempted in 14 patients. Five were unsuccessful because of pleural symphysis or inability to collapse the upper lung. Ten cases of VATS were successfully performed in the remaining nine patients (eight males, one female; age range from 22 days to 15 years old). These included two drainages and limited decortications for loculated pleural effusion, one guided drainage of pericardial effusion, one thymectomy for thymic hyperplasia, three wedge resections for metastatic pulmonary osteosarcoma and three bleb excisions and pleurodesis for primary spontaneous pneumothoraces. There were no intra-operative complications. There was one death from dysrhythmia following an uneventful wedge resection. The mean duration of chest tube drainage was 1.4 days and postoperative hospital stay 2.6 days excluding two patients who stayed for further medical treatment.

CONCLUSION

VATS is a useful approach in selected cases but further development of this approach awaits refinement of anaesthetic technique and endoscopic instrumentation.

Video-assisted thoracoscopic lobectomy: a word of caution

Advances in video-assisted thoracoscopic (VAT) surgery allow it to assume an increasingly important therapeutic role. Two successful VAT lobectomies (left upper lobe and right lower lobe) were performed in patients with stage I adenocarcinoma. An 8 cm access minithoracotomy for hilar dissection and subsequent specimen delivery was used. Routine mediastinal node sampling was performed thoracoscopically as would be done conventionally. Video-assisted thoracoscopic lobectomy of the right upper lobe was attempted in another patient but he required emergency conversion to open thoracotomy because of bleeding from mechanical failure of the vascular staple-cutter. Although VAT lobectomy is feasible technically, attention to detail is important when mechanical devices are used to minimize the chance of malfunctioning. Once disaster occurs the surgeon should be capable of dealing with the consequences.

Thoracoscopic management of pleural effusions revisited

Pleural effusion is a commonly encountered clinical condition. We report our experience with video assisted thoracoscopic surgery (VATS) in the management of pleural effusions in three groups of patients: (1) Patients with cryptogenic pleural effusions for diagnosis; (2) patients with established malignant effusions for talc insufflation and limited decortication; and (3) patients with early empyema for debridement and drainage. From September 1992 to March 1994, we have successfully managed 28 patients with pleural effusions (12 males, 16 females; age ranged from 22 days to 73 years). Management consisted of 16 diagnostic thoracoscopies with guided pleural biopsies, seven limited decortications for trapped lungs, 12 talc insufflation for recurrent symptomatic malignant effusions and debridement and drainage of five empyemata. There was no mortality or intra-operative complications. The procedure was tolerated well by all patients. The mean duration of chest drainage and hospital stay were 1.2 and 2.8 days for group 1 patients, 4.5 and 6.4 days for group 2, and 5.6 and 7.1 days for group 3. Specific histological diagnosis was obtained in all but two patients (88%). Thoracoscopic talc insufflation was successful in 92% of cases at mean follow up of 8 months. Thoracoscopic debridement and drainage of empyema resulted in rapid resolution of sepsis in all cases. Advances in video camera technology and instrumentation have allowed more therapeutic manoeuvres to be carried out. We conclude that VATS is a safe and effective way of managing selected patients with pleural effusions.

Primary spontaneous pneumothorax treated by video assisted thoracoscopic surgery--results of intermediate follow up

BACKGROUND

Primary spontaneous pneumothorax (PSP) is a common clinical condition associated with high recurrence if no definitive treatment is given and could be life threatening if left untreated. The best treatment for this condition, however, remains controversial.

AIMS

A prospective study of patients with PSP treated by video assisted thoracoscopic surgery (VATS) after a mean follow up of 16 months.

METHODS

Between September 1992 and April 1994, 114 VATS procedures were performed on 110 patients with PSP (including four patients with bilateral presentation) by one surgical team from a single institution. Mechanical pleurodesis with Marlex mesh was performed on all patients. In addition, apical bullae were identified in 100 cases (88%) and these were resected.

RESULTS

There was no mortality. The median hospital stay was three days. The procedure was well accepted by patients and this was reflected subjectively in a visual analogue scale and objectively in the requirement of postoperative analgesia. Complications included one wound infection, one bleeding, eight persistent air leaks over ten days. We had two failures with recurrence of pneumothorax occurring one week and two months postoperatively (mean follow up of 16 months). Late morbidity with intercostal neuropathy was identified in nine patients but only two of them required oral analgesics.

CONCLUSION

VATS is a quick and effective treatment for PSP. We currently recommend VATS for patients with recurrent spontaneous pneumothorax, as well as first time pneumothoraces associated with tension, bilaterality, frequent travelling, unreliable follow up and persistent air leak over three days.

One hundred consecutive cases of video-assisted thoracoscopic surgery for primary spontaneous pneumothorax

We reviewed our experience on video-assisted thoracoscopic surgery (VATS) from our first 100 cases of primary spontaneous pneumothorax (PSP) performed at our institution from September 1992 to January 1994. Apical bullae were identified in 87% of cases. Mechanical pleurodesis with Marlex mesh was performed on all patients. Excision with endoscopic staple cutter was performed in 69 cases; an endoloop was used in five cases; ablation with an argon beam coagulator (ABC) was done in six cases; excision with endoscopic suturing occurred in seven cases; and mechanical pleurodesis alone was used in 13 cases. The overall median postoperative chest tube duration was 2 days (range 1-25 days) and hospital stay 4 days (range 1-30 days). Complications occurred in 8 cases (8%): 1 wound infection; 1 chest wall bleeding; and 6 persistent air leaks which lasted for more than 10 days (one of which eventually required an axillary thoracotomy for control). Procedure failure with recurrence occurred in three cases (3%) at a mean follow-up of 17 months (range 8-24 months). The ABC group alone was responsible for one recurrence and two persistent leaks. We conclude that with the VATS approach in the treatment of PSP, staple resection of apical bullae is quick and most reliable but costly. Endoloop and hand suturing are applicable to selected patients with small and localized bullae and should be further studied, while our limited experience does not favor ABC as the primary treatment modality.

One hundred and sixty-three consecutive video thoracoscopic procedures: the Hong Kong experience

Video-assisted thoracoscopy (VAT) offers a new approach to the diagnosis and treatment of many thoracic conditions. From September 1992 to August 1993, a total of 163 VAT procedures were successfully performed on 108 patients (87 male, 21 female; age range from 12 to 77) which consisted of 42 bleb eliminations and 64 mechanical pleurodesis for spontaneous pneumothorax, 11 wedge resections for pulmonary nodules, three wedge biopsies for diffuse pulmonary infiltrate, four thoracic sympathectomies, resections of two mediastinal masses, three pericardial windows, 10 guided pleural biopsies for undiagnosed effusions, six guided drainage of empyema and haemothorax, 16 staging of intrathoracic tumours and two explorations for penetrating thoracic trauma. There was no procedure-related mortality. Complications included one recurrence for spontaneous pneumothorax, one re-exploration for bleeding (also by VAT approach), one wound infection, and six persistent air leaks for more than 10 days. The median duration of postoperative chest tube drainage was 2 days and the median hospital stay was 4 days. It was concluded that VAT is a safe and effective approach in thoracic surgery and with further refinement in instrumentation even more procedures will be technically feasible. The long-term results of VAT are being awaited in order to define its true merits in thoracic surgery.

Potent contractile actions of prostanoid EP3-receptor agonists on human isolated pulmonary artery

1. In 13 of 15 experiments, prostaglandin E2 (PGE2) and sulprostone (a prostanoid EP1/EP3-receptor agonist) contracted isolated rings of human pulmonary artery at low concentrations (> or = 5 and > or = 0.5 nM respectively). Tissue was obtained from patients undergoing surgery mainly for carcinoma of the lung. Characterization of the receptors involved was complicated by loss of sensitivity to the contractile PGE action over the experimental period. In contrast, contractile responses to KCl, phenylephrine and the specific thromboxane (TP-) receptor agonist, U-46619, did not decrease with time. 2. The relative contractile potencies for seven PGE analogues, measured during the first few hours after setting up the preparations, were as follows: sulprostone > misoprostol = gemeprost > or = PGE2 > or = GR 63799X > 17-phenyl-omega-trinor PGE2 > or = 11-deoxy PGE1. This ranking indicates that an EP3-receptor is involved. 3. The contractile action of sulprostone was not blocked by the TP-receptor antagonists, EP 169 and GR 32191, and the EP1-receptor antagonist, AH 6809. 4. In two experiments, PGE2 (50 nM) reduced basal tone and sulprostone was a weak contractile agent. Phenylephrine-induced tone was also inhibited by PGE2 (EC50 = 5-20 nM), 11-deoxy PGE1 and butaprost (a selective EP2-receptor agonist); the latter prostanoids were about 2 and 4 times less potent than PGE2 respectively. Interactions with phenylephrine were different in experiments where PGE2 alone was contractile: PGE2 induced contraction superimposed on the phenylephrine response and 11-deoxy PGE1 induced either further contraction or had no effect. Butaprost produced relaxation at high concentrations;this may not be an EP2 action since preparations were highly sensitive to relaxant actions of prostacyclin (IP-) receptor agonists (cicaprost and TEI-9063).5 The study has shown that in the majority of experiments on the human isolated pulmonary artery,the contractile EP3 system outweighed the relaxant EP2 system. However, in two experiments the reverse was true. It is not clear to what extent these differences are due to disease processes affecting the tissues.The findings are discussed in relation to the adverse cardiovascular responses occasionally encountered during treatment of postpartum haemorrhage with sulprostone, and more generally to the clinical use of EP-receptor agonists in man.

Effects of long-acting beta 2-adrenoceptor agonists on mast cells of rat, guinea pig, and human

The effects of two recently developed long-acting beta 2-adrenoceptor agonists, formoterol and salmeterol, on mast cells from different sources were compared with those of the prototype short-acting analogue, salbutamol. With the exception of high concentrations of salmeterol (> 10(-5) M), none of the tested beta 2-adrenoceptor agonists inhibited the anti-IgE-induced histamine release from rat peritoneal mast cells. In contrast, all three compounds dose dependently inhibited the immunologically induced histamine release from isolated lung mast cells of guinea pig and human at concentrations < or = 10(-5) M.

Video-assisted thoracoscopic surgery for primary spontaneous pneumothorax

Video-assisted thoracoscopic surgery (VATS) has been suggested as the most appropriate choice for spontaneous pneumothorax. Thirty-two patients (30 males, two females, age range from 16 to 42) with primary spontaneous pneumothorax (PSP) are reported. All had mechanical pleurodesis with Marlex mesh. Blebs or bullae could be identified in 24 patients (75%). All bullae over 2 cm were either excised (11 patients) or ligated (five patients). The median operating time was 45 min. There was minimal postoperative discomfort and the median postoperative hospital stay was 4 days. There was one minor wound infection and one recurrence (mean follow up of 11 months). It is concluded that VATS is a quick, safe and effective approach for the treatment of PSP. Long-term results will better define its true merit in thoracic surgery.

Preterm infants with patent ductus arteriosus: treatment with an enteral preparation of indomethacin

Forty-one preterm infants with a mean gestational age and birthweight of 29.7 weeks and 1322 g, respectively, were treated with an enteral preparation of indomethacin for the closure of haemodynamically significant patent ductus arteriosus. The indomethacin was prepared by diluting the content of the commercially available 25-mg indomethacin capsule with lactose by the method of trituration. The mixture was suspended in solution form just prior to administration to the infants. The ductus arteriosus was successfully closed in 29 infants, giving an overall success rate of 71%. The response to treatment was considered satisfactory, except for infants whose birthweights were less than 750 g. Only two infants (5%) developed major complications, both in the form of ileal perforation. As the outcome of treatment with this enteral preparation of indomethacin was comparable with that of the intravenous preparation reported in previous studies, it would be an acceptable alternative to the intravenous preparation in areas where the latter is not available or considered expensive.

Echocardiography as a tool for determining the incidence of congenital heart disease in newborn babies: a pilot study in Hong Kong

We studied, with echocardiography as the main tool, the incidence of congenital heart disease in newborn babies in Hong Kong. The population examined was the 20,928 babies who were born alive in the Prince of Wales Hospital from January 1987 to December 1989. All had a thorough physical examination by a paediatrician after birth, and an estimated 95% of the babies who were discharged from hospital received another routine physical examination at one of the five local Maternal and Child Health Centres within two months of birth. All babies with either suspected congenital heart disease or multiple congenital abnormalities were referred to the paediatric cardiologists in the Prince of Wales Hospital for further cardiovascular assessment that included echocardiographic examination. In all, 492 babies had Doppler and cross-sectional echocardiographic studies. Various abnormalities of the cardiovascular system were diagnosed in 216 babies. Almost all the babies who died within two months of life underwent autopsy. This proved the presence of congenital cardiac malformations in 15 babies, of whom 10 had correct echocardiographic diagnoses during life. One had a patent arterial duct which was missed by the echocardiography. The other four babies did not have echocardiographic examination while alive, either because of early death or absence of clinical suspicion. In total, congenital cardiac malformations were confirmed in 221 babies by echocardiographic examination and autopsy. Excluding 82 premature babies with patency of the arterial duct, and 6 babies with transient tricuspid regurgitation, there were 133 cases of structural cardiac malformation in the studied population, giving an incidence of 6.35 per thousand live births.(ABSTRACT TRUNCATED AT 250 WORDS)

Subzonal transfer of multiple sperm (MIST) into early human embryos

Microinsemination sperm transfer (MIST) is a technique whereby sperm are transferred into the perivitelline space (PVS) with the aid of a micromanipulator. MIST is now used to investigate whether blastomere membranes of early human embryos are capable of fusing with the sperm as in the metaphase II oocyte. Between 10 and 30 sperm were transferred into 11 donated human embryos between pronuclear and 16 cell stage. After culture for 6-24 hr in vitro, the embryos were fixed for transmission electron microscopy (TEM). Both acrosome-intact and acrosome-reacted sperm were located in the PVS and between blastomeres. Sperm in the PVS were sometimes penetrating the inner regions of the zona. Sperm-blastomere membrane fusion was not observed, but sperm tail incorporation by phagocytosis was occasionally evident. Sperm heads incorporated into blastomeres were often located in membrane-bound vesicles. Both acrosome-intact and acrosome-reacted sperm heads were found in vacuoles. Acrosome-reacted sperm heads were lying passively in vacuoles or were undergoing degenerative changes at their surfaces. Sperm chromatin decondensation was not observed in any of the sperm heads that were detected in the blastomeres. The evidence presented clearly shows that sperm heads are incapable of expanding their chromatin to form typical male pronuclei following MIST into early human embryos.

Establishment and characterization of two nasopharyngeal carcinoma cell lines

Two human nasopharyngeal carcinoma (NPC) cell lines have been established. One derived from a 64-year-old male, and the other from a 36-year-old female Chinese patient living in Taiwan. Both were keratinizing squamous cell carcinoma in nature and designated as NPC-TW039 and NPC-TW076. Both have been grown in culture system for more than 100 passages. Single cells from both cell lines could form colonies in 0.3% soft agar. In the nude mouse transplantation experiment, both cell lines could produce tumor mass with metastasis. The karyotypic analysis showed multiple chromosomal abnormality. The number of chromosomes ranged between 76 to 109 and 80 to 105 with an average of 98 and 95, respectively. The doubling time was 10.5 hours and 10.8 hours, respectively. The NPC-TW039 cell line has been subcloned and three subclones have been obtained. Ultrastructural studies from those two cell line, three subcloned cell lines and two transplanted tumor masses, all showed two types of morphology: the dark and light cells. This morphologic difference is probably derived from the different metabolic state, but not due to an artifact. Three oncogene probes have been used to check the oncogene expression; none of those five cell lines is positive. Similarly, six Epstein-Barr virus fragments have been labeled to hybridize with NPC cellular DNA preparations, results from the Southern blotting showed no detectable Epstein-Barr virus DNA sequence.

Management of a hydropic infant with congenital heart block

A baby with congenital heart block and hydrops fetalis diagnosed prenatally was delivered at 36 weeks of gestation. Heart failure was controlled with temporary cardiac pacing which was complicated by perforation of the myocardium. She made an uneventful recovery after implantation of a permanent pacemaker. Sjögren's syndrome A antibodies were detected in her serum. Coincidentally, she also had pulmonary valvular stenosis as a structural abnormality.