Sentinel lymph node biopsy for breast cancer: impact of the number of sentinel nodes removed on the false-negative rate

BACKGROUND

Numerous studies have demonstrated that sentinel lymph node (SLN) biopsy can accurately determine axillary nodal status for breast cancer, but unacceptably high false negative rates have also been reported. Attention has been focused on factors associated with improved accuracy. We have previously shown that injection of blue dye in combination with radioactive colloid reduces the false negative rate compared with injection of blue dye alone. We hypothesized that this may be from the increased ability to identify multiple sentinel nodes. The purpose of this analysis was to determine whether removal of multiple SLNs results in a lower false negative rate.

STUDY DESIGN

The University of Louisville Breast Cancer Sentinel Lymph Node Study is a prospective multiinstitutional study. Patients with clinical stage T1-2, N0 breast cancer were eligible for enrollment. All patients underwent SLN biopsy using blue dye alone, radioactive colloid alone, or both agents in combination, followed by completion level I and II axillary dissection.

RESULTS

A total of 1,436 patients were enrolled in the study from August 1997 to February 2000. SLNs were identified in 1,287 patients (90%), with an overall false negative rate of 8.3%. A single SLN was removed in 537 patients. Multiple SLNs were removed in 750 patients. The false negative rates were 14.3% and 4.3% for patients with a single sentinel node versus multiple sentinel nodes removed, respectively (p = 0.0004, chi-square). Logistic regression analysis revealed that use of blue dye injection alone was the only factor independently associated with identification of a single SLN (p<0.0001), and patient age, tumor size, tumor location, surgeon's previous experience, and type of operation were not significant.

CONCLUSIONS

The ability to identify multiple sentinel nodes, when they exist, improves the diagnostic accuracy of SLN biopsy. Injection of radioactive colloid in combination with blue dye improves the ability to identify multiple sentinel nodes compared with the use of blue dye alone.

Predicting the status of the nonsentinel axillary nodes: a multicenter study

BACKGROUND

Sentinel lymph node (SLN) biopsy is a minimally invasive procedure that provides accurate nodal staging information. The need for completion axillary dissection after finding a positive SLN for breast cancer has been questioned.

HYPOTHESIS

The presence of nonsentinel node (NSN) metastases in the axillary dissection specimen correlates with tumor size, the number of SLNs removed, and the number of positive SLNs.

DESIGN

Prospective, multi-institutional study.

PARTICIPANTS AND METHODS

The University of Louisville Breast Cancer Sentinel Lymph Node Study is a nationwide study involving 148 surgeons. All patients underwent SLN biopsy, followed by level I/II axillary dissection. All SLNs were evaluated histologically at a minimum of 2-mm intervals. Immunohistochemical analysis using antibodies for cytokeratin was performed at the discretion of each participating institution. All NSNs were evaluated by routine histologic examination.

RESULTS

An SLN was identified in 1268 (90%) of 1415 patients. Increasing tumor size was significantly correlated with increasing likelihood of positive NSNs: T1a, 14%; T1b, 22%; T1c, 30%; T2, 45%; and T3, 57% (P =.002, chi(2) test). The presence of positive NSNs was not significantly associated with the number of SLNs removed. Patients with more than 1 positive SLN were more likely to have positive NSNs than those with only 1 positive SLN (50% vs 32%; P<.001, chi(2) test). Increasing tumor size and the presence of multiple positive SLNs were also associated with the presence 4 or more positive axillary nodes. Multivariate analysis confirmed that tumor size and the number of positive SLNs were independent factors predicting the presence of positive NSNs.

CONCLUSIONS

The likelihood of positive NSNs correlates with increasing tumor size and the presence of multiple positive SLNs. However, even patients with small primary tumors have a substantial risk of residual axillary nodal disease after SLN biopsy. These data will be helpful in counseling patients regarding the need for completion axillary dissection after a positive SLN is identified.

Adverse effects of low-level air pollution on the respiratory health of schoolchildren in Hong Kong

To evaluate the respiratory effects of long-term exposure to air pollution, schoolchildren (ages 8 to 12 years) from two districts in Hong Kong with contrasting air quality were studied. Parents of 1660 children completed questionnaires on respiratory symptoms, and 1294 children had their ventilatory function tested with a spirometer. After adjustment for relevant covariates, children living in the more polluted district had increased odds ratios for frequent cough (1.74), frequent sputum (1.87), chronic sputum (1.84), and doctor-diagnosed asthma (1.98). Children of both sexes in the more polluted district had significantly poorer lung function, and the differences among girls were more marked. The study provides additional evidence for the adverse effects of long-term exposure to relatively low-level air pollution.

Additive effect of adenovirus-mediated E2F-1 gene transfer and topoisomerase II inhibitors on apoptosis in human osteosarcoma cells

Recently, it has been demonstrated that Etoposide, a topoisomerase II inhibitor, can induce apoptosis in MDM2-overexpressing tumor cells by inhibition of MDM2 synthesis. We have previously shown that E2F-1 overexpression induces apoptosis of MDM2-overexpressing sarcoma cells, which is related to the inhibition of MDM2 expression. Therefore, the present study was designed to investigate the in vitro and in vivo effect of combined treatment of adenovirus-mediated E2F-1 and topoisomerase II inhibitors on the growth inhibition and apoptosis in human sarcoma cells. Two human sarcoma cell lines, OsACL and U2OS, were treated with topoisomerase II inhibitors (Etoposide and Adriamycin), alone or in combination with adenoviral vectors expressing beta-galactosidase (Ad-LacZ) or E2F-1 (Ad-E2F-1). E2F-1 expression was confirmed by Western blot analysis. Ad-E2F-1 gene transfer at a low dose (multiplicity of infection, 2) markedly increased the sensitivity of human sarcoma cells to topoisomerase II inhibitor treatment. This cooperative effect of E2F-1 and topoisomerase II inhibitors was less marked in SAOS-2 cells (p53 and pRb null). Topoisomerase II inhibitors also cooperated with E2F-1 overexpression to enhance tumor cell killing in an in vivo model using xenografts in nude mice. When combined with Adriamycin or Etoposide, E2F-1 adenovirus therapy resulted in approximately 95% and 85% decrease in tumor size, respectively, compared to controls (P<.05). These results suggest a new chemosensitization strategy that is effective in MDM2-overexpressing tumors and may have clinical utility.

Sentinel lymph node biopsy for melanoma: how many radioactive nodes should be removed?

BACKGROUND

Sentinel lymph node (SLN) biopsy has become a standard method of staging patients with cutaneous melanoma. Sentinel lymph node biopsy usually is performed by intradermal injection of a vital blue dye (isosulfan blue) plus radioactive colloid (technetium sulfur colloid) around the site of the tumor. Intraoperative gamma probe detection has been shown to improve the rate of SLN identification compared to the use of blue dye alone. However, multiple sentinel nodes often are detected using the gamma probe. It is not clear whether these additional lymph nodes represent true sentinel nodes, or second-echelon lymph nodes that have received radiocolloid particles that have passed through the true sentinel node. This analysis was performed to determine the frequency with which these less radioactive lymph nodes contain metastatic disease when the most radioactive, or "hottest," node does not.

MATERIALS AND METHODS

In the Sunbelt Melanoma Trial, 1184 patients with cutaneous melanoma of Breslow thickness 1.0 mm or more had sentinel lymph nodes identified. Sentinel lymph node biopsy was performed by injection of technetium sulfur colloid plus isosulfan blue dye in 99% of cases. Intraoperative determination of the degree of radioactivity of sentinel nodes (ex vivo) was measured, as well as the degree of blue dye staining.

RESULTS

Sentinel nodes were identified in 1373 nodal basins in 1184 patients. A total of 288 of 1184 patients (24.3%) were found to have sentinel node metastases detected by histology or immunohistochemistry. Nodal metastases were detected in 306 nodal basins in these 288 patients. There were 175 nodal basins from 170 patients in which at least one positive sentinel node was found and more than one sentinel node was harvested. Blue dye staining was found in 86.3% of the histologically positive sentinel nodes and 66.4% of the negative sentinel nodes. In 40 of 306 positive nodal basins (13.1%), the most radioactive sentinel node was negative for tumor when another, less radioactive, sentinel node was positive for tumor. In 20 of 40 cases (50%), the less radioactive positive sentinel node contained 50% or less of the radioactive count of the hottest lymph node. The cervical lymph node basin was associated with an increased likelihood of finding a positive sentinel node other than the hottest node.

CONCLUSIONS

If only the most radioactive sentinel node in each basin had been removed, 13.1% of the nodal basins with positive sentinel nodes would have been missed. It is recommended that all blue lymph nodes and all nodes that measure 10% or higher of the ex vivo radioactive count of the hottest sentinel node should be harvested for optimal detection of nodal metastases.

Roles of glucitol in the GutR-mediated transcription activation process in Bacillus subtilis: tight binding of GutR to tis binding site

Glucitol induction in Bacillus subtilis requires a transcription activator, GutR, and a sequence located upstream of the gut promoter. To understand the initial steps involved in the GutR-mediated transcription activation process and the physiological roles of glucitol, GutR was overproduced and purified. In the absence of glucitol, GutR exists as a monomer and binds directly to its binding site in the gut regulatory region. This binding site was mapped to a 29-base pair imperfect inverted repeat located between -78 and -50, and there is only one GutR binding site within the regulatory region. The kinetic parameters of the interaction between GutR and its binding site were monitored in real time using surface plasmon resonance. The half-life of the GutR-DNA complex in the absence of glucitol was estimated to be 6.8 min. In contrast, in the presence of glucitol, the half-life of the complex was extended to longer than 19 h by affecting only the off-rate but not the on-rate. This effect is glucitol-specific. These data indicate that glucitol binds to GutR and induces GutR to have an extremely tight binding at its binding site. The physiological relevance of this process in transcription activation is discussed.

Intra-operative blood loss and operating time in orthognathic surgery using induced hypotensive general anaesthesia: prospective study

We investigated the average operating time and extent of intra-operative blood loss in orthognathic surgeries performed using induced hypotensive general anaesthesia, with the intention of devising a practical guideline for blood unit preparation for these procedures. We prospectively studied 32 Chinese patients undergoing surgery to correct dentofacial deformities at a public hospital in Hong Kong from 1 December 1997 to 1 December 1998. Most patients (72. 4%) needed double-jaw surgery. The mean estimated blood loss was approximately 617.6 mL. The blood loss during simple Le Fort I osteotomies was about half that of multiple segmentalised osteotomies. For mandibular ramus osteotomies, the mean blood loss and operating time for were approximately 280 mL and 2 hours, respectively; for anterior mandibular osteotomies, the corresponding values were 171.3 mL and 1 hour 13 minutes. The average drop in the haematocrit value was 15.4%, and the crossmatch to transfusion ratio was 29. A bivariate correlation test between the blood loss and operating time gave a strong correlation (P<0.01), as did blood loss with a drop in haematocrit value (P<0.01). Orthognathic surgeries are thus safe and predictable in terms of intra-operative blood loss and operating time, and a 'type, screen, and save' policy for blood unit preparation is more appropriate than a 'crossmatch' policy.

Practical guidelines for optimal gamma probe detection of sentinel lymph nodes in breast cancer: results of a multi-institutional study. For the University of Louisville Breast Cancer Study Group

INTRODUCTION

Multiple radioactive lymph nodes are often removed during the course of sentinel lymph node (SLN) biopsy for breast cancer when both blue dye and radioactive colloid injection are used. Some of the less radioactive lymph nodes are second echelon nodes, not true SLNs. The purpose of this analysis was to determine whether harvesting these less radioactive nodes, in addition to the "hottest" SLNs, reduces the false-negative rate.

METHODS

Patients were enrolled in this multicenter (121 surgeons) prospective, institutional review board-approved study after informed consent was obtained. Patients with clinical stage T1-2, N0, M0 invasive breast cancer were eligible. This analysis includes all patients who underwent axillary SLN biopsy with the use of an injection of both isosulfan blue dye and radioactive colloid. The protocol specified that all blue nodes and all nodes with 10% or more of the ex vivo count of the hottest node should be removed and designated SLNs. All patients underwent completion level I/II axillary dissection.

RESULTS

SLNs were identified in 672 of 758 patients (89%). Of the patients with SLNs identified, 403 patients (60%) had more than 1 SLN removed (mean, 1.96 SLN/patient) and 207 patients (31%) had nodal metastases. The use of filtered or unfiltered technetium sulfur colloid had no impact on the number of SLNs identified. Overall, 33% of histologically positive SLNs had no evidence of blue dye staining. Of those patients with multiple SLNs removed, histologically positive SLNs were found in 130 patients. In 15 of these 130 patients (11.5%), the hottest SLN was negative when a less radioactive node was positive for tumor. If only the hottest node had been removed, the false-negative rate would have been 13.0% versus 5.8% when all nodes with 10% or more of the ex vivo count of the hottest node were removed (P =.01).

CONCLUSIONS

These data support the policy that all blue nodes and all nodes with 10% or more of the ex vivo count of the hottest SLN should be harvested for optimal nodal staging.

Oxidative modification of neurogranin by nitric oxide: an amperometric study

Neurogranin (Ng) is a neuron-specific protein kinase C (PKC) substrate, which contains four cysteine (Cys) residues. Recently, it has been shown that Ng is a redox-sensitive protein and is a likely target of nitric oxide (NO) and other oxidants [F.-S. Sheu, C.W. Mahoney, K. Seki, K.-P. Huang, Nitric oxide modification of rat brain neurogranin affects its phosphorylation by protein kinase C and affinity for calmodulin, J. Biol. Chem. 271 (1996) 22407-22413: J. Li, J.H. Pak, F.L. Huang, K.-P. Huang, N-methyl-D-aspartate induces neurogranin/RC3 oxidation in rat brain slices, J. Biol. Chem. 274 (1999) 1294-1300]. In this study, we directly examine the redox reactions between dissolved NO and Cys as well as between NO and bacterial expressed Ng in its reduced form, at concentrations approximate to the physiological levels in phosphate buffer solution (PBS) under aerobic conditions. The reaction kinetics are measured directly by our newly developed electrochemical sensor. Our sensor is based on the chemical modification of electrode with immobilized nanoparticles of transition metal palladium (Pd) which serves as catalytic centers for the electrochemical oxidation of thiol and NO selectively and quantitatively at different potentials. It detects Cys and Ng in a linear range from nano to micromolar concentration at + 450 mV, vs. a saturated calomel reference electrode (SCE), while the detection of NO at the sensor can be optimally achieved at + 700 mV (vs. SCE) with a linear current-to-concentration range of nM to microM. It thus provides a selective control to monitor two reactants independently. With this sensor as a detector, we found that (1) the oxidation of either Cys or Ng by NO is a fast reaction which reaches a near completion within 1-2 min at its physiological concentration; and (2) after the completion of reaction, NO is mostly, if not all, regenerated, an observation consistent with the reaction mechanism involving the formation of S-nitrosothiol as an intermediate. The reaction kinetics of both NO to Cys and NO to Ng implies that NO can achieve local action on cellular proteins in addition to its effect on targets located in neighboring cells via concentration-gradient-dependent diffusion.

Preoperative lymphoscintigraphy for breast cancer does not improve the ability to identify axillary sentinel lymph nodes

OBJECTIVE

To evaluate the role of preoperative lymphoscintigraphy in sentinel lymph node (SLN) biopsy for breast cancer.

SUMMARY BACKGROUND DATA

Numerous studies have demonstrated that SLN biopsy can be used to stage axillary lymph nodes for breast cancer. SLN biopsy is performed using injection of radioactive colloid, blue dye, or both. When radioactive colloid is used, a preoperative lymphoscintigram (nuclear medicine scan) is often obtained to ease SLN identification. Whether a preoperative lymphoscintigram adds diagnostic accuracy to offset the additional time and cost required is not clear.

METHODS

After informed consent was obtained, 805 patients were enrolled in the University of Louisville Breast Cancer Sentinel Lymph Node Study, a multiinstitutional study involving 99 surgeons. Patients with clinical stage T1-2, N0 breast cancer were eligible for the study. All patients underwent SLN biopsy, followed by level I/II axillary dissection. Preoperative lymphoscintigraphy was performed at the discretion of the individual surgeon. Biopsy of nonaxillary SLNs was not required in the protocol. Chi-square analysis and analysis of variance were used for statistical comparison.

RESULTS

Radioactive colloid injection was performed in 588 patients. In 560, peritumoral injection of isosulfan blue dye was also performed. A preoperative lymphoscintigram was obtained in 348 of the 588 patients (59%). The SLN was identified in 221 of 240 patients (92.1%) who did not undergo a preoperative lymphoscintigram, with a false-negative rate of 1.6%. In the 348 patients who underwent a preoperative lymphoscintigram, the SLN was identified in 310 (89.1%), with a false-negative rate of 8.7%. A mean of 2.2 and 2. 0 SLNs per patient were removed in the groups without and with a preoperative lymphoscintigram, respectively. There was no statistically significant difference in the SLN identification rate, false-negative rate, or number of SLNs removed when a preoperative lymphoscintigram was obtained.

CONCLUSIONS

Preoperative lymphoscintigraphy does not improve the ability to identify axillary SLN during surgery, nor does it decrease the false-negative rate. Routine preoperative lymphoscintigraphy is not necessary for the identification of axillary SLNs in breast cancer.

Determination of cyclamate in low-calorie foods by high-performance liquid chromatography with indirect visible photometry

A rapid and simple method using reversed-phase high-performance liquid chromatography combined with indirect visible photometry at 433 nm was developed to determine cyclamate in some food samples. Cyclamate was not detected in these chosen samples as its use is banned in Hong Kong. Cyclamate can easily be detected in spiked samples using a mobile phase consisting of 30 mumol dm-3 Methyl Red and 0.02 mol dm-3 phosphate buffer (pH 7.0)-methanol in a volume ratio of 3:2. The column temperature was set at 23 degrees C. The detection limit was 0.14 mmol dm-3 and the relative standard deviation of the peak area response was 0.58% for a solution containing 5.0 mmol dm-3 of cyclamate (n = 8). This method was successfully applied to the analysis of eight spiked food samples and the cyclamate recoveries for these samples ranged from 93 to 99%.

Air pollution and hospital admissions for respiratory and cardiovascular diseases in Hong Kong

OBJECTIVE

To investigate short term effects of concentrations of pollutants in ambient air on hospital admissions for cardiovascular and respiratory diseases in Hong Kong.

METHODS

Retrospective ecological study. A Poisson regression was performed of concentrations of daily air pollutant on daily counts of emergency hospital admissions in 12 major hospitals. The effects of time trend, season, and other cyclical factors, temperature, and humidity were accounted for. Autocorrelation and overdispersion were corrected. Daily concentrations of nitrogen dioxide (NO2), sulphur dioxide (SO2), ozone (O3), and particulate matter < 10 microns in aerodynamic diameter (PM10) were obtained from seven air monitoring stations in Hong Kong in 1994 and 1995. Relative risks (RR) of respiratory and cardiovascular disease admissions (for an increase of 10 micrograms/m3 in concentration of air pollutant) were calculated.

RESULTS

Significant associations were found between hospital admissions for all respiratory diseases, all cardiovascular diseases, chronic obstructive pulmonary diseases, and heart failure and the concentrations of all four pollutants. Admissions for asthma, pneumonia, and influenza were significantly associated with NO2, O3, and PM10. Relative risk (RR) for admissions for respiratory disease for the four pollutants ranged from 1.013 (for SO2) to 1.022 (for O3), and for admissions for cardiovascular disease, from 1.006 (for PM10) to 1.016 (for SO2). Those aged > or = 65 years were at higher risk. Significant positive interactions were detected between NO2, O3, and PM10, and between O3 and winter months.

CONCLUSIONS

Adverse health effects are evident at current ambient concentrations of air pollutants. Further reduction in air pollution is necessary to protect the health of the community, especially that of the high risk group.

Development of improved pUB110-based vectors for expression and secretion studies in Bacillus subtilis

pUb110-based vectors are commonly used for expression and secretion studies in Bacillus subtilis. Two of these plasmids, pUB18P43 and pWB705, have been applies to produce several proteins of interest. To offer greater flexibility and compatibility in this system, the authors have also constructed a pE194-based plasmid vector (pE18). To determine whether the pUB110-based or the pE194-based vector serves as a better expression system, three structural genes encoding cytoplasmic BirA, extracytoplasmic PrsA and extracellular staphylokinase, respectively, were used as models. Production of these products using pUB110-based vectors was consistently 2--3-fold lower than that using the pE194-based vectors. The observed difference in the protein yield did not result from either the rearrangement of the plasmid or the difference in the plasmid copy number. By using three different approaches, the lower production yield from the pUB110-based vectors was found to be due to the transcription interference from the plasmid encoded genes. These findings illustrate that the orientation of the inserted gene in pUB110-based vector can greatly affect gene expression. Two new expression vectors, pUB19P43 and pWB980, were constructed to allow better gene expression.

Multiple myeloma presenting with a paraspinal tumor and malignant effusion: case report

We describe a patient with multiple myeloma which presented as a thoracic paraspinal tumor and myelomatous pleural effusion. He had manifested a gradual onset of upper back pain with radiation to the left chest wall for 3 months. A radiographic examination showed left pleural effusion and a paraspinal tumor with rib destruction at the--left T5-6 level. Laboratory data showed anemia and a reversed serum albumin to globulin ratio. Protein electrophoresis and immunoelectrophoresis showed a monoclonal IgG-lambda chain component in the serum, urine, and pleural effusion fluid. Ultrasound-guided transthoracic mass biopsy and thoracentesis were performed for diagnosis. Biopsy of the thoracic tumor showed a solid mass composed of immature plasma cells. The pleural effusion fluid contained numerous immature plasma cells. An immunophenotype study of the pleural effusion fluid revealed monoclonal plasma cells, compatible with malignant pleural effusion. A specimen of bone marrow was interpreted as typical for plasma cell myeloma. Local radiotherapy and chemotherapy with melphalan and prednisolone resulted in good partial remission with a stable condition. Later, however, the disease flared up and hyperviscosity syndrome developed with epistaxis and retinal hemorrhage. He died of sepsis about 15 months after the initial diagnosis.

Endobronchial metastatic disease

BACKGROUND

Endobronchial metastasis (EM) is rare. Patients with EM are in advanced stages of disease and have poor prognoses. However, some patients have had long-term survival after aggressive treatment.

METHODS

We retrospectively reviewed the records of 9678 patients who had undergone bronchoscopic procedures. Forty patients were diagnosed as having EM.

RESULTS

The most common site of primary tumors was the head and neck [10 nasopharyngeal carcinomas (NPC), 2 buccal cancers, 2 glossal cancers, 2 laryngeal cancers]. Clinical manifestations included cough (50%), hemoptysis (20%), dyspnea (15%), and absence of respiratory symptoms (15%). The most common findings in chest roentgenograms (CXR) were single masses (40%). The median length of survival for all patients was 12 months (range, 6 to 18 months). The median length of survival in patients whose ages were over 70 years was 1 months and in patients less than 70 years old it was 12 months (range, 7 to 19 months) (p = 0.002). In patients whose EM extent was to the main bronchus, the median length of survival was 1 month (range, 1 to 3 months) and that in those whose EM did not extend to main bronchus was 12 months (range, 11 to 21 months) (p = 0.0004). In patients whose primary tumors were due to head and neck cancer other than NPC, the survival time was 1 month (range, 1 to 11 months), and in others it was 12 months (range, 7 to 19 months) (p = 0.0008).

CONCLUSION

Three factors contributed to a poor prognosis, including the patient's age being over 70 years, primary tumors due to head and neck cancer other than NPC, and extension of the endobronchial metastatic lesion to the main bronchus.

Expression of Trk receptors in the developing mouse trigeminal ganglion: in vivo evidence for NT-3 activation of TrkA and TrkB in addition to TrkC

Animals lacking neurotrophin-3 (NT-3) are born with deficits in almost all sensory ganglia. Among these, the trigeminal ganglion is missing 70% of the normal number of neurons, a deficit which develops during the major period of neurogenesis between embryonic stages (E) 10.5 and E13.5. In order to identify the mechanisms for this deficit, we used antisera specific for TrkA, TrkB, and TrkC to characterize and compare the expression patterns of each Trk receptor in trigeminal ganglia of wild type and NT-3 mutants between E10.5 and E15.5. Strikingly, TrkA, TrkB, and TrkC proteins appear to be exclusively associated with neurons, not precursors. While some neurons show limited co-expression of Trk receptors at E11.5, by E13. 5 each neuron expresses only one Trk receptor. Neuronal birth dating and cell counts show that in wild-type animals all TrkB- and TrkC-expressing neurons are generated before E11.5, while the majority of TrkA-expressing neurons are generated between E11.5 and E13.5. In mice lacking NT-3, the initial formation of the ganglion, as assessed at E10.5, is similar to that in wild-type animals. At E11.5, however, the number of TrkC-expressing neurons is dramatically reduced and the number of TrkC-immunopositive apoptotic profiles is markedly elevated. By E13.5, TrkC-expressing neurons are virtually eliminated. At E11.5, compared to wild type, the number of TrkB-expressing neurons is also reduced and the number of TrkB immunoreactive apoptotic profiles is increased. TrkA neurons are also reduced in the NT-3 mutants, but the major deficit develops between E12.5 and E13.5 when elevated numbers of TrkA-immunoreactive apoptotic profiles are detected. Normal numbers of TrkA- and TrkB-expressing neurons are seen in a TrkC-deficient mutant. Therefore, our data provide evidence that NT-3 supports the survival of TrkA-, TrkB- and TrkC-expressing neurons in the trigeminal ganglion by activating directly each of these receptors in vivo.

Prevalence and determinants of the use of traditional Chinese medicine in Hong Kong

We studied 2,822 subjects above 18 years of age in Hong Kong by random telephone interview to assess the role of traditional Chinese medicine in health care. During their most recent illness, 73% consulted Western doctors, 17% self-medicated while 9% consulted herbalists. Age and education were important determinants of their health care choice. The most common reason given for their choice was faith in the practitioners they consulted. When they needed further consultation for the same illness, 42% consulted herbalists, illustrating that herbalists played an important supplementary role when Western medicine failed to provide relief. Compared with previous findings, there appeared to be little decline in the popularity of traditional Chinese medicine in Hong Kong.

Expression, purification, and characterization of recombinant forms of membrane-bound cytochrome c-550nm from Bacillus subtilis

Bacillus subtilis expresses a cytochrome c-550nm that participates in respiratory electron transfer and is an integral membrane protein. Analysis of the B. subtilis cytochrome c-550nm amino acid sequence predicts a single N-terminal transmembrane helix attached to a water-soluble heme binding domain [C. von Wachenfeldt and L. Hederstedt (1990) J. Biol. Chem. 265, 13939-13948]. We have purified cytochrome c-550nm from wild-type B. subtilis and B. subtilis transformed with the shuttle vector pHP13 containing the gene for B. subtilis cytochrome c-550nm (cccA). In B. subtilis transformed with pHP13/cccA there is better than eightfold more membrane-bound cytochrome c-550nm than in wild-type B. subtilis. The overexpressed cytochrome c-550nm can be purified by chromatography on hydroxylapatite and Q-Sepharose media. A six-histidine tag has been added to the C-terminus of cytochrome c-550nm from B. subtilis as a further aid for purification. This strain produces cytochrome c-550nm to a level fourfold greater than wild type and allows for one-step purification using metal affinity chromatography. UV-Vis spectroscopy detects no change in the heme C spectrum due to the addition of six histidines. Neither form of B. subtilis cytochrome c-550nm is stable in its reduced state in aerated buffer, unless EDTA is added. The two forms, wild-type and his-tagged, of cytochromes c have similar midpoint redox potentials of 195 and 185 mV, respectively, and are equally good substrates for B. subtilis cytochrome c oxidase. We conclude that the addition of the histidine tag eases the purification of cytochrome c-550nm from B. subtilis plasma membranes and that the additional metal binding site does not compromise the stability or functional properties of the protein.

Endobronchial metastasis of glioblastoma multiforme diagnosed by fiberoptic bronchoscopic biopsy

We report a case of extraneural metastasis of an intracranial glioblastoma multiforme (GBM) to the left upper lung, in which fiberoptic bronchoscopy played a key role in the diagnosis. The patient, a 20-year-old woman, presented with dry cough and hoarseness 2 years after total excision of the brain tumor and postoperative radiotherapy. Tissue samples obtained during fiberoptic bronchoscopic biopsy had the same morphologic appearance as the primary intracranial tumor, which was consistent with GBM. In cases of pulmonary metastasis of GBM, antemortem diagnosis is rare. Our experience from this case suggests that fiberoptic bronchoscopy may be a valuable diagnostic tool for metastatic GBM.

High-level secretory production of intact, biologically active staphylokinase from Bacillus subtilis

Staphylokinase is a promising blood-clot dissolving agent for the treatment of patients suffering from a heart attack. It would be desirable to produce this protein in large quantities for biochemical characterization and clinical trials. Production of intact, biologically active staphylokinase from bacterial expression systems has been a challenge because of N-terminal microheterogeneity, plasmid instability, or low-production yield. By using a seven-extracellular-protease deficient Bacillus subtilis strain, WB700, intact staphylokinase can be produced via secretion. However, native staphylokinase gene (sak) in a high-copy number plasmid was found to be unstable in B. subtilis. To optimize the production and the stability of the expression vectors, both the promoter and the signal sequence of sak were replaced by B. subtilis promoters (P43, a constitutively expressed promoter; Pamy, a stationary-phase promoter; and PsacB, a sucrose-inducible promoter) and the levansucrase-signal sequence, respectively. This overcame the plasmid instability problem. To enhance transcription from the sacB promoter, degQ encoding a transcriptional activator for sacB and other protease genes was also installed in the expression vector. The use of WB700 as the expression host allowed enhanced production of staphylokinase from the sucrose-inducible plasmid without causing any obvious degradation of staphylokinase. Both the P43 and PsacB (with DegQ) promoters worked well. Over 90% of staphylokinase synthesized can be secreted effectively. With the optimization of both the culture media and the fermentation conditions, production of staphylokinase reached a level of 337 mg/L, and staphylokinase could be purified to homogeneity by a simple three-step purification scheme. Secreted staphylokinase did not show any N-terminal heterogeneity. This presents an attractive system for the production of staphylokinase in both high quality and quantity.

Modeling of sertindole pharmacokinetic disposition in healthy volunteers in short term dose-escalation studies

The pharmacokinetics of sertindole were studied in young, healthy volunteers after single and multiple oral dose administered under an escalating manner. In a low-dose study (study 1), subjects received 4-8 mg with a maintenance dose period of 7 days. In a high-dose study (study 2), subjects received 4 mg daily for 2 days, and the dose was increased by 4 mg increments every third day until reaching 20 mg daily. The mean terminal t 1,2 was 73 h after the final 8 mg dose in study 1 and 60 h after the 20 mg dose in study 2. The terminal elimination phase appeared to be monophasic in all the study subjects, suggesting that Michaelis-Menten saturable metabolism was not involved in the elimination of sertindole. Compartmental analyses suggested that the disproportional increase of the Cmax and AUC values from 4 mg to 20 mg during multiple dosing may be explained by saturable presystemic elimination of sertindole, leading to a higher fraction of sertindole available for absorption at higher doses.

Socioeconomic correlates of infant mortality in Hong Kong, 1979-93

Although Hong Kong's infant mortality is among the lowest in the world, there may still be subgroups in the population with unusually high and possibly avoidable mortality rates. We conducted an ecological study on the relationship between socioeconomic deprivation and infant mortality in Hong Kong by using government data from three periods: 1979-83, 1984-88 and 1989-93. The study population comprised all infant births in 65 modified districts in Hong Kong in the period 1979-93. Infant, neonatal and post-neonatal mortality rates (IMRs, NMRs and PNMRs) were used as the health indicators. An F score was derived from highly correlated socioeconomic variables by factor analysis and used as a summary index of socioeconomic status. In 1979-83, socioeconomic deprivation was found to be significantly associated with high IMRs and high NMRs in both sexes, while in 1984-88 this association was observed only in baby girls. None of the observed associations were significant in 1989-93. Overall, the territory's infant mortality rates fell from 10.2 per thousand live births in 1979-83 to 5.6 per thousand live births in 1989-93. Individual-based studies are needed to ascertain whether this apparent disappearance of the socioeconomic relationship with infant and neonatal mortality is real.

Pharmacokinetics of a novel 5-lipoxygenase inhibitor (ABT-761) in pediatric patients with asthma

OBJECTIVE

The pharmacokinetics of an N-hydroxyurea analog, ABT-761 in asthmatic pediatric patients with asthma were investigated.

METHODS

A total of 24 patients were enrolled into this 8-day single- and multiple-dose study. Patients received daily doses of ABT-761 according to their body weight: patients of 20-38 kg received 50 mg; patients >38 kg but < or = 55 kg received 100 mg, and patients >55 kg received 150 mg.

RESULTS

The mean values for the terminal phase t1/2 were 16-17 h after multiple-dose administration. When normalized for body weight, the mean day 8 Cl(f) values for 50-, 100-mg, and 150-mg doses were 0.57 (n=13), 0.51 (n=10), and 0.43 (n=1) ml x min(-1) x kg(-1), respectively, while the mean Vz/f values ranged from 0.75 to 0.77 l x kg(-1). The mean accumulation ratio observed (day 8 to day 1 AUC0-24 ratio) of ABT-761 was approximately 1.7, which is consistent with the t1/2 of this drug. Body weight, age, and body surface area were virtually identical in explaining the variability in dose-normalized Cmax and AUC values (R2=0.61-0.68). The percents of variance explained by these three variables were within a range of 3% for each pharmacokinetic parameter.

CONCLUSIONS

The pharmacokinetics of ABT-761 in children were similar to those previously reported in adults. Body weight, age, or body surface area can be used to provide dosing adjustment for ABT-761 in pediatric patients.

Lack of cytochrome P450 1A2 interaction effect of ABT-761 on the pharmacokinetics of theophylline

ABT-761 is a second-generation 5-lipoxygenase inhibitor for the treatment of asthma. The effects of ABT-761 on the pharmacokinetics of theophylline were assessed in 15 adult volunteers in a phase I, multiple-dose, open-label, one-period study. Subjects received a single 400-mg dose of theophylline on days 1 and 8 and 200-mg oral doses of ABT-761 once daily beginning on day 3 and continuing through day 9. The pharmacokinetic parameters of theophylline after administration of theophylline alone and concomitantly with ABT-761 were compared using a paired t-test. No statistically significant differences were observed between the pharmacokinetic parameters of theophylline administered alone and theophylline with concomitant administration of ABT-761. The 95% confidence interval for the ratio of the mean with ABT-761 dosing to the mean for theophylline alone was 0.970 to 1.127 for area under the plasma concentration-time curve and 0.887 to 1.036 for maximal plasma concentration. The lack of an inhibition effect by ABT-761 on theophylline clearance suggested that ABT-761 may have a low affinity for the cytochrome P450 1A2 isozyme, the primary isozyme responsible for theophylline metabolism.