[TGF beta subtypes in hepatocellular carcinoma]

OBJECTIVE

To detect the expression of three TGF beta isoforms and its clinicopathologic significance in hepatocellular carcinoma(HCC).

METHODS

Surgical specimens of 52 patients with small HCC resection during 1992-1995 were used to determine the immunoreactivity of TGF beta protein by ABC immunohistochemistry. These specimens were divided into recurrence group(G1) and recurrence group(G2) according to whether HCC recurred two years after resection. The relations with recurrence of HCC were analyzed.

RESULTS

The positive rates in G1 and G2 were 85% (17/20) versus 47% (15/32) for TGF beta 1, 90% (18/20) vs. 78% (25/32) for TGF beta 2, and 45% (9/20) vs. 63% (20/32) for TGF beta 3. Significant difference was found in TGF beta 1 and TGF beta 2, but not in TGF beta 3.

CONCLUSION

The high immunoreactivity to TGF beta 1 or TGF beta 2 is positively related to the recurrence of HCC.

Malignancy detection by molecular cytogenetics in clinically normal mucosa adjacent to head and neck tumors

OBJECTIVE

To identify the potential use of chromosome imbalances as biomarkers for tumorigenesis in head and neck squamous cell carcinoma (HNSCC) by fluorescence in situ hybridization (FISH).

DESIGN

In this case-control study, chromosome copy numbers were assessed in dual-target, dual-color FISH assays using DNA probes specific for 14 human chromosomes (1, 2, 3, 6, 7, 8, 9, 10, 11, 12, 15, 17, X, and Y) applied to exfoliated epithelial cells.

SETTING

University medical center.

PATIENTS

We examined 20 cell brushings (from 10 primary tumors and 10 clinically normal margins) collected from 10 patients with HNSCC and compared these with cell brushings from the oral cavity of 10 nonsmoker and 10 smoker control subjects.

INTERVENTION

None.

MAIN OUTCOME MEASURE

Chromosomal aneuploidy.

RESULTS

Specimens from nonsmokers displayed greater than 91% of cells with normal signals, indicating high analytical sensitivity for the probes. Specimens from smokers demonstrated large variability without significant imbalance (P>.05) compared with those from nonsmokers. Tumor specimens from patients with HNSCC displayed significant chromosomal imbalance (P<.05) for all probes except chromosome Y. Similar imbalance, although in lower frequency, was found in all clinically normal adjacent mucosa specimens.

CONCLUSIONS

Interphase FISH demonstrated great applicability in detecting chromosome imbalance associated with malignancy in HNSCC and clinically normal adjacent cells, thereby detecting subclinical tumorigenesis. A panel of chromosome probes (chromosomes 3, 8, 9, and 10) is proposed as an efficient and sensitive additional tool for future routine screening of tumor margins and potential diagnosis of residual disease in HNSCC.

[Investigation of the clinicopathologic features, immunophenotype and Epstein-Barr virus infection of the upper respiratory tract lymphomas in patients]

OBJECTIVE

To study the clinicopathologic features, immunophenotype and Epstein-Barr virus (EBV) infection of the upper respiratory tract lymphomas in patients from north China.

METHODS

112 cases of upper respiratory tract lymphomas in patients from north China were investigated. HE stain for histologic features. Immunohistochemistry studies were performed using monoclonal antibodies, UCHL-1 for T-lymphocyte, L26 and 4KB5 for B lymphocyte, CS1-4 for latent membrane protein-1 (LMP-1). In situ hybridization for EBV encoded small nuclear RNA (EBER 1/2, Y017, DAKO).

RESULTS

77/112 cases (68.75%) were T-cell lymphomas, 35 cases (31.25%) were B cell lymphomas. EBV-EBER 1/2 in situ hybridization positive in 54/101 (53.46%) cases, including 48 T-cell lymphoma cases and 6 B-cell lymphoma cases.

CONCLUSION

Most upper respiratory tract lymphoma cases in patients from north China are T-cell lymphomas and are strongly associated with EBV.

Aspirin inhibition and acetylation of the plant cytochrome P450, allene oxide synthase, resembles that of animal prostaglandin endoperoxide H synthase

The enzymatic reactions leading to octadecanoid lipid signaling intermediates in plants are similar to those of animals and are inhibited by nonsteroidal anti-inflammatory drugs (NSAIDs) such as salicylic acid and aspirin. In animals, NSAIDs inhibit the cyclooxygenase (COX) activity of prostaglandin endoperoxide H synthase, which ultimately blocks the formation of prostaglandins. In plants, NSAIDs block the formation of 12-oxo-phytodienoic acid and jasmonates, which are the equivalent signaling compounds. In this study we show that NSAIDs act as competitive inhibitors of allene oxide synthase (AOS), the cytochrome P450 that initiates plant oxylipin synthesis. We also show that aspirin causes the time-dependent inhibition and acetylation of AOS, which leads the irreversible inactivation of this enzyme. This inhibition and acetylation superficially resembles that observed for the inactivation of COX in animals. In AOS, aspirin acetylates three serine residues near the C-terminal region that appear to be highly conserved among AOS sequences from other plants but are not conserved among "classical" type P450s. The role of these serine residues is unclear. Unlike animal COX, where acetylation of a single serine residue within the substrate channel leads to inactivation of prostaglandin endoperoxide H synthase, the three serine residues in AOS are not thought to line the putative substrate channel. Thus, inhibition by aspirin may be by a different mechanism. It is possible that aspirin and related NSAIDs could inhibit other P450s that have motifs similar to AOS and consequently serve as potential biochemical targets for this class of drugs.

Epidemiological survey on clonorchiasis sinensis in Yangxin County of Hubei Province of PR China

An epidemiological survey of clonorchiasis was conducted at Panqiao township of Yangxin County of Hubei Province from June to November, 1993. The positive rate of cercaria in the body of intermediate hosts, Parafossarulus stratulus and Alocinma longicornis was 12.25% and 3.84% respectively. Positive rates of metacercariae in the bodies of Pseudonaphona parva was 48.15%, Ctenopharyngodon idellus 17.24% and Hypophthalmichthys nobilis 18.18%. Positive rate of eggs in the feces of cats was 36.36% and pigs 16.67%. It has been confirmed that there is a natural focus of clonorchiasis sinensis at Yangxin County of Hubei Province. A total population of 6,865 in 20 sites of 10 production brigades of Panqiao township was surveyed for infection with Clonorchis sinensis. The average infection rate in the local residents was 5.80%. Male had a higher infection rate than female. The infected persons were mainly peasants and school girls and boys. Most of the infected persons had light infections (I0) without a serious clinical manifestations.

Glycophorin variants and contents of sialic acid and total sulfhydryl groups on erythrocyte membranes of residents in a malaria hyperendemic area

OBJECTIVE

To conduct a screening survey of glycophorin (GP) variants and observe the content changes of sialic acid (SA) and total sulfhydryl (SH) groups on the erythrocyte membranes among residents in a tertian malaria hyperendemic area of Guizhou Province.

METHODS

GP variants were detected in the erythrocyte hemolysates of 173 local residents at two villages of Libo County by SDS-PAGE on 10% to 15% gradients gel and Western immunoblotting. Their SA and total SH group contents were estimated in erythrocyte membranes by spectrophotometric methods. 114 healthy subjects in Changsha and 49 individuals at a neighbouring village of the above area showing low morbidity of malaria served as normal and endemic controls respectively.

RESULTS

Three distinct types of GP variants were found among 19 propositi in this hyperendemic area. The incidence of GP variants was 7.9% (8/101) at Yaolu Village whose population was mainly composed of Yao ethnic group; while that of Buyi ethnic group at Maolan Village was higher (15.3%; 11/72). The erythrocyte membrane contents of SA in residents at both villages exhibited a very significant tendency of decline (P < 0.01), whereas those of total SH groups increased prominently in residents of Yaolu Village only (P < 0.05).

CONCLUSIONS

The frequency of GP variants in this hyperendemic area does not depend upon the severity of malarial prevalence. The evident reduction of SA contents in the residents may be related to the breaking down of the SA residues on membrane GPs by the invasion of Plasmodium vivax.

[Histopathological study of local invasiveness of transglottic cancer]

OBJECTIVE

To explore the characteristics and relevant factors of transglottic cancer invading paraglottic space (PGS) and pre-epiglottic space (PES).

METHODS

Whole-organ serial sections of 50 transglottic cancer specimens were studied histopathologically.

RESULTS

Transglottic cancer invading PGS was observed in 39 of the 50 (78.0%) specimens. In 32 of the 39 specimens, the invasion outstripped PGS, involving elastic cone in 26(81.3%), thyroid cartilage in 24(75.0%) and cricothyroid membrane in 20(62.5%). Transglottic cancer invading PES was seen in 23 of the 50 specimens (46.0%). With the increase in tumor staging and tumor size, PGS and PES became increasingly invaded. There were two possible routes of invasion to PES: a) extending anteriorly and upward via PGS; b) extending upward via anterior commissure to destroy the stem of epiglottic cartilage.

CONCLUSION

PGS is easily invaded by transglottic cancer. Partial laryngectomy is recommended in patients with T3, T4 transglottic cancer larger than 20 mm in diameter.

Peptide mass fingerprint sequence coverage from differently stained proteins on two-dimensional electrophoresis patterns by matrix assisted laser desorption/ionization-mass spectrometry (MALDI-MS)

Identification of proteins separated by two-dimensional electrophoresis (2-DE) is a necessary task to overcome the purely descriptive character of 2-DE and a prerequisite to the construction of 2-DE databases in proteome projects. Matrix assisted laser desorption/ionization-mass spectrometry (MALDI-MS) has a sensitivity for peptide detection in the lower fmol range, which should be sufficient for an analysis of even weakly silver-stained protein spots by peptide mass fingerprinting. Unfortunately, proteins are modified by the silver staining procedure, leading to low sequence coverage. Omission of glutaraldehyde increased the sequence coverage, but this improved sequence coverage is still clearly below the sequence coverage starting with Coomassie Brilliant Blue (CBB) R-250-stained spots. Other factors additionally seem to modify proteins during silver staining. By decreasing the protein amount, the advantage of very sensitive detection on the gel is lost during identification, because the resulting low sequence coverage is not sufficient for secure identification. Low-quantity proteins can be identified better starting with CBB G-250 or Zn-imidazol-stained proteins. In contrast, for high-quantity CBB R-250-stained spots, a sequence coverage of up to 90% can be obtained by using only one cleaving enzyme, and up to 80% was reached for medium-quantity spots after combination of tryptic digest with Asp-N- and Glu-C digest.

[Quality control for huoxiang-zhengqi liquid]

The Rhizoma Atractylodis, Cortex Magnoliae Officinalis and Pericarpium Citri Reticulatae in Huoxiang-zhengqi Liquid were identified by TLC. The total contents of magnolol and honokiol were determined by HPLC to be no less than 1.9 mg/ml, with an average recovery of 104.4% and 103.3%, RSD 1.23% and 0.91% respectively.

Effects of different subtypes of histamine receptors on proliferation and differentiation of murine colony forming unit granulocyte-macrophage and colony forming unit megakaryocyte

OBJECTIVE

To investigate the function and characteristics of histamine receptors on the hemopoietic progenitor cells.

METHODS

BDF1 mice (both male and female), inbred at our university, aged 8-12 weeks, weighing 20-24 g, were used in this study. Bone marrow cells were incubated for 1 hour at 37 degrees C with 2-AT (H1 receptor agonist) or impromidine (H2 receptor agonist) alone, or in combination with the antagonists pyrilamine or cimetidine respectively. Control experiment was performed in Dulbecco's modified Eagle's Medium (DMEM) alone. Cells treated with different drugs were performed by colony forming unit-granulocyte-macrophage (CFU-GM) and colony forming unit-megakaryocyte (CFU-Meg) assay.

RESULTS

When bone marrow cells were treated with 10(-8) mol/L to 10(-5) mol/L of 2-thiazolylethylamine (2-AT) which had no influence on CFU-GM and CFU-Meg proliferation, 10(-8) mol/L to 10(-5) mol/L of impromidine could increase the number of CFU-GM and CFU-Meg colonies. The effects of H2 receptor agonists on CFU-GM, CFU-Meg could be antagonized by H1 receptor agonist.

CONCLUSIONS

Our findings suggest the existence of histamine H1 and H2 receptors on the hemopoietic progenitor cells and the antagonism between two different histamine receptor subtypes on the proliferation of CFU-GM and CFU-Meg.

A phase I study of daily carboplatin and simultaneous accelerated, hyperfractionated chest irradiation in patients with regionally inoperable non-small cell lung cancer

PURPOSE

This Phase I study was designed to determine the maximally tolerated dose (MTD) of daily low dose carboplatin with concurrent accelerated hyperfractionated radiotherapy (AHFX) in patients with locally advanced non-small-cell lung cancer. Patients also received consolidation chemotherapy with carboplatin. Secondary objectives were to determine the response rate, response duration, sites of first relapse, and survival.

METHODS AND MATERIALS

Thirty patients received daily carboplatin at doses of 25 or 30 mg/m2. Concurrent radiotherapy was given in 1.5 Gy fractions twice daily for a total dose of 60 Gy. Following chemoradiotherapy, patients received four cycles of carboplatin at 350 mg/m2.

RESULTS

Grade 4 esophagitis developed in 2 of 6 (33%) patients receiving 30 mg/m2 of daily carboplatin and was dose limiting. The remaining 24 patients received carboplatin at 25 mg/m2, with 3 patients developing Grade 4 esophagitis (13%). One of 22 patients who received consolidation carboplatin developed Grade 4 thrombocytopenia. An objective response was observed in 70% of patients (2 complete and 17 partial). Sites of failure were local (7 patients), distant (7 patients), and both (3 patients). The median time to progression was 8.3 months, with a median survival time of 18.3 months. The 1- and 2-year survival rates were 63 and 49%, respectively.

CONCLUSIONS

Esophagitis was dose limiting when 30 mg/m2 of daily carboplatin was administered with AHFX. At the MTD of 25 mg/m2 of daily carboplatin plus AHFX followed by four cycles of carboplatin, the regimen was shown to be safe and as active or more active than other regimens. Thus, further studies with this regimen are warranted.

[Cerebrospinal aporrhinosis of nasal sinus operation]

OBJECTIVE

To study the treatment of cerebrospinal aporrhinosis after nasal sinus operation, especially frontal, ethmoid tumor resection.

METHODS

Fourteen cases of cerebrospinal aporrhinosis after nasal sinus operations were reported.

RESULTS

Seven cases of cerebrospinal apporrhinosis were found during the operation. Two cases were repaired with tensor facia latae, 3 with mucosoperichondrium of nasal septum and EC otocerebral glue and 1 with TJ bone cement. Seven cases cerebrospinal aporrhinosis were found after the operations when intranasal packing was removed. They were cured by cerebral decompression and antibiotics, none complicated with intracranial infection.

CONCLUSION

Careful examination should be taken daring the operation. If aporrhinosis was found, it should be repaired immediately.

[Transglottic carcinoma and transglottic invasion of laryngeal carcinoma]

OBJECTIVE

To explore the definition of transglottic carcinoma and its pathological characteristics of local invasion, and to determine the distinction between transglottic carcinoma and transglottic invasion of laryngeal carcinoma.

METHODS

Fifty total laryngectomy specimens of transglottic carcinoma were subject to whole-organ serial section, HE staining and microscopic observation.

RESULTS

The ventricles of 50 cases were all invaded, the main lesion of carcinoma was in the ventricle, or the ventricle was the center of the lesion. The rate of invasion to paraglottic space(PGS) was 82%(41/50). Submucosal invasion was seen in 52%(26/50) and that with superficial mucosal invasion was seen in 38%(19/50). Superficial mucosal invasion rate was 10%(5/50). Deep submucosal invasion was the major way of tumor spread in transglottic carcinoma which equally involved the supraglottic and glottic regions.

CONCLUSION

Transglottic carcinoma originates from the center of ventricle where it spreads to transglottic region. Submucosal extension is characteristic of local invasion. There are fundamental differences between transglottic carcinoma and transglottic invasion of laryngeal carcinoma in the late stage of the lesion.

The presence of masked antiribosomal P autoantibodies in healthy children

OBJECTIVE

To determine if antiribosomal P (anti-P) autoantibodies are present in healthy children.

METHODS

Sera from healthy children were screened for anti-P by conventional enzyme-linked immunosorbent assay and immunoblot techniques. Sera were also treated with immobilized ribosomal P antigens on nitrocellulose strips; affinity-purified fractions were tested for anti-P by high-sensitivity immunoblot. The relative binding affinities were compared for affinity-purified anti-P antibodies from healthy children and adults, and patients with systemic lupus erythematosus. IgG fractions of anti-P-depleted sera from healthy children were assessed for inhibition of autologous anti-P activity.

RESULTS

Conventional serologic screening showed no IgG nor IgM anti-P in 88 untreated sera. IgG anti-P were unmasked in all 79 sera treated by the membrane batch affinity technique. IgM anti-P were identified in 27 of the treated sera; the percentage of positive sera decreased with increasing age (chi(2) for linear trend P = 0.00081). Affinity-purified anti-P from children had relative binding affinities similar to those of anti-P from other groups. Sera from healthy children contained inhibitory IgG antibodies to anti-P.

CONCLUSION

These results show that anti-P autoantibodies are present in all healthy children. The majority of these autoantibodies are masked by IgG antibodies, suggesting concordant development of a regulatory network.

Identification of two nervous system-specific members of the erg potassium channel gene family

Two new potassium channel genes, erg2 and erg3, that are expressed in the nervous system of the rat were identified. These two genes form a small gene family with the previously described erg1 (HERG) gene. The erg2 and erg3 genes are expressed exclusively in the nervous system, in marked contrast to erg1, which is expressed in both neural and non-neural tissues. All three genes are expressed in peripheral sympathetic ganglia. The erg3 channel produces a current that has a large transient component at positive potentials, whereas the other two channels are slowly activating delayed rectifiers. Expression of the erg1 gene in the sympathetic nervous system has potential implications for the etiology of the LQT2 form of the human genetic disease long QT syndrome.

[Influence of cerebral traumatic dementia treated with acupuncture at houxi and shenmen]

Sixty-two cerebral traumatic dementia patients were randomly divided into two groups acupuncture treatment group (Group A, 32 cases) and physical treatment group (Group B, 30 cases). The changes of MMSE scores and auditory P300 were observed before and after the treatment. It were found that the indexes in group A changed significantly (P < 0.05-0.001), and the indexes in group B didn't change significantly (P > 0.1-0.4). The therapeutic effect in group A was better than that in group B(P < 0.001). The results confirmed that the cognitive function of cerebral traumatic dementia patients was increased effectively with acupuncture at Houxi and Shenmen.

Intermittent on/off prostaglandin E2 and risedronate are equally anabolic as daily PGE2 alone treatment in cortical bone of ovariectomized rats

In this study, we evaluated the rat cortical bone changes after a two-cycle, 60-day each (ON/OFF/ON/OFF) treatment with either prostaglandin E2 (OVX/c-PGE2) alone or in combination with risedronate (OVX/c-PGE2+Ris), in comparison with daily treatment with PGE2 for 240 days (OVX/PGE2-240d) in ovariectomized (OVX) rats. At the end of the study, we found that: (1) the overall effectiveness of the treatment on bone mass in the tibial shaft indicates the following ranking: OVX/PGE2-240d = OVX/c-PGE2+Ris > OVX/c-PGE2 > OVX/c-Ris > or = OVX = aging; (2) the same bone mass and architecture were produced in the OVX/PGE2-240d and the OVX/c-PGE2+Ris groups, but the histomorphometric profiles differed in that the former exhibited a higher bone turnover and index of resorption; (3) OVX/c-PGE2+Ris treatment prevented endocortical bone loss and minimized trabecular bone loss during the OFF periods; and (4) the OVX/c-PGE2 alone treatment resulted in the accumulation of less total bone than OVX/PGE2-240d and OVX/c-PGE2+Ris because it could not maintain most of the new subendocortical and marrow trabecular bone generated earlier. In summary, both continuous daily PGE2 and two cycles ON/OFF combined PGE2 and Ris treatments result in more bone mass than two cycles ON/OFF PGE2 alone and Ris alone in estrogen-deficient rats. This study showed that the anabolic effects of PGE2 can be induced and maintained either by continuous administration or by cyclical PGE2+Ris.

[Histopathological study of local invasion and cervical lymph node metastasis in transglottic carcinoma]

To study the histopathological characteristics of local invasion and cervical lymph node metastasis in transglottic carcinoma and provide theoretical guide to clinical practice, 30 laryngectomy and 35 neck dissection specimens were studied by serial section, HE staining and observation under light microscope. The results showed that transglottic carcinomas originated from the ventricle invaded supraglottic and glottic areas equally. The metastatic rate of cervical lymph nodes was 43.3%; the latent metastatic rate was 30%. The metastatic and extracapsular perforation rates as well as the number of the aggregated fusion lymphnodes increased with the increase in the size of the lymphonodes. It was concluded that the transglottic carcinoma should be defined as one with the main lesion locates in the ventricle, or the ventricle being the center with transglottic spread. Since the barrier of ventricle was weak, partial laryngectomy should be performed with care, and ipsilateral neck dissection shoud be included during operation.

[Improvements of laryngectomy cricopharyngeal anastomosis laryngeal reconstruction (report of 27 cases)]

To alleviate the deglutition and increase decannulation rate in Arslan's operation, 27 patients who had undergone laryngectomy cricopharyngeal anastomosis reconstruction from 1989 to 1995 in our hospital were reported. There were T1bN0 8 cases, T2N0 17 cases, T3N0 2 cases according to UICC staging in 1987. All lesions located in vocale cords bilaterally. On the side of the mild lesion, over half of the vocale cord was invaded. The main points of surgical procedure were that the epiglottic and cricoid cartilage were restored. Hyoid bone and arytenoid cartilages were resected and cricoid cartilage anastomosis with the base of the tongue and submental muscles. Phonation was restored in all postoperative patients. Deglutition was alleviated significantly. Decannulation rate was 92.6% (25/27). The follow-up period of 14 cases was over 3 years. Of the 14 cases, 1 died. The 3 years survival rate was 92.86% (13/14). The follow-up period of 6 cases was over 5 years. Of the 6 cases, 1 was lost, the 5 years survival rate was 83.33% (5/6). The operation has great effects on alleviating deglutition and increasing decannulation rate.

[The effect of repair of paratendon in tendon healing]

In order to investigate the effect of repair of paratendon in tendon healing, two different ways were performed to repair the transected extensor tendons of chick's toe. End to end suture of the extensor tenon was performed in group 1 while the paratendon was also repaired simultaneously in addition to suture of the tendon in group 2. Gross observation and histological examination were undertaken in the 3rd and 6th week after operation. The result showed, in group 1, extensive adhesion and irregular proliferation of fibroblasts was found in the 3rd week, severe adhesion and irregular arrangement of fibroblasts with less collagen fiber was found in the 6th week; while in group 2, smooth and regular "fusiform structure" was formed, slight adhesion and regular proliferation of fibroblasts were found in the 3rd week, adhesion disappeared and the structure of paratendon and tondon recovered in the 6th week. It was concluded that repair of extensor tendon and paratendon simultaneously could promote the intrinsic tendon healing and prevent tendon adhesion.

A phase I trial of paclitaxel plus carboplatin in untreated patients with advanced non-small cell lung cancer

This Phase I study was designed to determine the maximally tolerated doses of paclitaxel (given as an outpatient 3-h infusion) plus carboplatin in advanced, untreated non-small cell lung cancer. Secondary objectives were to determine the response rate, response duration, and survival. Fifty-six patients were accrued, and all were evaluable for toxicity; 50 patients were assessable for response. Paclitaxel doses ranged from 135-250 mg/m2, whereas carboplatin dosing started at 250 mg/m2 and was escalated to 400 mg/m2. Patients received therapy on day 1 every 21 days for a maximum of six cycles. Prophylactic granulocyte colony-stimulating factor was not given initially but was allowed if grade 4 neutropenia developed. Neutropenia was the major toxicity observed (41% of patients; 16% of courses) and was dose related. However, febrile neutropenia was uncommon (4%), and no patient receiving growth factor developed subsequent grade 4 neutropenia. Only one patient developed grade 4 thrombocytopenia. No grade 4 neuropathy or grade 3 or 4 myalgias/arthralgias were reported. Grade 4 allergic reactions occurred in three patients (5%), and two patients sustained grade 4 cardiac toxicity (4%). Partial responses were observed in 13 of 50 patients (26%). One of 13 patients (8%) receiving paclitaxel at 135 mg/m2 and carboplatin (250-350 mg/m2) responded versus 12 of 37 patients (32%) receiving paclitaxel doses >/= 175 mg/m2 with carboplatin doses of 350-400 mg/m2. The median time to progression, median survival, and 1-year survival rates seemed to be dose related, with median times to progression of 6, 18, and 27 weeks; median survival of 13, 29, and 39 weeks; and 1-year survival rates of 15, 28, and 41% for the 135, 175-200, and 225-250 mg/m2 groups. We conclude that full doses of both paclitaxel and carboplatin can be given safely on an outpatient basis with 3-h paclitaxel infusions. Neutropenia is the most common toxicity; response rates and survival at higher dose levels were encouraging. Phase III trials to determine the optimal dose and infusion schedule of this combination are warranted, as are trials to compare paclitaxel/carboplatin to other active single agents or combination regimens.

[Study on the direct determination of Pb and Cd in milk powder by GFAAS]

The paper reports the direct determination of Pb and Cd in milk powder by GFAAS. The mothed does not need any pre-treatment to the samples and fully use some function of pre-treatment which the Graphite Furnace have. The result indicates that the method is simple, rapid and accurate, and the false result from any pre-treatment to the samples can be reduced. The recover rate of Pb is 100.1%, CV =2.7 ; and Cd is 98.6%, CV = 3.1 %. This method is also applied to the rapid determination of Pb and Cd in soluble samples with satisfactory results.

[A report of 50 cases of transglottic carcinoma]

50 cases of transglottic carcinoma were chosen and the collodion-embedded specimens of whole-organ serial section were observed. We found that: 1. Transglottic carcinoma was of laryngeal ventricle origin; 2. There were 1 case in T1 and 2 cases in T2 category; 3. Deep infiltration was the main local growth pattern (90%, 45/50), and paraglottic space and thyroid cartilage were easily involved (82%, 41/50 and 65%, 32/50 respectively), clinical stage was not parallel to pathological stage (48%, 24/50).

The role of the T-lymphocyte in estrogen deficiency osteopenia

Our laboratory has previously demonstrated that the T-lymphocyte is critical in the development of cyclosporin A-induced osteopenia in the rat model. A similar state of osteopenia is induced by estrogen depletion in the ovariectomized (OVX) rat, which is the animal model of postmenopausal bone loss. However, the role of the immune system, and particularly the T-lymphocyte, in estrogen deplete osteopenia has not been elucidated. We used the Rowett athymic nude rat as our model of T-lymphocyte deficiency. In this study, the experimental rats were divided into four groups as follows: (1) sham-operated Rowett heterozygous (rnu/+) euthymic rats (control group); (2) OVX Rowett heterozygous (rnu/+) euthymic rats; (3) sham-operated Rowett homozygous (rnu/rnu) athymic nude rats, which are T-lymphocyte deficient; and (4) ovariectomized Rowett homozygous (rnu/rnu) rats. Rats were weighed, and venous blood was taken in weeks 2, 4, and 6 for determination of serum osteocalcin. Serum 1,25-dihydroxyvitamin D (1,25(OH)2D) was determined on the day of sacrifice. Following sacrifice, histomorphometry was performed on double-labeled proximal tibial metaphyses. Flow cytometric analysis of splenic mononu-clear cell isolates stained for OX19-positive (CD5) T-lymphocytes was performed. T-lymphocyte analysis revealed significant reductions in both athymic nude groups, while OVX euthymic rats demonstrated a diminished number of T-cells relative to their sham-operated counterparts. Histomorphometric data indicated that both OVX groups exhibited a significant loss of trabecular volume, with associated increases in indices for bone formation and resorption, with resorption likely outstripping formation, resulting in osteopenia. Serum osteocalcin was significantly elevated in the ovariectomized euthymic group throughout the experimental period compared with the control group (p < 0.01); it was elevated in the ovariectomized athymic group on week 4 only (p < 0.01 vs. control). It appears that the T-lymphocyte may not be an essential component in the pathogenesis of estrogen deficiency osteopenia. The contribution of circulating T-lymphocytes as well as other T-lymphocyte-rich organs needs to be explored further.

Increased uptake of L-cysteine and L-cystine by nerve growth factor in rat pheochromocytoma cells

Nerve growth factor is a neurotrophic factor which promotes cell survival and differentiation in the central and peripheral nervous system. The rat pheochromocytoma (PC12) cell has been frequently used to study the actions of nerve growth factor (NGF). Our previous studies demonstrate that pretreatment with NGF for 24 h protects PC12 cells from oxidative stress by increasing glutathione (GSH) concentrations and the activity of gamma-glutamylcysteine synthetase, which is a rate-limiting enzyme in GSH synthesis. The synthesis of intracellular GSH is dependent on the availability of the precursor amino acid, L-cysteine. Cells take up L-cystine from the extracellular fluid and convert it to L-cysteine intracellularly. L-Cysteine is then released from cells to maintain extracellular L-cysteine. Here we report that NGF increased the uptake of L-cysteine or L-cystine. The increased concentrations of L-cysteine or L-cystine by NGF was responsible for the enhanced intracellular GSH concentrations. The increased GSH and L-cysteine concentrations by NGF also served as intracellular antioxidants. The protection of PC12 cells by NGF from oxidative stress was due to the stimulated increased levels of intracellular glutathione and L-cysteine or L-cystine.

Role of calmodulin in HIV-potentiated Fas-mediated apoptosis

The recently demonstrated extraordinary rate of turnover of T cells in human immunodeficiency virus (HIV)-1-infected patients and the apparently concomitant high rate of viral production and death are consistent with a large amount of cell death directly due to infection. Apoptosis may be one of the major forms of T cell death in HIV-1 infection. Many apoptotic pathways depend on calcium and therefore would be expected to involve calmodulin. As the HIV-1 envelope glycoprotein, gp160, contains two known calmodulin-binding domains, we investigated the possibility that the cytoplasmic domain of the HIV-1 envelope protein gp160 could enhance Fas-mediated apoptosis, the major form of apoptosis in lymphocytes. Our studies have shown that 1) transfection of H9 and MOLT-4 cells with a non-infectious HIV proviral clone, pFN, which expresses wild-type gp160, leads to enhanced Fas-mediated apoptosis, 2) transfection of MOLT-4 cells with a pFN construct pFN delta 147, which expresses a carboxyl-terminally truncated gp160 lacking the calmodulin-binding domains, produces less Fas-mediated apoptosis than transfection with pFN, and 3) the calmodulin antagonists trifluoperazine and tamoxifen completely inhibit the pFN enhancement of Fas-mediated apoptosis in MOLT-4 cells. We have replicated all of these results using the vectors pSRHS and pSRHS delta 147, which express wild-type gp160 and truncated gp160, respectively, in the absence of other viral proteins. These investigations provide a mechanism by which HIV-1 may induce apoptosis and a possible intracellular target for future therapeutics.

Regulation of gamma-glutamylcysteine synthetase activity by nerve growth factor

Nerve growth factor is a neurotrophic factor that regulates neuronal cell development, maintenance, and injury responses in the peripheral and central nervous system. Nerve growth factor reduces injury owing to oxidative stress in rat pheochromocytoma (PC12) cells by increasing intracellular glutathione, in part owing to its stimulation of the activity of gamma-glutamylcysteine synthetase, which is the rate-limiting enzyme in the synthesis of glutathione. Here we show that nerve growth factor did not increase the activity of gamma-glutamylcysteine synthetase in PC12 cells at the transcriptional level. Rather, nerve growth factor enhanced the stability of gamma-glutamylcysteine synthetase mRNA in PC12 cells. These results suggest that, during oxidative stress, nerve growth factor extended the half-life of gamma-glutamylcysteine synthetase mRNA, thus increasing gamma-glutamylcysteine synthetase mRNA levels compared to nerve growth factor-deprived PC12 cells.

Cloning, characterization, and heterologous expression of cDNAs for farnesyl diphosphate synthase from the guayule rubber plant reveals that this prenyltransferase occurs in rubber particles

Two farnesyl diphosphate synthase (FPS) cDNA's from a guayule stembark library were isolated and characterized. Both encode M(r) 39,000 proteins containing 432 amino acids that differ slightly in their deduced molecular weights and isoelectric points. They both contain the DDXXD motifs that are characteristic of prenyltransferases, and both isoforms show high homology to other plant FPS sequences but less overall homology to FPS sequences from nonplant sources. The two isoforms differ by 5% in their amino acid sequence. When expressed in Escherichia coli, each guayule isoform exhibits high specific activity that produces farnesyl diphosphate as the major isoprenoid and small amounts of geranyl diphosphate. Biochemical and immunological evidence also indicates that FPS is associated with guayule rubber particles. Antibodies to chicken FPS cross-react with both guayule isoforms expressed in E. coli and recognize a low abundance M(r) 39,000 protein in rubber particles purified from guayule stembark. Guayule FPS sequences show high homology to peptide fragments of the prenyltransferase associated with rubber particles from Hevea brasiliensis, suggesting that this enzyme may be important for rubber biosynthesis in both species.

Correlation of tumor markers p53, bcl-2, CD34, CD44H, CD44v6, and Ki-67 with survival and metastasis in laryngeal squamous cell carcinoma

BACKGROUND

Recent basic discoveries about the biological significance of nuclear and cell-surface marker proteins have opened new areas of research into head and neck cancer. However, the clinical significance of these markers is not yet understood.

OBJECTIVE

To perform a historical prospective study of 70 patients with squamous cell carcinoma of the larynx who were treated at our institution between 1979 and 1989 to correlate tumor marker expression with survival and metastasis.

DESIGN

Archival tissue was immunohistochemically stained for the p53 tumor suppressor gene product, the inhibitor of apoptosis (bcl-2), the stem cell marker CD34, the cell adhesion molecules CD44H and CD44v6, and a marker of cellular proliferation (Ki-67). The slides were examined using a light microscope and scored according to intensity and percentage of cells labeled. The patients were stratified by tumor stage, and survival and metastatic data were correlated with staining scores.

RESULTS

For the stage IV group, increased expression of p53 and decreased expression of CD44H and CD44v6 correlated with a decreased survival (P = .03, P = .03, and P = .02, respectively), and decreased expression of CD44H correlated with an increase in metastasis (P = .01). For all stages, excluding metastatic cases, increased p53 expression was consistent with a shorter survival (P < .03), while increased CD44v6 expression was consistent with a longer survival (P < .02).

CONCLUSIONS

The present study suggests that a loss of cell proliferation control implied by overexpression of p53 and loss of cell adhesion implied by decreased expression of CD44 may be determinants of survival in patients with carcinoma of the larynx. The tumor markers bcl-2 and Ki-67 were not prognostic discriminators in this limited series. This study also indicates that the stem cell marker CD34 is rarely expressed by laryngeal carcinoma cells.

Progesterone receptor-induced bending of its target DNA: distinct effects of the A and B receptor forms

We have used circular permutation and phasing electrophoretic mobility shift assays to determine the ability of the A and B forms of human progesterone receptor (PR) to bend target DNA. Studies were done with baculovirus-expressed full-length receptors purified to apparent homogeneity. By circular permutation analysis, both forms of PR induced substantial distortions in the structure of target DNA with calculated distortion angles (alpha D) of 57 degrees for PR-A and 84 degrees for PR-B. The apparent bend centers for both forms of PR were similarly located a few base pairs (-4 to -2 bp) from the middle of the progesterone response element. No differences were detected in the magnitude of distortion or apparent bend centers when PR was bound to hormone agonist (R5020) or the antagonist RU486. Phasing analysis, which can determine the orientation of a DNA bend, revealed that both forms of PR mediated directional bends toward the major groove of the DNA helix. Calculated directed bend angles (alpha B) were 40 degrees for PR-B and 31 degrees for PR-A. The chromatin high mobility group protein HMG-1, which acts as an accessory factor to enhance the binding affinity of purified PR for progesterone response elements, had minimal influence on PR-mediated DNA bending. This result, taken together with the fact that HMG-1 can form a ternary complex with PR and DNA, is consistent with the conclusion that HMG-1 facilitates PR binding by stabilizing a receptor-induced DNA conformation that is required for assembly of a high affinity PR-DNA complex. The results of this study also suggest that DNA bending may be coupled to transcriptional regulation since PR-B is generally a stronger transcriptional activator than PR-A and also mediates a larger bend in target DNA than PR-A.

cDNA cloning of a novel G protein-coupled receptor with a large extracellular loop structure

A cDNA designated as AZ3B has been isolated from a differentiated HL-6 0 cell cDNA library with a probe derived from the N-formyl peptide receptor gene. The 1.97-kb cDNA encodes a novel G protein-coupled receptor (GPCR) with 482 amino acids. In addition to the predicted 7 transmembrane domains common to all GPCRs, the protein encoded by AZ3B contains a large extracellular loop of approximately 172 amino acids between the fourth and the fifth transmembrane domains, a feature unique among the hundreds of GPCRs identified to date. High sequence homology exists between the AZ3B protein and a number of chemoattractant receptors in the amino-terminal 170 residues and the carboxyl-terminal 150 residues. Northern and flow cytometric analyses suggested that the AZ3B message and protein are widely expressed in several differentiated hematopoietic cell lines, in the lung, placenta, heart, and endothelial cells. We postulate that the AZ3B protein defines a distinct group of receptors within the GPCR superfamily.

[Serodiagnosis of Helicobacter pylori infections by detection of immunoglobulin G antibodies with an immunoblot technique]

Serological testing has recently been proposed as an aid in diagnosis of H. pylori infections. In this study, an immunoblot method has been evaluated to diagnose H. pylori infection serologically by comparing 104 serum specimens from patients with a positive Gram stain and/or culture result and a positive urease test on biopsy material, as well as 30 serum specimens from patients with negative urease test, and negative microscopy and culture results. Thirteen bands could be identified by immunoblotting and were found significantly more frequent in patients with H. pylori infections than in patients without such infections. A semiquantitative grading system was introduced with score 1 for each reactive band and score 1/2 for a weakly reactive band. If score 2 was the cut-off value for IgG antibody, then the sensitivity, specificity, positive predictive value and negative predictive value of the immunoblot test were 100.0%, 90.0%, 97.2% and 100.0% respectively. There was no marked cross reaction with both Campylobacter jejuni and Campylobacter coli.

Stimulation of NF-kappa B activation and gene expression by platelet-activating factor

PAF stimulation of NF-kappa B activation and transcription of immediate-early genes have been investigated in peripheral blood mononuclear cells and in transfected Chinese hamster ovary cells expressing the cloned PAF receptor. These studies identified a G protein-coupled pathway for PAF induction of gene expression and transcription factor activation, which differs from the mechanisms employed by other immediate-early gene inducers. Potential significance of PAF induced NF-kappa B activation is discussed.

Intermittent treatments of prostaglandin E2 plus risedronate and prostaglandin E2 alone are equally anabolic on tibial shaft of ovariectomized rats

Effects of intermittent administration of prostaglandin E2 (PGE2), risedronate (Ris) and their combination on bone mass were studied on the cortical bone of tibial shafts of ovariectomized (ovx) rats. Six month old ovx rats were treated immediately after operation with subcutaneous injections of 6 mg PGE2/kg/d, 5 micrograms Ris/kg/2x/wk or their combination for 60 days each of an on/off/on cycle. PGE2 alone and in combination with Ris added the same amount of new bone in the first 60 days on period. During the 60 days off period, newly added endocortical and marrow trabecular bone disappeared in PGE2 alone treatment groups. In co-treatment group, the marrow trabeculae were only partly lost. There was no difference in total bone area between co-treatment and PGE2 alone groups after another 60 days on treatment. Our findings indicate that co-treatment was better in the maintenance of newly added endocortical and marrow trabecular bone during the off period; however, it formed less bone than PGE2 alone during the second treatment period, and ended up with the same amount of bone with both treatments.

Risedronate plus prostaglandin E2 is superior to prostaglandin E2 alone in maintaining the added bone after withdrawal in a non-growing bone site in ovariectomized rats

Effects of risedronate and prostaglandin E2 (PGE2) alone or in combination on the distal tibia, a non-growing bone site with closed epiphysis at 3 months of age, were studied in ovariectomized (ovx) rats. Six-month-old Sprague-Dawley female rats were either ovx or sham-ovx. Rats were treated immediately after operation either with risedronate (5 micrograms/kg/2x/wk), PGE2 (6 mg/kg/d), or risedronate+PGE2 for 60 days (on-groups) and followed by 60 days without treatment (off-groups). Trabecular area, width and numbers were determined in metaphyseal cancellous bone of the distal tibia. No significant bone loss or structural changes were observed in the distal tibial metaphysis after 120 days of ovx. Risedronate alone did not produce any effect on bone mass during the treatment and the withdrawal periods. PGE2 alone increased the trabecular bone mass associated with thickened trabeculae and increased trabecular numbers. However, some of the newly formed bone was lost at the end of 60 days withdrawal. Combination of risedronate and PGE2 treatment added the same amount of bone mass as PGE2 alone, and the added new bone was maintained during the 60 days withdrawal. These results indicate that treatment with risedronate and PGE2 can preserve the anabolic effect of PGE2 on bone mass for at least 60 days after treatment.

Intermittent treatment of prostaglandin E2 with risedronate is more anabolic than prostaglandin E2 alone in the proximal tibial metaphysis of ovariectomized rats

This study is designed to test how intermittent application of prostaglandin E2 (PGE2) and risedronate (Ris) alone or in combination acts on the cancellous bone mass in estrogen-deficient rats. Sprague-Dawley rats were ovariectomized (ovx) or sham-ovx'd at 6 months of age. PGE2 (6mg/kg/d), Ris (5 micrograms/kg/twice a week) or PGE2 plus Ris were given for 60 days to ovx rats immediately after operation and followed by 60 days without treatment. The drugs were then reapplied for another 60 days. Static histomorphometry was performed on the secondary spongiosa of proximal tibial metaphysis (PTM). Sixty days of ovx lost trabecular bone and number, Ris prevented ovx-induced bone loss. PGE2 added 48% extra cancellous bone, but the new bone was completely lost after 60 days of withdrawal. Another 60 days of PGE2 treatment only partially restored the trabecular bone, the bone mass was still -42% lower than that of sham-ovx controls. Co-treatment of PGE2 with Ris added the same amount of bone as PGE2 alone after the first 60 days treatment period, but differed from PGE2 alone in that the new bone lost less during the 60 days withdrawal period. Re-application of co-treatment for another 60 days added more extra bone. We concluded that intermittent co-treatment with anabolic and anti-resorptive agents is more effective than anabolic agent alone in long-term therapy of cancellous bone in estrogen-deficient rats.

Platelet-activating factor induces NF-kappa B activation through a G protein-coupled pathway

The capability of platelet-activating factor (PAF) to induce transcription factor activation was examined. In stably transfected Chinese hamster ovary cells expressing the PAF receptor (CHO-PAFR), PAF stimulation resulted in the nuclear expression of a DNA binding activity with specificity to the kappa B sequence. The p50 and p65 proteins, constituents of the prototypic nuclear factor kappa B (NF-kappa B), were identified as components of the DNA protein complexes by antipeptide antibodies in gel supershift as well as UV cross-linking experiments. PAF induced an initial decrease and subsequent increase of cytoplasmic I kappa B alpha levels, accompanied by up-regulation of the I kappa B alpha messenger RNA, a feature of NF-kappa B activation. PAF-induced kappa B binding activity was detected within 15 min after agonist stimulation, peaked at 30-40 min, and remained detectable by 2.5 h. SR 27417, a PAF receptor antagonist, blocked PAF-induced kappa B binding activity but not that induced by tumor necrosis factor-alpha (TNF alpha). Cholera toxin treatment markedly reduced PAF-induced kappa B binding activity, whereas pertussis toxin had no significant inhibitory effect. Neither of the two toxins affected the kappa B binding activity induced by TNF alpha in the same cells. In addition to the CHO-PAFR cells, PAF stimulated kappa B binding activity in the murine P388D1 macrophage and the human ASK.0 B cell lines that express endogenous PAF receptors. These results imply a potential role of PAF in the regulation of gene expression through a G protein-coupled transcription factor activation pathway.

The major protein of guayule rubber particles is a cytochrome P450. Characterization based on cDNA cloning and spectroscopic analysis of the solubilized enzyme and its reaction products

Guayule plants accumulate large quantities of rubber within parenchyma cells of their stembark tissues. This rubber is packed within discrete organelles called rubber particles composed primarily of a lipophilic, cis-polyisoprene core, small amounts of lipids, and several proteins, the most abundant of which is the M(r) 53,000 rubber particle protein (RPP). We have cloned and sequenced a full-length cDNA for RPP and show that it has 65% amino acid identity and 85% similarity to a cytochrome P450 known as allene oxide synthase (AOS), recently identified from flaxseed. RPP contains the same unusual heme-binding region and possesses a similar defective I-helix region as AOS, suggesting an equivalent biochemical function. Spectral analysis of solubilized RPP verifies it as a P450, and enzymatic assays reveal that it also metabolizes 13(S)-hydroperoxy-(9Z,11E)-octadecadienoic acid into the expected ketol fatty acids at rates comparable with flaxseed AOS. RPP is unusual in that it lacks the amino-terminal membrane anchor and the established organelle targeting sequences found on other conventional P450s. Together, these factors place RPP in the CYP74 family of P450s and establish it as the first P450 localized in rubber particles and the first eukaryotic P450 to be identified outside endoplasmic reticulum, mitochondria, or plastids.

Platelet-activating factor stimulates transcription of the heparin-binding epidermal growth factor-like growth factor in monocytes. Correlation with an increased kappa B binding activity

Human peripheral blood monocytes responded to stimulation of platelet-activating factor (PAF) with up-regulation of the transcript for heparin-binding epidermal growth factor-like growth factor (HB-EGF), a potent mitogen for vascular smooth muscle cells. This function of PAF was observed at nanomolar concentrations of the ligand, starting at 30 min after stimulation. The PAF-induced up-regulation of HB-EGF mRNA was accompanied by an increase in kappa B binding activity. These functions of PAF appeared to be mediated through the cell surface PAF receptors, as two PAF receptor antagonists, WEB 2086 and L-659,989, blocked both the up-regulation of HB-EGF mRNA and kappa B binding activity induced by PAF. The antagonists, however, had no effect on phorbol ester-induced up-regulation of HB-EGF mRNA and kappa B binding activity. Pretreatment of monocytes with pertussis toxin inhibited these functions of PAF, whereas cholera toxin had no inhibitory effect. Pyrrolidine dithiocarbamate, an inhibitor for NF-kappa B activation, markedly reduced PAF-stimulated kappa B binding activity as well as up-regulation of HB-EGF mRNA. These results suggest a potential role of PAF in HB-EGF expression and provide evidence that this stimulation may occur through increased kappa B binding activity.

Immunization with vesicular stomatitis virus nucleocapsid protein induces autoantibodies to the 60 kD Ro ribonucleoprotein particle

BACKGROUND

Systemic lupus erythematosus (SLE) is an autoimmune disorder of unknown etiology that is characterized by antibodies binding ribonucleoprotein complexes. The epitopes of SLE associated 60 kd Ro (or SSA) autoantigen share sequence with vesicular stomatitis virus (VSV) nucleocapsid (N) protein and SLE patients with anti-Ro are more likely to bind the N-protein than anti-Ro negative patients.

METHOD

We immunized New Zealand white (NZW) rabbits with purified VSV N-protein to examine the relationship between the immune response to N-protein and anti-Ro.

RESULTS

After multiple immunizations with VSV N-protein, NZW rabbits produced not only IgG antibodies to VSV N-protein but also an autoimmune response to Ro antigen. The IgG fraction of the rabbit immune serum precipitates 60 kd Ro protein as well as its associated Y RNAs. Antibodies elicited by 10 immunizations of VSV N-protein bind to at least 20 linear epitope groups on VSV N-protein and over 25 linear epitope groups on 60 kd Ro protein. These antibodies also bound 5 of the 6 shared sequences between 60 kd Ro protein and VSV N-protein.

CONCLUSIONS

Our data demonstrate that an immune response initiated towards a foreign antigen, selected on the basis of sharing short sequence similarity with the autoantigenic epitopes of an autoantigen, can lead to an autoimmune response.

Neurotrophin regulation of energy homeostasis in the central nervous system

Our hypothesis is that one cause of neuronal cell death and shrinkage in the aged central nervous system is an inability of neurons to maintain oxidant homeostasis in the face of increased levels of reactive oxygen species, decreased endogenous antioxidants, and impaired energy metabolism associated with physiological senescence, Alzheimer's, and Parkinson's diseases. Since treatment with nerve growth factor (NGF) reverses behavioral impairments in aged rats and stimulates cholinergic activity in the basal forebrain, while brain-derived neurotrophic factor appears to play a similar role in the striatum, we propose that neurotrophin-mediated cell-sparing reflects effects on oxidant homeostasis. Neurotrophins may play a similar cell-sparing role in hypoxic/ischemic injury to the nervous system, which also is mediated in part by reactive oxygen species. The degradation of one such species, H2O2, is catalyzed by catalase and glutathione peroxidase (GSH Px). The activity of the latter enzyme is dependent on glutathione reductase and the availability of NADPH for regeneration of reduced GSH. The GSH redox cycle is also regulated by enzymes of the hexose monophosphate shunt. NGF protects PC12 cells from H2O2 injury by stimulating the synthesis of antioxidant enzymes including catalase, GSH Px, glucose-6-phosphate dehydrogenase, and gamma-glutamylcysteine synthetase, the rate-limiting enzyme for glutathione synthesis. NGF also enhances recovery from the NAD+ losses occurring as a consequence of H2O2 treatment.

Role of nerve growth factor in oxidant homeostasis: glutathione metabolism

Free radicals are generated in the CNS by ongoing oxygen metabolism and biological events associated with injury and inflammation. Increased free radical levels may also persist in some chronic neurological diseases and in the aged. Nerve growth factor (NGF) is a member of the neurotrophin family of proteins that can regulate neuronal development, maintenance, and recovery from injury. NGF protected rat pheochromocytoma PC12 cells, an adrenal chromaffin-like NGF-responsive cell line, from the oxidant stress accompanying hydrogen peroxide treatment by stimulating GSH levels and enzymes in the GSH metabolism cycle and in the GSH/GSH peroxidase antioxidant redox system, a ubiquitous cellular antioxidant system. Specifically, NGF increased gamma-glutamylcysteine synthetase (GCS) activity, the rate-limiting enzyme for GSH synthesis, by 50% after 9 h and GSH levels by 100% after 24 h of treatment. NGF stimulated GSH peroxidase by 30% after 3 days and glucose 6-phosphate dehydrogenase by 50% after 2 days. Treatment with NGF and cycloheximide, or actinomycin D, which inhibit protein and RNA synthesis, respectively, blocked the NGF stimulation of GCS and glucose 6-phosphate dehydrogenase. Increased GSH levels due to NGF treatment were responsible for the significant protection of PC12 cells from hydrogen peroxide-induced stress. Pretreatment of PC12 cells with NGF for 24 h rescued cells from the toxic effects of the extracellular hydrogen peroxide generated by the glucose/glucose oxidase system but did not rescue cells that were subjected to GSH deprivation due to treatment with 10 microM L-buthionine-(S,R)-sulfoximine, an inhibitor of GCS.(ABSTRACT TRUNCATED AT 250 WORDS)

Tunable dual-wavelength continuous-wave diode laser operated at 830 nm

An external grating cavity semiconductor diode laser is made to operate simultaneously at two separately adjustable wavelengths. Lasing is restricted to the vicinity of the solitary laser 6talon resonances.

Tunable external cavity diode laser that incorporates a polarization half-wave plate

The threshold current and specttal properties of a grating tuned external cavity semiconductor laser are improved by utilizing an intracavity half-wave plate to optimize the grating feedback.