Inhibition of neutrophil oxidative burst and granule secretion by wortmannin: potential role of MAP kinase and renaturable kinases

Exposure of neutrophils to a variety of agonists including soluble chemoattractant peptides and cytokines results in degranulation and activation of the oxidative burst (effector functions) that are required for bacterial killing. At present, the signaling pathways regulating these important functions are incompletely characterized. Mitogen-activated protein (MAP) kinases (MAPK) as well as members of a family of "renaturable kinases" are rapidly activated in neutrophils in response to diverse physiological agonists, suggesting that they may regulate cell activation. Antagonists of phosphatidyl inositol-3-(OH) kinase (PI3-kinase) such as wortmannin (Wtmn) inhibit these effector responses as well as certain of the above-mentioned kinases, leading to the suggestion that these enzymes lie downstream of PI3-kinase in the pathway regulating the oxidative burst and granule secretion. However, an apparent discrepancy exists in that, while virtually obliterating activity of PI3-kinase and the oxidase at low concentrations (ID50 < 20 nM), Wtmn has only variable inhibitory effects on MAPK even at substantially higher concentrations (75-100 nM). This raises the possibility that the inhibitory effects of Wtmn are mediated via other enzyme systems. The purpose of the current study was therefore to compare the effects of Wtmn on PI3-kinase activity and on the chemoattractant-activated kinases, and to determine the potential relationship of these pathways to microbicidal responses. In human neutrophils, both the oxidative burst and granule secretion induced by fMLP were inhibited by Wtmn but at markedly different concentrations: the oxidative burst was inhibited with an ID50 of < 5 nM while granule secretion was only partially inhibited at concentrations exceeding 75 nM. Activation of both MEK-1 and MAPK in response to fMLP was only partially inhibited by high doses of Wtmn (ID50 of > 100 nM and approximately 75 nM, respectively). In contrast, Wtmn potently inhibited fMLP-induced activation of the 63 and 69 kDa renaturable kinases (ID50 approximately 5-10 nM). We speculate that the renaturable kinases may be involved in the regulation of the oxidative burst, whereas the MAPK pathway may play a role in other neutrophil functions such as granule secretion.

Non-invasive measurements of breast tissue optical properties using frequency-domain photon migration

A multiwavelength, high bandwidth (1 GHz) frequency-domain photon migration (FDPM) instrument has been developed for quantitative, non-invasive measurements of tissue optical and physiological properties. The instrument produces 300 kHz to 1 GHz photon density waves (PDWs) in optically turbid media using a network analyser, an avalanche photodiode detector and four amplitude-modulated diode lasers (674 nm, 811 nm, 849 nm, and 956 nm). The frequency of PDW phase and amplitude is measured and compared to analytically derived model functions in order to calculate absorption, mu a, and reduced scattering, mu s, parameters. The wavelength-dependence of absorption is used to determine tissue haemoglobin concentration (total, oxy- and deoxy- forms), oxygen saturation and water concentration. We present preliminary results of non-invasive FDPM measurements obtained from normal and tumour-containing human breast tissue. Our data clearly demonstrate that physiological changes caused by the presence of small (about 1 cm diameter) palpable lesions can be detected using a handheld FDPM probe.

Comet assay studies on the activation of two diaziridinylbenzoquinones in K562 cells

Two versions of the comet assay have been used to identify the difference in the modes of action of AZQ (2,5-diaziridinyl-3,6-bis(carboethoxyamino)-1,4-benzoquinone) and BZQ (2,5-diaziridinyl-3,6-bis(ethanolamino)-1,4-benzoquinone) in human leukaemia K562 cells and a K562-derived resistant cell line, BZQR. Using the standard alkaline assay, AZQ produced dose-dependent changes in the mean comet moments from K562 cells, consistent with the formation of strand breaks. This damage was repaired over a period of 6 hr after removal of the drug. The resistant cell line, BZQR, showed much smaller changes in comet moment under identical conditions. In contrast to AZQ, BZQ did not produce any measurable strand breaks in the K562 or BZQR cells. However, the comet radiation/crosslinking assay and a fluorescence-based assay revealed that BZQ extensively cross-links DNA in K562 cells. The extent of cross-linking is greatly reduced in the resistant cell line.

Changes in growth hormone, insulin, insulinlike growth factors (IGFs), and IGF-binding protein-1 in chronic fatigue syndrome

Chronic fatigue syndrome (CFS) is characterized by severe physical and mental fatigue of central origin. Similar clinical features may occur in disorders of the hypothalamopituitary axis. The aim of the study was to determine whether patients with CFS have abnormalities of the growth hormone/insulinlike growth factor (GH-IGF) axis basally or following hypothalamic stimulation with insulin-induced hypoglycemia. We compared levels of GH, IGF-I, IGF-II, IGF-binding protein-1 (IGFBP-1), insulin, and C-peptide in nondepressed CFS patients and normal controls. We found attenuated basal levels of IGF-I (214 +/- 17 vs. 263.4 +/- 13.4 micrograms/L, p = .036) and IGF-II (420 +/- 19.8 vs. 536 +/- 24.3 micrograms/L, p = .02) in CFS patients and a reduced GH response to hypoglycemia (peak GH; 41.9 +/- 11.5 vs. 106.0 +/- 25.6 mU/L, p = .017). Insulin levels were higher (7.6 +/- 1.0 vs. 4.3 +/- 0.8 mU/L, p = .02) and IGFBP-1 levels were lower (19.7 +/- 4.6 vs. 43.2 +/- 2.7 mg/L, p = .004) in CFS patients compared with controls. This study provides preliminary data abnormalities of the GH-IGF axis in CFS. It is not apparent whether these changes are components of a primary pathological process or are acquired secondary to behavioral aspects of CFS such as reduced physical activity.

Unilateral recurrent laryngeal nerve paralysis: the importance of "preoperative" voice therapy

This preliminary retrospective study of 19 female patients and 22 male patients with unilateral recurrent nerve lesions demonstrated the promise of objective measurements in predicting the need for surgery, the efficacy of voice therapy in ameliorating vocal symptoms, and the effects of therapy in conjunction with surgery. Sixty-eight percent (68%) of the female patients and 64% of the male patients did not elect to have surgery. Outcome satisfaction of nonsurgical and surgical patients appeared to be similar. The data from this study support the importance of preoperative therapy for patients with unilateral vocal fold paralysis.

Abdominal metastases of infiltrating lobular breast carcinoma: CT and fluoroscopic imaging findings

Infiltrating lobular carcinoma accounts for only a small fraction of breast carcinomas, with most patients having infiltrating ductal carcinoma. The metastatic patterns of ductal and lobular carcinoma have been shown to be markedly different. Infiltrating lobular carcinoma metastasizes significantly more often to the gastrointestinal tract, pelvic organs, peritoneum/retroperitoneum, and urinary tract than does infiltrating ductal carcinoma. This point has significance for follow-up, the diagnosis of abdominal symptoms, and the therapeutic options for these patients. This article illustrates the broad spectrum of abdominal metastases from lobular breast carcinoma that may be detected with computed tomographic and fluoroscopic examinations, and it describes the role of imaging in the diagnosis of metastatic disease in these patients.

Cross-linking and sequence specific alkylation of DNA by aziridinyl quinones. 2. Structure requirements for sequence selectivity

The cytotoxicities and DNA sequence selectivity for guanine-N7 alkylation of 22 mono- and disubstituted 2,5-diaziridinyl-1,4-benzoquinones have been investigated. Several quinones produced patterns of alkylation following reduction with a selectivity for 5'-TGC-3' sequences. This sequence selectivity appeared to be dependent only on the presence of a hydrogen in position-6 of the quinone. A computer model, based on published crystallographic data, was used to explain this selectivity. The sequence selective quinones were generally more cytotoxic that the quinones which reacted randomly.

Regulation of Src homology 2-containing tyrosine phosphatase 1 during activation of human neutrophils. Role of protein kinase C

The tyrosine phosphorylation of several proteins induced in neutrophils by soluble and particulate stimuli is thought to be crucial for initiating antimicrobial responses. Although activation of tyrosine kinases is thought to mediate this event, the role of tyrosine phosphatases in the initiation and modulation of neutrophil responses remains largely undefined. We investigated the role of Src homology 2-containing tyrosine phosphatase 1 (SHP-1; also known as protein tyrosine phosphatase 1C (PTP1C), hematopoetic cell phosphatase, PTP-N6, and SHPTP-1), a phosphatase expressed primarily in hemopoietic cells, in the activation of human neutrophils. SHP-1 mRNA and protein were detected in these cells, and the enzyme was found to be predominantly localized to the cytosol in unstimulated cells. Following stimulation with neutrophil agonists such as phorbol ester, chemotactic peptide, or opsonized zymosan, a fraction of the phosphatase redistributed to the cytoskeleton. Agonist treatment also induced significant decreases (30-60%) in SHP-1 activity, which correlated temporally with increases in the cellular phosphotyrosine content. Phosphorylation of SHP-1 on serine residues was associated with the inhibition of its enzymatic activity, suggesting a causal relationship. Accordingly, both the agonist-evoked phosphorylation of SHP-1 and the inhibition of its catalytic activity were blocked by treatment with bisindolylmaleimide I, a potent and specific inhibitor of protein kinase C (PKC) activity. Immunoprecipitated SHP-1 was found to be phosphorylated efficiently by purified PKC in vitro. Such phosphorylation also caused a decrease in the phosphatase activity of SHP-1. Together, these data suggest that inhibition of SHP-1 by PKC-mediated serine phosphorylation plays a role in facilitating the accumulation of tyrosine-phosphorylated proteins following neutrophil stimulation. These findings provide a new link between the PKC and tyrosine phosphorylation branches of the signaling cascade that triggers antimicrobial responses in human neutrophils.

Imaging inflammatory diseases with neutrophil-specific technetium-99m-labeled monoclonal antibody anti-SSEA-1

Imaging inflammatory diseases with a 99mTc-labeled neutrophil-specific agent that can be injected directly intravenously continues to be a challenge.

METHODS

The antibody, anti-SSEA-1, chosen from studies of 10 neutrophil-specific MAbs, recognizes CD-15 antigens (5.1 x 10(5)/human PMN) with a high association constant (kd = 10(-11) M). One hundred micrograms of MAb labeled with 10-20 mCi 99mTc either by a direct or DTPA conjugation method were injected intravenously into 12 patients (9 men, 3 women, aged 19-48 yr) with clinical evidence of ongoing inflammatory processes. Vital signs of all patients were recorded before and up to 3 hr following administration of the MAb. HAMA was determined in two patients. Anterior and posterior spot views and whole-body images were obtained. All patients except one underwent biopsy, US or CT examinations and/or surgical procedures. Blood samples collected from five patients were analyzed. In nine patients, quantitative organ distribution was determined and radiation dosimetry was calculated.

RESULTS

Labeling yields were 94.8% +/- 1.4% and 95.8% +/- 3.5%, respectively. All patients had unequivocally positive images within 3 hr of the MAb injection. Eleven of these were confirmed by other modalities. One patient recovered on antibiotics and was sent home without surgery or other procedures. The lack of radioactivity in the thyroid or gastrointestinal tract indicated that the in vivo stability of the agent was excellent. At 3 hr postinjection, bladder activity in six patients was 1.3% +/- 0.4% of the administered dose. At this time, splenic uptake (7.7% +/- 1.0% ad. dose) and red marrow uptake (14 +/- 1.8%) were lower than those of 111In-WBC. At 49.0% +/- 3.2% administrated dose, liver uptake was at the upper limit with 111In-WBC uptake. Renal uptake was only 2.4% +/- 0.03% administered dose. At 2 hr postinjection, 14% to 51% of the radioactivity was associated with PMN. Radioactivity with lymphocytes was 0.7% to 10.9%, 1.2% to 4.3% with platelets and 1.1% to 2.4% with RBC. No HAMA were detectable in either patient, and no adverse reaction was detectable in any patient.

CONCLUSION

Results are highly encouaging and have prompted us to prepare a kit for instant preparation and to initiate clinical trials.

Impact of endoscopic ultrasound with fine-needle aspiration on the surgical management of pancreatic cancer

BACKGROUND

Endoscopic ultrasound (EUS) with EUS-guided fine-needle aspiration (EUS-FNA) enables one to visualize the pancreas and surrounding structures and can provide access for FNA of those structures that appear suspicious for tumor.

PATIENTS AND METHODS

From 1993 to 1995, 50 patients suspected of having pancreatic cancer underwent EUS/EUS-FNA and abdominal computed tomography (CT). Malignancy was found in 30 (60%) cases, which included 24 (48%) pancreatic adenocarcinomas.

RESULTS

Endoscopic ultrasound/EUS-FNA identified 26 of the 30 malignancies (85%) and 21 of the 24 pancreatic adenocarcinomas (88%), with no false positives. Thirteen of the 24 pancreatic cancer patients had lymph nodes that were sampled with EUS/EUS-FNA. Seven of these 13 patients (62%) were found to have metastatic spread to lymph nodes. Operations were performed on 11 of the pancreatic cancer patients. Of these 11, the 5 that were predicted to be resectable by EUS/EUS-FNA underwent successful resection. Of the 6 predicted to be unresectable, 5 had palliative biliary bypasses, and 1 had a grossly positive margin of resection.

CONCLUSIONS

Endoscopic ultrasound/EUS-FNA can identify patients for curative surgical resection. It can also preoperatively identify patients with regional nodal disease for inclusion in appropriately designed clinical trials.

IPDAS: a novel technology brings new benefits when applied to naproxen sodium

The Intestinal Protective Drug Absorption System (IPDAS) is a new oral drug delivery approach that is applicable to gastrointestinal (GI) irritant drugs, including the nonsteroidal anti-inflammatory drug (NSAID) class. Although naproxen, as the free acid or the sodium salt, has pharmacokinetic characteristics that are consistent with once-daily dosing, the GI irritant and ulcerogenic potential associated with a large bolus dose of naproxen precludes safe use of an immediate-release form. In addition, the desired pharmacodynamic activity of a once-daily dosage form of naproxen requires rapidly available naproxen for a prompt onset of analgesic activity, as well as a prolonged phase of absorption to provide 24-hour analgesic/anti-inflammatory activity. Naprelan (naproxen sodium; Wyeth-Ayerst Laboratories, Philadelphia, Pennsylvania) controlled-release tablets are a unique dosage form designed to achieve the desired features of such a once-daily presentation. Through a series of in vivo studies, the pharmaceutical design features of the product have been confirmed in humans using a combination of imaging and pharmacokinetic characterization. In addition, the potential for limiting any undesirable GI adverse events has been supported by evaluation of the GI toxicity of Naprelan in specialized animal toxicity studies. Naprelan exhibited in vivo performance characteristics that support the hypothesis that, as a once-daily dosage form, it may demonstrate safety and efficacy advantages in clinical evaluation.

The autoxidation of the reduced forms of EO9

The properties of the semiquinone radical from [3-hydroxy-5-aziridinyl-1-methyl-2-(1H-indole-4,7-indi one)-prop-beta-en-alpha-ol], EO9, have been studied using pulse-radiolysis techniques. The reduction potential of the semiquinone of EO9 at pH7.4, E(EO9/EO9-), is -253 +/- 6 mV and hence this quinone can be readily reduced by one-electron reducing enzymes such as cytochrome P450 reductase and xanthine oxidase. However, the radical is unstable in the presence of oxygen (k = 1.3 +/- 0.15 x 10(8) M-1 s-1). The semiquinone radicals and the hydroquinone are in equilibrium although the formation of the hydroquinone is favoured t physiologically relevant pH. The hydroquinone of EO9 is also unstable in the presence of oxygen and it is predicted that in fully aerated solutions, its half life is 1.5 +/- 0.3 seconds. These results are discussed in view of the selective cytotoxicity of EO9 and its ability to undergo bioreductive activation by one-electron reducing enzymes and DT-diaphorase.

Acute-phase responses to cardiopulmonary bypass in children weighing less than 10 kilograms

BACKGROUND

Cardiopulmonary bypass induces a systemic inflammatory response. This study investigated, in a pediatric population, cytokine-induced responses and their potential modification by intraoperative steroid administration.

METHODS

Markers of the acute-phase response were measured perioperatively in 24 children weighing less than 10 kg undergoing cardiac operations. Those having operations with cardiopulmonary bypass were randomized to receive either no steroid (group I, n = 8) or 10 mg/kg methylprednisolone in the pump prime (group II, n = 10); patients undergoing nonbypass procedures were controls (group III, n = 6).

RESULTS

In all groups, plasma interleukin-6 level was elevated (p < 0.01) above baseline throughout the post-operative period, peaking earlier in group I. Levels of C-reactive protein peaked at 48 hours, and postoperative core temperature was raised in all groups. Levels of interleukin-6 from 2 to 6 hours and C-reactive protein at 24 hours postoperatively were greater (p < 0.05) in group I than in group II. Maximum interleukin-6 level, C-reactive protein level, and temperature were all significantly greater in group I than in group III. Maximum interleukin-6 level correlated with maximum C-reactive protein level in group I only (rs = 0.76; p < 0.05) and showed no association with temperature. Duration of bypass did not correlate with levels of interleukin-6.

CONCLUSIONS

This study demonstrated a marked acute-phase response to operation; the greater response to procedures with cardiopulmonary bypass was abrogated by intraoperative steroid administration. The importance of interleukin-6 as an inducer of acute phase proteins after bypass is supported by its association with C-reactive protein levels, but other factors must be important in the induction of pyrexia.

New breast-feeding standards used as tool of change

This paper describes a breast-feeding standard that was set and audited in the early stages of a trust's midwifery project five years ago. It describes the audit cycle as an example of how care can be improved through standard setting and as a way of highlighting issues for consideration.