Retrograde transport of toxins across the endoplasmic reticulum membrane

Several protein toxins, including the A chain of the plant protein ricin (RTA), enter mammalian cells by endocytosis and catalytically modify cellular components to disrupt essential cellular processes. In the case of ricin, the process inhibited is protein synthesis. In order to reach their cytosolic substrates, several toxins undergo retrograde transport to the ER (endoplasmic reticulum) before translocating across the ER membrane. To achieve this export, these toxins exploit the ERAD (ER-associated protein degradation) pathway but must escape, at least in part, the normal degradative fate of ERAD substrates in order to intoxicate the cell. Toxins that translocate from the ER have an unusually low lysine content that reduces the likelihood of ubiquitination and ubiquitin-mediated proteasomal degradation. We have changed the two lysyl residues normally present in RTA to arginyl residues. Their replacement in RTA did not have a significant stabilizing effect on the protein, suggesting that the endogenous lysyl residues are not sites for ubiquitin attachment. However, when four additional lysyl residues were introduced into RTA in a way that did not compromise the activity, structure or stability of the toxin, degradation was significantly enhanced. Enhanced degradation resulted from ubiquitination that predisposed the toxin to proteasomal degradation. Treatment with the proteasomal inhibitor lactacystin increased the cytotoxicity of the lysine-enriched RTA to a level approaching that of wild-type RTA.

Catalogue of 45 reference Raman spectra of minerals concerning research in art history or archaeology, especially on corroded metals and coloured glass

Small catalogues of reference Raman spectra of interest for analysing geomaterials or biomaterials of relevance to art history or archaeology are gradually being published by different research groups. However, except for some older catalogues, they are all concerned primarily with pigments, whether inorganic or organic. Here we present for the first time a catalogue of Raman spectra of minerals that may be found in corroded metal artworks or artefacts. At the same time we include some inorganic pigments that may be found in or on stained glass. Most of the minerals analysed came from the Gallery of Mineralogy at the Muséum National d'Histoire Naturelle and most were verified by X-ray diffraction in order to augment the confidence in the mineral identity (which is not the case with many other catalogues). A number of problems encountered with mineral terminology are discussed. Comments are made on the spectra where appropriate.

An instrument to investigate temporal processing mechanisms with the multifocal ERG

The multifocal ERG technique is a powerful method of studying the function of different areas of the retina. Display systems such as the CRT, which are commonly used for stimulation, are subject to limitations such as those imposed by the raster method of scanning. This work describes a novel stimulating display using LEDs that retains the established hexagonal areas but overcomes some of the limitations of the CRT display systems. The design and construction of the instrument is described together with some preliminary results.

Instrument for scanning the angular variation of irradiance in ultraviolet phototherapy cabinets

An instrument is described that measures irradiance and the angular distribution of the intensity of ultraviolet radiation sources inside phototherapy cabinets. Failed lamps and lamps with higher or lower outputs are readily identified. The measurements are controlled from outside the cabinet, thus reducing the risk to staff from exposure to ultraviolet radiation.

Angioplasty or stent placement in the proximal common iliac artery: is protection of the contralateral side necessary?

PURPOSE

To determine if protection of the contralateral common iliac artery is necessary when performing angioplasty or stent placement in a proximal common iliac artery.

MATERIALS AND METHODS

A retrospective review of all patients undergoing endovascular treatment for unilateral common iliac artery stenosis or occlusion from 1979 to 2000 was performed. All angiograms were reviewed independently by three experienced vascular interventional radiologists who evaluated both common iliac arteries before and after angioplasty or stent placement.

RESULTS

The medical records or angiograms of 514 patients were located. Of these, complete records and angiograms were found for 175 patients who underwent proximal (within 2 cm of its origin) common iliac artery angioplasty or stent placement without treatment or protection of the contralateral common iliac artery. Treatment of proximal common iliac stenosis in 160 patients resulted in luminal compromise of the contralateral common iliac in two patients (17% and 24% reduction in luminal diameter). No contralateral compromise was noted in 15 patients treated for iliac occlusion.

CONCLUSION

The data reported herein suggest that protection of the contralateral common iliac artery during angioplasty or stent placement in a proximal common iliac artery is not mandatory.

A novel tandem quadrupole mass spectrometer allowing gaseous collisional activation and surface induced dissociation

A novel tandem quadrupole mass spectrometer is described that enables gaseous collision-induced dissociation (CID) and surface-induced dissociation (SID) experiments. The instrument consists of a commercially available triple quadrupole mass spectrometer connected to an SID region and an additional, orthogonal quadrupole mass analyser. The performance of the instrument was evaluated using leucine-enkephalin, allowing a comparison between CID and SID, and with previous reports of other SID instruments. The reproducibility of SID data was assessed by replicate determinations of the collision energy required for 50% dissociation of leucine-enkephalin; excellent precision was observed (standard deviation of 0.6 eV) though, unexpectedly, the reproducibility of the equivalent figure for CID was superior. Several peptides were analysed using SID in conjunction with liquid secondary-ion mass spectrometry or electrospray; a comparison of the fragmentation of singly protonated peptide ions and the further dissociation of y-type fragments was consistent with the equivalence of the latter fragments to protonated peptides. Few product ions attributable to high-energy cleavages of amino acid side-chains were observed. The SID properties were investigated of a series of peptides differing only in the derivatization of a cysteine residue; similar decomposition efficiencies were observed for all except the cysteic acid analogue, which demonstrated significantly more facile fragmentation.

Phase I trial of radiation dose escalation with concurrent weekly full-dose gemcitabine in patients with advanced pancreatic cancer

PURPOSE

The primary objective of this phase I trial was to determine the maximum-tolerated dose of radiation that could be delivered to the primary tumor concurrent with full-dose gemcitabine in patients with advanced pancreatic cancer.

PATIENTS AND METHODS

Thirty seven patients with unresectable (n = 34) or incompletely resected pancreatic cancer (n = 3) were treated. Gemcitabine was administered as a 30-minute intravenous infusion at a dose of 1,000 mg/m(2) on days 1, 8, and 15 of a 28-day cycle. Radiation therapy was initiated on day 1 and directed at the primary tumor alone, without prophylactic nodal coverage. The starting radiation dose was 24 Gy in 1.6-Gy fractions. Escalation was achieved by increasing the fraction size in increments of 0.2 Gy, keeping the duration of radiation constant at 3 weeks. A second cycle of gemcitabine alone was intended after a 1-week rest.

RESULTS

Two of six assessable patients experienced dose-limiting toxicity at the final planned dose level of the trial (42 Gy in 2.8-Gy fractions), one with grade 4 vomiting and one with gastric/duodenal ulceration. Two additional patients at this dose level experienced late gastrointestinal toxicity that required surgical management.

CONCLUSION

The final dose investigated (42 Gy) is not recommended for further study considering the occurrence of both acute and late toxicity. However, a phase II trial of this novel gemcitabine-based chemoradiotherapy approach, at a radiation dose of 36 Gy in 2.4-Gy fractions, is recommended on the basis of tolerance, patterns of failure, and survival data.

Aspiration of an oropharyngeal airway during nasotracheal intubation

The oropharyngeal airway (OPA) has been a remarkably safe device since its invention by Guedel in 1933. This plastic device is easily placed in the mouth and used for aiding in mask ventilation. We report a case of the aspiration of an OPA causing near total upper airway obstruction.

Chemotherapy in patients with prostate specific antigen-only disease after primary therapy for prostate carcinoma: a phase II trial of oral estramustine and oral etoposide

BACKGROUND

A Phase II study was initiated to evaluate the effectiveness of an oral regimen of etoposide and estramustine in patients with early recurrent prostate carcinoma.

METHODS

Patients with early recurrent prostate carcinoma as indicated by an increasing prostate specific antigen (PSA) level and without any evidence of metastatic disease were treated with oral etoposide 50 mg/m2/day and estramustine 15 mg/kg/day in divided doses for 21 days, followed by a 7-day rest period. Patients received a maximum of four cycles.

RESULTS

Eighteen patients were entered in this study. The median serum PSA was 3.1 (range, 0.3-30.3) at the time of entry into the trial. Sixteen patients were assessable for response. Serum PSA declined to undetectable levels in 13 patients with 2 additional patients meeting the criteria for partial response; the median duration of response was 8.5 months (range, 1-18 months). Most patients developed gastrointestinal, cardiac, or hematologic complications. Grade 3 toxicities included neutropenia (one patient), deep venous thrombosis (three patients), and chest pain (one patient). One patient developed acute myelogenous leukemia (French-American-British, acute myelogenous leukemia M5) 23 months after initiating the chemotherapy.

CONCLUSIONS

The combination of oral etoposide and oral estramustine resulted in a high rate but only a short duration of response in patients with early recurrent prostate carcinoma. The regimen was poorly tolerated, and the toxicity was significant. This regimen should not be considered standard therapy for the treatment of early recurrent prostate carcinoma, but further exploration of treatment in this setting is warranted.

Combination paclitaxel, carboplatin, and gemcitabine is an active treatment for advanced urothelial cancer

PURPOSE

To determine the efficacy and toxicity of the drug combination of carboplatin, paclitaxel, and gemcitabine in patients with advanced urothelial carcinoma.

PATIENTS AND METHODS

Patients eligible included those with advanced urothelial malignancy of any histology, no previous chemotherapy for metastatic disease, Southwest Oncology Group performance status of 2 or less, serum creatinine levels of 2 mg/dL or less, and adequate bone marrow and hepatic function. Treatment consisted of paclitaxel 200 mg/m2, carboplatin (target area under the curve = 5) on day 1, and gemcitabine 800 mg/m2 on days 1 and 8, repeated every 21 days.

RESULTS

Forty-nine patients (44 men and five women) were enrolled; the patients' median age was 63 years, and their median creatinine clearance was 78 mL/min (range, 26 to 165 mL/min). Forty-three patients had transitional cell carcinoma, and six had squamous cell carcinoma or mixed histology. Ten patients had metastases to lymph nodes only, six had locally advanced disease, four had locally recurrent disease, 24 patients had visceral metastases, and five had soft tissue metastases. Twenty-one patients had disease in one site, 16 in two sites, and 12 in three sites. A total of 272 cycles were administered (median, six cycles; range, 1 to 15 cycles). Major toxicities were grade 3 and 4 neutropenia in 17 and 19 patients, respectively; grade 3 and 4 thrombocytopenia in 15 and six patients, respectively; grade 3 and 4 anemia in 10 and two patients, respectively; grade 3 neuropathy in four patients; and diarrhea in two patients. The incidence of febrile neutropenia was 1.4%; no patients died of drug toxicity. Forty-seven of the 49 patients were assessable for response. Fifteen (32%) patients experienced a complete response, and 17 (36%) patients experienced a partial response (32 of 47 patients, 68%; 95% confidence interval, 56.27 to 82.86). Responses were seen in all sites, including 15 (68%) of 22 patients with visceral metastases. The median survival was 14.7 months, with a 1-year survival of 59%.

CONCLUSION

Combination paclitaxel, carboplatin, and gemcitabine is active; an encouraging number of patients with advanced urothelial carcinoma treated with this regimen experienced complete remission.

Elective removal of an intramyocardial bullet

A 26-year-old man had a gunshot wound in the right posterolateral aspect of the chest. A chest radiograph showed the bullet in the region of the cardiac silhouette. The patient was hemodynamically stable and had no complaints of dyspnea or abdominal pain. Echocardiography and computed tomography identified the bullet in the wall of the right ventricle. The surgical management of the injury is discussed in detail.

The auditory evoked response as an awareness monitor during anaesthesia

We investigated the relationship between the latency of the Nb wave of the auditory evoked response (AER) and periods of awareness during propofol anaesthesia. In the anaesthetic room before cardiac surgery the AER was recorded continuously in 14 patients. Awareness was measured by the ability of the patient to respond to command using the isolated forearm technique (IFT). The Nb latencies were shorter when the patients were able to respond than at loss of response (P<0.001). In six patients who repeated this transition from response to loss of response, there was a high and significant correlation between Nb latencies. None of the patients had any recollection of events after the initial induction of anaesthesia as measured by explicit and implicit memory tests. These results suggest that the Nb latency of the AER may represent an indication of awareness in individual patients, but wide inter-patient variability limits its practical usefulness. In addition, because no evidence of memory was demonstrated, even when patients were known to be awake, the relationship between AER and memory processing remains unclear.

Sheathless technique of Ash Split-Cath insertion

A novel technique for insertion of the Ash Split-Cath without a peel-away sheath to decrease the potential for air embolism is described. A retrospective review of 62 attempted Ash Split-Cath insertions at three hospitals was made. Conversion to the usual technique using a sheath was necessary in four cases, mostly because of extensive scarring from previous catheters. There was no air embolus, hematoma, or immediate catheter malfunction. The authors believe that the occurrence of air embolism during placement of Ash Split-Cath may be lessened by eliminating the use of a peel-away sheath.

Adjuvant and neoadjuvant therapy in prostate cancer

While surgery and radiation therapy remain the only definitive treatments for prostate cancer, single modality therapy has been associated with high failure rates in patients with aggressive disease. Although hormonal therapy has been effective in cases of metastatic disease, the timing of treatment with respect to definitive therapy remains controversial. This review will explore the efficacy of hormonal and chemotherapy in both the adjuvant and neoadjuvant settings. A MEDLINE search was performed to identify pertinent articles regarding both adjuvant and neoadjuvant therapy in prostate cancer. Articles of historical relevance in addition to those using large patient numbers with a randomized design were reviewed preferentially. Since hormonal therapy has been considered standard treatment at the time of cancer progression after definitive therapy, many of the randomized trials essentially compared adjuvant therapy to delayed therapy. Historical trials using adjuvant hormonal therapy have been limited due to difficulties in clinical staging, as well as toxicities attributed to the formulations used. More recently, hormonal therapy has been found to delay disease progression, increase disease-free survival, and decrease mortality when given immediately after prostatectomy or radiation therapy in selected patients. Neoadjuvant hormonal therapy can improve disease-free survival and local control when given before radiation therapy; it has only decreased positive surgical margins when given prior to radical prostatectomy. Although hormonal therapy given immediately after either radical prostatectomy or radiation therapy is highly effective, the side effects of persistent long-term use must be weighed for each patient. While the use of chemotherapy has been limited by the lack of active agents, newer combinations have shown effectiveness in patients with hormone refractory disease, raising the possibility of their use in the adjuvant setting.

Pelvic recurrences post cystectomy: current treatment strategies

Pelvic recurrence following cystectomy is a devastating problem for both physician and patient. Patients who recur locally usually do so within the first 2 years following surgery. Stage, grade, and possibly p53 status of the tumor are prognostic indicators for local failure. Patients with extensive disease at the time of diagnosis may benefit from adjuvant or neoadjuvant treatment to attempt to decrease the rate of recurrence. Treatment of patients with local failure should use a multimodality approach that includes systemic chemotherapy with or without local radiation therapy or surgery. Although rare, long-term survival can be achieved in selected patients.

Combination cisplatin, 5-fluorouracil and radiation therapy for locally advanced unresectable or medically unfit bladder cancer cases: a Southwest Oncology Group Study

PURPOSE

Patients with locally advanced bladder cancer or who are not medically fit for surgery are a therapeutic dilemma. Radiotherapy with or without single agent cisplatin has been the major therapeutic modality. A phase II Southwest Oncology Group trial investigated the efficacy and feasibility of 5-fluorouracil, cisplatin and radiation in this patient subset.

MATERIALS AND METHODS

Eligible patients had muscle invasive bladder cancer (clinical stages T2-T4) with nodal involvement at or below the level of bifurcation of the iliac vessels, were medically or surgically inoperable, or refused cystectomy. Patients underwent pretreatment cystoscopy and detailed tumor mapping, and were treated with 75 mg. /m.2 cisplatin on day 1 and 1 gm./m.2 daily, 5-fluorouracil on days 1 to 4 and definitive radiotherapy. Chemotherapy was repeated every 28 days, twice during and twice after radiation.

RESULTS

From October 1993 to April 1998, 60 patients were enrolled in study. Of the 56 eligible patients 34% had unresectable tumors, 21% were not medically fit for surgery and 45% refused cystectomy. Overall, 68% of the patients had clinical T3 tumors or greater and 22% had nodal metastasis. Treatment was completed as planned in 32 of 56 (57%) patients. The most frequent grade 3 or 4 toxicities were neutropenia, stomatitis or mucositis, diarrhea, neuropathy and nausea. There were 53 patients who were evaluable for response, although response was not determined for 18. The overall response rate was 51% (95% confidence interval [CI] 37 to 65) based on intent to treat with a complete response rate of 49% (95% CI 35 to 63). Estimated median survival of the 56 patients was 27 months (95% CI 21 to 40 months) with an overall 5-year survival of 32%. The 5-year survival of the 25 patients who refused surgery was 45%.

CONCLUSIONS

Concurrent 5-fluorouracil, cisplatin and radiation therapy is feasible. Despite a promising complete response rate, the overall 5-year survival suggests the need for more effective systemic therapy. The 5-year survival of patients who refused cystectomy suggests that this combined modality may provide another alternative to cystectomy for these patients.

One stop breast clinics--victims of their own success? A prospective audit of referrals to a specialist breast clinic

AIMS

We aimed to assess the number of unnecessary referrals to a specialist breast clinic, with special reference to urgent referrals, and to compare referrals with published guidelines for referral to these clinics.

METHODS

We carried out a prospective audit of new patient referrals from primary care to a specialist breast clinic. We assessed the total number of referrals, proportion of urgent and non-urgent referrals, proportion of unnecessary referrals according to published guidelines, waiting times for outpatient appointments and outcomes for these patients.

RESULTS

Of the total of 321 referrals, 35% were urgent. Twenty-eight per cent of urgent referrals and 37% of non-urgent were inappropriate according to published guidelines. Ten per cent of referrals had breast cancer while 90% had benign disease or no pathology.

CONCLUSIONS

There is a proliferation of guidelines (NHS, SIGN, BASO, Patients' Charter) for the organization of specialist breast clinics with the aim of providing rapid diagnosis for patients with malignant disease, or reassurance for symptomatic patients that they do not have breast cancer. However increasing numbers of patients are being referred to these clinics with minimal or no pathology, and this is not acknowledged by these guidelines. In this prospective study of referrals from primary care to a specialist breast clinic, one-third of referrals were inappropriate and this inevitably reduced the efficiency of the service provided for patients with significant symptoms.

Determination of intermediate biomarker expression levels by quantitative reverse transcription-polymerase chain reaction in oral mucosa of cancer patients treated with liarozole

Liarozole is a 1-substituted imidazole derivative that inhibits cytochrome P450 activity and increases endogenous plasma concentrations of retinoid acid (RA). We have previously demonstrated that RA down-modulates transforming growth factor (TGF)-alpha and epidermal growth factor receptor (EGFR) levels in head and neck squamous cell carcinoma by decreasing the transcription rate of these two genes. Previous reports suggest that RA receptor (RAR)-beta levels are down-modulated in head and neck cancer and are restored by RA therapy. Cellular RA-binding protein (CRABP)-II is up-regulated by RA and appears to modulate intracellular RA metabolism. In conjunction with a Phase I clinical trial, total intact RNA was extracted from oral cavity mucosa biopsied from 17 patients with advanced malignancies, before and after treatment with a 4-week course of liarozole. To analyze these limited quantities of total RNA (as little as 0.6 microg/sample), a quantitative reverse transcription-PCR assay was developed using delayed dropping of the 5' beta-actin primer to amplify the highly abundant beta-actin gene as an internal control. We used this method to determine the expression levels of TGF-alpha, EGFR, RAR-beta, and CRABP-II before and after treatment. There was a trend toward elevation of RAR-beta levels in oral mucosa after liarozole therapy (P = 0.107), whereas TGF-alpha, EGFR, and CRABP-II were not modulated by systemic liarozole treatment. These results suggest that liarozole may up-regulate RAR-beta in tissues from cancer patients and that expression levels of potential intermediate biomarkers may be determined in small tissue biopsies using a quantitative reverse transcription-PCR assay.

Oral chemotherapy in the treatment of hormone-refractory prostate cancer

Oral chemotherapy has become a major component of the treatment of advanced prostate cancer. The recognition that prostate cancer grows very slowly and must be treated continuously with active agents has led to the development of several therapeutic regimens. These regimens employ oral agents such as estramustine, cyclophosphamide, and etoposide, as they can be taken on a daily basis at home by the patients. These regimens have demonstrated activity in patients with hormone-refractory prostate cancer; declines in both prostate specific antigen and soft tissue lesions have been demonstrated.