Quality of vision clinical outcomes for a new fully-refractive extended depth of focus Intraocular Lens

BACKGROUND/OBJECTIVE

To evaluate the visual performance of a purely refractive extended depth of focus (EDF) intraocular lens (IOL).

SUBJECTS/METHODS

A prospective, multi-center, randomized, subject/evaluator-masked study. Subjects were bilaterally implanted with the EDF test (Model ZEN00V, N = 60) or an enhanced monofocal control (Model ICB00, N = 57) IOL. Monocular corrected distance (CDVA), intermediate (DCIVA), near acuities (DCNVA) and patient reported visual symptoms were evaluated at the 6-month visit. Monocular mesopic contrast sensitivity (CS) and depth of focus (DOF) testing were assessed at 3 months.

RESULTS

CDVA (Mean ± SD) was -0.06 ± 0.08 for test and -0.05 ± 0.08 logMAR for control groups. DCIVA was 0.13 ± 0.08 for test and 0.18 ± 0.14 logMAR for control groups (p = 0.0127). DCNVA was 0.37 ± 0.10 for test and 0.43 ± 0.16 logMAR for control groups (p = 0.0137). Test lens was statistically superior for intermediate and near. Overall, 91.7% (halos), 95.0% (starbursts) and 95.0% (glare) of test lens patients reported that they did not experience, were not bothered, or were slightly bothered by specific visual symptoms, compared to 98.2%, 100% and 96.5% in the control group. The DOF range over which monocular visual acuity was 0.20 logMAR or better was -1.6 D for the test lens. Mesopic CS was comparable between both groups, falling within 0.11 log units for all measured cycles per degree with and without glare.

CONCLUSION

The EDF IOL demonstrated extended range of vision and statistically superior intermediate and near performance compared to the monofocal IOL. Distance visual acuity, contrast sensitivity and dysphotopsia profile were similar to the monofocal IOL.

Oxygen-supplemented and topography-guided epithelium-on corneal crosslinking with pulsed irradiation for progressive keratoconus

PURPOSE

To investigate the effects of customized topography-guided epithelium-on crosslinking (epi-on CXL) with oxygen supplementation on procedural efficacy and corrected distance visual acuity (CDVA) in patients with progressive keratoconus (KC) at 1 year.

SETTING

Private eye clinic, Brisbane, Australia.

DESIGN

Retrospective, single-center, nonrandomized case series.

METHODS

Topography-guided epi-on CXL using the Mosaic system was performed on patients with progressive KC. Oxygen goggles; transepithelial riboflavin; and pulsed, high UV-A irradiance (1 second on, 1 second off; 30 mW/cm2) were applied to enhance oxygen kinetics and bioavailabilities of riboflavin and UV-A. Guided by baseline topography, a higher UV-A dose (15 J/cm2) was applied to the area of steepest anterior curvature with decreasing fluence (as low as 7.2 J/cm2) toward the outer 9 mm. Postoperative CDVA and maximum keratometry (Kmax) were evaluated.

RESULTS

102 eyes (80 patients) were followed for 11.5 ± 4.8 months. At the latest follow-up, mean CDVA (logMAR), mean K, and Kmax (diopters [D]) improved from 0.18 ± 0.28, 46.2 ± 3.8, and 53.0 ± 5.67 at baseline to 0.07 ± 0.18, 45.8 ± 3.7, and 51.9 ± 5.56, respectively (P < .001). 3 eyes (3%) lost more than 1 CDVA line, and another 3 eyes (3%) had increased Kmax greater than 2 D. 43 eyes were followed for at least 12 months (n = 43): mean CDVA, mean K, and Kmax improved from 0.19 ± 0.33 logMAR, 46.5 ± 3.5 D, and 53.6 ± 5.67 D to 0.07 ± 0.17 logMAR, 46.0 ± 3.5 D, and 52.33 ± 5.49 D, respectively (P ≤ .002). No complications were observed.

CONCLUSIONS

Tailoring oxygen-supplemented epi-on CXL with differential UV-A energy distributions, guided by baseline topography, in patients with KC seems to be safe and effective. At 1 year, study reports sustained improved CDVA and corneal stabilization.

Oxygen-supplemented transepithelial-accelerated corneal crosslinking with pulsed irradiation for progressive keratoconus: 1 year outcomes

PURPOSE

To investigate the effects of combining oxygen supplementation with enhanced UV-A light and increased riboflavin permeability in improving the efficacy of epithelium-on crosslinking (epi-on CXL).

SETTING

Private eye clinic in Brisbane, Queensland, Australia.

DESIGN

Retrospective single-center nonrandomized uncontrolled longitudinal cohort case series.

METHODS

Transepithelial CXL was performed on keratoconic eyes. Applications of an oxygen goggle and pulsed UV-A irradiation (1 second on, 1 second off) were used to enhance oxygen kinetics during epi-on CXL. Additional procedural modifications included the use of benzalkonium chloride and high UV-A irradiance level (30 mW/cm 2 ) to improve the stromal bioavailability of riboflavin and UV-A. The main efficacy outcomes were the changes in mean corrected distance visual acuity (CDVA) and safety over 12 months. Additional refractive and keratometry (K) outcomes were also observed.

RESULTS

53 eyes (38 patients) were included in this study. 12 months postoperatively, mean CDVA improved from a mean of 0.18 ± 0.2 at baseline to 0.07 ± 0.1 logMAR ( P < .0001). No statistically significant change was observed in maximum K (Kmax) and mean K, which were respectively 51.7 ± 5.8 diopters (D) and 46.4 ± 3.85 D at baseline and 51.2 ± 5.7 D ( P = .152) and 46.0 ± 3.84 D ( P = .06) 12 months postoperatively. Only 3 eyes experienced an increase of more than 2 D in Kmax; however, none of these eyes experienced a CDVA loss. There were no reported infections, corneal scarring, or other severe adverse effects.

CONCLUSIONS

Performing supplemental oxygen epi-on CXL with accelerated, pulsed UV-A irradiation in conjunction with riboflavin permeability enhancers resulted in improved CDVA ( P < .0001) and stable keratometry up to 12 months postoperatively with a good safety profile.

The Hydrus Microstent in Pseudophakic Patients With Medically Refractory Open-angle Glaucoma

PURPOSE

Minimally invasive glaucoma surgery (MIGS) is an emerging therapy for glaucoma. The Hydrus Microstent is a MIGS device that stents Schlemm's canal, thereby increasing aqueous drainage and lowering intraocular pressure (IOP). This article describes the use of the microstent in pseudophakic patients with medically refractory glaucoma, a patient population undocumented in the current literature.

PATIENTS AND METHODS

We present a retrospective case series of 11 pseudophakic eyes using 3 or more pressure lowering medications daily for open-angle glaucoma who underwent Hydrus Microstent insertion. Patients were followed up at 1, 3, 6, 12, 24, 36, 48, and 60 months postoperatively and assessed for reductions in IOP and medication burden.

RESULTS

At intervals 12 and 24 months, medication burden reduced by 75.6% at both junctures, and IOP reduced by 43.8% and 34.1%. Complications included 4 hyphaemas and 1 corneal epithelial defect, each of which resolved.

DISCUSSION

This case series demonstrated effective pressure and medication reduction in medically refractory open-angle glaucoma patients using the Hydrus Microstent. Use of this device in this population is thus far undocumented in the literature and may represent an optimal therapeutic modality in the future.

Clinical Evaluation of a Novel Preloaded Intraocular Lens Delivery System During Routine Cataract Surgery

Purpose

To evaluate the clinical handleability and acceptability of a novel preloaded intraocular lens (IOL) delivery system for implantation of the TECNIS ZCB00 IOL (Johnson & Johnson Surgical Vision, Inc., Santa Ana, CA, USA) during routine small-incision cataract surgery.

Subjects and Methods

In this prospective, open-label, noncomparative, unilateral or bilateral, multicenter study, adult subjects with unilateral or bilateral cataracts scheduled for IOL implantation were enrolled. Surgeons and surgical technicians completed per-eye day-of-surgery and end-of-surgical-day questionnaires. The primary endpoint of the study was the rate of acceptable overall clinical performance of the preloaded IOL delivery system. Other endpoints included additional responses from the questionnaires, preimplantation incision size, and safety.

Results

The study included 91 eyes that underwent cataract surgery and IOL implantation using the preloaded delivery system and were available for the 1-day postoperative visit. Five surgeons and 14 surgical technicians from four investigational sites participated in the study. The rate of acceptable overall clinical performance was 100% (91/91) of eyes, with most responses (78/91; 85.7%) being the highest possible rating of 5 (very satisfied). Favorable responses by most surgeons and surgical technicians regarding additional endpoints further highlighted the handleability and acceptability of the preloaded delivery system. No ocular adverse events or lens findings (ie, no cases of IOL instability, haptic breakage, IOL marking, or crimping) were reported.

Conclusion

The results of this study demonstrated that this preloaded IOL delivery system was safe and effective during routine small-incision cataract surgery.

Trial Registration

German Clinical Trials Register identifier, DRKS00014757.

Imaging the lipid-phase-dependent pore formation of equinatoxin II in droplet interface bilayers

Using phase-separated droplet interface bilayers, we observe membrane binding and pore formation of a eukaryotic cytolysin, Equinatoxin II (EqtII). EqtII activity is known to depend on the presence of sphingomyelin in the target membrane and is enhanced by lipid phase separation. By imaging the ionic flux through individual pores in vitro, we observe that EqtII pores form predominantly within the liquid-disordered phase. We observe preferential binding of labeled EqtII at liquid-ordered/liquid-disordered domain boundaries before it accumulates in the liquid-disordered phase.

Evaluation of the cytotoxicity of the indoloquinone eo9 in a human colon adenocarcinoma model

The development of anti-cancer drugs that are active in regions of low oxygen tension within solid tumours is an important goal for the chemotherapist. Equally as important is the utilization of appropriate model systems for their selection. This study describes morphological characteristics of multicellular spheroids derived from the human carcinoma cell line, DLD-1 and the evaluation of an investigational bioreductive alkylating agent (EO9) in monolayers, spheroids and xenografts. Histological examination of the cell line in vitro revealed typical features of glandular epithelium with microvilli on free surfaces and cell junction formation. Spheroids had acina formation, extensive necrosis and hypoxia at the time of treatment suggesting the spheroid model to be more representative of solid tumour geometry than more conventional in vitro test systems. EO9 is active against this cell line grown as a monolayer (IC50=0.76 mug ml-1) but is inactive against spheroids or established solid tumours in vivo. The suitability of this system for evaluating bioreductive drugs is discussed.

The red eye in contact lens wearers--a high risk presentation

Sore eyes are a common primary care presentation. Within this group, contact lens wearers are at risk of developing serious complications and should be identified accordingly. Contact lens associated bacterial keratitis is a sight pathogen from corneal scrapings in patients who wear contact lenses and develop this condition. Pseudomonas is not sensitive to chloramphenicol and as such, will not respond to the most commonly prescribed antibiotic for sore eyes. These patients require urgent referral for corneal scrapings to allow culture and sensitivity, which will direct treatment.

Photofragment slice imaging studies of pyrrole and the Xe⋯pyrrole cluster

The photolysis of pyrrole has been studied in a molecular beam at wavelengths of 250, 240, and 193.3 nm, using two different carrier gases, He and Xe. A broad bimodal distribution of H-atom fragment velocities has been observed at all wavelengths. Near threshold at both 240 and 250 nm, sharp features have been observed in the fast part of the H-atom distribution. Under appropriate molecular beam conditions, the entire H-atom loss signal from the photolysis of pyrrole at both 240 and 250 nm (including the sharp features) disappear when using Xe as opposed to He as the carrier gas. We attribute this phenomenon to cluster formation between Xe and pyrrole, and this assumption is supported by the observation of resonance enhanced multiphoton ionization spectra for the (Xe...pyrrole) cluster followed by photofragmentation of the nascent cation cluster. Ab initio calculations are presented for the ground states of the neutral and cationic (Xe...pyrrole) clusters as a means of understanding their structural and energetic properties.

A phase II study of docetaxel (D) plus imatinib (I) in patients with previously treated non-small cell lung cancer

18200

Background: Docetaxel(D) has been shown to improve overall survival in pts with previously treated NSCLC. Pre-clinical data suggest synergistic activity with the combination of D and I. Paul Matthew; et al demonstrated the safety of this combination in pts with prostate cancer. Methods: This is a Phase II study of the combination of D and I in prev tx NSCLC to determine response rate, toxicity and assess overall survival. Pts must have received at least 1 prior regimen and have an ECOG PS of 2 or less. Prior tx with D was allowed. D was admin at 30 mg/m2 on a weekly schedule for 3 weeks followed by 1 week rest. I was admin at a starting dose of 600 mg/day throughout the study. Results: A total of 10 pts were enrolled. Seven male and 3 female with a median age of 66 years (range 58 - 74). A total of 26 cycles were delivered to 10 pts (mean = 3). Responses included 1 PR/3SD/2PD/4NE. One pt with a PR responded after cycle 4 but progressed after cycle 6. One pt maintained SD for 21 wks then expired due to an unrelated PE (h/o peripheral vascular disease). Grade 4 toxicity included periorbital edema (1 pt), pneumonia (2 pts), diarrhea (1 pt), dehydration (1 pt), dyspnea (1pt), anorexia (1 pt), pleural effusion (1 pt), and neutropenia (2 pts). Grade 3 toxicity included hyponatremia (1 pt), renal failure (1 pt), hypotension (2 pts), mental status changes (1 pt), anorexia (1 pt), azotemia (1 pt), dyspnea (1 pt), herpetic esophageal ulcer (1 pt), pneumonia (1 pt), neutropenia (2 pts), weakness & fatigue (1 pt), and anemia (1 pt). Four of 10 pts received only 1 cycle. (Three of those 4 suffered a fatal adverse event during cycle 1, not felt to be treatment related. The fourth developed herpetic esophageal lesions and was taken off study prior to tumor assessment.) Conclusions: The study was closed before the initial planned pts were enrolled due to low activity and unexpected high tox. Only 1 of 10 pts achieved a PR. Stable disease was observed in 3 pts but was of short duration in 2 of the 3. Despite supportive treatment, nausea, vomiting, diarrhea, and anorexia were difficult to control. Hematologic toxicity was encouragingly infrequent with only 2 pts experiencing Grade 4 neutropenia. Alternative dosing schedules would be recommended before pursuing this combination in NSCLC pts. Study supported by a grant from Novartis.

No significant financial relationships to disclose.

The Role of * Excited States in the Photodissociation of Heteroaromatic Molecules

High-resolution measurements of the kinetic energies of hydrogen atom fragments formed during ultraviolet photolysis of imidazole, pyrrole, and phenol in the gas phase confirm that N(O)-H bond fission is an important nonradiative decay process from their respective 1pisigma* excited states. The measurements also reveal that the respective cofragments (imidazolyl, pyrrolyl, and phenoxyl) are formed in very limited subsets of their available vibrational states. Identification of these product states yields uniquely detailed insights into the vibronic couplings involved in the photoinduced evolution from parent molecule to ultimate fragments.

High resolution photofragment translational spectroscopy of the near UV photolysis of indole: Dissociation via the1πσ* state

The fragmentation dynamics of indole molecules following excitation at 193.3 nm, and at a number of different wavelengths in the range 240 < or = lambda(phot) < or = 286 nm, have been investigated by H Rydberg atom photofragment translational spectroscopy. The longer wavelength measurements have been complemented by measurements of excitation spectra for forming parent and fragment ions by two (or more) photon ionisation processes. Analysis identifies at least three distinct contributions to the observed H atom yield, two of which are attributable to dissociation of indole following radiationless transfer from the 1pi pi* excited states (traditionally labelled 1L(b) and 1L(a)) prepared by UV single photon absorption. The structured channel evident in total kinetic energy release (TKER) spectra recorded at lambda(phot) < or = 263 nm is rationalised in terms of N-H bond fission following initial pi* <-- pi excitation and subsequent coupling to the 1pi sigma* potential energy surface via a conical intersection between the respective surfaces--thereby validating recent theoretical predictions regarding the importance of this process (Sobolewski et al., Phys. Chem. Chem. Phys., 2002, 4, 1093). Analysis provides an upper limit for the N-H bond strength in indole: D0(H-indolyl) < or = 31,900 cm(-1). Unimolecular decay of highly vibrationally excited ground state molecules formed by internal conversion from the initially prepared 1pi pi* states is a source of (slow) H atoms but their contribution to the TKER spectra measured in the present work is dwarfed by that from H atoms generated by one or more (unintended but unavoidable) multiphoton processes.

Quantification of skeletal kinetic indices in Paget's disease using dynamic 18F-fluoride positron emission tomography

The purpose of this study was to quantify indices of regional bone metabolism in Paget's disease and to compare these indices with normal bone using dynamic 18F-fluoride positron emission tomography (PET). Seven patients with vertebral Paget's disease had 1 h dynamic 18F-fluoride PET scans performed. The scans included a diseased vertebra and an adjacent normal vertebra. Arterial plasma input functions were also measured. A three-compartment, four-parameter model was used with nonlinear regression analysis to estimate bone kinetic variables. Compared with normal bone, pagetic bone demonstrated higher values of plasma clearance to bone mineral (Ki; 1.03 x 10(-1) vs. 0.36 x 10(-1) ml/min per milliliter; p = 0.018) and clearance to total bone tissue (K1; 2.38 x 10(-1) vs. 1.25 x 10(-1) ml/min per milliliter; p = 0.018), reflecting increased mineralization and blood flow, respectively. Release of 18F-fluoride from bone mineral (k4) was lower in pagetic bone (p = 0.022), suggesting tighter binding of 18F-fluoride to bone mineral. The notional volume of the extravascular bone compartment (K1/k2) was greater in pagetic bone (p = 0.018). Although the unidirectional extraction efficiency from the extravascular space to bone mineral (Ki/K1) was greater in pagetic bone (p = 0.018), a lower pagetic value of k2 (p = 0.028), describing the rate of transfer from the bone extravascular compartment to plasma, suggests that the 18F-fluoride that enters the relatively fibrotic marrow space of pagetic bone may be less accessible for return to plasma. These findings confirm some of the known pathophysiology of Paget's disease, introduce some new observations, and show how dynamic 18F-fluoride PET may be of value in the measurement of regional metabolic parameters in focal bone disorders.

Are restrictions to behaviour of patients required following fluorine-18 fluorodeoxyglucose positron emission tomographic studies?

The clinical use of positron emission tomography (PET) is expanding rapidly in most European countries. It is likely therefore that patients receiving the tracer fluorine-18 fluorodeoxyglucose (18FDG) will be discharged to come into contact with family members, members of the public and ward staff. There are few direct measurements on which to base any recommendations with regard to radiation protection, and so we have measured the dose rates from patients undergoing clinical PET examinations in our centre. Seventy-five patients who underwent whole-body and brain 18FDG PET examinations were studied. Dose rates were measured at 0.1, 0.5, 1.0 and 2.0 m from the mid thorax on leaving the department. The median administered activity was 323 MBq with a 95th percentile value of 360 MBq. The median dose rates measured at the four distances were 90.0, 35.0, 14.0 and 5.0 microSv h-1 (the median dose rates per unit administered activity at 2 h post injection were 0.31, 0.11, 0.04 and 0.02 microSv h-1 MBq-1). The corresponding 95th percentile values were 174.0, 69.0, 29.0 and 7.5 microSv h-1 (0.43, 0.2, 0.08 and 0.03 microSv h-1 MBq-1). A number of social situations were modelled and an annual dose limit of 1 mSv was used to determine whether restrictive behavioural advice was required. In the case of nursing staff on wards a value of 6 mSv was regarded as the annual limit, which translates to a daily limit of approximately 24 microSv. There is no need for restrictive advice for patients travelling by public or private transport when they leave the department 2 h after the administration of 18FDG. Similarly, there is no need for restrictive advice with regard to their contact with partners, work colleagues or children of any age, although it should be stressed that children should not accompany the patient to the scanning department. The only possible area of concern is in an oncology ward, where patients may be regularly referred for PET investigations and other high activity radionuclide studies and are partially helpless. Even in this area, however, it is unlikely that a nurse would receive a daily dose of more than 24 microSv. We conclude that there is no need for restrictive advice for patients undergoing 18FDG PET studies given the current administered activities.

Noninvasive monitoring of tumor metabolism using fluorodeoxyglucose and positron emission tomography in colorectal cancer liver metastases: correlation with tumor response to fluorouracil

PURPOSE

To investigate and measure the metabolism of colorectal cancer liver metastases using 18F-fluorodeoxyglucose positron emission tomography (FDG PET), before and during the first month of chemotherapy. The findings were compared with tumor outcome conventionally assessed using changes in tumor size.

PATIENTS AND METHODS

Patients with colorectal cancer liver metastases were treated with fluorouracil (5FU) as a protracted venous infusion (300 mg/m2/d), with or without interferon-alpha 2b for two 10-week blocks separated by a 2-week break. Before and at 1 to 2 and 4 to 5 weeks on treatment, FDG PET scans were performed. Patients fasted, were injected intravenously with FDG (50 to 100 MBq), and scanned using a large-area positron camera; the image data was processed such that regions of interest could be identified. The results were expressed as a ratio of FDG uptake in the tumor and normal liver (T:L) or as a semiquantitative standardized uptake value (SUV). These measures were compared with the tumor dimensions measured on a computed tomographic (CT) scan performed at 12 weeks from commencement of chemotherapy.

RESULTS

Twenty patients were studied; however, two did not have assessable liver metastases. Objective partial responses were observed in 11 of 18 patients. A total of 27 metastatic lesions were assessable. Pretreatment T:L ratios and SUVs did not correlate with tumor response, although response was associated with lower 1- to 2-week (1.84 v 2.17; t=2.667; P < .02) and 4- to 5-week (1.36 v 2.28; t=5.02; P < .001) T:L ratios, and 4- to 5-week (3.57 v 4.95; t=2.492; P < .05) SUVs. Expressed as a percent of the baseline values of the T:L ratio, responding lesions had a greater reduction in metabolism (67% v 99%; t=7.53; P < .001). The 4- to 5-week T:L ratio was able to discriminate response from nonresponse both in a lesion-by-lesion and overall patient response assessment (sensitivity 100%; specificity 90% and 75%, respectively).

CONCLUSION

Positron emission tomography used to evaluate the uptake of FDG in tumors yields data that correlate with the antitumor effect of chemotherapy in patients with liver metastases from colorectal cancer.

Blood flow measurement in extremity soft tissue sarcoma with technetium-99m hexamethyl-propyleneamineoxime and single photon emission computed tomography

Blood flow measurements were made in 28 patients with soft tissue sarcoma of the extremities to investigate the prognostic significance of tumour vascularity. Four patients with benign tumours also underwent blood flow measurement. Mean and maximum tumour blood flow was calculated from technetium-99m hexamethyl-propyleneamineoxime uptake measured using single photon emission computed tomography (SPECT), tumour volume measured from SPECT transaxial image reconstructions and cardiac output assessed with Doppler ultrasonography. Twenty-seven malignant lesions and one benign tumour showed increased uptake of isotope relative to surrounding tissues. Mean sarcoma blood flow varied between 1 and 33 ml per 100 ml tumour per min, and maximum flow between 5 and 57 ml per 100 ml per min. Fourteen patients developed progressive disease during the first year of follow-up. Eight of 11 patients with a high isotope uptake ratio, eight of 12 with a high mean blood flow and eight of 14 with a high maximum blood flow relative to the respective medians for the series showed disease progression.

Quantitative single-photon emission tomography for tumour blood flow measurement in bronchial carcinoma

A single-photon emission tomography (SPET) technique for the absolute measurement of tumour perfusion is described. Phantom studies have shown that source-background ratios are dependent upon source size and radial position within the phantom. A means of correcting source-background count ratios for these variables has been developed and used to correct tumour-lung ratios obtained in 28 patients with bronchial carcinomas who underwent technetium-99m hexamethylpropyleneamine oxime (99mTc-HMPAO) SPET. On SPET images, the normal lung appears as a relatively homogeneous background. The relationship between 99mTc background concentration (kBq/ml) and counts/pixel was determined from phantom studies and the tumour 99mTc concentration from the background 99mTc concentration and corrected tumour-lung ratio. The total activity of the lipophilic 99mTc-HMPAO species injected was measured. The activity reaching the systemic circulation (Asys) was obtained by subtracting the activity trapped in the pulmonary circulation (obtained from background 99mTc concentration and lung volume). Tumour blood flow may then be calculated from fraction of Asys contained in the tumour provided cardiac output and extraction fraction are known. Blood flow through the central region of tumours ranged from zero to 59.0 (mean 14.1) ml min-1 100 g-1 and through the whole tumour from 0.6 to 68.0 (mean 20.6) ml min-1 100 g-1.

Anatomically derived attenuation coefficients for use in quantitative single photon emission tomography studies of the thorax

Elimination of errors due to poor attenuation correction is an essential part of any quantitative single photon emission tomography (SPET) technique. Attenuation coefficients (mu Tc) for use in attenuation correction of SPET data were determined using technetium 99m and cobalt 57 flood sources and using topographical information obtained from computed tomography (CT) scans and magnetic resonance (MR) images. In patients with carcinoma of the bronchus, the mean attenuation coefficient for 99mTc was 0.096 cm-1 when determined across a transverse section of the thorax at the level of the tumour by means of a 57Co flood source (13 patients) and 0.093 and 0.074 cm-1 as determined from CT scans for points in the centre of the tumour and contralateral normal lung, respectively (21 patients). In 18 patients with breast tumours, the mean attenuation coefficient for 99mTc was 0.110 and 0.076 cm-1 when determined from MRI cross-sections for points in the centre of the tumour and normal contralateral lung, respectively. This indicates significant overcorrection for attenuation when the conventional value of 0.12 cm-1 is used. A value in the range 0.08-0.09 cm-1 would be more appropriate for SPET studies of the thorax. An alternative approach to quantitative region of interest (ROI) analysis is to perform attenuation correction appropriate to the centre of each ROI (using topographical information derived from CT or MRI) on non-attenuation-corrected reconstructions.

The effects of single dose oral hydralazine on blood flow through human lung tumours

Hydralazine has been shown to reduce tumour blood flow and to potentiate the cytotoxicity of melphalan and bioreductive agents in mice. In order to determine whether such a strategy might have clinical potential, a study was undertaken to investigate the effects of hydralazine on blood flow through human tumours. Twenty-two patients with carcinoma of the bronchus received a single oral dose of hydralazine in the range 25 to 150 mg (0.37-2.86 mg/kg) according to age and acetylator status. Tumour blood flow was assessed by single photon emission computed tomography (SPECT) performed 10 min following intravenous 99Tcm-HMPAO on two occasions 2-8 days apart, the second being performed 60 min after hydralazine administration. In 20 evaluable patients, hydralazine caused a 38% increase in blood flow through the whole tumour (p = 0.007) and a 28% increase in flow through the tumour centre (p = 0.03) with greater increases occurring in patients sustaining greater falls in peripheral resistance. Tumour vascular resistance fell indicating active vasodilation in arterioles supplying tumours. Side-effects due to hydralazine were reported by eight patients.

99Tcm-labelled meso-HMPAO and glutathione content of human lung tumours

Levels of reduced glutathione (GSH) are increased in some types of malignant tumours and are known to influence the response to radio- and chemotherapy. In vitro studies suggest a correlation between cellular GSH concentration and retention of the meso form of hexamethyl propyleneamineoxime (HMPAO). This study investigates the relationship between in vivo tissue retention of 99Tcm-labelled HMPAO and GSH concentration in ten patients referred for thoracotomy for possible lung cancer. Retention of 99Tcm-HMPAO was measured using single photon emission computed tomography (SPECT). The tumour and normal lung concentration of reduced glutathione (GSH) was measured in tissue specimens collected peroperatively. Malignancy was confirmed in eight patients. Of seven patients undergoing curative resection for carcinoma, tumour GSH concentration was higher (mean 2.76 mM) than normal lung (mean 1.04 mM). In one neurofibroma, the GSH concentration was 1.80 mM. No correlation was found between 99Tcm meso-HMPAO retention and either the tumour GSH concentration or the tumour:lung GSH ratio. The results from this small series demonstrate that the intracellular GSH concentration of malignant lung tumours is generally higher than that in normal lung but that meso-HMPAO retention could not be used to predict these levels.

Technetium-99m HMPAO and SPECT in the assessment of blood flow in human lung tumours

In order to assess the blood flow patterns through human lung tumours, 20 patients received 400-750 MBq 99TcmHMPAO intravenously 10 min before single photon emission computed tomography (SPECT). Ratios of uptake in the whole tumour relative to normal lung ranged from 0.35 to 1.53 (mean 1.01) with eight tumours showing less uptake than normal lung and ten showing greater uptake. In one patient the tumour was not distinguishable from surrounding lung and in another a large pleural effusion prevented evaluation. Tumour: lung ratios for central tumour regions ranged from 0 to 1.83 (mean 0.80) with 13 showing lower uptake than normal lung and five showing greater uptake. Duplicate scans were performed in eight patients demonstrating satisfactory reproducibility. This technique provides a simple and reproducible method for the assessment of tumour blood flow.

Functions of the two adenovirus early E1A proteins and their conserved domains in cell cycle alteration, actin reorganization, and gene activation in rat cells

Rat embryo cells were infected with adenovirus type 5 mutants that code for only one of the two early E1A proteins, mutants with defects in one of the two conserved regions common to the two proteins, or mutants with defects in the 46-amino-acid region unique to the 289-amino-acid E1A protein. Cells were scored for altered cell cycle progression, disruption of actin stress fibers, and activation of E2A expression. Mutants lacking either E1A protein were able to cause all of these effects; but mutants lacking a 243-amino-acid protein had less effect, and mutants lacking a 289-amino-acid protein much less effect, than wild-type virus. A mutation in any of the three conserved regions caused a defect in each E1A effect. To investigate the reported function of conserved domain 2 in mitosis, we monitored by fluorescence-activated cell sorter the reduction in Hoechst 33342 fluorescence that occurs when cells divide after undergoing a round of DNA replication in 5-bromodeoxyuridine. A smaller percentage of adenovirus-infected cells than mock-infected cells divided within a given period after completing a round of DNA replication. Viruses with mutations in conserved domain 2 were defective for initiation of cellular DNA replication, as were all other E1A mutants we have examined, but had no specific defect in cell division compared with wild-type virus. Thus, although there may be some specialization of function between the two E1A proteins and between their conserved domains, it was not apparent in the aspects of E1A function and the mutants that we examined.