Association between psoriasis and the metabolic syndrome. A cross-sectional study

BACKGROUND

Previous reports have shown an association between inflammatory diseases such as systemic lupus erythematosus or rheumatoid arthritis and the metabolic syndrome. Recent data demonstrate that psoriasis is an inflammatory disease, suggesting that psoriasis may be one of the components of the metabolic syndrome.

OBJECTIVE

To assess the association between psoriasis and the metabolic syndrome.

METHODS

A cross-sectional study was performed utilizing the database of the Clalit Health Services. Case patients were defined as patients with a diagnosis of psoriasis vulgaris. Controls were randomly selected from the list of Clalit Health Services enrollees. The proportions of components of the metabolic syndrome (ischemic heart disease, hypertension, diabetes, obesity and dyslipidemia) were compared between case and control patients by univariate analyses. chi(2) tests were used to compare categorical parameters between the groups. Logistic and linear regression models served to measure the association between psoriasis and the metabolic syndrome.

RESULTS

The study included 16,851 patients with psoriasis and 48,681 controls. In the case group, there were 8,449 men (50.1%) and 8,402 women (49.9%), with a mean age of 42.7 years (SD = 20.3, range = 2-111). Diabetes mellitus was present in 13.8% of the patients with psoriasis as compared to 7.3% of the controls (p < 0.001). Hypertension occurred in 27.5% of the patients with psoriasis and in 14.4% of the controls (p < 0.001). Obesity was present in 8.4% of the patients with psoriasis as opposed to 3.6% of the controls (p < 0.001). Ischemic heart disease was observed in 14.2% of the patients with psoriasis as compared to 7.1% of the controls (p < 0.001). Multivariate models adjusting for age, gender and smoking status of the patients demonstrated that psoriasis was associated with the metabolic syndrome (OR = 1.3, 95% CI = 1.1-1.4), ischemic heart disease (OR = 1.1, 95% CI = 1.0-1.2), diabetes mellitus (OR = 1.2, 95% CI = 1.0-1.3), hypertension (OR = 1.3, 95% CI = 1.2-1.5) and obesity (OR = 1.7, 95% CI = 1.5-1.9).

LIMITATIONS

The study is designed as a case-control study, thus an association alone was proven and not causality.

CONCLUSION

Our findings demonstrate a possible association between psoriasis and the metabolic syndrome. Appropriate treatment of the metabolic syndrome may be an important part of the management of patients with psoriasis.

Long-term outcomes of patients with localized rectal cancer treated with chemoradiation or radiotherapy alone because of medical inoperability or patient refusal

PURPOSE

The standard management of rectal cancer continues to be defined by the results of randomized, clinical trials exploring the optimal timing and use of adjuvant chemotherapy and radiation therapy in relation to surgery. The patient with rectal cancer who is elderly and/or has significant comorbidities and the patient who refuses surgery are clinical contexts for which there is limited current data to guide decision making.

METHODS

A retrospective analysis was performed at six Australian centers of patients with rectal cancer treated with radiation therapy or chemoradiation alone because of excessive operative risk or patient refusal of surgery.

RESULTS

We identified 48 patients treated between August 1998 and June 2005 with a median age of 76 (range, 49-94) years. Twenty-four patients (50 percent) were considered medically inoperable and 24 patients refused surgery. Treatment was with chemoradiation (with 5-fluorouracil) in 36 patients and radiotherapy alone in 12 patients; 93 percent completed the planned therapy. A clinical complete response was seen in 56 percent and a partial response in 30 percent of patients. At a median follow-up of 49 months, 18 patients have disease progression, including 10 of 24 in the medically inoperable group and 8 of 24 in the refused surgery group. Of the 25 deceased patients, 16 died from progressive disease and 9 from noncancer causes.

CONCLUSIONS

Chemoradiation or radiotherapy alone is a safe alternative that results in significant progression-free and overall survival times in patients who are considered medically inoperable or refuse to undergo surgery. Ultimately, however, many patients will progress.

Lack of benefit of early protocol biopsies in renal transplant patients receiving TAC and MMF: a randomized study

We conducted a randomized, multicenter study to determine whether treatment of subclinical rejection with increased corticosteroids resulted in beneficial outcomes in renal transplant patients receiving tacrolimus (TAC), mycophenolate mofetil (MMF) and prednisone. One hundred and twenty-one patients were randomized to biopsies at 0,1,2,3 and 6 months (Biopsy arm), and 119 to biopsies at 0 and 6 months only (Control arm). The primary endpoint of the study was the prevalence of the sum of the interstitial and tubular scores (ci + ct)> 2 (Banff) at 6 months. Secondary endpoints included clinical and subclinical rejection and renal function. At 6 months, 34.8% of the Biopsy and 20.5% of the Control arm patients had a ci + ct score >or= 2 (p = 0.07). Between months 0 and 6, clinical rejection episodes were 12 in 10 Biopsy arm patients and 8 in 8 Control arm patients (p = 0.44). Overall prevalence of subclinical rejection in the Biopsy arm was 4.6%. Creatinine clearance at 6 months was 72.9 +/- 21.7 in the Biopsy and 68.90 mL/min +/- 18.35 mL/min in the Control arm patients (p = 0.18). In conclusion, we found no benefit to the procurement of early protocol biopsies in renal transplant patients receiving TAC, MMF and prednisone, at least in the short term. This is likely due to their low prevalence of subclinical rejection.

Unwanted facial hair: affects, effects and solutions

The following is a review of a satellite symposium held at the EHRS Meeting in June 2006. U.B.P. reminded the audience that unwanted facial hair (UFH) is an important issue; over 40% of the women in the general population have some degree of UFH, and its psychological and psychosocial impact should not be underestimated. The treatment of UFH involves many different disciplines, and the symposium offered the latest thinking in different aspects of the disorder. S.L. outlined the current concepts surrounding polycystic ovarian syndrome, and U.G. addressed the psychological aspects of UFH. J.S. described the current treatment options for UFH, followed by U.B.P.'s evidence-based therapy review. Finally, R.H. reviewed the latest trial results with Trichoscan, a method being investigated for assessing UFH removal.

Gemcitabine with a specific conformal 3D 5FU radiochemotherapy technique is safe and effective in the definitive management of locally advanced pancreatic cancer

The aim of this phase II study was to assess the feasibility and efficacy of a specific three-dimensional conformal radiotherapy technique with concurrent continuous infusion of 5-fluorouracil (CI 5FU) sandwiched between gemcitabine chemotherapy in patients with locally advanced pancreatic cancer. Patients with inoperable cancer in the pancreatic head or body without metastases were given gemcitabine at 1000 mg m(-2) weekly for 3 weeks followed by a 1-week rest and a 6-week period of radiotherapy and concurrent CI 5FU (200 mg m(-2) day(-1)). The defined target volume was treated to 54 Gy in 30 daily fractions of 1.8 Gy. After 4 weeks' rest, gemcitabine treatment was re-initiated for three cycles (days 1, 8, 15, q28). Forty-one patients were enrolled. At the end of radiotherapy, one patient (2.4%) had a complete response and four patients (9.6%) had a partial response; at the end of treatment, three patients (7.3%) had a complete response and two patients (4.9%) had a partial response. Median survival time was 11.7 months, median time to progression was 7.1 months, and median time to failure of local control was 11.9 months. The 1- and 2-year survival rates were 46.3 and 9.8%, respectively. Treatment-related grade 3 and 4 toxicities were reported by 16 (39.0%) and four (9.8%) patients, respectively. Sixteen out of 41 patients did not complete the planned treatment and nine due to disease progression. This approach to treatment of locally advanced pancreatic cancer is safe and promising, with good local control for a substantial proportion of patients, and merits testing in a randomised trial.

Quality of life in patients with advanced colorectal cancer treated with cetuximab: Results of the NCIC CTG and AGITG CO.17 trial

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Background: Cetuximab prolongs survival in pretreated advanced colorectal cancer (CRC) patients (pts). For these pts, the effect of palliative treatment on quality of life (QOL) is also an important outcome. Methods: CO.17 was a randomized controlled trial (n=572) of cetuximab combined with best supportive care (BSC) vs BSC alone in pts with pretreated epidermal growth factor receptor-positive advanced CRC. Primary endpoint was survival. QOL was a secondary endpoint using the EORTC QLQ-C30 at baseline, 4, 8, 16, and 24 weeks (wks). Primary endpoint for QOL compared physical function (PF) and global health status (Global) mean changes from baseline to 8 and 16 wks using Wilcoxon test. Negative change scores denote worsening QOL. The proportion of pts in either arm with at least a 10 unit deterioration at 8 and 16 wks from baseline was compared using Fischer’s exact test. Kaplan-Meier estimates and logrank tests on median time to definitive QOL deterioration, defined as at least a 10 unit deterioration in PF or Global, were evaluated. Exploratory analyses of all other scale and symptom change scores at 8 and 16 wks were also performed. Results: Compliance rates for QOL questionnaires was high at baseline, 94% each arm, but did drop off over time: 73% vs 60% at week 8 and 60% vs 39% at week 16 for cetuximab vs BSC, respectively. PF change scores at 8 wks were -3.9 for cetuximab vs -8.6 for BSC (p=.046); at 16 wks -5.9 vs -12.5 (p=.027). Global change scores were -0.5 vs -7.1 (p=.008) and -3.6 vs -15.2 (p=.008) at 8 and 16 wks respectively. The proportion of pts with deteriorating PF was 25% for cetuximab vs 35% for BSC at 8 wks (p=.051) and 30 vs 43% at 16 wks (p=.069). Deteriorating Global was seen in 23 vs 38% at 8 wks (p=.004) and 31 vs 49% at 16 wks (p=.0011). Time to PF deterioration was 5.4 months [95% CI 3.8–5.7] for cetuximab vs 3.7 months [2.0–3.9] for BSC (p=.022). Time to Global deterioration was 5.4 [3.9–5.7] vs 3.7 months [2.1–3.9] (p=.062). Exploratory analyses of all other scale and symptom change scores at 8 and 16 wks showed all differences of p<.05 also favored cetuximab. Conclusions: Cetuximab provides palliation in pretreated pts with advanced CRC, delaying deterioration in QOL as well as improving survival.

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Treatment with zoledronic acid ameliorates negative geometric changes in the proximal femur following acute spinal cord injury

Acute spinal cord injury is associated with rapid bone loss and an increased risk of fracture. In this double-blind, randomized, placebo-controlled trial, 17 patients were followed for 1 year after administration of either 4 or 5 mg of zoledronic acid or placebo. Bone mineral density (BMD) and structural analyses of the proximal femur were performed using the hip structural analysis program at entry, 6 months, and 12 months. The 17 subjects completed 12 months of observation, nine receiving placebo and eight zoledronic acid. The placebo group showed a decrease in BMD, cross-sectional area, and section modulus and an increase in buckling ratio at each proximal femur site at 6 and 12 months. Six months after zoledronic acid, BMD, cross-sectional area, and section modulus increased at the femoral neck and intertrochanteric regions and buckling ratio decreased consistent with improved bone stability. However, at 12 months, the femoral narrow-neck values declined to baseline. In contrast to placebo, the intertrochanteric region and femur shaft were maintained at or near baseline through 12 months in the zoledronic acid-treated group. Urine N-telopeptide excretion was increased at baseline and declined in both the placebo and treatment groups during the 12 months of observation. We conclude that a single administration of zoledronic acid will ameliorate bone loss and maintain parameters of bone strength at the three proximal femur sites for 6 months and at the femur intertrochanteric and shaft sites for 12 months.

Improved outcomes in islet isolation and transplantation by the use of a novel hemoglobin-based O2 carrier

During isolation, islets are exposed to warm ischemia. In this study, intraductal administration of oxygenated polymerized, stroma-free hemoglobin-pyridoxalated (Poly SFH-P) was performed to improve O2 delivery. Rat pancreata subjected to 30-min warm ischemia were perfused intraductally with collagenase in oxygenated Poly SFH-P/RPMI or RPMI (control). PO2 was increased by Poly SFH-P (381.7 +/- 35.3 mmHg vs. 202.3 +/- 28.2, p = 0.01) and pH maintained within physiological range (7.4-7.2 vs. 7.1-6.6, p = 0.009). Islet viability (77% +/- 4.6 vs. 63% +/- 4.7, p = 0.04) was improved and apoptosis lower with Poly SFH-P (caspase-3: 34,714 +/- 2167 vs. 45,985 +/- 1382, respectively, p = 0.01). Poly SFH-P improved islet responsiveness to glucose as determined by increased intracellular Ca2+ levels and improved insulin secretion (SI 5.4 +/- 0.1 vs. 3.1 +/- 0.2, p = 0.03). Mitochondrial integrity was improved in Poly SFH-P-treated islets, which showed higher percentage change in membrane potential after glucose stimulation (14.7% +/- 1.8 vs. 9.8 +/- 1.4, respectively, p < 0.05). O2 delivery by Poly SFH-P did not increase oxidative stress (GSH 7.1 +/- 2.9 nm/mg protein for Poly SFH-P vs. 6.8 +/- 2.4 control, p = 0.9) or oxidative injury (MDA 1.8 +/- 0.9 nmol/mg protein vs. 6.2 +/- 2.4, p = 0.19). Time to reach normoglycemia in transplanted diabetic nude mice was shorter (1.8 +/- 0.4 vs. 7 +/- 2.5 days, p = 0.02), and glucose tolerance improved in the Poly SFH-P group (AUC 8106 +/- 590 vs. 10,863 +/- 946, p = 0.03). Oxygenated Poly SFH-P improves islet isolation and transplantation outcomes by preserving mitochondrial integrity.

Combined modality therapy for pancreatic carcinoma: An Australian Pancreatic Cancer Group study of the addition of gemcitabine (G) to concurrent infusional 5-fluorouracil (CI 5FU) and 3D conformal radiotherapy (RT)—Final outcomes

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Background: This open-label Phase II study (B9E-AY-S168) examined whether CI 5FU plus 3D conformal planning RT is well tolerated and may be combined with G pre and post chemoradiotherapy in patients (pts) with pancreatic cancer (PC). Methods: Eligible pts were enrolled in two strata: (1) inoperable PC in head or body without metastases (LAD) or (2) resected PC at high risk of relapse (Surg). G was given at 1000 mg/m2 weekly for 3 wks followed by 1 wk rest and a 5–6 wk period of RT and concurrent CI 5FU (200 mg/m2/day). The defined target volume was treated to 54Gy in 30# of 1.8Gy (LAD) or 45Gy in 25# (Surg). After 4 wks rest, G was given for 12 wks. Results: 63 pts were enrolled: 39 females, 24 males; mean age 61 yr, range 31–79; 43% ECOG PS 0, 51% PS 1, 5% PS 2. Follow-up was 2 yr. 1- and 2-yr survival (KM) were 46% and 10% (LAD) and 59% and 27% (Surg). 1- and 2-yr local control (KM) were 48% and 21% (LAD) and 80% and 80% (Surg). The % planned dose delivered was (i) G pre RT: 87.6% (LAD)/94.6% (Surg); (ii) 5FU: 100.7%/96.4%; (iii) RT: 96.2%/99.5%; (iv) G post RT: 67.4%/65.3%. The baseline CA 19.9 level was significantly associated with a shorter TTPD (p=0.0002) and a shorter survival time (p=0.0071). Using Time Dependent Covariate analysis, CA 19.9 levels were strongly associated with TTPD and survival (both p < 0.0001); a person with a 10-fold higher level has a 1.95-fold higher risk of death over the next time period than their counterpart (95% CI: 1.53–2.49-fold). In 22 pts we found no statistically significant associations between outcome and mutations in K-RAS or TP53 or with microsatellite instability. Grade 3/4 hematological and non-hematological toxicity was reported by 29 (46%) and 42 pts (67%), respectively. There was one treatment-related death. Conclusions: This approach to treatment is safe and promising, with good local control for a substantial proportion of patients, and merits testing in a randomized trial.

[Table: see text]

[Table: see text]

A multicentre analysis of the long-term outcomes of patients with localized rectal cancer treated with chemotherapy and/or radiotherapy alone due to medical inoperability or patient refusal

3633

Background: The outcome for patients with localized rectal cancer treated with chemoradiotherapy (CMT) or radiotherapy alone (RT) and no planned subsequent surgery is unknown. Insights can be provided by study of patients that do not undergo surgery due to excessive operative risk (medically inoperable) as a result of advanced age and/or co-morbidities, or patient refusal. Methods: A retrospective analysis at 6 Australian centers. Patients with recurrent rectal cancer, metastatic disease or primary tumors that were considered unresectable were excluded from the study. Results: We identified 48 patients treated between August 1998 and June 2005 meeting our criteria. There were 13 females and 35 males with a median age of 76 years (range 49 - 94). 24 patients (50%) were deemed medically inoperable and 24 patients refused surgery (the most common reasons were the desire to avoid a stoma or fear of surgery). Treatment was with standard long course radiation plus 5-FU (either bolus or continuous infusion) in 36 patients (75%) and 12 (25%) received RT alone. A complete clinical response was documented in 23 patients (48%) and a partial clinical response was documented in 14 patients (30%). At a median follow-up of 49 months, 18 patients (37.5%) have documented disease progression including 10 of 24 in the medically inoperable group and 8 of 24 in the refused surgery group. The median progression-free survival for all patients was 30+ months. 7 had local progression only, 7 had distant progression only and 4 patients had both local and distant progression. Of the 23 deceased patients, 16 (70%) died from progressive disease and 7 (30%) from non-cancer causes, including 4 from the refused surgery group. The median survival for all patients was 35 + months. Conclusions: In patients who are not suitable candidates for surgical resection due to advanced age and/or comorbidity CRT or RT alone is a safe alternative that results in significant progression-free and overall survival times, with many patients succumbing to co-morbidities rather than progressive disease. Many of these patients refusing surgery will have long periods of disease control after treatment with CRT or RT.

No significant financial relationships to disclose.

Beneficial effects of nerve growth factor on islet transplantation

OBJECTIVE

Development of the Edmonton protocol was a pivotal contribution to clinical islet transplantation (ITx). Persistent limitations to ITx include insufficient supply and posttransplant functional failure of islets. In this study, nerve growth factor (NGF) was used to enhance both cultured and transplanted beta-cell function, thus achieving prolonged graft survival.

METHODS

Fluorescence microscopy with ethidium bromide and SYTO green staining was used to evaluate balb/c mouse islet viability. Islets were syngeneically transplanted under the kidney capsule of recipients with streptozotocin-induced diabetes. Intraperitoneal glucose tolerance was used to test posttransplant function.

RESULTS

Improved viability was found in murine islets cultured for 48 hours in 500 ng/mL NGF (P < .05). A submarginal islet mass (260 islet equivalents/recipient) was used for ITx. The NGF-culture resulted in prolonged islet survival (24.7 days vs 5.5 days without NFG culture, n = 6). Intravenous injection of NGF (6 mug) on the day of transplant and postoperative days (POD) 1 + 2 prolonged islet survival from 4.1 days (no treatment) to 13.2 days (n = 6). Glucose tolerance testing performed at posttransplant day 4 showed improvement at 60 and 120 minutes in recipients treated intravenously with NGF (blood glucose of 95 +/- 15 vs 210 +/- 78 and 57 +/- 6 vs 176 +/- 70 mg/dL, respectively).

CONCLUSION

NGF may improve beta-cell function and result in prolonged survival of both cultured and transplanted islets.

Treatments for unwanted facial hair

Twenty-two percent of women in North America have unwanted facial hair, which can cause embarrassment and result in a significant emotional burden. Treatment options include plucking, waxing (including the sugar forms), depilatories, bleaching, shaving, electrolysis, laser, intense pulsed light (IPL), and eflornithine 13.9% cream (Vaniqa, Barrier Therapeutics in Canada and Shire Pharmaceuticals elsewhere). Eflornithine 13.9% cream is a topical treatment that does not remove the hairs, but acts to reduce the rate of growth and appears to be effective for unwanted facial hair on the mustache and chin area. Eflornithine 13.9% cream can be used in combination with other treatments such as lasers and IPL to give the patient the best chance for successful hair removal.

Intra-ductal glutamine administration reduces oxidative injury during human pancreatic islet isolation

Oxidative stress during islet isolation induces a cascade of events injuring islets and hampering islet engraftment. This study evaluated islet isolation and transplantation outcomes after intra-ductal glutamine administration. Human pancreata deemed unsuitable for pancreas or islet transplantation were treated with either a 5 mM solution of l-glutamine (n = 6) or collagenase enzyme alone (n = 6) through the main pancreatic duct. Islet yield, viability, in vitro function; markers of oxidative stress [malondialdehyde (MDA) and Glutathione (GSH)] and apoptosis were assessed. Islet yields were significantly increased in the glutamine group compared to controls (318, 559 +/- 25, 800 vs. 165, 582 +/- 39, 944 mean +/- SEM, p < 0.01). The amount of apoptotic cells per islet was smaller in the glutamine group than the control. The percentage of nude mice rendered normoglycemic with glutamine-treated islets was higher than the controls (83% n = 10/12 vs. 26% n = 6/23; p < 0.01), and the time to reach normoglycemia was decreased in the glutamine group (1.83 +/- 0.4 vs. 7.3 +/- 3 days; p < 0.01). Glutamine administration increased GSH levels (7.6 +/- 1.7 nmol/mg protein vs. 4.03 +/- 0.5 in control, p < 0.05) and reduced lipid-peroxidation (MDA 2.45 +/- 0.7 nmol/mg of protein vs. 6.54 +/- 1.7 in control; p < 0.05). We conclude that intra-ductal administration of glutamine reduces oxidative injury and apoptosis and improves islet yield and islet graft function after transplantation.

Towards evidence-based use of serum tumour marker requests: an audit of use in a tertiary hospital

BACKGROUND

Serum tumour markers (TM) are often measured in hospital patients. The reasons for their use and their benefits with regards to earlier cancer diagnosis and patient management are not known.

AIMS

To identify the patterns of TM use in a tertiary hospital and to determine the usefulness and appropriateness of requests in this setting.

METHODS

A cross-sectional, retrospective study of TM ordered over a 3-month period was conducted. Data were obtained from patient records. CA-125, CA 15-3, CA 19-9, carcinoembryonic antigen (CEA), and alpha-fetoprotein (AFP) were studied. Prostate specific antigen was not separately investigated. The reasons for ordering, usefulness and appropriateness of use were defined prior to analysis.

RESULTS

A total of 476 TM was ordered in 373 patients. One hundred and six (22%) of all results were abnormal by laboratory criteria. AFP was the most popular test ordered. Forty-seven per cent of patients had no cancer diagnosis. Oncological units (ONC) ordered 27% of tests. The most popular reasons for TM ordering were for screening (36%) followed by diagnostic aid (19%). ONC units ordered TM mainly for monitoring disease status, as opposed to non-ONC units who ordered TM usually for diagnostic aid. TM were deemed appropriately ordered in 69% of cases. Twenty-nine per cent of TM were helpful in patient management. Only four results (<1%) aided in diagnosis.

CONCLUSIONS

The reasons and appropriateness of TM use varied depending on the specialization of the requesting clinician. The current serum TM are most useful as aids in cancer patients, rather than for diagnosis (P <0.0001). Apart from AFP, these TM seem to have limited use in the general medical, non-oncological patients. Guidelines for their use in this setting are needed.

Acute Toxicity of Intravenously Administered Microfabricated Silicon Dioxide Drug Delivery Particles in Mice

BACKGROUND AND OBJECTIVE

Microfabricated particles with nanosized features may serve an important role in the next generation of drug delivery vehicles. Microfabrication (micro-electromechanical systems) technologies offer the promise of both structural elements (e.g., pores, reservoirs) and electromechanical features (e.g., timers, valves, actuators) built into a single particle. In order to serve as carriers to deliver drugs to systemic sites of action, such as tumors, the particles must be safe to administer intravenously. An acute safety study was performed in a mouse model, using intravenous injection of solid silicon dioxide particles created to simulate the size and shape of potential targeted drug delivery vehicles.

DESIGN

Two-micron thick, square and circular, parallelepiped-shaped particles were produced with varying sizes of 2 microm, 5 microm and 10 microm using microfabrication techniques and injected into groups of mice (six mice per group) over a range of doses. End-points included acute lethality, clinical signs of toxicity and weight loss. Sections of major organs were sampled for histological examination.

RESULTS

At dose levels of 1 x 10(8) particles per mouse, circular particles of 2 microm and 5 microm showed no signs of acute toxicity. Similar results were obtained with the 2 microm and 5 microm square silicon dioxide particles; however, 14-day necropsy indicates fewer 5 microm circular particles in the lung than 5 microm square particles, indicating that the shape of the particles may impact on safety. Acute lethality was observed for 10 microm particles; none of the mice injected with the 10 microm particles survived except at very low dose levels of 6 x 10(5) particles per mouse.

CONCLUSIONS

Solid silicon particles greater than 5 microm in their largest dimension are cleared in the lungs and are not safe for intravenous delivery. Particles of 2-5 microm in size do not lodge predominantly in the lung and do not cause acute toxicity, but accumulate in organs such as the liver and spleen. Possible chronic toxicities associated with organ uptake of such non-biodegradable particles have yet to be addressed.