USPIO-enhanced dynamic MRI: evaluation of normal and transplanted rat kidneys

To evaluate first-pass renal perfusion with ultrasmall superparamagnetic iron oxide (USPIO) particles by MRI, 40 normal rats (20 Dark Agouti (DA) rats and 20 Brown Norway (BN) rats) and 16 transplanted rats (12 allografts and four isografts) were studied on day 4 post-transplantation with different USPIO doses (3.0-18.1 mg Fe/kg/body weight). All animals underwent 128 consecutive snapshot fast low-angle shot (FLASH) coronal dynamic studies in 43 s. In the normal rats, a larger maximum signal decrease (MSD) in the cortex and the outer medulla is observed with an increasing dose of USPIO particles (P < 0.01). No significant differences were observed between the right and left kidneys at all doses studied. Higher MSD, time of occurrence of MSD (tMSD), and wash-in slope appear with higher doses of USPIO particles. The dynamic curves for DA rats show similar shapes when compared to those for BN rats. In the transplanted rats, allograft kidneys show lower MSD, longer tMSD, and lower wash-in slope compared to those in the normal kidneys. Isograft kidneys show perfusion patterns similar to those of normal kidneys in the cortex and the outer medulla. Histopathology indicates acute vascular rejection in all allografts and normal kidney architecture in all isografts. The results clearly show good agreement between the renal graft perfusion measurements and histopathological changes associated with rejection. This work also introduces a new signal analysis methodology for the automatic detection of transplanted organ rejection. This method compares the dynamics of the intrarenal signal intensities for native and transplanted kidneys. A quantitative measurement to detect significant differences between these signals was developed, and showed that this technique exhibits good performance in identifying renal rejection.

Pharmacological properties of A-204176, a novel and selective alpha1A adrenergic agonist, in in vitro and in vivo models of urethral function

A-204176 (N-[5-(1H-imidazol-4-y1)-5,6,7,8-tetrahydro-1-naphthalenyl]methanesulfonamide) is a potent and selective alpha1A adrenoceptor agonist that binds with 17-fold and 9-fold greater affinity to the alpha1A (Ki=176 nM) than the alpha1b and alpha1d subtypes, respectively. In functional studies A-204176 is potent (pD2=6.4) and efficacious (83% of maximum control phenylephrine response) at rabbit urethra alpha1A receptors, with weaker potency and greatly reduced efficacy at rat spleen alpha1B (pD2=5.3, 11%) and rat aorta alpha1D (pD2=4.4, 10%) subtypes. In anesthetized female dogs, A-204176 is more potent than the non-selective alpha1 adrenoceptor agonist phenylpropanolamine (PPA) to increase measures of urethral tone and is more efficacious to increase pressure in the proximal region of the urethra. Significant increases on parameters of the urethral pressure profilometry were induced at 100 and 300 nmol/kg, i.v., by A-204176 and PPA, respectively. A-204176 was more potent than PPA to increase the abdominal pressure required to produce leakage. In the simultaneous measurement of intraurethral pressure and mean arterial blood pressure, A-204176 displays enhanced urethral selectivity relative to PPA. However, despite its selectivity for alpha1A versus alpha1B and alpha1D adrenoceptors in vitro, A-204176 did not display the degree of urethral selectivity in vivo that would have been expected. The observed effect of A-204176 on blood pressure may be due to the presence of extra-synaptic alpha1A adrenoceptors in the vasculature or to activation of spinal and supraspinal alpha1A adrenoceptors. These data indicate that A-204176 may represent a useful pharmacological tool to investigate the functional role of the alpha1A adrenoceptor in the urethra and to elucidate the lack of uroselectivity observed in vivo.

Assessment of tolerant sunfish populations (Lepomis sp.) inhabiting selenium-laden coal ash effluents. 2. Tissue biochemistry evaluation

Sunfish were collected from a fly ash pond-receiving stream and an Ohio River reference site to assess biochemical responses to coal ash effluent exposure. Selenium levels in sunfish from the receiving stream were higher than toxic thresholds associated with adverse population effects and reproductive impairment. Tissue biochemistry was found to be indicative of metal exposure and effect, but varied widely. Liver glycogen was positively correlated with increased liver metal levels, indicating no adverse effect upon stored carbohydrate levels. Lipid levels decreased with increasing metals, indicating possible nutritional stress. Protein levels increased with increasing metal levels, possibly due to the synthesis of proteins to sequester the metals. ATPase, dUTPase, and alkaline phosphatase activity generally decreased with exposure to ash pond metals, but remained within normal physiological ranges. Fish condition factors and liver somatic indices were correlated with liver lipid levels, dUTPase activity, and gill ATPase and alkaline phosphatase activity. Exposure to coal ash effluents produced biochemical markers of exposure that were associated with fish condition indicators; however, the indices themselves were not significantly affected by effluent exposure.

Critical care unit design: a nursing perspective

The task of designing a new critical care unit is best accomplished with the input of people representing multiple disciplines including architects, engineers, physicians, nurses, and equipment manufacturers. It is imperative that the critical care nursing staff and management take an active role in planning the layout of the unit and patient rooms, as the nurses will be the bedside providers 24 hours a day. The new unit should be designed to offer efficient patient care as well as a healing, comfortable environment for both the patients and their families.

Vertical anthropometric measures and low back pain in adolescents

BACKGROUND AND PURPOSE

The present paper explores aspects of a large dataset of adolescent potentiates of low back pain. Standing, trunk and shoulder height, subischial height, weight and mean leg length are examined in relation to reports of low back pain in the last two weeks, in strata of age and gender.

METHOD

The present study examined 1254 adolescents, aged 11-18 years, drawn from 12 Adelaide public high schools during 1998.

RESULTS

At each year of age, girls reported significantly more low back pain than boys. Girls and boys at each year of age provided different relationships between low back pain and anthropometric features, highlighting the unique nature of adolescent growth. The most consistent findings were anthropometric differences between 16-year-old boys, and 13- and 15-year-old girls, with and without low back pain, who may be at critical stages of the peak growth curve.

CONCLUSION

We suggest a high prevalence of low back pain in adolescents, and that young sufferers with low back pain may be reflecting attributes of their stage of anthropometric growth.

Zinc regulates the function and expression of the iron transporters DMT1 and IREG1 in human intestinal Caco-2 cells

Trace metals influence the absorption of each other from the diet and it has been suggested that the divalent metal transporter (DMT1) represents a common uptake pathway for these important micronutrients. However, compelling evidence from our laboratory suggests that DMT1 is predominantly an iron transporter, with lower affinity for other metals. Several studies have shown that increasing dietary iron downregulates DMT1. Interestingly, our current data indicate that zinc upregulates DMT1 protein and mRNA expression and also pH-dependent iron uptake. Transepithelial flux of iron was also increased and was associated with a rise in IREG1 mRNA expression.

An investigation of psychological distress in patients who have been treated for head and neck cancer

There is now ample evidence that psychological distress is common in patients with head and neck cancer and that psychology has a role in reducing this distress. In this study, the prevalence, nature, and correlates of distress were investigated, in 18 patients who were no longer being actively treated but were attending a follow-up clinic or support group (n= 9 each). Four of the patients had appreciable psychological distress and four each had anxiety or depression of at least borderline importance. The degree of depression and distress decreased with increasing age and there were trends for depression to decrease with time after the onset of the illness and to be slightly less common among those attending the support group (2/9 compared to 4/9). Numerous psychosocial difficulties were reported and perceptions of support available from friends and family were mixed. There are implications for services, and in particular, patients need to be given clear information about the resources available to give them psychosocial support.

Crack smokers' intention to use condoms with loved partners: intervention development using the theory of reasoned action, condom beliefs, and processes of change

Prevalence rates of HIV infection acquired through heterosexual contacts have risen steadily since 1982. Crack cocaine smokers are at particular risk of HIV infection due to heterosexual exposure. HIV risk reduction interventions seeking to increase condom use among drug users have met with minimal success, and there is a need for interventions to be strongly grounded in psychosocial models of behaviour change. This study presents the results of an investigation of predictors of intention to use condoms and related therapy processes among heterosexual drug users. Data were analyzed from 586 crack smokers recruited in Washington, DC, Miami, Florida, and Collier County, Florida who reported having both primary and casual sex partners. Participants responded to items derived from the theory of reasoned action, the theory of planned behaviour and the transtheoretical model of change. Condom use beliefs and therapy processes used to initiate and maintain condom use were assessed. Outcome expectancies and normative beliefs were the strongest predictors of intention to use condoms with a primary sexual partner. In turn, beliefs that condoms inhibit sexual romance and decrease sexual pleasure strongly predicted outcome expectancies. Therapy processes found to be associated with these constructs included: self-liberation, counter conditioning and stimulus control/reinforcement. Results suggest that HIV risk reduction interventions using a group format and targeting condom beliefs related to sexual romance and pleasure will decrease negative outcome expectancies about condom use. Also, reinforcing attempts to use condoms with intimate partners should increase positive outcome expectancies and intention to initiate or maintain condoms with a primary sexual partner.

The organic content of the Tagish Lake meteorite

The Tagish Lake meteorite fell last year on a frozen lake in Canada and may provide the most pristine material of its kind. Analyses have now shown this carbonaceous chondrite to contain a suite of soluble organic compounds (approximately 100 parts per million) that includes mono- and dicarboxylic acids, dicarboximides, pyridine carboxylic acids, a sulfonic acid, and both aliphatic and aromatic hydrocarbons. The insoluble carbon exhibits exclusive aromatic character, deuterium enrichment, and fullerenes containing "planetary" helium and argon. The findings provide insight into an outcome of early solar chemical evolution that differs from any seen so far in meteorites.

CXCR2 regulation of tumor necrosis factor-alpha adherence-dependent peroxide production is significantly diminished after severe injury in human neutrophils

BACKGROUND

Primed neutrophils are thought to play a key role in inflammatory pathology. We have shown though in vitro studies that interleukin (IL)-8 and growth-related oncogene-alpha (GROalpha) (CXCR2-specific chemokines) regulate the respiratory burst via the CXCR2 receptor. We have also shown in vivo, CXCR2 receptors are down-regulated in severely injured patients. Our hypothesis is that regulation of the respiratory burst by CXCR2 is lost after severe injury.

METHODS

Patient neutrophils were studied within 24 hours of admission to the hospital; excluded were severe head injury and patients with Injury Severity Score < 16. Patient and normal neutrophils were isolated by Ficoll-Hypaque centrifugation after dextran sedimentation. Neutrophils were plated with buffer, 50 nmol/L IL-8 or GROalpha on fibronectin-coated plates for 15 minutes, then stimulated with 10 ng/mL of TNFalpha. CXCR2 expression was measured by flow cytometry. Receptor function was assessed by calcium mobilization.

RESULTS

One female and 10 male patients with an average age of 37 +/- 3 and Injury Severity Score of 24 +/- 5 suffered blunt injury. CXCR2 showed a 32% +/- 7% loss, whereas CXCR1 showed 15% +/- 6% reduction. GROalpha stimulation of patient neutrophils showed 60% +/- 16% decrease in calcium mobilization, whereas IL-8 showed no decline. At 40 minutes, IL-8 and GROalpha significantly inhibited TNFalpha adherence-dependent peroxide production in normal neutrophils (35% +/- 4% and 45% +/- 3%, respectively; p < 0.05). Both IL-8 and GROalpha lost the ability to suppress the respiratory burst in severely injured patients, but GROalpha had a significantly greater loss of this suppression (p = 0.004).

CONCLUSION

IL-8 and GROalpha lose the ability to regulate the TNFalpha-induced respiratory burst. This may contribute to neutrophil dysregulation after injury and result in organ injury.

Previous creatinine levels safely predict amantadine dose for influenza A outbreak control

BACKGROUND

Amantadine, an antiviral agent, is the only drug currently approved in Canada for prophylaxis of influenza A virus infection. To minimize side effects, the amantadine dose is adjusted for age and estimated creatinine clearance (CrCl) based on plasma creatinine (Cr) levels. As amantadine is used more frequently for influenza A outbreak control in care facilities for elderly people, physicians are increasingly called on to prescribe it for residents and to consider the necessity of requesting plasma Cr levels.

OBJECTIVE

To determine whether previous Cr levels are predictive in estimating current CrCl and safe amantadine dose determination.

DESIGN AND SETTING

Residents' charts were reviewed in two facilities in Vancouver, British Columbia. CrCl estimated using previous or current Cr results, current weight and age, as well as recommended amantadine doses based on Canadian National Advisory Committee on Immunization guidelines, were studied.

RESULTS

165 charts with Cr results in March 1998 were included; 122 had results before March 1998, and 103 had Cr results after March 1998. Pearson's correlation coefficient for CrCl estimated from current and previous Cr values was 0.929 for results less than six months previously, 0.974 for six to 12 months previously and 0.952 for 12 to 18 months previously. The same or a more conservative dose of amantadine was predicted in 92% of cases when using a Cr result taken within the previous year and in 76% of cases when using a Cr result taken 12 to 18 months previously.

CONCLUSION

In long term care facilities, Cr levels measured up to 12 months previously can usually safely be used to estimate CrCl. Using previous Cr results permits advance preparation of doctor's orders for amantadine prophylaxis and avoids repeating Cr testing on every resident when an outbreak occurs, reducing related staff time and cost.

Metabolic impact of puberty on the course of type 1 diabetes

Puberty is characterised by important physiological and hormonal changes. In type 1 diabetes, abnormalities in the growth hormone/insulin-like growth factor-1 (GH/IGF-1) axis play a important role. Spontaneous hyper-GH secretion arises, with reduced circulating IGF-1 levels, both leading to a reduction in insulin sensitivity. From a clinical point of view, these abnormalities are linked to a deterioration glycaemic control, often more marked in females (in whom the degree of insulin resistance during puberty seems to be higher). These abnormalities in the GH/IGF-1 axis in may constitute a risk for the development of microangiopathic complications. Optimisation of insulin therapy has practical limitations and intensification of insulin therapy poses problems (weight gain, nocturnal hypoglycaemia). Several alternative therapeutic approaches have been explored to restore insulin sensitivity, either through a direct effect on the GH/IGF-1 axis, or through drugs with a direct insulin sensitivity effect, but all these approaches remain to be confirmed and the safety and acceptability of these treatments to be established on a long-term basis.

Burr holes

Neurosurgical procedures may sometimes take place in general operating theatres, usually when a patient has sustained a life-threatening head injury. Burr holes may be made in accident and emergency departments before patients are transferred for further treatment. For these reasons it is useful for perioperative nurses in general hospitals to have some knowledge of neurosurgical operating techniques and instrumentation.

Prevalence of vaginal colonization by drug-resistant Candida species in college-age women with previous exposure to over-the-counter azole antifungals

We enrolled 382 college-age women in a cross-sectional survey to investigate the relationship between use of over-the-counter (OTC) azole-based antifungal drugs and vaginal colonization by drug-resistant Candida. This study showed no correlation (P=.506) between previous OTC exposure and colonization of drug-resistant Candida in vaginal flora. However, a small number of resistant Candida species isolates were obtained from women with a history of multiple exposures to OTC antifungals; given the widespread use of these products, this may be an emerging concern.

Adrogolide HCl (ABT-431; DAS-431), a prodrug of the dopamine D1 receptor agonist, A-86929: preclinical pharmacology and clinical data

Adrogolide (ABT-431; DAS-431) is a chemically stable prodrug that is converted rapidly (<1 min) in plasma to A-86929, a full agonist at dopamine D1 receptors. In in vitro functional assays, A-86929 is over 400 times more selective for dopamine D1 than D2 receptors. In rats with a unilateral loss of striatal dopamine, A-86929 produces contralateral rotations that are inhibited by dopamine D1 but not by dopamine D2 receptor antagonists. Adrogolide improves behavioral disability and locomotor activity scores in MPTP-lesioned marmosets, a model of Parkinson's disease (PD), and shows no tolerance upon repeated dosing for 28 days. In PD patients, intravenous (i.v.) adrogolide has antiparkinson efficacy equivalent to that of L-DOPA with a tendency towards a reduced liability to induce dyskinesia. The adverse events associated with its use were of mild-to-moderate severity and included injection site reaction, asthenia, headache, nausea, vomiting, postural hypotension, vasodilitation, and dizziness. Adrogolide can also attenuate the ability of cocaine to induce cocaine-seeking behavior and does not itself induce cocaine-seeking behavior in a rodent model of cocaine craving and relapse. In human cocaine abusers, i.v. adrogolide reduces cocaine craving and other cocaine-induced subjective effects. The results of animal abuse liability studies indicate that adrogolide is unlikely to have abuse potential in man. Adrogolide has also been reported to reverse haloperidol-induced cognitive deficits in monkeys, suggesting that it may be an effective treatment for the cognitive dysfunction associated with aging and disease. Adrogolide undergoes a high hepatic "first-pass" metabolism in man after oral dosing and, as a result, has a low oral bioavailability (approximately 4%). This limitation may potentially be circumvented by oral inhalation formulations for intrapulmonary delivery that greatly increase the bioavailability of adrogolide. As the first full dopamine D1 receptor agonist to show efficacy in PD patients and to reduce the craving and subjective effects of cocaine in cocaine abusers, adrogolide represents an important tool in understanding the pharmacotherapeutic potential of dopamine D1 receptor agonists.

Macrophage accumulation associated with rat cardiac allograft rejection detected by magnetic resonance imaging with ultrasmall superparamagnetic iron oxide particles

BACKGROUND

Acute cardiac allograft rejection continues to be the cause of graft loss and contributes to the morbidity and mortality after cardiac transplantation. In this study, we report a new method for detecting organ rejection in transplantation with an MR-based technique using dextran-coated ultrasmall superparamagnetic iron oxide (USPIO) particles. These particles ( approximately 27 nm in diameter) are known to shorten relaxation times in MRI experiments.

METHODS AND RESULTS

A new rat model of heterotopic heart and lung transplantation has been developed for MRI experiments. Allotransplantations (DA-->BN) were performed (n=8), with syngeneic transplantations (BN-->BN) serving as controls (n=8). MR images were obtained with a gradient echo method. At postoperative day 7, allotransplants developed moderate rejection as determined histopathologically. A significant reduction in MR signal intensity was observed after USPIO injection into rats with allotransplanted hearts. Syngeneic transplants showed no differences in MR signal intensity before and after USPIO injections. After injection of USPIO particles at postoperative day 6, a group of allotransplanted rats was treated with cyclosporin A (3 mg/kg). Animals treated with cyclosporin A for 7 days showed no reduction in MR signal intensity after USPIO reinjection at day 14, whereas animals treated for 4 days showed a significant decrease in MR signal intensity in the transplanted hearts indicative of acute graft rejection. Pathological analysis of these animals revealed that dextran-coated USPIO particles were taken up by the infiltrating macrophages that accumulated within the rejecting cardiac graft.

CONCLUSIONS

This MRI method offers promise as a noninvasive method for detecting transplant allograft rejection.

Phase I and pharmacokinetic study of two sequences of gemcitabine and docetaxel administered weekly to patients with advanced cancer

PURPOSE

To determine the maximum tolerated dose (MTD), dose-limiting toxicity (DLT), and effect of drug sequence on toxicities and pharmacokinetics of the combination of gemcitabine and docetaxel.

METHODS

A total of 34 patients with advanced cancers were treated with gemcitabine and docetaxel on days 1 and 8 of each 21-day cycle according to the following dose escalation schedule: level 1, 800 and 30 mg/m2, respectively; level 2, 800 and 40 mg/m2; level 3, 1,000 and 40 mg/m2; and level 4, 1,250 and 40 mg/m2. At each dose level, at least three patients were assigned to one of the two sequences of drug administration: gemcitabine-->docetaxel or docetaxel-->gemcitabine. Once the MTD had been reached, six additional patients, who had received no more than one chemotherapy regimen, were enrolled to dose levels 3 and 4 (gemcitabine-->docetaxel) to determine the MTD in minimally pretreated patients.

RESULTS

Neutropenia was the most frequent DLT with an overall incidence of 23.5%. Grade 3/4 neutropenia occurred in 62% of patients (8/13) who had received two or more prior chemotherapy regimens, but not at all (0/15) in patients who had received no more than one prior chemotherapy regimens (P< 0.001). Additional DLTs included grade 4 diarrhea and grade 4 stomatitis in one patient each. The MTD was determined to be gemcitabine 800 mg/m2 and docetaxel 40 mg/m2 in patients who had received two or more prior chemotherapy regimens. However, minimally pretreated patients (no more than one prior chemotherapy regimen) were able to tolerate higher doses with an MTD of gemcitabine 1,250 mg/m2 and docetaxel 40 mg/m2. There were no significant differences in toxicities or pharmacokinetics between the two sequences of administration. Partial and minor responses were observed in 23.5% of patients: non-small-cell lung (two of eight), gastric (two of three), head and neck (one of two), bladder (two of four) and hepatocellular cancer (one of one).

CONCLUSIONS

The combination of gemcitabine and docetaxel administered on days 1 and 8 every 21 days was feasible and well tolerated in patients with advanced malignancies. The sequence of administration had no significant effect on the toxicity or pharmacokinetics of either drug. Minimally pretreated patients tolerated higher doses of this combination without significant toxicities. This schedule and combination demonstrated activity in a variety of solid tumors, and merits further evaluation.

Do physiological changes in pregnancy change defibrillation energy requirements?

Resuscitation during pregnancy is uncommon, with approximately 70 deaths occurring during pregnancy in the UK per annum. Physiological changes during pregnancy may affect transthoracic impedance (TTI), which determines transmyocardial current. Increased blood volume, cardiomegaly, haemodilution, changes in lung volume and changes in thoracic volume may alter impedance in ways that are difficult to predict. We measured TTI at term and after delivery once physiological changes had resolved. Mean (SD) TTI was 91.3 (15.8) Omega at term and 91.6 (11.8) Omega 6-8 weeks after delivery; the difference was not statistically significant. We conclude that current energy requirements for adult defibrillation are appropriate for use during pregnancy.

In vitro study of relationship between signal intensity and gadolinium-DTPA concentration at high magnetic field strength

Although gadolinium-diethylene triamine pentaacetic acid (Gd-DTPA) has been used as a contrast material in MRI, it is known that the contrast enhancement effect is not uniform for high concentrations of Gd-DTPA. In order to evaluate the proper pulse sequences for dynamic MRI in aqueous solutions of Gd-DTPA, blood samples and melanoma cells, the signal intensity for several concentrations of Gd-DTPA were measured under inversion recovery (T1-weighted) at high magnetic field strength (7.0 Tesla). For aqueous solutions of Gd-DTPA, signal intensity correlated linearly with the concentration of Gd-DTPA between 0 mmol/L and 4 mmol/L. Using blood and melanoma cells, signal intensity correlated non-linearly with the concentration of Gd-DTPA between 0 mmol/L and 1.5 mmol/L. For concentrations of more than 4 mmol/L in aqueous solutions of Gd-DTPA, 1 mmol/L in blood and 1.5 mmol/L in melanoma, signal intensity decreased with increased Gd-DTPA concentration.

In vivo studies of Gd-DTPA-monoclonal antibody and gd-porphyrins: potential magnetic resonance imaging contrast agents for melanoma

New tumor-specific contrast agents for clinical imaging and therapy for cancer are required. To this end Gd-H (Gd-hematoporphyrin), Gd-TCP (Gd-tetra-carboranylmethoxyphenyl-porphyrin), Gd-DTPA-WM53, and Gd-DTPA-9.2.27 were synthesized and administered by systemic injection to nude mice with human melanoma (MM-138) xenografts. The biodistribution T1 relaxation times and magnetic resonance (MR) image signal enhancement of the contrast agents are presented for the first time and compared for each group of five mice. A change (20%) in T1 relaxation times of water in human melanoma tumor xenografts was revealed 24 hours after injection of the labeled immunoconjugate Gd-DTPA-9.2.27. The percent of injected antibody or gadolinium that localized to the tumor was measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES) to be approximately 35%. A higher concentration of gadolinium was achieved compared with nonspecific compounds, indicating selective delivery of Gd-DTPA-9.2.27 to the melanoma xenografts. Porphyrin-based contrast agents (Gd-H and Gd-TCP) also showed significant uptake in melanomas. The uptake of Gd-TCP by the tumor was sufficient to deliver boron atoms into the tumor, making possible dual use for both MR imaging (MRI) and boron neutron capture therapy (BNCT). The linear relationship found between the paramagnetic contribution to the relaxation rates and contrast agent concentration allows quantitative studies of paramagnetic contrast agent uptake.

A phosphatocopid crustacean with appendages from the Lower Cambrian

Here we describe a phosphatocopid arthropod with preserved soft anatomy from Lower Cambrian rocks of Shropshire, England, which provides evidence for the occurrence of Crustacea, including Eucrustacea, in the Early Cambrian. The find identifies an important, stratigraphically early source of well-preserved fossils (Konservat-Lagerstätte).

Activation of expression of hedgehog target genes in basal cell carcinomas

Mutations in hedgehog signaling pathway genes, especially PTC1 and SMO, are pivotal to the development of basal cell carcinomas. The study of basal cell carcinoma gene expression not only may elucidate mechanisms by which hedgehog signaling abnormalities produce aberrant tumor cell behavior but also can provide data on in vivo hedgehog target gene control in humans. We have found, in comparison with normal skin, that basal cell carcinomas have increased levels of mRNA for PTC1, GLI1, HIP, WNT2B, and WNT5a; decreased levels of mRNA for c-MYC, c-FOS, and WNT4; and unchanged levels of mRNA for PTC2, GLI2, WNT7B, and BMP2 and 4. These findings suggest that mutations in hedgehog signaling pathway genes may exert both cell autonomous and indirect effects and indicate that basal cell carcinoma tumor cells have a phenotype that at least in some aspects resembles that of epidermal stem cells.