Maurice H Zissen

Stanford Medicine, Stanford, California, United States

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Publications (9)24.01 Total impact

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    ABSTRACT: The aim of this study was to evaluate the potential of fluorine-18 (F)-5-fluorouracil (F-5-FU) positron emission tomography/computed tomography (PET/CT) to show differences in 5-FU activity in metastatic colorectal cancer before and after treatment with bevacizumab. This was a pilot study of five patients with newly diagnosed and untreated metastatic colorectal adenocarcinoma. The presence of cancer was confirmed by histopathological analysis before enrollment. Patients underwent F-5-FU PET/CT scanning before treatment and at approximately 24 h postbevacizumab. PET/CT scanning consisted of a dynamic acquisition of images taken 0-20 min after injection of radiotracer. The degree of F-5-FU activity at the metastatic sites was assessed using visual interpretation and semiquantitative standardized uptake value analyses. The sizes of the metastatic lesions ranged from the smallest lesion measuring 3.04 × 1.50 cm to the largest measuring 4.19 × 2.76 cm. By drawing regions of interest, time-activity curves were generated at each tumor site and area under the curve (AUC) analyses were carried out. At baseline, during the first 5 min after F-5-FU injection the mean AUCtumor/AUCaorta ratio was 1.24 ± 0.30 (range, 0.424-2.14). Less than 24 h after the administration of bevacizumab, the AUCtumor/AUCaorta ratio decreased to 1.06 ± 0.32 (range, 0.23-2.13, P=0.04), which represented an average decline of 20.2% (range, 0.4-45%). Radiotracer uptake on the 5, 10, 15, and 20-min images did not show any significant change between baseline and posttreatment. Follow-up CT imaging showed stable tumor size in one patient and a decrease in metastasis size in the remaining four patients. In this pilot study of five patients with metastatic colorectal carcinoma, F-5-FU PET/CT scanning showed a significant perfusion-related decrease in tracer activity 24 h postbevacizumab.
    Nuclear Medicine Communications 03/2011; 32(5):343-7. · 1.38 Impact Factor
  • Maurice Henry Zissen, Pamela Kunz, George Fisher, Andrew Quon
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    ABSTRACT: PURPOSE The aim of this study was to evaluate the potential for 18F-5-fluorouracil (18F-5FU) PET/CT to reveal differences in 5FU uptake in metastatic colorectal cancer before and after treatment with bevacizumab. METHOD AND MATERIALS This was a pilot study of five consecutive patients (4 female, 1 male; mean age, 54.6 years; range, 27-85 years) with newly diagnosed and untreated metastatic colorectal adenocarcinoma. The presence of cancer was confirmed by histopathological analysis and patients served as their own internal control. Each patient underwent baseline 18F-5FU PET/CT scanning prior to treatment with bevacizumab, then received a 90-minute infusion of bevacizumab at a dose of 7.5 mg/kg (mean dose, 437.4 mg; range, 350-518 mg). Approximately 24-hours post-bevacizumab, patients underwent a second 18F-5FU PET/CT. Using CT as an anatomical reference, manually drawn regions-of-interest (ROIs) were drawn around the aorta and all colorectal metastases and time-activity-curves (TAC) were generated at each tumor site. Differences between pre- and post-bevacizumab SUVmax and 5-minute Area Under the Curve ratios (AUCtumor/AUCaorta) were calculated for each lesion as the primary outcome measures. RESULTS The sizes of the metastatic lesions ranged from the smallest lesion measuring 3.04 cm x 1.50 cm to the largest measuring 4.19 cm x 2.76 cm. At baseline, the average SUVmax for 18F-5FU uptake at the metastatic sites 5-minutes after tracer infusion was 3.9 ± 1.4 (range, 0.98 to 8.06) and was not significantly different in patients 24-hours after the administration of bevacizumab, 3.1 ± 1.13 (range, 0.45 to 6.6, p = 0.125). In each of the 5 subjects, the 5-minute AUCtumor/AUCaorta ratio decreased 24 hours after treatment. At baseline, the mean AUCtumor/AUCaorta was 1.24 ± 0.30 (range, 0.424 to 2.14) and was significantly lower in patients 24-hours after the administration of bevacizumab, 1.06 ± 0.32 (range, 0.23 to 2.13, p = 0.04). This represents an average decline in the AUCtumor/AUCaorta of 20.2% (range, 0.4% to 45%). CONCLUSION In this pilot study of five patients with metastatic colorectal carcinoma, 18F-5FU PET/CT scanning revealed decreased tracer uptake 24-hours post-bevacizumab. CLINICAL RELEVANCE/APPLICATION The ability of 18F-5FU PET/CT to visually demonstrate differential chemotherapy delivery may allow for improved therapy monitoring and treatment efficacy in patients with advanced colorectal cancer.
    Radiological Society of North America 2010 Scientific Assembly and Annual Meeting; 11/2010
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    ABSTRACT: OBJECTIVE: The goals of this study were to review the MRI and sonographic findings in patients diagnosed clinically with high hamstring tendinopathy and to evaluate the efficacy of ultrasound-guided corticosteroid injections in providing symptomatic relief. CONCLUSION: MRI is more sensitive than ultrasound in detecting peritendinous edema and tendinopathy at the proximal hamstring origin. Fifty percent of patients had symptomatic improvement lasting longer than 1 month after percutaneous corticosteroid injection, and 24% of patients had symptom relief for more than 6 months.
    American Journal of Roentgenology 10/2010; 195(4):993-8. · 2.90 Impact Factor
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    Maurice H Zissen, Andrew Quon
    European Journal of Nuclear Medicine 07/2009; 36(9):1527. · 4.53 Impact Factor
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    ABSTRACT: Our laboratory has previously characterized age-dependent changes in nociception upon acute morphine withdrawal. This study characterizes changes in mechanical and thermal nociception following acute, intermittent, or continuous morphine administration in infant (postnatal days 5-8) and young (postnatal days 19-21) rats. Morphine was given as a single acute administration (AM), intermittently twice a day for 3 days (IM), or continuously for 72 h via pump (CM). AM did not produce long-term changes in mechanical or thermal nociception in either infant or young rats. CM produced changes in mechanical nociception that included the development of tolerance, opioid-induced mechanical allodynia and withdrawal-associated mechanical allodynia in young rats, but only tolerance and a prolonged withdrawal-associated mechanical allodynia in infant rats. IM produced withdrawal-associated mechanical allodynia in both infant and young rats. Measuring paw withdrawal responses to thermal stimuli, infant and young rats showed tolerance without opioid-induced thermal hyperalgesia or withdrawal-associated thermal hyperalgesia following CM. In contrast to CM, withdrawal-associated thermal hyperalgesia was seen in both ages following IM. In conclusion, CM versus IM differentially modified mechanical and thermal nociception, suggesting that opioid-dependent thermal hyperalgesia and mechanical allodynia can be dissociated from each other in infant and young rats. Furthermore, tolerance, opioid-induced hypersensitivity, and withdrawal-associated hypersensitivity are age-specific and may be mediated by distinct mechanisms.
    Neuroscience 02/2007; 144(1):247-62. · 3.12 Impact Factor
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    ABSTRACT: Matrix Metalloproteinases (MMPs) are zinc-containing proteinases that are responsible for the metabolism of extracellular matrix proteins. Overexpression of MMPs has been associated with a wide range of pathological diseases such as arthritis, cancer, multiple sclerosis and Alzheimer's disease. The excessive and unregulated activity of Matrix Metalloproteinases type 2 (MMP-2), also known as gelatinase A, has been identified in a numbers of cancer metastases. Several MMP inhibitors (MMPi) have been proposed in the literature aiming to interfere in the MMPs activity. In this work we performed long MD simulations in order to study the dynamical behavior of the binding pocket S1' in the apo forms of MMP type 2 and 3, and identify, at the molecular level, the structural properties relevant for the designing of specific inhibitor of MMP-2.
    Current pharmaceutical design 02/2007; 13(34):3471-5. · 4.41 Impact Factor
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    ABSTRACT: The present study tested the hypothesis that morphine exposure during the human developmental equivalent of the third trimester would alter inflammatory pain. This study examined whether acute or continuous opioid exposure in the neonatal rat alters formalin-induced nociception after 4 days of abstinence. Rats were exposed to a single acute administration of morphine on postnatal day 7 or 72 h of opioid infusion from postnatal days 5-7 via osmotic pump. When challenged with intraplantar formalin on postnatal day 11, rats exposed to acute or chronic morphine had increased phase II pain-associated behaviors. These findings suggest that neonatal morphine exposure may have unintended consequences on inflammatory pain.
    Neuroscience Letters 06/2006; 400(1-2):154-7. · 2.03 Impact Factor
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    ABSTRACT: Upon withdrawal from opioids many patients experience a heightened sensitivity to stimuli and an exaggerated pain response. We present evidence that neonatal rats exhibit allodynia and hyperalgesia on acute opiate withdrawal. Postnatal 7 and 21 day rats were used to approximately model a full term human infant and a human child, respectively. The opiate antagonist naloxone was used to precipitate withdrawal at 30 or 120 min after a single acute administration of morphine. Alternatively, rats were allowed to undergo spontaneous withdrawal. Behavioral manifestations of withdrawal syndrome were not observed when naloxone was administered at 30 min post-morphine, but were present when withdrawal was precipitated at 120 min. Spontaneous and precipitated withdrawal from a single acute administration of morphine produced mechanical allodynia and thermal hyperalgesia in postnatal day 7 rats and mechanical allodynia in postnatal day 21 rats. A higher dose of morphine was required to produce mechanical allodynia in postnatal day 21 versus 7 rats but this increase was independent of the analgesic efficacy of morphine at these two ages. The present work illustrates the need to examine the phenomenon of hypersensitivity upon opioid withdrawal in the human pediatric population.
    Pain 08/2004; 110(1-2):269-80. · 5.64 Impact Factor
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    ABSTRACT: Acute morphine withdrawal results in enhanced responsiveness to noxious stimulation in adult humans and rodents. This study extends these findings by demonstrating that acute morphine withdrawal produces allodynia in neonatal rats that is dependent on the translocation of protein kinase C ϵ and γ (ϵPKC and γPKC, respectively) in a developmentally specific manner. Basal expression of ϵPKC in dorsal root ganglia, and γPKC in lamina II of the lumbar spinal cord, were lower in postnatal day 7 (P7) compared with P21 rats. ϵPKC immunoreactivity increased in P7 rats at 4 hours after acute administration of morphine, whereas ϵPKC immunoreactivity decreased at 4 hours in P21 rats. In contrast to ϵPKC, there was a loss of γPKC immunoreactivity following morphine administration in both P7 and P21 rats. To determine whether ϵ and γPKC contribute to acute withdrawal-induced allodynia in neonatal rats, isozyme-specific inhibitors of ϵ and γPKC translocation were administered before or after morphine administration. Naloxone was used to precipitate withdrawal at either 30 or 120 minutes after morphine, or animals were allowed to undergo natural withdrawal from a single dose of morphine. Inhibition of ϵ but not γPKC prevented naloxone-precipitated allodynia 30 minutes after morphine administration in P7 rats. In contrast, both ϵ and γPKC inhibitors attenuated naloxone-precipitated allodynia in P21 rats. Allodynia was attenuated in P7 and P21 rats by administration of either ϵ or γPKC inhibitor when withdrawal was precipitated at 2 hours after morphine or animals underwent natural withdrawal. This work demonstrates that the role of ϵ and γPKC in acute withdrawal-induced allodynia is developmentally regulated in a temporally specific manner.
    Seminars in Pain Medicine. 01/2003; 1(4):206-219.

Publication Stats

59 Citations
24.01 Total Impact Points

Institutions

  • 2003–2011
    • Stanford Medicine
      • Department of Anesthesia
      Stanford, California, United States
  • 2006–2010
    • Stanford University
      • • Department of Radiology
      • • Department of Anesthesia
      Stanford, CA, United States