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M Guarnieri

Publications and source records attributed to M Guarnieri.

At least 19 recordsLinked to original sources
PubMed2006

Pollen carbohydrates and water content during development, presentation, and dispersal: a short review.

Pollen accumulates starch reserves during development and the final stage of ripening. Before the anther opens, starch is totally or partially converted to pectins, glucose, fructose, sucrose, and to some unknown polysaccharides. Pollen is exposed to dispersing agents in an arrested developmental state which differs according to pollen water content. Pollen is classified as partially dehydrated or partially hydrated. The final water content may be reached before or after anther opening. Especially during exposure and dispersal, partially dehydrated pollen may interconvert soluble and insoluble reserves, modifying internal turgor pressure and hindering water loss or gain. Partially hydrated pollen is commonly devoid of mechanisms to conserve viability in time but has the advantage of quickly emitting pollen tubes on reaching the stigma.

Carbohydrates↗
PubMed2004

An open-label evaluation of the tolerability and safety of Stalevo (carbidopa, levodopa and entacapone) in Parkinson's disease patients experiencing wearing-off.

OBJECTIVES: To evaluate the tolerability, safety and efficacy of Stalevo (carbidopa, levodopa and entacapone) in Parkinson's disease (PD). BACKGROUND: Levodopa provides the most effective symptom control for the treatment of Parkinson's disease (PD). However, its long-term use is limited by the development of motor complications such as wearing-off. Catechol-O-methyltransferase (COMT) inhibitors such as entacapone extend the plasma half-life of levodopa and reduce 'off' time. Stalevo is a new levodopa product that combines carbidopa, levodopa and entacapone in one tablet. Clinical studies have not been reported with this compound. DESIGN METHODS: An open-label, multi-center US trial evaluated 169 consecutive PD patients experiencing end-of-dose wearing-off, with (n = 39) and without (n = 130) mild dyskinesia. Patients were switched from immediate-release carbidopa/levodopa to Stalevo and were treated for four weeks. Assessments included tolerability measures, adverse events profile, the disease-specific quality of life instrument PDQ-39, UPDRS parts II, III, and question 39 and investigator and patient global clinical assessments. RESULTS: 14 subjects (8%) discontinued treatment with Stalevo, of which 12 (7%) were due to adverse events. 11/130 (8.5%) subjects developed new onset dyskinesia and 17/39 (43.6%) of patients with existing dyskinesia reported a worsening in their dyskinesia. However, this was managed by a change in dose in 21.4% of patients and in another 10.7% dyskinesias resolved without any need for dose adjustment. Other side effects were infrequent and mild, the most common being nausea (12.4%) dizziness (6.5%) and somnolence (6.5%). Stalevo treatment resulted in significant improvements in PDQ-39 and UPDRS (II + III) scores (p < 0.001). Assessment of 'off' time demonstrated a reduction in off time in 32% of patients, compared with an increase in 7% of patients. Improvements were noted by both investigator (68.1%) and patient (68.6%) assessments. CONCLUSIONS: Switching PD patients experiencing wearing-off from carbidopa/levodopa therapy to Stalevo was safe, well tolerated and resulted in clinical improvement.

Adult↗
PubMed2004

Double-blind, placebo-controlled study of entacapone in levodopa-treated patients with stable Parkinson disease.

BACKGROUND: The catechol O-methyltransferase inhibitor entacapone acts by extending the elimination half-life of levodopa and is currently approved as an adjunct to levodopa for the treatment of patients with Parkinson disease (PD) with motor fluctuations. OBJECTIVE: To determine if the addition of entacapone administration provides benefit to levodopa-treated PD patients who have a stable response to levodopa and do not experience motor complications. DESIGN: Prospective, double-blind, placebo-controlled trial. SETTING: Outpatient multicenter study. PATIENTS: Female and male patients 30 years or older with idiopathic PD receiving stable doses of levodopa or carbidopa with or without other dopaminergic therapies and who did not experience motor fluctuations were eligible for the study. MAIN OUTCOME MEASURES: Parkinsonian function and quality of life. RESULTS: The addition of entacapone did not improve motor scores on the Unified Parkinson's Disease Rating Scale in levodopa-treated PD patients who did not experience motor fluctuations. The mean +/- SE adjusted change between baseline and final treatment visit was -0.9 +/- 0.35 in the entacapone group and -0.8 +/- 0.35 in the placebo group (P = .83). Significant improvement with entacapone treatment was detected in several quality-of-life measures, including the Parkinson Disease Questionnaire 39, the 36-item Short-Form Health Survey, the Parkinson's Symptom Inventory, and investigator and subject Clinical Global Assessments. The drug was well tolerated by patients in this population. CONCLUSIONS: The catechol O-methyltransferase inhibitor entacapone, used as an adjunct to levodopa in PD patients who do not experience motor fluctuations, does not improve Unified Parkinson's Disease Rating Scale motor scores but does improve a variety of quality-of-life measures.

Aged↗
PubMed2004

Toxicity and cerebrospinal fluid levels of carboplatin chronically infused into the brainstem of a primate.

PURPOSE: Carboplatin was infused into the brainstem of cynomolgus monkeys to investigate neurotoxicity and systemic exposures following chronic local delivery. METHODS: Infusions at 0.42 microl/h were intended to deliver 0.025 (n = 2), 0.075 (n = 3), 0.25 (n = 5), and 0.75 (n = 3) mg/kg by day 30. Laboratory tests, radiographic measurements, and clinical observations were used to monitor toxicity. Blood and cerebrospinal fluid (CSF) were sampled for platinum. RESULTS: Lethargy and ataxia were observed after week 4 in the monkeys given 0.075 mg/kg, and week 2 in the monkeys given 0.25 mg/kg when the infused doses were approximately 250 and 400 microg, respectively. Rapidly progressive neurotoxicity with the 0.75 mg/kg dose required termination of the infusions at days 4-10. Hematology and chemistry values were unremarkable in all groups. Blood levels of platinum remained undetectable in 0.025 and 0.075 mg/kg dose groups. Levels in the 0.25 mg/kg group were 3.1 +/- 0.6 microg/l at 2 weeks and 5.2 +/- 0.8 microg/l at 1 month. The CSF platinum levels varied. Animals in the 0.25 mg/kg group had higher CSF levels at 2 weeks (avg. 65 microg/l, range 36-89) compared to their 1 month value (avg. 60 microg/l, range 7-170), despite the constant infusion. CONCLUSION: Carboplatin can be chronically infused into monkey brainstems. Neurotoxicity is the predominant side effect and is dose-dependent. Pharmacokinetics of local and systemic delivery are different for carboplatin. Further studies are needed to monitor toxicity at higher flow rates and to investigate drug binding to abnormal central nervous system (CNS) tissues.

Animals↗
PubMed2002

Experimental rodent models of brainstem tumors.

Despite recent advances in surgical technology, resection is not an option for many brainstem tumors. Experimental models have played essential roles in examining new approaches to therapy. The objective of the present study was to generate models by determining coordinates for safe inoculation into the brainstem of mice and rats, and to establish whether the implantation of heterotopic cells would create reproducible survival curves. Morbidity and survival studies were used to map stereotactic coordinates allowing successful inoculation of tumor cells. Survival studies were used to investigate the time course of tumor growth. Tumor location was examined by light microscopy and magnetic resonance imaging. Mice survived injections of 2 microL of saline at interaural, lateral, and depth coordinates of -2.5, 1.0, and 3.5 mm and -1.5, 1.0, and 3.5 mm. Rats survived injections at interaural, lateral, and depth coordinates of -2.0, 2.0, and 7.0 mm and -3.0, 0, and 7.0 mm. Median survival of mice challenged with 5 x 10(5) EMT6 and 10(4) B16 tumor cells was 11 and 10 days, respectively. Median survival for rats challenged with 10(4) 9L and F98 cells was 14 and 13 days, respectively. The present study demonstrates a feasible approach to preparing models of brainstem tumors. Limitations of these models are discussed.

Animals↗
PubMed2000

An assistive device for the treatment of positional plagiocephaly.

An assistive device (AD) was used to treat 122 infants with moderate-to-severe positional plagiocephaly. Clinical evaluations indicate that the AD provided the most benefit when applied to 2- to 8-month-old children. Our results suggest that the AD may join molding helmets and physical therapy as a treatment for moderate-to-severe positional plagiocephaly in infants under the age of 1 year.

Craniosynostoses↗
PubMed2000

Current opinions for the treatment of syringomyelia and chiari malformations: survey of the Pediatric Section of the American Association of Neurological Surgeons.

INTRODUCTION: A variety of surgical interventions have been recommended for patients with syringomyelia and Chiari malformation. To obtain a better understanding of currently used management strategies and surgical interventions, this study evaluates current opinions in the treatment of these entities. METHODS: Members of the Pediatric Section of the American Association of Neurological Surgeons (AANS) were surveyed in July of 1998. A questionnaire was designed to assess (1) management of asymptomatic and symptomatic cases; (2) signs and symptoms that warrant surgical intervention, and (3) surgical strategies. Seventy-seven of 234 surveys (33%) were returned. Responses were entered in a Microsoft Excel spreadsheet for data analysis. RESULTS: Each year, respondents evaluated on average 10 patients with confirmed syringomyelia and operated on 7. There was substantial agreement to operate on patients with syringomyelia who had progressive scoliosis or progressive motor/sensory loss. For isolated syringomyelia without a Chiari malformation, the majority of respondents recommended shunting of the syrinx. Opinion was mixed concerning physical restrictions for asymptomatic patients with syringomyelia and Chiari malformations. For Chiari malformations, the majority of respondents recommended a minimum cervicomedullary decompression with dural patch grafting. No consensus was obtained on whether dural patch grafting should be done alone or in combination with intradural dissection or manipulation of the tonsils. CONCLUSION: Although many respondents agreed on the management and surgical treatment of symptomatic patients with syringomyelia and/or Chiari malformations, there was disagreement with regard to the optimal surgical procedure. Respondents rejected prophylactic surgery for their asymptomatic patients, choosing to follow them conservatively with serial imaging and neurological examinations.

Arnold-Chiari Malformation↗
PubMed2000

Paracrine delivery of IL-12 against intracranial 9L gliosarcoma in rats.

OBJECT: Interleukin-12 (IL- 12) has potential for the treatment of tumors because it can stimulate an antitumor immune response and possesses antiangiogenic properties. In the study reported here, the authors investigated the therapeutic role of locally delivered IL-12 in a malignant brain tumor model. METHODS: After genetically engineering 9L gliosarcoma cells to express IL-12 (9L-IL12 cells), the authors used these cells as a source of locally delivered cytokine. First, they investigated the behavior of these cells, which were implanted with the aid of stereotactic guidance into the rat brain, by using serial magnetic resonance imaging and histopathological examination. Second, they assessed the antitumor efficacy of proliferating, as well as nonproliferating (irradiated), 9L-IL12 cells by implanting these cells in animals challenged by wild-type 9L gliosarcoma (9Lwt) cells. The IL-12 expression in brain regions injected with 9L-IL12 was confirmed by reverse transcription-polymerase chain reaction. Last, the authors explored whether animals treated with 9L-IL12 cells developed an antitumor immunological memory by rechallenging the survivors with a second injection of 9Lwt cells. The authors demonstrated that local delivery of IL-12 into the rat brain by genetically engineered cells significantly prolongs survival time in animals challenged intracranially with a malignant glioma. CONCLUSIONS: These findings support continued efforts to refine local delivery systems of IL-12 in an attempt to bring this therapy to clinical trials.

Animals↗
PubMed2000

Asymptomatic Chiari Type I malformations identified on magnetic resonance imaging.

OBJECT: Chiari Type I malformation (CMI) is a congenital disorder recognized by caudal displacement of the cerebellar tonsils through the foramen magnum and into the cervical canal. Frequently, associated findings include abnormalities of nearby bony and neural elements as well as syringomyelia. Cerebellar tonsillar ectopia is generally considered pathological when greater than 5 mm below the foramen magnum. However, asymptomatic tonsillar ectopia is an increasingly recognized phenomenon, the significance of which is poorly understood. METHODS: The authors retrospectively reviewed the records of all brain magnetic resonance (MR) images obtained at our hospital over a 43-month period in an attempt to ascertain the relative prevalence and MR imaging characteristics of asymptomatic CMIs. Of 22,591 patients who underwent MR imaging of the head and cervical spine, 175 were found to have CMIs with tonsillar herniation extending more than 5 mm below the foramen magnum. Of these, 25 (14%) were found to be clinically asymptomatic. The average extent of ectopia in this population was 11.4 +/- 4.86 mm, and was significantly associated with a smaller cisterna magna. Syringomyelia and osseous anomalies were found in only one asymptomatic patient. CONCLUSIONS: The authors suggest that the isolated finding of tonsillar herniation is of limited prognostic utility and must be considered in the context of all available clinical and radiographic data. Strategies for treating patients with asymptomatic CMIs are discussed.

Adult↗
PubMed1999

Cave painting hazard?

Explore the source record for details and available documents.

Carbon Monoxide Poisoning↗
PubMed1999

Fiberoptic delivery of laser energy to remove occlusions from ventricular shunts: technical report.

OBJECTIVES: Shunts frequently require surgical replacement because occlusions block the ventricular tubing. We have examined the hypothesis that a surgical laser coupled to an optical fiber can deliver sufficient energy to disrupt the occlusion in situ and thus afford a less invasive method of repair. METHODS: Choroid plexus tissue found in shunts explanted from patients, model tissues such as polyacrylamide gel, and animal tissues inserted into shunts were examined. Occlusions were fragmented by pulsed laser energy of 2.09-microm wavelength and 300-microsecond duration delivered via a flexible optical fiber several meters in length. The methods and conditions were similar to those likely to be used for preclinical in vivo studies. RESULTS: Short-lived vapor bubbles generated at the fiber tip disrupted occlusions within the shunt and expelled tissue blocking the inflow holes. Energy requirements to disrupt and remove occlusions in vitro were determined. Laser pulse energies and exposure thresholds that cause intentional damage to shunts also were determined. CONCLUSION: Laser energies needed to disrupt occlusions were below the energy needed to damage the shunt components. Our results show that a strategy using surgical lasers and optical fibers is feasible and suggest that the procedure could be used to repair blocked shunts without requiring surgical replacement.

Animals↗
PubMed1998

Regional cerebral blood flow in juvenile systemic lupus erythematosus: a prospective SPECT study. Single photon emission computed tomography.

OBJECTIVE: Using single photon emission computed tomography (SPECT) we evaluated the presence and evolution of changes in brain perfusion in juvenile systemic lupus erythematosus (JSLE). METHODS: SPECT was performed in 14 patients with active JSLE divided in 2 groups: the first included 7 patients without central nervous system (CNS) involvement and the second 7 patients with minor neuropsychiatric symptoms (headache, reactive depression, cognitive impairment, mood swing). SPECT findings were compared to seroimmunological and magnetic resonance imaging (MRI) data. After 6 month followup, a second SPECT scan was performed in 12 of 14 patients. RESULTS: At baseline, SPECT showed perfusion defects in 2 patients without neuropsychiatric symptoms and in 5 patients with CNS involvement. In one of the 7 patients with altered SPECT, MRI showed focal hyperintensities. MRI alterations were observed in another patient who had a normal SPECT scan. Cortical atrophy was present in 5 of 14 patients. Correlation between neuropsychiatric manifestations and SPECT findings was not clearly evident because the major part of JSLE patients with CNS involvement and with SPECT alterations had multiple symptoms, but showed focal hypoperfusion on SPECT imaging. No significant association was found between seroimmunological data and SPECT findings. At followup, improvement of perfusion alterations was observed in 6 of 7 patients with altered SPECT and, in 3 of them, findings might be attributed to changes in steroid treatment. CONCLUSION: Perfusion abnormalities in SLE may represent reversible lesions or subclinical CNS involvement. Moreover, SPECT imaging appears to be useful in detecting and monitoring CNS involvement in SLE.

Adolescent↗
PubMed1997

Lambdoid synostosis and occipital plagiocephaly: clinical decision rules for surgical intervention.

Lambdoid craniosynostosis has been regarded as one of the least common categories of premature fusion of the cranial sutures, yet reports have suggested the incidence may be increasing. To guide treatment decisions, the authors describe a set of rules based on radiographic indicators and clinical assessment in the child. Experience suggests that children can have abnormal-appearing cranial sutures with normal neurological status and normal-appearing sutures with neurological deficits or marked cerebral compression. Early evaluation and follow-up treatment is essential for children with suspected craniosynostosis.

Journal Article↗
PubMed1997

Third ventricular choroid plexus papilloma with psychosis. Case report.

This 9-year-old boy with a history of behavioral problems and worsening psychosis responded initially to treatment with haloperidol. However, a magnetic resonance image obtained as part of his psychiatric evaluation revealed an anterior third ventricle tumor and mild-to-moderate hydrocephalus. The resected tumor was found on pathological examination to be a choroid plexus papilloma. The patient had an uneventful postoperative course and remained free of psychosis or mood disorder at 1-year follow-up examination.

Cerebral Ventricles↗
PubMed1996

Accidents and acts of God: a history of the terms.

Despite criticism from safety professionals, scientists continue to use the word accident, meaning an unexpected, unintended injury, or event. Some argue for its use based on tradition, but "traditional" arguments appear to be invalid given our examination of the history of the word and its companion phrase act of God in statistics, law, and religion. People who were interested in public health recognized in the 1600s that unintended injuries were neither random nor unexpected. Legal scholars in the 1800s saw the word was useless for technical purposes. The word does not appear in the Bible until the mid 1900s and then only in a para-phrased edition. Others have maintained that the meaning of accident is well understood, even though it has not been perfectly defined. We maintain that without a clear definition, people substitute an image, which may be distorted or damaging.

Accidents↗
PubMed1996

Hemispherectomy: a hemidecortication approach and review of 52 cases.

Between 1975 and 1994, 52 hemispherectomies, of which two were anatomical and 50 hemidecortications, were performed at Johns Hopkins Medical Institutions. Eighteen patients were 2 years old or less. There were three perioperative mortalities and one patient died 9 months later from causes not related to surgery. One patient developed hydrocephalus 6 years postsurgery and has been treated effectively. Seizure control and the functional status of each patient were measured as outcome variables. Forty-six (96%) of the surviving patients were seizure free or had reduced seizures as of their last follow-up examination. Twenty-one individuals (44%) were participating in age-appropriate classes or working independently, 18 were classified as semiindependent, and nine children will likely depend on a lifetime of assisted living. The relationships between the outcome variables and the patient's age at surgery, the interval to surgery, and the etiology of the disease were compared. The authors' clinical experiences strongly suggest the importance of a multidisciplinary approach to patient selection and follow-up care. Moreover, anesthetic management of infant surgery is a major component of success.

Adolescent↗