Deep brain stimulation for the treatment of Parkinson's disease: the experience of the Neurosurgical Department in Monza

deep brain stimulation is a widely accepted surgical therapy for the symptomatic treatment of advanced parkinson's disease; high frequency chronic stimulation of the subthalamic nucleus proved its efficacy to control the major motor symptoms. In the neurosurgical department of Monza we treated 72 parkinsonian patients (November 1998-January 2003). One year follow-up results are: decrease of tremor 90%, hypertonous 56%, bradykinesia 70%, voice impairment amelioration 30%, mean total daily L-dopa intake reduced 58%. Freezing and balance did not ameliorate, some voice impairment and psychic derangement have been observed. Major surgical complications were: haemorrage (1 case - transient hemiparesis), infections (2 cases), pulmonary embolisation (1 case). To optimise the surgical results, careful clinical and instrumental selection of the patients are mandatory before surgery.

MRI indirect stereotactic targeting for deep brain stimulation in Parkinson's disease

AIM

Stereotactic localisation of brain targets for functional neurosurgery might be obtained with different neuroimaging sources. Magnetic resonance (MR) might be of particular interest for its high definition of the various brain structures; unfortunately, magnetic field distortion and inaccuracy in imaging reproduction constrain the use of MRI in stereotactic surgery.

METHODS

We present an experimental work devoted to the utilization of MRI in the targeting of the subthalamic nucleus for deep brain stimulation (DBS) in Parkinsonian patients.

RESULTS

Experimental data were obtained after PVC phantom and fixed human brain measurements of the stereotactic coordinates of specific basal ganglia structures. Intrinsic and external sources of error and imaging distortion have been carefully corrected. Afterwards, 36 patients, operated for DBS in the subthalamus for Parkinson's disease (PD), have been investigated. MRI targeting proved to be clinically successful; comparing anatomical and neurophysiological findings, MRI targeting scattered from the neurophysiological targeting in a minority of cases.

CONCLUSION

MRI targeting proved to be reliable for functional stereotactic surgery, pending careful and adequate quality control of the distortion and of the sources of error.

[Skull base fractures with TMJ involvement: literary review and case report]

The authors report their experience in the treatment of middle skull base fractures with TMJ involvement of ten patients affected by fractures of the glenoid cavity and of the petrous part of the temporal bone, with TMJ disfunction and facial nerve palsy. The treatment has been based on functional rest, a liquid diet for 5 days and than a functional physiotherapy aimed at rehabilitation of the TMJ. The efficacy of treatment has been showed after 2 months by restoring the dental occlusion and the TMJ's function in nine out of ten cases. Three out of four patients (75%) at the same control showed a full resolution of the facial nerve palsy. At an eighth month's follow-up all the cases had a complete resolution of the symptoms. Finally no significant studies have been reported in literature to set standardized protocols for the treatment of glenoid cavity fractures. According to the experience of authors the fractures of the medium cranial base involving the glenoid cavity should be treated as the current trends of intracapsular TMJ fractures. The orthopedic-functional treatment turns out particularly efficacious when there isn't a reduction of mandibular vertical heights.

An assessment of factors related to tumor thickness and delay in diagnosis of melanoma in southern Italy

BACKGROUND

Since survival of patients with melanoma is strongly correlated with the Breslow tumor thickness of the primary lesion, factors that influence stage at diagnosis and delay in diagnosis are considered to be crucial. To test the relationship between tumor thickness and some social and clinical variables (including diagnosis/treatment delay) and the relationship between the diagnosis/treatment delay and some clinical variables, we analyzed data on 530 patients with melanoma from our Institute.

METHODS

In the analysis, Breslow tumor thickness was categorized into two categories (< or =1.49, > or =1.5). Three time intervals were examined to evaluate diagnostic delay: patient delay, time from first symptom to seeking medical advice; medical delay, time from first medical consultation to hospital admission; total delay, time from first symptom to resection. The variables evaluated in the analysis were: age at diagnosis, education, occupational status, first symptom, visibility of tumor, anatomic site, and physician who made the initial diagnosis.

RESULTS

A significant risk of having a Breslow tumor thickness > or =1.5 mm was noted in patients who had a low level of education (odds ratio 3.0, 95% confidence interval 1.9-5.0) or who were unemployed (odds ratio 1.7, 95% confidence interval 1.1-2.8). With respect to patient delay, a delay >3 months for anatomic locations visible to patients was associated with significant risk (odds ratio 1.7, 95% confidence interval 1.1-2.6); with respect to medical delay, a delay >3 months was associated with a higher risk in patients examined by a dermatologist (odds ratio 2.0, 95% confidence interval 1.2-3.4).

CONCLUSIONS

Our results clearly indicate that in Southern Italy poorly educated and unemployed subjects are at risk of being diagnosed at a more advanced stage, and admission to an oncological hospital causes a delay (waiting list) in the time interval related to the doctor (medical delay).

[Prospective regional study of an epidemic of respiratory syncytial virus (RSV) bronchiolitis]

This prospective study was designed to identify risk factors associated with admission in pediatric intensive care units (PICU) among infants hospitalized for treatment of RSV induced bronchiolitis. This study was population-based and was conducted in Burgundy, a French region with 1,800,000 inhabitants where passive immunoprophylaxis for RSV bronchiolitis was not set up at the time of the study.

RESULTS

From December 1st 1999 to April 30th 2000, 484 infants were hospitalized for RSV bronchiolitis in Burgundy: 19.6% were born prematurely (gestational age [GA] below 37 weeks) and at admission, 68.3% had a postnatal age below six months (mean = 5 +/- 5.9 months; median value = 3 months). The duration of hospitalization was 7.3 +/- 12.4 days (median value = 6 days). Among the 484 infants, 31 (6.4%) needed admission in PICU, eight needed mechanical ventilation (1.7%) and one died (0.2%). Univariate analysis identified anamnestic risk factors associated with admission in PICU: prematurity; low birth weight; past history of neonatal respiratory distress syndrome (RDS); mechanical ventilation for RDS treatment; bronchopulmonary dysplasia (BPD) and congenital heart disease. Multivariate analysis identified three independent factors associated with an increased risk for admission in PICU: GA below 32 weeks; RDS and congenital heart disease.

CONCLUSION

This study suggests that population at risk for severe RSV bronchiolitis with PICU admission should include all very preterm infants with RDS whatever the outcome of RDS (with or without BPD). These epidemiological data could be helpful to set up indications for passive immunoprophylaxis of RSV induced bronchiolitis.

Weekly docetaxel in the treatment of elderly patients with advanced breast cancer: a Minnie Pearl Cancer Research Network phase II trial

PURPOSE

To evaluate the efficacy and toxicity of docetaxel administered weekly to elderly or poor-performance status patients with advanced breast cancer.

PATIENTS AND METHODS

Forty-one patients with advanced breast cancer who were either over the age of 65 or considered to be poor candidates for combination chemotherapy received docetaxel 36 mg/m2 weekly for 6 consecutive weeks, followed by 2 weeks without treatment. The median age of patients in this trial was 74 years, and 73% of patients had one or more visceral sites of metastases. Seventy-five percent of patients received weekly docetaxel as first-line treatment for metastatic breast cancer, and the other 25% received it as second-line treatment. Thirty-six patients were assessable for efficacy, and all patients were assessed for toxicity.

RESULTS

A total of 448 doses of weekly docetaxel were administered to 41 patients. Thirteen patients (36%) had objective responses to treatment, and an additional 13 patients (36%) had stable disease or minor response. Median time to progression for responding and stable patients was 7 months (range, 3 to 27 months). Median survival for the entire group was 13 months, with 1- and 2-year actuarial survival rates of 61% and 29%, respectively. Severe neutropenia occurred in only 0.4% of courses, and no other hematologic toxicity was observed. Grade 3/4 fatigue was the most common toxicity, occurring in 20% of patients.

CONCLUSION

Weekly docetaxel therapy is active and well tolerated by elderly and/or poor-performance status patients with advanced breast cancer. This treatment can be administered with minimal myelosuppression. Weekly docetaxel provides an additional option for treatment in this difficult subgroup of patients with metastatic breast cancer. Well-tolerated combination regimens containing weekly docetaxel merit evaluation for this patient population.

Mobilization of calcium from intracellular stores, potentiation of neurotransmitter-induced calcium transients, and capacitative calcium entry by 4-aminopyridine

In this study we analyzed the effect of 4-aminopyridine (4-AP) on free cytosolic calcium concentration ([Ca(2+)](i)) in basal conditions, after stimulation with neurotransmitters, and during capacitative calcium entry. Using fura-2 ratiometric calcium imaging, we found that 4-AP increased [Ca(2+)](i) in type I astrocytes, neurons, and in skeletal muscle cells. The [Ca(2+)](i) elevation induced by 4-AP was concentration-dependent and consisted of two phases: the first was dependent on intracellular calcium mobilization, and the second was dependent on extracellular calcium influx. 4-AP also increased the second messenger inositol trisphosphate in both neurons and astrocytes. In astrocytes, 4-AP treatment potentiated the sustained phase of the [Ca(2+)](i) elevation induced by ATP and bradykinin. In addition, capacitative calcium entry was potentiated severalfold by 4-AP, in astrocytes and muscle cells but not in neurons. These effects of 4-AP were completely and promptly reversible. 4-AP blocked voltage-sensitive K(+) currents in astrocytes. However, voltage-sensitive K(+) channel blockers inhibiting these currents did not affect agonist-induced calcium transients or capacitative calcium entry, indicating that 4-AP effects on [Ca(2+)](i) were not caused by the blockade of voltage-gated K(+) channels. We conclude that 4-AP is able to affect calcium homeostasis at multiple levels, from increasing basal [Ca(2+)](i) to potentiating capacitative calcium entry. The potentiation of capacitative calcium entry in astrocytes or muscle cells may explain some of the therapeutic activities of 4-AP as a neurotransmission enhancer.

Cannabinoid receptor activation and elevated cyclic AMP reduce glutamate neurotoxicity

Cannabinoid receptor activation in vivo reduces ischemic injury, a phenomenon that has not been successfully reproduced in vitro. Because cyclic adenosine monophosphate (cAMP) levels are radically elevated during ischemic reperfusion, but cannabinoid receptor activation reduces cAMP levels, we hypothesized that cannabinoids might prevent in vitro glutamate toxicity if reperfusion was simulated by cAMP supplementation after glutamate removal. Although neuronal cultures were unaffected by the single addition of either cannabinoid or dibutyryl cAMP (dbcAMP), glutamate toxicity was reduced by 20% when cannabinoid was present during glutamate exposure and either dbcAMP or forskolin was added after glutamate removal. Further studies revealed that cannabinoid receptor activation reduces glutamate toxicity by attenuating calcium influx through N- and P/Q-type calcium channels. The effect of glutamate exposure on neuronal cAMP levels was also examined. Glutamate exposure significantly reduced neuronal cAMP levels, although suppression was even greater when cannabinoid was present. Because neurological outcome after ischemia is poor when cAMP levels during reperfusion are low, it is hypothesized that cAMP elevation after glutamate exposure may offset excitotoxic and/or cannabinoid receptor-induced cAMP depletion. Cannabinoids protect against ischemic injury in vivo, but only reduce toxicity in vitro when cAMP levels are elevated, possibly suggesting that cAMP elevation during reperfusion reduces brain injury by off-setting the effect of Gi/o protein-coupled systems on adenylate cyclase.

Usefulness of handgrip to improve ibutilide efficacy in organizing atrial electrical activity during atrial fibrillation

We analyzed the effect of handgrip on atrial electrical activity during atrial fibrillation (AF) by recording right and left atrial activity in 15 patients with persistent AF under baseline conditions and after saline and ibutilide infusions. The handgrip test for 15 seconds, which was always associated with a significant increase in mean atrial cycle length, was recorded in both atria (right atrium: saline vs saline + handgrip 141 +/- 29 vs 171 +/- 24 ms, p <0.001; ibutilide vs ibutilide + handgrip: 197 +/- 43 vs 221 +/- 39 ms, p <0.005). Handgrip favorably modifies atrial electrophysiologic properties during AF.

Regional and cellular expression of the parkin gene in the rat cerebral cortex

A mutation in the parkin gene has been identified as the cause for an autosomal recessively inherited form of early onset Parkinson's disease. We have recently isolated the mRNA coding for the rat homologue of parkin and showed its widespread expression in the central nervous system (CNS) by in situ hybridization. In the present study we investigated the distribution of parkin in the rat cerebral cortex with a polyclonal antibody that reacts with a single approximately 52-kDa protein, corresponding to the predicted molecular mass of parkin. Conventional light microscopic studies revealed intense parkin immunoreactivity (IR) throughout the cortex. Examination of mixed cortical neuro-glial cultures by indirect immunofluorescence technique coupled to traditional epifluorescence and confocal microscopy analysis demonstrated the expression of parkin in the cytoplasm and neurites of neurons, and its absence in glial fibrillary acidic protein (GFAP)-positive astrocytes. The predominant neuronal parkin-IR and -mRNA expression was confirmed by Western blot analysis and reverse transcription-polymerase chain reaction (RT-PCR), respectively, performed on highly enriched neuronal and type I astrocytes cultures. The information gathered in our study about the cellular and subcellular distribution of parkin should facilitate further research on its physiological role in the nervous system.

Prevention of beta-amyloid neurotoxicity by blockade of the ubiquitin-proteasome proteolytic pathway

In many neurodegenerative disorders, such as Alzheimer's disease, inclusions containing ubiquitinated proteins have been found in the brain, suggesting a pathophysiological role for ubiquitin-mediated proteasomal degradation of neuronal proteins. Here we show for the first time that the beta-amyloid fragment 1-40, which in micromolar levels causes the death of cortical neurons, also induces the ubiquitination of several neuronal proteins. Prevention of ubiquitination and inhibition of proteasome activity block the neurotoxic effect of beta-amyloid. These data suggest that beta-amyloid neurotoxicity may cause toxicity through the activation of protein degradation via the ubiquitin-proteasome pathway. These findings suggest possible new pharmacological targets for the prophylaxis and/or treatment of Alzheimer's disease and possibly for other related neurodegenerative disorders.

Neuroprotective antioxidants from marijuana

Cannabidiol and other cannabinoids were examined as neuroprotectants in rat cortical neuron cultures exposed to toxic levels of the neurotransmitter, glutamate. The psychotropic cannabinoid receptor agonist delta 9-tetrahydrocannabinol (THC) and cannabidiol, (a non-psychoactive constituent of marijuana), both reduced NMDA, AMPA and kainate receptor mediated neurotoxicities. Neuroprotection was not affected by cannabinoid receptor antagonist, indicating a (cannabinoid) receptor-independent mechanism of action. Glutamate toxicity can be reduced by antioxidants. Using cyclic voltametry and a fenton reaction based system, it was demonstrated that Cannabidiol, THC and other cannabinoids are potent antioxidants. As evidence that cannabinoids can act as an antioxidants in neuronal cultures, cannabidiol was demonstrated to reduce hydroperoxide toxicity in neurons. In a head to head trial of the abilities of various antioxidants to prevent glutamate toxicity, cannabidiol was superior to both alpha-tocopherol and ascorbate in protective capacity. Recent preliminary studies in a rat model of focal cerebral ischemia suggest that cannabidiol may be at least as effective in vivo as seen in these in vitro studies.

[Diabetic foot. Physiopathology, clinical aspects, and recent therapeutic approaches]

Diabetic foot is a complication of diabetes mellitus occurring in 15% of patients that is of specific surgical interest. Over the past few years, preventive measures and the use of new therapeutic resources has reduced the number of patients undergoing demolitive surgery. The authors present a concise but at the same time sufficiently detailed picture of modern knowledge of the physiopathology, clinical aspects and current therapeutic guidelines for diabetic foot. In particular, they analyse the validity of various forms of complementary treatment to surgery, including techniques to stimulate tissue repair processes, hyperbaric oxygen therapy and laser therapy, and they underline the importance of using a multidisciplinary approach to this pathology. To this end, they review all the articles on the subject reported on Medline from 1992 to June 1998, presenting and commenting on the most significant results.

Randomized trial of sequential administration of G-CSF and GM-CSF vs. G-CSF alone following peripheral blood progenitor cell autograft in solid tumors

A trial was conducted to investigate whether the sequential administration of recombinant human granulocyte colony-stimulating factor (G-CSF) and recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF) could accelerate reconstitution of hematopoiesis, compared with G-CSF alone following high-dose chemotherapy (HDCT). A group of 34 consecutive patients with solid tumors undergoing HDCT and autologous peripheral blood progenitor cell (PBPC) transplantation was studied. Conditioning regimen included carboplatin, etoposide, mitoxantrone, and melphalan for breast cancer and cyclophosphamide or ifosfamide, carboplatin, and etoposide for the other tumors. HDCT was delivered from day -3 to day -1. PBPC were infused on day 0, and on the same day growth factors were administered subcutaneously (s.c.) 5 microg/kg each. Seventeen patients were randomized to receive G-CSF from day 0 to day 13 after HDCT (arm A), and 17 patients received G-CSF from day 0 to day 6 and GM-CSF from day 7 to day 13 (arm B). Patients were stratified, and their characteristics were homogeneous in both arms for age, performance status, and number of previous chemotherapy courses and CD34+ infused. The median time to absolute neutrophil count (ANC) >500/microl was 10 days in arm A and 9 days in arm B (p = 0.96). Days to platelet (PLT) count >20,000 were not different in the two treatment arms (p = 0.1), but patients randomized to arm A had a lower platelet count compared with patients in arm B. One month after PBPC transplantation, a statistically significant difference in PLT count was observed (arm A median 150x10(3)/microl (90-310), arm B median 254x10(3)/microl (117-387),p = 0.0013). The days patients had fever >38 degrees C were 39 in arm A and 26 in arm B (p = 0.18). The difference in the length of hospital stay was not statistically significant between the groups (Mann-Whitney sum rank test). After a median follow-up of 30 months, 21 patients were alive and 20 were disease free. These data show that the two growth factors are associated with different patterns of hematopoietic recovery, and larger randomized trials in groups of more homogeneous patients will be needed to define the effects and benefits of combination growth factor therapies.

Effect of lengthening of peptide backbone by insertion of chiral beta-homo amino acid residues: conformational behavior of linear peptides containing alternating L-leucine and beta-homo L-leucine residues

The synthesis and the solution behavior of the linear peptides containing a beta-homo (beta-H) leucine residue-Boc-Leu-beta-HLeu-Leu-OMe, Boc-beta-HLeu-Leu-beta-HLeu-Leu-OMe, and Boc-Leu-beta-HLeu-Leu-beta-HLeu-Leu-OMe-as well as the solid structure of the tripeptide, are reported. The conformational behavior of the peptides was investigated in solution by two-dimensional nmr. Our data support the existence in solution with different families of conformers in rapid interchange. The crystals of the tripeptide are orthorhombic, space group P2(1)2(1)2, with a = 15.829(1) A, b = 29.659(1) A, c = 6.563(1) A, and Z = 4. The structure has been solved by direct methods and refined to final R1 and wR2 indexes of 0.0530 and 0.1436 for 2420 reflections with I > 2sigma(I). In the solid state, the tripeptide does not present intramolecular H bonds, and the peptide backbone of the two leucine residues adopts a quasi-extended conformation. For the beta-HLeu residue, the backbone conformation is specified by the torsion angles straight phi(2) = -120.9(4) degrees, mu(2) = 56.7(4) degrees, psi(3) = -133.2(4) degrees. The side chains of the three residues assume the same conformation (g(-), g(-), trans), and all peptide bonds, except the urethane group at the N-terminus, are in the trans conformation. Preliminary conformational energy calculations carried out on the Ac-NH-beta-HAla-NHMe underline that the conformations with mu angle equal to 180 degrees and 60 degrees assume lower energy with respect to the others. In addition, we found a larger conformational freedom for the psi angle with respect to the straight phi angle.

Natural history of cirrhotic patients with small esophageal varices: a prospective study

OBJECTIVE

Contrasting data are available on the natural history and bleeding risk of small esophageal varices. The aim of this prospective study was to evaluate a large series of consecutive cirrhotics with a first endoscopic diagnosis of small varices.

METHODS

Between 1987 and 1992, 258 patients with small varices and no previous bleeding were enrolled. Patients were clinically examined every 6 months and were followed until a first episode of bleeding and/or death, or until June 1998. None received any treatment to prevent bleeding. Endoscopies were planned at 18-month intervals.

RESULTS

The cumulative risk of bleeding was low (3% at 2 yr and 8% at 4 yr) and remained low in patients in whom varices remained small at 2nd endoscopy, whereas it increased significantly when varices enlarged. The increase of varices appeared to be rather linear in time: at the 2nd endoscopy varices remained small in 79% of patients and increased in 21%; at the 3rd endoscopy varices remained small in 55%, whereas at the 4th 33% of patients still had small varices. Clinical and biochemical data at the 1st and 2nd endoscopy were included in a multiple logistic regression analysis. Only the increase in Child-Pugh score appeared to be a significant predictor of enlarged varices; the risk of aggravation increased by 37.5% for every unit of impairment of the score.

CONCLUSIONS

The present study shows that patients with small varices have a low bleeding risk. An increase in Child-Pugh score during follow-up suggests enlargement of varices, thus an increase in bleeding risk. In these patients closer endoscopic surveillance is recommended.

cAMP-induced cytoskeleton rearrangement increases calcium transients through the enhancement of capacitative calcium entry

In this report we investigated the correlation between cell morphology and regulation of cytosolic calcium homeostasis. Type I astrocytes were differentiated to stellate process-bearing cells by a 100-min exposure to cAMP. Differentiation of cortical astrocytes increased the magnitude and duration of calcium transients elicited by phospholipase C-activating agents as measured by single cell Fura-2-based imaging. Calcium imaging showed differences in the spatial pattern of the response. In both differentiated and the control cells, the response originated in the periphery and gradually extended into the center of the cell. However, the elevation of cytosolic calcium concentration ([Ca(2+)](i)) was particularly evident within the processes and adjacent to the inner cell membrane of the differentiated astrocytes. In addition, differentiation significantly prolonged the duration of the [Ca(2+)](i) elevation. Potentiation of the calcium transients was mimicked by forskolin-induced differentiation and abolished by a specific protein kinase-A blocker. Conversely, the enhancement of the calcium transients was not mimicked by brief exposure to cAMP not causing morphological differentiation, and in PC12 cells that did not undergo morphological changes after 100 min of cAMP treatment. Impairing cAMP-induced cytoskeleton re-organization, by means of cytochalasin D and nocodazole, prevented the potentiation of the calcium transients in cAMP-treated astrocytes. Phospholipase C activity and sensitivity to inositol (1,4,5)-trisphosphate were not involved in the enhancement of the calcium responses. Also, potentiation of the calcium transients was dependent on extracellular calcium. Calcium storage and thapsigargin-depletable intracellular calcium reservoirs were analogously not increased in differentiated astrocytes. Rearrangement of the cell shape also caused a condensation of the endoplasmic reticulum and altered the spatial relationship between the endoplasmic reticulum and the cell membrane. In conclusion, morphological rearrangements of type I astrocytes increase the magnitude and the duration of agonist-induced calcium transients via enhancement of capacitative calcium entry and is associated with a spatial reorganization of the relationship between cell membrane and the endoplasmic reticulum structures.