Detecting new Buffel grass infestations in Australian arid lands: evaluation of methods using high-resolution multispectral imagery and aerial photography.

We assess the feasibility of using airborne imagery for Buffel grass detection in Australian arid lands and evaluate four commonly used image classification techniques (visual estimate, manual digitisation, unsupervised classification and normalised difference vegetation index (NDVI) thresholding) for their suitability to this purpose. Colour digital aerial photography captured at approximately 5 cm of ground sample distance (GSD) and four-band (visible­near-infrared) multispectral imagery (25 cm GSD) were acquired (14 February 2012) across overlapping subsets of our study site. In the field, Buffel grass projected cover estimates were collected for quadrates (10 m diameter), which were subsequently used to evaluate the four image classification techniques. Buffel grass was found to be widespread throughout our study site; it was particularly prevalent in riparian land systems and alluvial plains. On hill slopes, Buffel grass was often present in depressions, valleys and crevices of rock outcrops, but the spread appeared to be dependent on soil type and vegetation communities. Visual cover estimates performed best (r 2 0.39), and pixel-based classifiers (unsupervised classification and NDVI thresholding) performed worst (r 2 0.21). Manual digitising consistently underrepresented Buffel grass cover compared with field- and image-based visual cover estimates; we did not find the labours of digitising rewarding. Our recommendation for regional documentation of new infestation of Buffel grass is to acquire ultra-high-resolution aerial photography and have a trained observer score cover against visual standards and use the scored sites to interpolate density across the region.

Asymmetrical lateral ventricular enlargement in Parkinson's disease.

BACKGROUND: A recent case report suggested the presence of asymmetrical lateral ventricular enlargement associated with motor asymmetry in Parkinson's disease (PD). The current study explored these associations further. METHODS: Magnetic resonance imaging (3T) scans were obtained on 17 PD and 15 healthy control subjects at baseline and 12-43 months later. Baseline and longitudinal lateral ventricular volumetric changes were compared between contralateral and ipsilateral ventricles in PD subjects relative to symptom onset side and in controls relative to their dominant hand. Correlations between changes in ventricular volume and United Parkinson's disease rating scale motor scores (UPDRS-III) whilst on medication were determined. RESULTS: The lateral ventricle contralateral to symptom onset side displayed a faster rate of enlargement compared to the ipsilateral (P = 0.004) in PD subjects, with no such asymmetry detected (P = 0.312) in controls. There was a positive correlation between ventricular enlargement and worsening motor function assessed by UPDRS-III scores (r = 0.96, P < 0.001). DISCUSSION: There is asymmetrical lateral ventricular enlargement that is associated with PD motor asymmetry and progression. Further studies are warranted to investigate the underlying mechanism(s), as well as the potential of using volumetric measurements as a marker for PD progression.

Task specific influences of Parkinson's disease on the striato-thalamo-cortical and cerebello-thalamo-cortical motor circuitries.

The motor deficits in Parkinson's disease (PD) have been primarily associated with internally guided (IG), but not externally guided (EG), tasks. This study investigated the functional mechanisms underlying this phenomenon using genetically-matched twins. Functional magnetic resonance images were obtained from a monozygotic twin pair discordant for clinical PD. Single-photon emission computed tomography neuroimaging using [(123)I](-)-2-beta-carboxymethoxy-3-beta-(4-iodophenyl)tropane confirmed their disease-discordant status by demonstrating a severe loss of transporter binding in the PD-twin, whereas the non-PD-twin was normal. Six runs of functional magnetic resonance imaging (fMRI) data were acquired from each twin performing EG and IG right-hand finger sequential tasks. The percentage of voxels activated in each of several regions of interest (ROI) was calculated. Multiple analysis of variance was used to compare each twin's activity in ROIs constituting the striato-thalamo-cortical motor circuits [basal ganglia (BG)-cortical circuitry, but including the globus pallidus/putamen, thalamus, supplementary motor area, and primary motor cortex] and cerebello-thalamo-cortical circuits (cerebellar-cortical circuitry, including the cerebellum, thalamus, somatosensory cortex, and lateral premotor cortex). During the EG task, there were no significant differences between the twins in bilateral BG-cortical pathways, either basally or after levodopa, whereas the PD-twin had relatively increased activity in the cerebellar-cortical pathways basally that was normalized by levodopa. During the IG task, the PD-twin had less activation than the non-PD-twin in ROIs of the bilateral BG-cortical and cerebellar-cortical pathways. Levodopa normalized the hypoactivation in the contralateral BG-cortical pathway, but "over-corrected" the activation in the ipsilateral BG-cortical and bilateral cerebellar-cortical pathways. In this first fMRI study of twins discordant for PD, the data support the hypothesis that BG-cortical and cerebellar-cortical pathways are task-specifically influenced by PD. The levodopa-induced "over-activation" of BG-cortical and cerebellar-cortical pathways, and its relevance to both compensatory changes in PD and the long-term effects of levodopa in PD, merit further exploration.

Combined Diffusion Tensor Imaging and Apparent Transverse Relaxation Rate Differentiate Parkinson Disease and Atypical Parkinsonism.

BACKGROUND AND PURPOSE: Both diffusion tensor imaging and the apparent transverse relaxation rate have shown promise in differentiating Parkinson disease from atypical parkinsonism (particularly multiple system atrophy and progressive supranuclear palsy). The objective of the study was to assess the ability of DTI, the apparent transverse relaxation rate, and their combination for differentiating Parkinson disease, multiple system atrophy, progressive supranuclear palsy, and controls. MATERIALS AND METHODS: A total of 106 subjects (36 controls, 35 patients with Parkinson disease, 16 with multiple system atrophy, and 19 with progressive supranuclear palsy) were included. DTI and the apparent transverse relaxation rate measures from the striatal, midbrain, limbic, and cerebellar regions were obtained and compared among groups. The discrimination performance of DTI and the apparent transverse relaxation rate among groups was assessed by using Elastic-Net machine learning and receiver operating characteristic curve analysis. RESULTS: Compared with controls, patients with Parkinson disease showed significant apparent transverse relaxation rate differences in the red nucleus. Compared to those with Parkinson disease, patients with both multiple system atrophy and progressive supranuclear palsy showed more widespread changes, extending from the midbrain to striatal and cerebellar structures. The pattern of changes, however, was different between the 2 groups. For instance, patients with multiple system atrophy showed decreased fractional anisotropy and an increased apparent transverse relaxation rate in the subthalamic nucleus, whereas patients with progressive supranuclear palsy showed an increased mean diffusivity in the hippocampus. Combined, DTI and the apparent transverse relaxation rate were significantly better than DTI or the apparent transverse relaxation rate alone in separating controls from those with Parkinson disease/multiple system atrophy/progressive supranuclear palsy; controls from those with Parkinson disease; those with Parkinson disease from those with multiple system atrophy/progressive supranuclear palsy; and those with Parkinson disease from those with multiple system atrophy; but not those with Parkinson disease from those with progressive supranuclear palsy, or those with multiple system atrophy from those with progressive supranuclear palsy. CONCLUSIONS: DTI and the apparent transverse relaxation rate provide different but complementary information for different parkinsonisms. Combined DTI and apparent transverse relaxation rate may be a superior marker for the differential diagnosis of parkinsonisms.

Structural Imaging and Parkinson's Disease: Moving Toward Quantitative Markers of Disease Progression.

Parkinson's disease (PD) is a progressive age-related neurodegenerative disorder. Although the pathological hallmark of PD is dopaminergic cell death in the substantia nigra pars compacta, widespread neurodegenerative changes occur throughout the brain as disease progresses. Postmortem studies, for example, have demonstrated the presence of Lewy pathology, apoptosis, and loss of neurotransmitters and interneurons in both cortical and subcortical regions of PD patients. Many in vivo structural imaging studies have attempted to gauge PD-related pathology, particularly in gray matter, with the hope of identifying an imaging biomarker. Reports of brain atrophy in PD, however, have been inconsistent, most likely due to differences in the studied populations (i.e. different disease stages and/or clinical subtypes), experimental designs (i.e. cross-sectional vs. longitudinal), and image analysis methodologies (i.e. automatic vs. manual segmentation). This review attempts to summarize the current state of gray matter structural imaging research in PD in relationship to disease progression, reconciling some of the differences in reported results, and to identify challenges and future avenues.

Interactions of the novel antipsychotic aripiprazole (OPC-14597) with dopamine and serotonin receptor subtypes.

OPC-14597 {aripiprazole; 7-(-4(4-(2,3-dichlorophenyl)-1-piperazinyl) butyloxy)-3,4-dihydro-2(1H)-quinolinone} is a novel candidate antipsychotic that has high affinity for striatal dopamine D2-like receptors, but causes few extrapyramidal effects. These studies characterized the molecular pharmacology of OPC-14597, DM-1451 (its major rodent metabolite), and the related quinolinone derivative OPC-4392 at each of the cloned dopamine receptors, and at serotonin 5HT6 and 5HT7 receptors. All three compounds exhibited highest affinity for D2L and D2S receptors relative to the other cloned receptors examined. Both OPC-4392 and OPC-14597 demonstrated dual agonist/antagonist actions at D2L receptors, although the metabolite DM-1451 behaved as a pure antagonist. These data suggest that clinical atypicality can occur with drugs that exhibit selectivity for D2L/D2S rather than D3 or D4 receptors, and raise the possibility that the unusual profile of OPC-14597 in vivo (presynaptic agonist and postsynaptic antagonist) may reflect different functional consequences of this compound interacting with a single dopamine receptor subtype (D2) in distinct cellular locales.

Synthesis and dopaminergic properties of benzo-fused analogues of quinpirole and quinelorane.

In an analogy to the potent catechol dopamine D1 agonists dihydrexidine (1) and dinapsoline (2), benzo rings were fused onto the structures of the dopamine D2-selective agonists quinelorane (3) and quinpirole (4). Each of the phenyl ring-substituted derivatives had significant affinity for D2 receptors, albeit somewhat lower than the two parent compounds, 3 and 4. Compounds with N-propyl and N-allyl substituents (5b, 5c, 6c, and 6d) had higher affinity for the D2 dopamine receptor than did their corresponding secondary amines (5a and 6a). Slightly different effects on affinity of an n-propyl and an n-allyl group in the new analogues of 3 and 4 suggest that different binding orientations may be invoked at the receptor.

Substituted naphthofurans as hallucinogenic phenethylamine-ergoline hybrid molecules with unexpected muscarinic antagonist activity.

A series of substituted racemic naphthofurans were synthesized as "hybrid" molecules of the two major prototypical hallucinogenic drug classes, the phenethylamines and the tryptamines/ergolines. Although it was hypothesized that these new agents might possess high affinity for the serotonin 5-HT2A/2C receptor subtypes, unexpected affinity for muscarinic receptors was observed. The compounds initially synthesized for this study were (+/-)-anti- and syn-4-amino-6-methoxy-2a,3,4,5-tetrahydro-2H-naphtho[1,8-bc]furan (4a,b), respectively, and their 8-bromo derivatives 4c,d, respectively. The brominated primary amines 4c,d were assayed initially for activity in the two-lever drug discrimination (DD) paradigm in rats trained to discriminate saline from LSD tartrate (0. 08 mg/kg). Also, 4c,d were evaluated for their ability to compete against agonist and antagonist radioligands at cloned human 5-HT2A, 5-HT2B, and 5-HT2C receptors. After the syn diastereomers were found to have the highest activity in these preliminary assays, the N-alkylated analogues syn-N,N-dimethyl-4-amino-6-methoxy-2a,3,4, 5-tetrahydro-2H-naphtho[1,8-bc]furan (4e) and syn-N, N-dipropyl-4-amino-6-methoxy-2a,3,4,5-tetrahydro-2H-naphtho[1, 8-bc]furan (4f) were prepared and assayed for their affinities at [3H]ketanserin-labeled 5-HT2A and [3H]-8-OH-DPAT-labeled 5-HT1A sites. All of the molecules tested had relatively low affinity for serotonin receptors, yet a preliminary screen indicated that compound 4d had affinity for muscarinic receptors. Thus, 4b,d,e were evaluated for their affinity at muscarinic M1-M5 receptors and also assessed for their functional characteristics at the M1 and M2 isoforms. Compound 4d had affinities of 12-33 nM at all of the muscarinic sites, with 4b,e having much lower affinity. All three compounds fully antagonized the effects of carbachol at the M1 receptor, while only 4d completely antagonized carbachol at the M2 receptor. The fact that the naphthofurans lack LSD-like activity suggests that they do not bind to the serotonin receptor in a way such that the tricyclic naphthofuran nucleus is bioisosteric with, and directly superimposable upon, the A, B, and C rings of LSD. This also implies, therefore, that the hallucinogenic phenethylamines cannot be directly superimposed on LSD in a common binding orientation for these two chemical classes, contrary to previous hypotheses.

Relationship of neuronal discharges in the precentral gyrus of monkeys to the performance of arm movements.

Recordings have been made from 162 pyramidal tract neurones which discharged bursts of nerve impulses in characteristic temporal association with performances of a stereotyped motor task by monkeys. Clinical evaluation of the relationship between discharges of the neurones and free movement led to the view that each cell's firing was associated with a characteristic aspect of movement performance and the contraction of a particular group of muscles. Quantitative evaluation of these relationships led to the conclusion that coding of the recruitment of motor units to the movement task could have been conferred by the number of pyramidal tract neurones discharging to those motoneurone targets. A ramp of "recruitment" of pyramidal tract neurones preceded the development of a ramp of force by about 100 msec. This general conclusion was supported by the observations made in a single animal in which orderly discharge of precentral neurones in relation to a sterotyped movement performance was clearly evident.

Disturbed proprioception following a period of muscle vibration in humans.

Forearm position matching tasks were performed by blindfolded subjects before and after applying vibration for 60 s to the biceps or triceps muscle of one arm. Following cessation of vibration, statistically significant alignment (proprioceptive) errors occurred when a movement lengthened the previously vibrated muscle. The error was such that the length of the post-vibrated muscle was greater than the length of the same muscle in the non-vibrated arm. This effect is the opposite to that which occurs during vibration.

Soft-tissue tumors and tumor-like lesions of the foot. An analysis of eighty-three cases.

The cases of eighty-three patients who had a soft-tissue tumor or tumor-like lesion in the foot or ankle were retrospectively analyzed to determine the relative frequency of the lesions and which factors, if any, could be used to identify them preoperatively. Seventy-two (87 per cent) of the lesions were benign, with ganglion cysts and plantar fibromatoses being the most common, and eleven (13 per cent) were malignant tumors, five (45 per cent) of which were synovial sarcomas. The age of the patient and the location of the lesion were the two most important factors that characterized the malignant tumors. For eight patients (12 per cent), radiographs were helpful in identifying the nature of the lesion. The sex of the patient, a history of trauma, the duration of the symptoms, the size of the lesion, and the presence of pain or of neurological symptoms were not useful in discriminating a benign lesion from a malignant tumor.

Computed tomography--guided needle biopsy of head and neck lesions.

OBJECTIVE: To evaluate the diagnostic efficacy of computed tomography (CT)-guided needle biopsies of head and neck lesions. DESIGN: All CT-guided needle biopsies of head and neck lesions performed between September 1994 and February 1999 were included. Cytopathologic and histologic records, along with patient clinical records, were reviewed. SETTING: A tertiary care medical center. PATIENTS: Patients referred for evaluation of lesions inaccessible to routine methods of needle biopsy. RESULTS: Thirty-seven patients underwent 42 CT-guided biopsies. There were included 12 lesions in or adjacent to the skull base and 9 lesions around the pharyngoesophageal or laryngotracheal complex; the other lesions were located in the deep lobe of the parotid gland (n = 7), deep neck area (n = 12), and thyroid gland (n = 2). Diagnostic cytologic biopsy specimens were obtained in 38 (91%) of 42 needle biopsy procedures. The results were supported histologically and/or clinically in 36 cases (95%). Eighteen patients underwent open surgical procedures. Histologic confirmation was found in 86% of cases. Nineteen patients (51%) avoided an open surgical procedure: 11 with benign disease and 8 with recurrent malignancy. There were no false-positive or false-negative results, and no complications were identified. CONCLUSIONS: Computed tomography-guided needle biopsy is a safe and reliable minimally invasive technique for the diagnosis of poorly accessible or deep-seated lesions of the head and neck. Diagnostic needle biopsies allow improved preoperative planning and patient counseling in surgical patients and avoidance of open surgical procedures in patients with benign disease or recurrent malignant neoplasms.

Tumour and tumour-like conditions of the soft tissue: magnetic resonance imaging features differentiating benign from malignant masses.

49 primary soft-tissue masses were studied by magnetic resonance imaging (MRI) in an effort to differentiate benign from malignant lesions. There were 24 benign and 25 malignant tumours. Images were evaluated for the presence of low-signal septation, changes in pattern of homogeneity, signal intensity, and margin definition and shape. 20 of the 25 malignant tumours (80%) demonstrated low-signal septation, and two of the 24 benign tumours (8%) also demonstrated this feature. Malignant tumours tended to change pattern from being homogeneous on T1-weighted images to being heterogeneous on T2-weighted images (72%). Benign tumours maintained their pattern on both sequences (67%). Only three of the 24 benign tumours (12.5%) changed from being homogeneous to heterogeneous. Our findings suggest that tumours which change pattern, from homogeneous on T1-weighted images to heterogeneous on T2-weighted images, and tumours which have low-signal septations are likely to be malignant. Moreover benign lesions tend to have well defined margins, and some benign masses have characteristic appearances that aid in their differentiation from malignant processes.

Intramuscular myxoma: magnetic resonance features.

Magnetic resonance imaging (MRI) was performed in six cases of intramuscular myxoma of the extremities and revealed the following characteristics. All tumours were confined to muscle and had a sharply defined border. All had a signal intensity lower than skeletal muscles on T1-weighted images and brighter than fat on T2-weighted images. The signals were homogeneous on both T1- and T2-weighted images. This study did not include contrast enhancement. The diagnosis was confirmed by an open biopsy. All tumours were resected with no recurrence. Diagnosis based on these MRI characteristics was incorrect in two cases of intramuscular ganglia and in a case of intramuscular cysticercus cellulose. MRI features of intramuscular myxoma are typical in the majority of cases. Benign intramuscular lesions that contain mainly fluid can mimic intramuscular myxomas.

Sports tumors.

We present 36 patients who initially were thought to have sports-related injury but ultimately were diagnosed with a primary bone or soft tissue tumors or tumor-like condition. The awareness of this possibility in the individual with a sports-related complaint, who does not respond to standard management, may assist in earlier diagnosis and treatment of the suspected neoplasm.

Subperiosteal giant-cell reparative granuloma.

We present a case of subperiosteal giant-cell reparative granuloma followed over six years showing the complete evolution from the early phase of subperiosteal haematoma to the end stage of an ossified haematoma. Such lesions, although they are histologically similar to true giant-cell tumours, can be distinguished by the patients' age, their location on the diaphysis, and by their radiological and histological features.

Limb salvage in pediatric surgery. The use of the expandable prosthesis.

Limb sparing in growing children has proved to be very effective from an oncologic perspective, with good, long-term acceptance by the patients. As in the adult, when performed by experienced surgeons, limb sparing neither compromises the survival rate nor significantly increases the local recurrence rate, compared with cross-bone amputation. Discussions include patient evaluation, surgical options, materials and methods, and results.

Office evaluation of bone tumors.

A familiarity with the characteristics and behavior of musculoskeletal neoplasms will allow for the delivery of timely and appropriate treatment. In this article the significance of historical and clinical data is discussed in general terms, followed by a rationale for office-based evaluation of these lesions. Some of the more common lesions are then discussed in greater detail.

Osteosarcoma. Clinical and pathological considerations.

The current local recurrence rate following limb sparing surgery for osteosarcoma is on the order of 5 per cent. Major advances in both reconstructive surgery and adjuvant chemotherapy have dramatically improved the disease-free survival rate and the quality of life in patients with osteosarcoma.

The role of microvascular surgery in limb-sparing procedures for malignant tumors of the knee.

Limb-sparing surgery has proven to be a feasible alternative to amputation for treatment of malignant tumors about the knee. Microvascular surgery and the possibility of providing healthy, stable soft-tissue coverage to the affected limb have expanded the possible role of limb-sparing techniques. Microvascular free flaps were utilized in 26 patients undergoing resection for large malignant tumors of the knee or adjacent to the knee. Patients were then followed for a minimum of 3 years to a maximum of 7 years and evaluated for tumor recurrence and limb function. Survival and disease-free interval were 68 and 77 percent, respectively, in stage II patients and only 50 and 0 percent, respectively, in stage III patients. Function, as determined by the MSTS functional evaluation system, was found to be fair to good in all patients. Microvascular free-tissue transfer has proven to be a valuable adjunct in limb-sparing surgery.