Can fruit and vegetable aggregation systems better balance improved producer livelihoods with more equitable distribution?

The need for food systems to generate sustainable and equitable benefits for all is a global imperative. However, whilst ample evidence exists linking smallholder farmer coordination and aggregation (i.e. the collective transport and marketing of produce on behalf of multiple farmers) to improved market participation and farmer incomes, the extent to which interventions that aim to improve farmer market engagement may co-develop equitable consumer benefits remains uncertain. This challenge is pertinent to the horticultural systems of South Asia, where the increasing purchasing power of urban consumers, lengthening urban catchments, underdeveloped rural infrastructures and inadequate local demands combine to undermine the delivery of fresh fruits and vegetables to smaller, often rural or semi-rural markets serving nutritionally insecure populations. To this end, we investigate the potential for aggregation to be developed to increase fruit and vegetable delivery to these neglected smaller markets, whilst simultaneously improving farmer returns. Using an innovative system dynamics modelling approach based on an aggregation scheme in Bihar, India, we identify potential trade-offs between outcomes relating to farmers and consumers in smaller local markets. We find that changes to aggregation alone (i.e. scaling-up participation; subsidising small market transportation; mandating quotas for smaller markets) are unable to achieve significant improvements in smaller market delivery without risking reduced farmer participation in aggregation. Contrastingly, combining aggregation with the introduction of market-based cold storage and measures that boost demand improves fruit and vegetable availability significantly in smaller markets, whilst avoiding farmer-facing trade-offs. Critically, our study emphasises the benefits that may be attained from combining multiple nutrition-sensitive market interventions, and stresses the need for policies that narrow the fruit and vegetable cold storage deficits that exist away from more lucrative markets in developing countries. The future pathways and policy options discovered work towards making win-win futures for farmers and disadvantaged consumers a reality.

Current and future trade in livestock products

Rising per capita consumption, economic growth, and urbanisation, particularly in developing countries, have been driving an increased global demand for food. These changing socio-economic trends, which have greatly influenced changes in dietary patterns globally and, more specifically, have increased consumption of livestock products in developing countries, are expected to endure and to place new pressures on livestock-sector infrastructure and the delivery of veterinary services. This paper summarises current trade in meat and presents plausible projections for the future. It highlights the impact of animal disease on trade and considers the effect of ongoing disease outbreaks, particularly the outbreaks of African swine fever and COVID-19, on current and future trade dynamics. The authors analysed published statistics on the demand for, and international trade in, livestock products at national and regional levels and made projections of the same up to 2050, generated from an integrated model of the global agricultural and food system. The resulting analyses identified patterns of trade consistent with growing populations, increasing incomes and changing diets in developing countries. The analyses also pointed to slow expansion of livestock production, and the impacts of countries' disease status on livestock trade. For most of the livestock products analysed, economic model projections indicate increased consolidation of production and exports among a few countries. Marked increases in the trade in livestock products suggest a changing role for Veterinary Services in facilitating trade and extension in the years to come.

Animal production, animal health and food safety: Gaps and challenges in the chilean industry

This paper summarizes the gaps and challenges related to animal production, health, and food safety as discussed by a panel at the 1st International Symposium of Food Safety (ISFS) in Santiago, Chile, in December 2016. Participating representatives of academia, industry, and government and statements from the audience confirmed that food safety is essential for increasing food security. First, panelists identified the need for a science-based regulatory framework to implement effective regulations. Second, they highlighted the importance of a risk analysis framework to quantify the risk of the potential for antimicrobial resistance associated with the use of antimicrobials, and the need of studies to evaluate foodborne prevention/control strategies. Third, the challenges of filling the gaps between industry and academia were addressed, including examples of successful collaboration, opportunities, and weakness identified by industry. Finally, challenges in animal food production included issues related to changing consumer preferences, animal welfare, the use of antimicrobials, and sustainable animal production. The symposium provided a regional platform to share experiences from the implementation of methods and approaches for food safety. The roundtable successfully explored the future science and technology challenges that are of strategic importance for Chile and the region in animal health and food safety.

The economic impact of a new animal disease: same effects in developed and developing countries?

Animal disease outbreaks generate a range of economic and non-economic impacts. While a significant number of research studies have estimated the effects of various diseases in a variety of contexts, examining the differential impacts and implications associated with the introduction of a novel disease into a developing country, as opposed to a developed one, is a rich area for further research. In this paper, the authors highlight some of the key dimensions and implications associated with the impacts of new diseases, how they differ in different contexts, and their implications for public policy.

Controlling emerging infectious diseases in salmon aquaculture

In this paper, the authors review the impacts of diseases facing salmon aquaculture, drawing lessons from terrestrial animal diseases. They discuss the implementation of current control strategies, taking into account transmission patterns (vertical versus horizontal), disease reservoirs, and interactions with wild fish. In addition, the decision-making context of aquatic disease control and the institutional organisation of control strategies are considered, with particular emphasis on the roles and responsibilities of regulatory authorities and the private sector. Case studies on the emergence and control of infectious salmon anaemia worldwide and pancreas disease in Norway are used to examine some of the controversies that may influence decision making and provide lessons for the future.

Transfection of C6 glioma cells with the bax gene and increased sensitivity to treatment with cytosine arabinoside

Genes known to be involved in the regulation of apoptosis include members of the bcl-2 gene family, such as inhibitors of apoptosis (bcl-2 and bcl-xl) and promotors of apoptosis (bax). The authors investigated a potential approach for the treatment of malignant gliomas by using a gene transfection technique to manipulate the level of an intracellular protein involved in the control of apoptosis. The authors transfected the murine bax gene, which had been cloned into a mammalian expression vector, into the C6 rat glioma cell line. Overexpression of the bax gene resulted in a decreased growth rate (average doubling time of 32.96 hours compared with 22.49 hours for untransfected C6, and 23.11 hours for clones transfected with pcDNA3 only), which may be caused, in part, by an increased rate of spontaneous apoptosis (0.77 +/- 0.15% compared with 0.42 +/- 0.08% for the vector-only transfected C6 cell line; p = 0.038, two-tailed Student's t-test). Treatment with 1 microM of cytosine arabinoside (ara-C) resulted in significantly more cells undergoing apoptosis in the cell line overexpressing bax than in the vector-only control cell line (23.57 +/- 2.6% compared with 5.3 +/- 0.7% terminal deoxynucleotidyl transferase--mediated biotinylated--deoxyuridine triphosphate nick-end labeling technique-positive cells; p = 0.007). Furthermore, measurements of growth curves obtained immediately after treatment with 0.5 microM ara-C demonstrated a prolonged growth arrest of at least 6 days in the cell line overexpressing bax. These results can be used collectively to argue that overexpression of bax results in increased sensitivity of C6 cells to ara-C and that increasing bax expression may be a useful strategy, in general, for increasing the sensitivity of gliomas to antineoplastic treatments.

Poverty impacts of foot-and-mouth disease and the poverty reduction implications of its control

Foot-and-mouth disease (FMD) remains one of the most important livestock diseases of the world, given its highly infectious nature, its broad economic impacts on animal wellbeing and productivity, and its implications for successful access to domestic and export markets for livestock and products. The impacts of the disease vary markedly between developed and developing countries, and also within many developing countries. These differences in impact shape some markedly heterogeneous incentives for FMD control and eradication, which become of particular importance when setting priorities for poverty reduction in developing countries. Some consider that the benefits from FMD control accrue only to the better off in such societies and, as such, may not be a priority for investments targeted at poverty reduction. But is that view justified? Others see the control of FMD as a major development opportunity in a globalised environment. In this paper, Brian Perry and Karl Rich summarise the differential impacts of FMD and its control, and link these findings with the growing understanding of how the control of this globally important disease may contribute to the processes of pro-poor growth in certain countries of the developing world.

Transglutaminase 2 inhibitor, KCC009, disrupts fibronectin assembly in the extracellular matrix and sensitizes orthotopic glioblastomas to chemotherapy

Transglutaminase 2 (TG2, a.k.a. tissue transglutaminase) belongs to a family of transglutaminase enzymes that stabilize proteins by affecting covalent crosslinking via formation of amide bonds. Cell surface TG2 is directly involved as an adhesive receptor in cell-extracellular matrix (ECM) interactions. Here, we show that TG2 activity is elevated in glioblastomas compared with non-neoplastic brain. Immunofluorescent studies showed increased staining of fibronectin colocalized with TG2 in the ECM in glioblastomas. In addition, small clusters of invading human glioblastoma cells present in non-neoplastic brain parenchyma secrete high levels of TG2 and fibronectin that distinguish them from normal brain stroma. Downregulation of TG2 in U87MG glioblastoma cells with RNAi demonstrated decreased assembly of fibronectin in the ECM. Treatment with KCC009 blocked the remodeling of fibronectin in the ECM in glioblastomas in both in vitro and in vivo studies. KCC009 treatment in mice harboring orthotopic glioblastomas (DBT-FG) sensitized the tumors to N,N'-bis(2-chloroethyl)-N-nitrosourea chemotherapy, as measured by reduced bioluminescence, increased apoptosis and prolonged survival. The ability of KCC009 to interfere with the permissive remodeling of fibronectin in the ECM in glioblastomas suggests a novel target to enhance sensitivity to chemotherapy directed not only at the tumor mass, but also invading glioblastoma cells.

A review of economic tools for the assessment of animal disease outbreaks

This paper demonstrates how currently underutilised economic modelling techniques can enrich the analysis of animal disease problems. Increasingly, analyses of animal health programmes are expected to address a range of economic and social questions. These expectations can be addressed by better integration of epidemiological modelling with economic techniques whose application to animal health has not been thoroughly discussed in past reviews. This paper describes a range of economic models that can be applied in animal health research and provides guidance for determining the appropriate method given the issues at hand. The complexity of some of these approaches underlines the importance of multidisciplinary research and education.

Enhancing economic models for the analysis of animal disease

This paper discusses how economic tools can be targeted and combined to enhance their usefulness in analyses of animal disease problems. It briefly reviews the most commonly used economic modelling techniques to clarify the applicability of specific economic methods to different problems in animal health analysis. The paper then reviews applications of these methods in the literature and suggests how further research could integrate and improve different economic approaches and link epidemiological and economic methods to address a wider range of issues at different scales of analysis.

Ipsilateral thalamic stimulation after thalamotomy for essential tremor. A case report

We report a patient with severe essential tremor who was treated with thalamic stimulation ipsilateral to a prior thalamotomy. Thalamotomy performed 30 years prior to stimulator implantation provided tremor reduction for one year before the tremor recurred. An electrode lead was implanted in the thalmaic nucleus ventralis intermedius (Vim) with nearly complete control of his tremor with sustained benefit over an 18-month follow-up period. Vim thalamic stimulation is an effective treatment option for recurrent tremor in patients who have undergone ipsilateral thalamotomy.

Gene expression profiling with oligonucleotide microarrays distinguishes World Health Organization grade of oligodendrogliomas

Oligodendrogliomas are the second most common type of glial neoplasm with distinct prognostic and therapeutic implications. Although refinements have led to improved clinical stratification, current grading schemes are still limited by subjective histopathological criteria. In this report, we have used oligonucleotide array technology to perform expression profiling in morphologically classic oligodendrogliomas. Expression information from approximately 1100 genes divided tumors into two molecularly distinct groups that corresponded exactly to their previously assigned histological grades. Subsequent gene clustering identified a subset of 196 transcripts showing a common, differential expression pattern between tumor grades. A number of these genes have been associated with the maintenance of cytoarchitecture, cellular differentiation and maturation, immunogenicity, and chemotherapeutic resistance. These results demonstrate the utility of gene expression profiling as an objective, ancillary tool for grading oligodendrogliomas and a potential approach for classifying diffuse gliomas where histological assessment may be difficult or ambiguous.

Malignant giant-cell tumor of the parietal bone: case report and review of the literature

OBJECTIVE AND IMPORTANCE

Giant-cell tumors (GCTs) are primary bone tumors that involve long bones in 75 to 90% of patients. They seldom develop in the cranium and are very rare in patients older than 60 years of age. A GCT rarely occurs with Paget's disease; when it does, however, it is most commonly associated with the polyostotic form and tends to involve the craniofacial bones. Pagetic GCTs are less aggressive than GCTs that are not associated with Paget's disease.

CLINICAL PRESENTATION

We report the case of an 81-year-old woman with a painless left parietal mass and asymptomatic monostotic parietal Paget's disease.

INTERVENTION

Surgical resection was performed, and histological examination of the lesion demonstrated Paget's disease with a malignant GCT. An incidental, low-grade, small-cell lymphocytic lymphoma also was noted. The patient experienced local recurrence of the malignant GCT and eventually died after developing pulmonary metastases of the malignant GCT.

CONCLUSION

This case is the first reported example of a patient with a malignant GCT of the cranium associated with monostotic Paget's disease. It provides evidence that not all pagetic GCTs in the cranium are benign, as has been reported.

Overexpression of bax in human glioma cell lines

OBJECT

Cells that lose their ability to undergo apoptosis may promote the development of neoplasms and result in resistance to clinical treatment with DNA-damaging modalities such as radio- and chemotherapy. Four established human glioma cell lines that are resistant to apoptosis were transfected with the proapoptotic gene bax and assessed for their sensitivity to a proapoptotic stimulus.

METHODS

Two cell lines had a wild-type p53 genotype (U87 and D247MG) and two had mutant p53 genotypes (U138 and U373). Constitutive overexpression of murine bax was achieved in U138 and U373 only, which resulted in an increased sensitivity of these lines to the apoptosis-inducing effect of cytosine arabinoside (ara-C). Multiple attempts to produce constitutive overexpression of bax in U87 and D247MG cells resulted in spontaneous, near-complete cell loss. Vector-only control transfections were successful in all four cell lines. Inducible overexpression of bax was achieved in the U87 cells and elevated levels of BAX were observed as early as 6 hours after gene induction. This overexpression of BAX resulted in the spontaneous induction of apoptosis in these cells.

CONCLUSIONS

Overexpression of BAX in four human glioma cell lines resulted in increased sensitivity to apoptosis. In the two lines that had a wild-type p53 genotype, overexpression of BAX produced spontaneous apoptosis. In contrast, the lines that had mutant, nonfunctional P53 did not undergo spontaneous apoptosis, but they were rendered more sensitive to the apoptosis-inducing effect of ara-C. Modulation of BAX expression may be a useful therapeutic modality for gliomas, regardless of p53 genotype.

Developmental regulation of apoptosis in dorsal root ganglion neurons

The survival of dorsal root ganglion (DRG) neurons, both in vivo and in vitro, is dependent on the availability of nerve growth factor (NGF) for a transient period early in development after which these neurons become independent of NGF for survival. The precise molecular mechanism by which developing DRG neurons gain independence from NGF has not been determined. We used an in vitro model of DRG neuronal development to test hypotheses that independence from NGF in mature DRG neurons could be caused by developmental regulation of either elements of the NGF withdrawal signal transduction pathway or of proteins important for activation of the apoptosis output pathway. Interruption of phosphotidylinositol-3 kinase activation, by treatment with the specific inhibitor LY294002, resulted in apoptosis in immature but not mature DRG neurons in a manner similar to that observed with NGF withdrawal. Further downstream along the signal transduction pathway, c-JUN phosphorylation occurred in both immature and mature DRG neurons after NGF withdrawal or treatment with LY294002, despite the fact that the older neurons did not undergo apoptosis. In contrast, the ratio of expression of the proapoptotic gene bax to antiapoptotic gene bcl-xL was many times higher in immature than mature neurons, both in vivo and in vitro. Taken together, these results strongly suggest that developmental regulation of NGF withdrawal-induced apoptosis in DRG occurs via control of the relative level of expression of members of the bcl-2 gene family.

Dysembryoplastic neuroepithelial tumor and oligodendroglioma: the diagnostic value of magnetic resonance spectroscopy. Case report and review of the literature

Preoperative differentiation between dysembryoplastic neuroepithelial tumor (DNT) and low-grade glioma is often not possible. Dysembryoplastic neuroepithelial tumor is a recently described entity of uncertain origin; however, the diagnosis has important clinical implications. Clinical and radiological findings of DNT and low-grade glioma, especially oligodendroglioma, may be similar. Treatment options and prognosis differ significantly between these two lesions; consequently, accurate diagnosis is imperative. The authors describe two individuals who presented simultaneously at their institution: one patient with an oligodendroglioma and a second patient with DNT. The natural history, neurodiagnostic, and pathological features of each are reviewed with special emphasis on the potential utility of magnetic resonance spectroscopy in differentiating these lesions.

Transfection of C6 glioma cells with the bax gene and increased sensitivity to treatment with cytosine arabinoside

OBJECT

Genes known to be involved in the regulation of apoptosis include members of the bcl-2 gene family, such as inhibitors of apoptosis (bcl-2 and bcl-xl) and promoters of apoptosis (bax). The authors investigated a potential approach for the treatment of malignant gliomas by using a gene transfection technique to manipulate the level of an intracellular protein involved in the control of apoptosis.

METHODS

The authors transfected the murine bax gene, which had been cloned into a mammalian expression vector, into the C6 rat glioma cell line. Overexpression of the bax gene resulted in a decreased growth rate (average doubling time of 32.96 hours compared with 22.49 hours for untransfected C6, and 23.11 hours for clones transfected with pcDNA3 only), which may be caused, in part, by an increased rate of spontaneous apoptosis (0.77 +/- 0.15% compared with 0.42 +/- 0.08% for the vector-only transfected C6 cell line; p = 0.038, two-tailed Student's t-test). Treatment with 1 microM cytosine arabinoside (ara-C) resulted in significantly more cells undergoing apoptosis in the cell line overexpressing bax than in the vector-only control cell line (23.57 +/- 2.6% compared with 5.3 +/- 0.7% terminal deoxynucleotidyl transferase-mediated biotinylated-deoxyuridine triphosphate nick-end labeling technique-positive cells; p = 0.007). Furthermore, measurements of growth curves obtained immediately after treatment with 0.5 microM ara-C demonstrated a prolonged growth arrest of at least 6 days in the cell line overexpressing bax.

CONCLUSIONS

These results can be used collectively to argue that overexpression of bax results in increased sensitivity of C6 cells to ara-C and that increasing bax expression may be a useful strategy, in general, for increasing the sensitivity of gliomas to antineoplastic treatments.

Radiation-induced apoptosis in dorsal root ganglion neurons

Ionizing radiation (IR) results in apoptosis in a number of actively proliferating or immature cell types. The effect of IR on rat dorsal root ganglion (DRG) neurons was examined in dissociated cell cultures. After exposure to IR, embryonic DRG neurons, established in cell culture for six days, underwent cell death in a manner that was dose-dependent, requiring a minimum of 8 to 16 Gy. Twenty-five per cent cell loss occurred in embryonic day 15 (E-15) neurons, grown in cell culture for 6 days ('immature'), and then treated with 24 Gy IR. In contrast, only 2% cell loss occurred in E-15 neurons maintained in culture for 21 days ('mature') and then treated with 24 Gy IR. Staining with a fluorescent DNA-binding dye demonstrated clumping of the nuclear chromatin typical of apoptosis. Initiation of the apoptosis occurred within 24 h after exposure to IR. Apoptosis was prevented by inhibition of protein synthesis with cycloheximide. Apoptosis induced by IR occurred more frequently in immature than in mature neurons. Immature DRG neurons have a lower concentration of intracellular calcium ([Ca2+]i) than mature neurons. Elevation of [Ca2+]i by exposure to a high extracellular potassium ion concentration (35 microM) depolarizes the cell membrane with a resultant influx of calcium ions. The activation of programmed cell death after nerve growth factor (NGF) withdrawal is inversely correlated with [Ca2+]i in immature DRG neurons. When treated with high extracellular potassium, these immature neurons were resistant to IR exposure in a manner similar to that observed in mature neurons. These data suggest that [Ca2+]i modulates the apoptotic response of neurons after exposure to IR in a similar manner to that proposed by the "Ca2+ setpoint hypothesis" for control of NGF withdrawal-induced apoptosis.

Peripheral nerve regeneration through silicone chambers in streptozocin-induced diabetic rats

The silicone chamber model was used to evaluate peripheral nerve regeneration (PNR) in streptozocin (STZ)-induced diabetic rats. Diabetic and control animals underwent sciatic nerve transection and silicone chamber implantation establishing gaps of various lengths between the transected nerve ends. In animals with 5 and 10 mm gaps, diabetes was induced in experimental rats 1 week before surgery, and the animals were sacrificed 3 weeks after surgery. In animals with 8 mm gaps, diabetes induction occurred 3 days after surgery, and they were sacrificed after 7 weeks. Diabetic rats with 10 mm gaps demonstrated an impaired ability to form bridging cables, the initial step of regeneration through chambers. Morphometric studies of bridging cables between transected nerve ends demonstrated a significant reduction in the mean endoneurial area in diabetic animals with 5 and 8 mm gaps compared to controls. The number of regenerated myelinated axons in the chamber was significantly decreased in diabetic rats with 8 and 10 mm gaps. The mean myelinated fiber area in the regenerated cables of the diabetic group was significantly decreased with 5 mm gaps and significantly increased with 8 mm gaps compared to controls. Size-frequency histograms of regenerated myelinated fiber areas suggest a delay in the maturation of small caliber axons. Schwann cell migration across 5 mm gaps was examined with S-100 immunohistochemistry. The total distance of Schwann cell migration into cables from both proximal and distal ends was significantly reduced in diabetic animals. Characterization of PNR across gaps through silicone chambers in diabetic rats showed impairment in multiple aspects of the regenerative process, including cable formation, Schwann cell migration, and axonal regeneration.

Diphenylpiperazines enhance regeneration after facial nerve injury

Immature rat facial motoneurons are very sensitive to injury with nearly 80% dying during the first week after axotomy. This motoneuron death is apoptotic, similar to that induced in neurons after tropic factor withdrawal. The diphenylpiperazines, flunarizine and cinnarizine, protect dorsal root ganglion neurons from death after withdrawal of trophic support, i.e., nerve growth factor withdrawal, in vitro. Similarly, the monoamine oxidase inhibitor, deprenyl, promotes survival of facial motoneurons after axotomy. These pharmacological agents were assessed both alone and in combination for their ability to prevent death in non-nerve growth factor dependent CNS motoneurons after facial nerve axotomy in newborn rats. Long-term experiments were done with the diphenylpiperazines to evaluate potential enhancement of regeneration. Facial nerve transection resulted in 78% neuronal loss in the injured compared with the contralateral, uninjured nucleus. Systemic administration of diphenylpiperazines for 1 week after facial nerve transection doubled the number of surviving motoneurons from 23% to 47%. Similar results were obtained with deprenyl. Combinations of diphenylpiperazines and deprenyl provide a similar degree of neuronal protection 1 week after injury as that obtained by either agent alone. We assessed the ability of diphenylpiperazines to protect facial motoneurons from death over a prolonged period and enhance subsequent regeneration. Motor neuron counts in rats treated with diphenylpiperazines for 1 month after injury and assessed 2 months later demonstrated long-term enhancement of neuronal protection with an increase of 45% in the number of horseradish peroxidase-labelled motoneurons. The diphenylpiperazines group had approximately 80% more regenerated myelinated axons in the distal facial nerve than the control group. Thus, diphenylpiperazine treatment during the first month after injury provides long-term protection of non-nerve growth factor dependent CNS motoneurons with subsequent potentiation of long-term facial nerve regeneration.

Flunarizine enhances survival and regeneration of sensory and motor neurons after peripheral nerve injury

The diphenylpiperazine, flunarizine, partially prevents apoptosis after trophic factor deprivation in neural crest-derived neurons. Flunarizine protects dorsal root ganglion neurons (DRG) after nerve growth factor (NGF) withdrawal in vitro and after peripheral nerve injury in newborn rats in vivo. We have further studied the mechanisms of neuronal protection by flunarizine. Oligosomal DNA fragmentation, a hallmark of apoptosis, was significantly decreased by treatment of DRG neurons with flunarizine after NGF deprivation. We examined the effect on survival of the timing of administration of flunarizine to DRG neurons both in vitro and in vivo. Flunarizine effectively rescued dissociated DRG neurons if administered up to six hours after NGF withdrawal. In vivo, flunarizine prevented DRG neuronal death after sciatic axotomy in newborn rats if given soon after injury. Long-term experiments were done to test the ability of flunarizine to protect neurons and enhance regeneration after sciatic nerve injury. Newborn rats were subjected to peripheral nerve injury and administered flunarizine for four weeks; no further treatment was given for an additional 12 weeks. The group treated with flunarizine demonstrated a significantly increased number of DRG and spinal motor neurons that had regenerated axons into the distal sciatic nerve as determined by retrograde labeling with HRR Myelinated axons in the sural nerve in the group treated with flunarizine increased by nearly two-fold compared to control animals. Thus, flunarizine was able to enhance survival and promote long-term regeneration of sensory and motor spinal neurons after peripheral nerve injury.

Intracellular calcium levels influence apoptosis in mature sensory neurons after trophic factor deprivation

Embryonic dorsal root ganglion (DRG) neurons require nerve growth factor (NGF) for survival in vitro. Withdrawal of NGF results in an apoptotic death in these immature DRG neurons. After time in culture, DRG neurons become progressively less dependent upon NGF for survival. Immature embryonic DRG neurons remain highly dependent upon NGF during their first 14 days in cell culture but by Day 21 the majority lose their NGF dependence for survival. During this period of maturation the intracellular calcium concentration ([Ca2+]i) progressively increases from the lower levels found in immature DRG neurons to the higher levels that are characteristic of older or mature DRG neurons. By changing the cell culture medium to one with very low calcium, we were able to lower [Ca2+]i in the mature neurons to levels similar to those found in immature neurons. These mature neurons (e.g., E-15 DRG neurons grown for 21 days in culture), normally NGF independent, became highly dependent upon NGF for survival. The onset of DNA fragmentation is a marker of apoptotic cell death. We measured the onset of DNA fragmentation in apoptotic neurons with use of the fluorescent dye, Hoechst, in neurons maintained in either standard calcium medium (1800 mM) or in the low calcium medium (0.35 mM). A higher percentage of neurons with lowered [Ca2+]i showed initial signs of apoptosis, i.e., DNA condensation, at earlier times after NGF deprivation. This work provides further evidence to support a "set-point" hypothesis regarding the relationship between intracellular calcium concentration and NGF dependence for survival in DRG neurons.

Intrasellar abscess following transsphenoidal surgery

BACKGROUND

Intrasellar abscess following transsphenoidal surgery has been described only twice in the English language medical literature. Overall mortality associated with intrasellar abscesses is 51%, while mortality in reported cases not treated surgically is 100%.

METHODS

Two cases of intrasellar abscess following uncomplicated transsphenoidal surgery for pituitary pathology are reported. The incidence, radiographic features, clinical presentations, and treatment of intrasellar abscesses are discussed.

RESULTS

Both patients described underwent uncomplicated transsphenoidal procedures for treatment of a primary pituitary lesion. Neither developed postoperative CSF rhinorrhea, and initial recovery was uneventful. The first patient presented with new symptoms several weeks after transsphenoidal surgery; the second patient almost two years postoperatively. The first displayed signs of an expanding sellar mass, requiring transsphenoidal drainage and postoperative antibiotics. The second presented with recurrent meningitis without discernible CSF leak, and was treated with transnasal endoscopic drainage in conjunction with antibiotic therapy.

CONCLUSIONS

The high mortality associated with intrasellar abscess mandates its inclusion in the differential diagnosis of patients presenting with symptoms of meningitis or an expanding sellar mass after transsphenoidal intervention. Although antibiotic therapy is an important adjunct, surgical drainage is required for definitive treatment.

Stereotactic external beam irradiation using a linear accelerator: the Washington University experience

From February 1989 to December 1993, 139 patients with a variety of brain lesions were treated with stereotactic external beam irradiation using a 6MV linear accelerator. The largest group consisted of patients with recurrent brain metastases (n = 46). Twenty seven patients had malignant gliomas, most of which were recurrent. Several benign conditions were treated, including arteriovenous malformations (n = 27), acoustic neuromas (n = 9), meningiomas (n = 7), and pituitary adenomas (n = 2). Durable responses were seen in the majority of patients with transient, mild, side effects. This experience suggests that stereotactic external beam irradiation is a safe, reliable, and effective method for non-invasive treatment of selected patients with small, localized brain lesions.

Assurance of high quality linac-based stereotactic radiosurgery

PURPOSE

Stereotactic radiosurgery is generally a single, high-dose radiation treatment for the brain requiring targeting accuracy on the order of a millimeter. From the initial implementation of radiosurgery, therefore, quality assurance is an ongoing process of paramount importance. In this paper, we outline the basic elements of a quality assurance program for our linear accelerator that has been in use at Washington University Medical Center over the past 2 years.

METHODS AND MATERIALS

Various devices and procedures have been developed to verify the accuracy and safety of the stereotactic radiosurgery regimen. Specifically, we present methods for assessing the attainment of spatially correct patient images, the reliability of the computerized treatment planning system, achieving physical safety for the patient, as well as the proper operation of the radiation treatment device.

RESULTS

Our procedures have allowed us to assure quality patient treatments and, additionally, has permitted monitoring our performance for continual improvement. For example, a plot of targeting accuracy with the number of patients shows an asymptotic approach to a value within 0.6 mm of that ideally expected.

CONCLUSION

To maintain high-quality patient care, one must review critical aspects of the treatment regimen on a periodic basis. Providing for the appropriate level of staff training, periodic reviews of procedures and maintenance of forms are also very important.

The ability of diphenylpiperazines to prevent neuronal death in dorsal root ganglion neurons in vitro after nerve growth factor deprivation and in vivo after axotomy

The mechanism of neuroprotection by the calcium channel antagonist flunarizine against neuronal death is unknown. We investigated the ability of other calcium channel antagonists (cinnarizine, nimodipine, nicardipine, diltiazem, and verapamil), calmodulin antagonists, and calpain inhibitors to prevent neuronal death in rat dorsal root ganglion neurons in vitro after nerve growth factor (NGF) deprivation and the ability of cinnarizine and diltiazem to protect in vivo after axotomy. In vitro, only neurons treated with cinnarizine or flunarizine were protected from death after withdrawal. In vivo, cinnarizine, but not diltiazem, protected dorsal root ganglion neurons in rats after unilateral sciatic nerve crush. Intracellular calcium concentration ([Ca2+]i) was evaluated with fura 2 after NGF deprivation in vitro. Neurons "committed to die" 24 h after NGF deprivation displayed a decline in [Ca2+]i before visible morphological deterioration consistent with cell death. The influx of extracellular calcium was not necessary to produce neuronal death. Neurons deprived of NGF gradually lost the ability to respond to elevated external potassium with an increase in [Ca2+]i during the first 24 h after trophic factor deprivation. After 24 h, neurons deprived of NGF could not be rescued by readministration of NGF. Neurons protected from cell death with diphenylpiperazines maintained their response to high external potassium, suggesting continued membrane integrity. We speculate that diphenylpiperazines may protect sensory neurons via an unknown mechanism that stabilizes cell membranes.

Infantile meningioma

Childhood meningiomas are unusual, and meningiomas in patients less than 1 year of age are exceedingly rare. We report a case of a meningioma with malignant histologic features in a 6-month-old child who has had an excellent postoperative course. The pathologic features in relation to prognosis, as well as the magnetic resonance imaging characteristics of the case are presented. The literature is reviewed and implications for therapeutic management are discussed.

The influence of fibronectin and laminin during Schwann cell migration and peripheral nerve regeneration through silicon chambers

The ability of extracellular proteins to influence the regenerative process was examined in Sprague-Dawley rats. Silicon chambers, filled with sterile saline solutions of cytochrome-c, fibronectin, laminin, a combination of fibronectin and laminin, or nerve growth factor were surgically implanted between the severed ends of sciatic nerves to form gaps of 18 mm. Four months later, the various groups were examined to determine the success of regeneration. The incidence of cable formation that bridged the gap was similar in all groups. The group of animals that had implants containing the combination of fibronectin/laminin had increased numbers of myelinated axons in the regenerated segment within the chamber and in the distal sciatic tributary nerves. Horseradish peroxidase labelling demonstrated that increased numbers of sensory and motor neurons in the fibronectin/laminin group had regenerated axons across the gap into the distal tributaries of the sciatic nerve. The effect of the various agents on non-neuronal cells was measured by immunohistochemical staining with S-100 antibodies to determine the effects on Schwann cell migration. Silicon chambers, filled with sterile saline solutions of fibronectin, laminin, fibronectin/laminin, nerve growth factor, or cytochrome-c, were surgically implanted to form 5 mm gaps between severed sciatic nerve ends. Ten days later, Schwann cell migration into the bridging cables was examined in each group. Analysis revealed a greater influx of Schwann cells migrating into the regenerating segments in the fibronectin, the laminin, and the combination fibronectin/laminin groups compared to the control group (cytochrome-c).

Brain metastases from non-central nervous system tumors: evaluation with PET

Positron emission tomography (PET) with fluorine-18 fluorodeoxyglucose (FDG) was performed in 19 patients with brain metastases from non-central nervous system (CNS) neoplasms and one patient with a primary CNS lymphoma. Various histopathologic types were represented by the primary neoplasms in the patients with metastases. Only 21 of the 31 lesions (68%) were detected with FDG PET as discrete, metabolically active foci (relative to surrounding structures). Six of the nondetected lesions may have been nondiscernible owing to their small size and/or isointensity relative to closely apposed normal gray matter. However, four lesions of at least 1.2 cm in diameter showed frankly decreased FDG accumulation relative to normal brain. These findings suggest that studies of FDG accumulation by a variety of non-CNS neoplasms and their CNS metastases are in order and that extrapolation of the successes of FDG PET in imaging of primary glial tumors to imaging of brain metastases should proceed with caution.

Computerized electroencephalographic monitoring and selective shunting: influence on intraoperative administration of phenylephrine and myocardial infarction after general anesthesia for carotid endarterectomy

During carotid endarterectomy (CEA), phenylephrine infusions are commonly used to induce hypertension during carotid clamping in an attempt to increase collateral cerebral blood flow and prevent cerebral ischemia. Although this practice appears to increase the incidence of intraoperative myocardial ischemia during CEA when general anesthesia is employed, whether the limited use of phenylephrine infusions in specific instances of cerebral ischemia, as shown on an electro-encephalogram, results in low perioperative rates of both myocardial infarction (MI) and cerebral infarction remains unclear. We studied 171 CEAs done under general anesthesia performed with selective shunting based on the identification of cerebral ischemia by a two-channel computerized electroencephalographic monitor. The use of a phenylephrine infusion was restricted to the following instances of cerebral ischemia: 1) ischemia associated with hypotension that did not resolve within 2 minutes of decreases in anesthetic administration and treatment with fluid and/or colloid; 2) ischemia poorly or slowly responsive to shunt placement, accompanied by either hypo- or normotension; and 3) ischemia poorly or slowly responsive to removal of the carotid clamp, accompanied by either hypo- or normotension. Two non-Q wave MIs (1.2%) occurred, both nonfatal. There were two cerebral infarctions (1.2%) and three deaths not related to MI (1.8%). Based on these findings, in order to decrease the incidence of both MI and cerebral infarction after general anesthesia for CEA, we recommend the restrictive use of phenylephrine-induced hypertension for specific instances of slowly or poorly reversible cerebral ischemia, as shown on the electroencephalogram.

Neuronal death after trophic factor deprivation

Since the discovery of nerve growth factor (NGF) nearly 40 years ago, extensive studies have elaborated the trophic relationship between a neuron and its end organ. Much evidence has accumulated that depicts the crucial role of neurotrophic factors in determining neuronal survival both during development and after injury. The molecular events by which trophic factors determine whether an individual neuron lives or dies are poorly understood. The function of active protein synthesis as a prerequisite for neuronal death has led to the hypothesis that all neurons contain a mechanism to self-destruct or a phenomenon of programmed cell death. The loss of trophic support may, therefore, lead to the initiation of this so called "suicide" program within individual cells. Recently, multiple other trophic factors have been discovered. At least two of these factors, brain-derived neurotrophic factor and neurotrophin-3, appear related to members of the same gene family as the prototypic neurotrophic factor, nerve growth factor. Other metabolic factors, such as intracellular calcium, may be instrumental in determining the dependence of individual neurons on specific trophic support. A "set-point" hypothesis has been described concerning the relationship between intracellular calcium and the NGF dependency of embryonic neurons in cell culture. Changes in calcium metabolism may be an important determinant in altering trophic dependence and naturally occurring cell death. Neurotrophic factors also influence the reaction of the neuron to axotomy and subsequent axonal regeneration. Exogenously supplied trophic factors may prevent neuronal loss after axotomy when supplied at the site of injury. Both NGF and FGF have been shown to enhance early regeneration across gaps within silicone chambers.(ABSTRACT TRUNCATED AT 250 WORDS)

Relationship of intracellular calcium to dependence on nerve growth factor in dorsal root ganglion neurons in cell culture

During development, neural crest-derived sensory neurons require nerve growth factor (NGF) for survival, but lose this dependency postnatally. Similarly, dissociated embryonic sensory neurons lose their NGF dependence during the first 3 weeks in cell culture. It has been hypothesized that, in sympathetic neurons, intracellular levels of calcium are related to trophic factor dependence. In vitro during the period in which embryonic-day-15 sensory neurons become independent of NGF, intracellular calcium concentrations progressively increased in parallel to the decline in NGF dependence. This elevation of intracellular calcium was directly related to the absolute age of the neurons, not to the length of time in culture. Without NGF, immature sensory, i.e., dependent, neurons survived in the presence of high extracellular potassium, a condition that produces elevated intracellular calcium. In another paradigm, measurements of intracellular calcium were determined in NGF-dependent neurons "committed to die" after NGF withdrawal. These measurements were determined prior to the time that extensive morphological changes, consistent with cell death, were noted by phase-contrast microscopy. No elevation in intracellular calcium was found in these dying neurons, but rather, a small decrease was observed prior to the disintegration of the neurons. These findings support the hypothesis that trophic factor dependence of neurons may be inversely related to levels of intracellular calcium.

First place--Resident Basic Science Award 1990. Fibronectin-laminin combination enhances peripheral nerve regeneration across long gaps

An exogenous fibronectin-laminin (FN-LAM) solution was added into silicone chambers to determine the effects on peripheral nerve regeneration across 18-mm long gaps. The sciatic nerves of adult rats were sutured into silicone chambers 20 mm in length, creating an 18-mm gap between the proximal and distal nerve stumps. The chambers were filled with either a mixture of fibronectin and laminin (500 micrograms/ml each) or a solution of cytochrome C (1 mg/ml) as the control. After six weeks, the animals were killed and the chambers were examined for regeneration. Seventy percent of the animals from the FN-LAM group demonstrated regeneration across the 18-mm gaps, compared to only 30% in the control group. The combination of FN-LAM significantly increased the number of axons that grew into the distal end of the chamber (FN-LAM, 1325 +/- 522; cytochrome C, 153 +/- 104; p = 0.03). Examination of the distal tributaries of the sciatic nerve revealed axons only in the FN-LAM group; none were found in the control group. Quantitative analysis of neurons, retrogradely labeled with horseradish peroxidase via injection of the sciatic nerve distal to the regenerated segment, revealed a greater number of sensory and motor neurons in the FN-LAM group compared to the control group. Morphometric studies revealed that the mean area of the regenerated segment in the FN-LAM group was 37% larger than the controls, and ultrastructural analysis demonstrated a more mature regenerated nerve. This is the first in vivo demonstration that this combination of fibronectin and laminin significantly enhances the regeneration of myelinated axons across a long nerve gap in the rat sciatic nerve.

Sciatic nerve regeneration across gaps within silicone chambers: long-term effects of NGF and consideration of axonal branching

We examined whether the short-term beneficial effects of nerve growth factor (NGF) upon regeneration are sustained over a prolonged period of time across 8-mm gaps within silicone chambers. Rat sciatic nerve regeneration both with and without NGF was examined after 10 weeks. Myelinated counts from the regenerated sciatic and distal tributary nerves were correlated to the numbers of motor and sensory neurons retrogradely labeled with horseradish peroxidase (HRP) applied distal to the regenerated segment. Regenerated sciatic and sural nerves were examined ultrastructurally for morphological analysis. Both regenerated groups by 10 weeks achieved essentially complete counts of myelinated axons in the distal tributary nerves and the regenerated segment of the sciatic nerve compared to the uninjured controls. There were similar numbers of retrogradely labeled sensory and motor neurons in the dorsal root ganglia (DRG) and lumbar spinal cord of both groups and, surprisingly, of the uninjured normal control group. Ultrastructural analysis demonstrated no difference in the distribution of axonal diameters or myelin thickness between the regenerated groups. In evaluating regeneration in experimental silicone chamber models, it is important to determine such parameters as the percentage of neurons that grow across the gap and the incidence of axonal sprouting. One can then make accurate assessments of experimental perturbations and predict whether they improve the naturally occurring regeneration through chambers. These results must ultimately be compared with equivalent determinations in the uninjured nerve. At 10 weeks there was essentially complete regeneration of both the NGF and control regenerative groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Flunarizine protects neurons from death after axotomy or NGF deprivation

Systemically administered flunarizine enhanced neuronal survival in lumbar sensory ganglia in newborn rats after axotomy. Flunarizine-treated rats lost 71 percent fewer neurons than the untreated control rats at the end of 1 week. In cell culture, flunarizine at 30 to 40 microM also prevented neuronal death in nerve growth factor-dependent embryonic sensory and sympathetic neurons after the abrupt withdrawal of neurotrophic support. The drug may cause this effect by acting at an intracellular site, one distinct from its blockade of voltage-dependent calcium channels.

Nerve growth factor enhances regeneration through silicone chambers

The effect of exogenous NGF on axonal growth across a gap between sectioned ends of a sciatic nerve within silicone chambers was examined in Sprague-Dawley rats. After nerve section and surgical implantation, silicone chambers were filled with either a 1 mg/ml nerve growth factor (NGF)/saline solution (experimental) or a normal saline solution (control). Four weeks after surgery, the regenerated nerves from within the silicone chambers were dissected and fixed for histological studies at both light microscopic and ultrastructural levels. Morphological analysis of the nerves showed no difference between the NGF-treated and control groups in the size of the regenerated nerves within the chambers or in the diameters of myelinated axons. Total myelinated axonal counts were determined from within the distal chamber. NGF significantly increased the number of myelinated axons that grew into the distal end of the chamber (2126 +/- 437 NGF/saline; 1064 +/- 268 saline; P less than 0.05 Student's t test). Counts of the unmyelinated axons from the distal nerve segment from the two groups were not different. Myelin sheath thickness was 58% greater in the NGF-treated group compared with that in the saline group. There was no difference between the two groups in the size-frequency spectra of the diameters of the myelinated axons in the distal segment. The NGF/saline group showed a more mature-appearing regenerated nerve based on the percentage of myelinated axons, thickness of the myelin sheaths, and development of internal organization (e.g., amount of endoneurial collagen fibers, ensheathment of unmyelinated axons by Schwann cells, and interfascicular patterns).(ABSTRACT TRUNCATED AT 250 WORDS)

Use of computerized electroencephalographic monitoring during aneurysm surgery

The clinical usefulness of intraoperative electroencephalographic (EEG) monitoring of cerebral perfusion during aneurysm surgery has received little attention, primarily due to problems with electrode placement over the operative site, which is the area of maximal risk. In this report, 27 patients undergoing surgery for anterior circulation aneurysms were monitored intraoperatively with a two-channel computerized EEG complex using a bilateral frontal-occipital montage. In 16 patients, a normal EEG pattern was observed throughout surgery; all 16 awoke neurologically intact and their postoperative angiograms did not reveal cerebral vasospasm. In the other 11 patients, one of two patterns of persistent EEG abnormalities was identified. 1) In six of these patients a marked attenuation of EEG activity was observed ipsilaterally which coincided with various intraoperative events including brain retraction, hypotension, and aneurysm dissection/clipping. Five of these six patients awoke with new neurological deficits which persisted beyond 12 hours in two, both of whom had angiographically proven vasospasm 24 hours after surgery. 2) In the remaining five patients, a distinct abnormal EEG pattern consisting of marked hyperactivity in the delta, theta, and alpha frequency ranges was observed ipsilaterally. Four of these five patients had a poor neurological outcome and vasospasm on their angiogram 24 hours after surgery. Thus, EEG monitoring which spans the operative area during aneurysm surgery is practicable and appears to be of value in the detection of compromised cerebral perfusion during aneurysm surgery. The possible significance of the two abnormal EEG patterns identified in this report is discussed.

Death of sensory ganglion neurons after acute withdrawal of nerve growth factor in dissociated cell cultures

The time course of dependence on nerve growth factor (NGF) for survival in sensory neurons in vitro was examined with microscopic and biochemical methods. Primary dorsal root ganglion (DRG) cultures from embryonic-day-15 (E-15) and day-19 (E-19) rats were maintained with standard dissociated cell culture techniques in the absence of most non-neuronal cells. After various times in culture, neurons were acutely deprived of neurotrophic support by changing to NGF-free medium and adding NGF antiserum to eliminate any residual NGF. Neuronal cultures were examined with phase microscopy; and, their metabolic activity was measured with a protein assay at various time points after NGF deprivation. E-15 neurons grown in culture for 5 days were exquisitely sensitive to acute NGF deprivation. By 12 h after NGF deprivation, neuronal morphology was severely disrupted and the majority of neurons appeared dead. E-15 neurons grown in culture for 8 or 11 days showed progressively less dependence on NGF for survival. These older neurons did not die until 24 and 48 h, respectively, following NGF withdrawal. Neurons grown in culture for 20 days did not show any morphologic changes by phase microscopy up to 4 days after NGF deprivation. Protein incorporation progressively decreased between 12 and 48 h after NGF withdrawal in E-15 neurons grown in culture for 5, 8, or 11 days.(ABSTRACT TRUNCATED AT 250 WORDS)

Selective shunting during carotid endarterectomy based on two-channel computerized electroencephalographic/compressed spectral array analysis

The reliability of selective shunting based on computerized electroencephalographic (EEG) monitoring has not been addressed. In this study, 103 carotid endarterectomies were performed with selective shunting based on a two-channel computerized EEG monitor that processed the on-line, raw electroencephalogram (EEG) to produce a compressed spectral array (CSA). Ischemic EEG events were identified by amplitude attenuation of the raw EEG and/or loss of high-frequency activity on the CSA. Fourteen patients (13.6%) received a bypass shunt, and postoperative neurological examinations showed 97 patients (94.2%) to be intact. A correlation between total (cumulative) ischemic EEG time and the postoperative neurological exam was demonstrated (P less than 0.0001). Six postoperative deficits (5.8%) occurred, five in patients whose computerized EEGs demonstrated an ischemic EEG event late during carotid clamping, when it was no longer possible to place a shunt. The sixth deficit was found in a patient whose EEG did not demonstrate any patient whose EEG did not demonstrate any signs of cerebral ischemia. Five of these six new deficits resolved within 12 hours, and only one persisted for 72 hours, when the patient died of a pulmonary embolism (cerebral infarction and mortality rate of 1%). These results appear to demonstrate that two-channel monitoring of both the CSA and the unprocessed (raw) EEG simultaneously can be used as a reliable indicator of whether a bypass shunt is required during carotid cross-clamping in all patients, regardless of their preoperative neurological history or angiographic findings.

Posterior segmental spinal instrumentation (PSSI) with posterolateral decompression and debulking for metastatic thoracic and lumbar spine disease. Limitations of the technique

Twenty-five patients with metastatic thoracic and lumbar spine disease were initially treated by the authors with posterolateral debridement and decompression, along with posterior segmental spinal instrumentation. Ten patients had marked paresis, nine had signs of spinal cord or cauda equina compression without paresis, and all patients had pain severe enough to prevent sitting/standing/walking. The posterior approach was used in these patients instead of an anterior one because of translocation (4), three-column disease (16), three or more vertebral bodies involved (13), disease at two separate locations (2), and inability to tolerate an anterior approach (3). All patients had maintenance of spinal alignment for the length of follow-up or until their ultimate demise. Good pain relief was achieved in 19 of 25 patients. Six of ten patients with significant paresis recovered. Four patients developed recurrent spinal cord compression within 12 months postoperative from regrowth of tumor that was not controlled by radiotherapy or chemotherapy. Six of the 25 patients were not significantly palliated by the technique.

Nerve growth factor protects adult sensory neurons from cell death and atrophy caused by nerve injury

The reaction of dorsal root ganglia (DRG) neurons to axotomy and its alteration by locally supplied nerve growth factor (NGF) were examined in adult rats. Surgically implanted silicone chambers attached to the severed tip of the sciatic nerve acted as reservoirs capable of providing prolonged access of NGF to the site of injury. The time course of NGF activity within the chambers was determined by using the standard NGF chick DRG bioassay. The fluid from chambers filled with the NGF-saline solution maintained NGF activity for periods up to 6 weeks after implantation. By 9 weeks, however, the fluid from most chambers failed to show any NGF activity in the bioassay. Experiments were designed to compare the response in adult rats to injury of DRG neurons receiving chambers filled with either NGF-saline or with only saline. The total neuronal counts in the lumbar fourth and fifth DRG at 3 weeks and 6 weeks after sciatic nerve section showed 22% and 16% cell death, respectively, in those injured neurons receiving saline-filled chamber implants. The animals that received chamber implants which contained an NGF-saline solution showed no cell death in the ipsilateral DRG at either 3 or 6 weeks after injury. Morphometric analysis of injured DRG neurons showed evidence of atrophy in the injured neurons which did not receive NGF. The degree of atrophy among all cell sizes was significantly decreased in those injured neurons receiving NGF. At 3 weeks after section the mean volume of injured neurons not treated with NGF was decreased by 28% as compared with only a 13% decrease in neurons treated with NGF.(ABSTRACT TRUNCATED AT 250 WORDS)

Ventral rhizotomy enhances regeneration of uninjured sensory neurons

Uninjured sensory neurons show metabolic and morphologic changes, as well as enhanced regeneration, when exposed to adjacent degenerating ventral root fibers. The release of a neurotrophic factor from the degenerating nerve fibers may be responsible for 'priming' the uninjured neuron and thereby enhancing its response to injury.

Computed tomography in chronic seizure disorder caused by glioma

Since the introduction of computed tomography (CT) in 1974, 137 patients underwent cortical resection for intractable epilepsy. The CT scans of 32 of these patients demonstrated an isolated calcified or hypodense lesion of unknown origin. The mean interval from onset of the seizure disorder to surgery was 11 years. The referring physicians frequently considered these lesions to be of nonneoplastic origin, which usually delayed surgical management. Twenty-six of the 32 patients, however, proved to have a cerebral glioma, seven showing anaplastic changes. Because the majority of these patients were found to have a neoplasm and especially because the CT scan could not distinguish between a well-differentiated glioma and those with anaplastic changes, we recommend early surgical treatment in patients with chronic seizure disorders who are found to have an isolated lesion of unknown origin on CT scan.

The effects of nerve growth factor and its antiserum on the postnatal development and survival after injury of sensory neurons in rat dorsal root ganglia

Nerve growth factor (NGF) is known to be essential for survival and maintenance of sympathetic ganglia and of embryonic sensory ganglia of neural crest origin. The present study examined the physiological and pharmacological roles of NGF in the postnatal development of sensory neurons in the dorsal root ganglion (DRG). In contrast to what is generally stated in the literature, administration of NGF antiserum to newborn rats for a period of 7 days resulted in a significant (approximately 20%) reduction of neuronal number in the lumbar DRG. Size spectrum analysis of surviving neurons revealed a shift toward larger sizes, presumably due to a preferential loss of small cells. The number of neurons in the L5 DRG was studied at various times after unilateral sciatic nerve crush in 1-day-old rats. Axotomy resulted in a substantial loss (40 to 50%) of neurons in the immature DRG. Administration of NGF antiserum to animals with axotomized DRG did not increase cell death when compared with the axotomized controls. However, the number of neurons in the antiserum-treated ganglia decreased by the same percentage (20%) when compared with the control serum-treated ganglia before and after axotomy. Treatment with NGF initially prevented the loss of neurons in the axotomized DRG. However, some neurons died during the first week despite continued NGF administration; and, subsequent to NGF withdrawal, neuronal number decreased to the same level as in control animals. Thus, removal of exogenous NGF resulted in the death of the sensory neurons which had been maintained.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of nerve growth factor in the adult dorsal root ganglia neuron and its response to injury

The response of dorsal root ganglia (DRG) neurons to NGF deprivation and to axotomy was examined in adult guinea pigs. The success of NGF deprivation by means of an autoimmune approach was monitored by the measurement of serum antibody titer levels against guinea pig NGF with the standard bioassay for NGF activity. That the antibody produced NGF deprivation was confirmed by histologic evidence of neuronal atrophy and apparent cell loss in sections of the superior cervical ganglia (SCG) and by marked decreases (65-80%) of SCG neurotransmitter-synthesizing enzyme activity levels. By using the autoimmune approach a new source of guinea pigs was found which consistently produced high titers of cross-reacting anti-NGF antibodies. Experiments were designed to examine the response of the sensory neuron to injury while chronically deprived of NGF. Total neuronal counts in the sixth lumbar DRG 98 days after sciatic nerve crush showed no difference between NGF-deprived and control ganglia. Measurement of the size spectrum of DRG neurons showed evidence of atrophy of the NGF-deprived neurons in both the uninjured and axotomized side compared to respective controls. The mean volume of uninjured sensory neurons measured in the NGF-deprived guinea pigs was decreased 27.7% (P less than .05) compared with that of control guinea pigs. The degree of regeneration 6 days following a nerve crush was the same in NGF-deprived sensory neurons and in controls when measured by the "pinch test" and by isotope-labeled axonal transport studies.(ABSTRACT TRUNCATED AT 250 WORDS)