Top 50 most impactful publications on massive rotator cuff tears

Background

Bibliometric analysis is a useful tool for measuring the scholarly impact of a topic and its more and less heavily studied aspects. The purpose of this study is to use bibliometric analysis to comprehensively analyze the 50 articles with the highest citation indices in studies evaluating the treatment and outcomes of massive rotator cuff tears (mRCTs).

Methods

This cross-sectional study identified articles within the Scopus database published through December 2022. Keywords used were "massive rotator cuff tear." Articles were sorted in chronological order. The year published and number of citations were recorded. A citation index (CI) was calculated for each article by dividing the number of citations by number of years published [1 citation/1 year published (2021) = CI of 1]. Of these, the 50 articles with the highest CIs were carried forward for evaluation. Frequencies and distributions were assessed for data of each variable collected.

Results

These search methods produced 625 articles regarding mRCT research (ranging from January 1986 to December 2022). Four of the top 10 most impactful articles were published in the 2010s. The level of evidence (LOE) published with the greatest frequency was level of evidence 4 (41%). The journal Arthroscopy published the highest number within the top 50 (26%) followed by the Journal of Bone and Joint Surgery and the American Journal of Sports Medicine (20% each). Clinical studies composed 88% of the top 50. Case series (38%) predominated, while systematic reviews (20%) and randomized control trials (8%) were less prevalent. The majority of studies concentrated on the clinical outcomes of certain interventions (62%), mainly comparing multiple interventions.

Conclusion

Despite the relatively high prevalence of mRCTs (40% of all tears), this topic comprises only a small proportion of all rotator cuff research. This analysis has identified gaps within and limitations of the findings concerning mRCTs for researchers to propose research questions targeting understudied topics and influence the future treatment and outcomes of this clinically difficult diagnosis.

The Implications of Socioeconomic Status by ZIP Code on Maternal-Fetal Morbidity and Mortality in San Antonio, Texas

Introduction Over the past 20 years, the number of pregnancy-related fatalities in the United States has been on the rise. Increases in maternal and fetal mortality have been attributed to low socioeconomic status (SES). This raises the question of whether all geographical locations are proportionally affected by this upward trend in pregnancy-related fatalities. San Antonio is one of the largest cities in the United States and is known for its economic segregation. This study aims to compare the maternal and fetal health outcomes of mothers from diverse socioeconomic backgrounds in San Antonio, Texas. Methods To analyze the relationship between pregnancy-related mortality rates and SES in San Antonio, Texas, the International Classification of Diseases (ICD)-10 codes for maternal and fetal demise and their associated risk factors were identified. The ICD-10 codes were used to compare the health outcomes of pregnant women from the highest SES ZIP Code (78255, median income $124,397) to women from the lowest SES ZIP Code (78207, median income $25,415) using the Texas Inpatient Public Use Data File for 2016, which contains information on 93-97% of all hospital discharges in San Antonio, Texas. Results Notably, pregnant women from the high SES ZIP Code were admitted to the hospital from clinics or a physician's office (68.8%), while pregnant women from the low SES ZIP Code were admitted to the hospital from non-healthcare facilities like home or workplace (62.5%). In addition, a greater percentage of patients from the low SES ZIP Code were Black (4.3% vs 1.3%) or Hispanic (88.5% vs 35.1%). Compared to women from the high SES ZIP Code, women from the low SES ZIP Code experienced more fetal deaths and a higher prevalence of maternal and fetal risk factors such as obesity (47.6% vs 32.5%), asthma (1.7% vs 1.3%), hypertension (0.8% vs 0%), substance abuse (0.5% vs 0%), diabetes mellitus (9.8% vs 7.8%), preeclampsia (7.7% vs 2.6%), and multiple C-sections (35.5% vs 28.6%). Finally, fetal mortality rates were higher in the low SES ZIP Code (1.1% vs 0%). Although there were no statistically significant maternal or fetal mortality differences between the ZIP Codes, the trend suggests that women's health outcomes in San Antonio are not equitable. Discussion Analysis reveals disproportionate health outcomes for women in south San Antonio. Further investigation is warranted to better understand the role social and medical factors play in these results. Investigating the relationship between SES and pregnancy-related mortality can help to better inform healthcare providers and identify ways to improve women's health outcomes in San Antonio, Texas.

A 25-Year Analysis of Diversity, Equity, and Inclusion Research in Orthopaedics Shows Majority Female Authorship and Increasing Gender Parity Research

Introduction

Orthopaedic surgery is one of the least diverse fields in medicine. In recent decades, there has been a concerted effort to increase diversity, equity, and inclusion (DEI) in the specialty, in addition to the institution of several organizations to establish the pipeline and facilitate underrepresented minority students into orthopaedic surgery. The aim of this study was to examine trends in orthopaedic surgery DEI research.

Methods

A search of DEI articles was conducted in orthopaedic surgery using PubMed, MEDLINE, EMBASE, Scopus, Cumulative Index to Nursing and Allied Health Literature, and Education Resources Information Center. The year of publication, article topic of focus, sex of the primary author, publishing journal, citation index, and primary contributing institution were recorded for each article. Sex of the primary author was predicted by the authors using an online image search of the author and institution. Articles were excluded if the research was conducted outside of the United States or if they were not specific to orthopaedic surgery.

Results

A total of 143 articles met the inclusion criteria. A total of 52.4% of authors (n = 75) were women and 44.1% (n = 63) were men. A total of 42.7% of the articles were written about sex (n = 61), 39.9% about race/ethnicity and sex (n = 57), and 11.9% about race/ethnicity (n = 17). A total of 10 articles were affiliated with Washington University in St. Louis while 51 other institutions wrote the remaining articles, with none having more than 4. Information could not be confirmed for 5 articles. In 2018, 5 articles were published, followed by 17 in 2019, 25 in 2020, 34 in 2021, and 30 in 2022.

Conclusion

DEI research in orthopaedic surgery is a relatively new venture within the specialty and has room to grow, specifically in the examination of race/ethnicity and inclusion strategies. Leading journals and academic institutions in orthopaedic surgery should incentivize productivity and authorship in DEI research.

Level of Evidence

III.

Education Research in Orthopaedic Surgery

With the ever-changing dynamics of surgical training, it is essential for the content of educational research to evolve simultaneously. This study aimed to assess the current state of scholarly work in orthopaedic training education and to identify particular educational topics that are trending in the literature.

“Clots and Failures” A Case of COVID-19 Causing STEMI and Persistent Cardiogenic Shock Ultimately Requiring LVAD

Introduction

We present a case of COVID-19 causing hypercoagulability and inflammatory stress leading to STEMI in a patient who went on to develop persistent cardiogenic shock requiring LVA) implantation.

Case Report

57-year-old lady developed COVID-19 infection in May 2020. In June 2020, she presented with chest pain, was noted to have STEMI on EKG, complicated by cardiac arrest with ROSC in 14 minutes. She was in cardiogenic shock as well and was started on veno-arterial ECMO. She underwent left anterior descending artery stent placement. Further hospitalization was complicated by persistent cardiogenic shock and complete heart block and underwent pacemaker and cardiac-defibrillator implantation. She developed pulmonary edema, acute kidney injury requiring hemodialysis, shock liver, and persistent cardiogenic shock. She was weaned off VA-ECMO after 4 days but continued to have severely reduced cardiac function. RHC revealed severe volume overload, pulmonary venous hypertension, low cardiac output, and right heart dysfunction. Echo showed severe LV dysfunction with an EF of 15%. A femoral intra-aortic balloon pump(IABP) was placed on July 7, 2020. An attempt was made to wean her off of IABP on July 10^th,however, it was unsuccessful and she was transitioned to axillary intra-aortic balloon pump. She remained IABP dependent thereafter and on July 15th, given persistent cardiogenic shock, decision was made to pursue advanced heart failure therapies. After multi-disciplinary discussion, the decision to pursue LVAD implantation was made. She underwent a successful LVAD implantation on July 20^th . She failed an extubation trial and underwent tracheostomy on July 23^rd . Post LVAD, she developed atrial fibrillation and was started on digoxin and amiodarone. Her symptoms improved and she was subsequently discharged to rehabilitation in late August on amiodarone, digoxin, metoprolol, prasugrel, warfarin, spironolactone and lisinopril. The detailed timeline is shown in figure 1.

Summary

Hypercoagulability and severe inflammatory stress leading to life-threatening illness is a significant complication of COVID-19 infection. A low threshold for suspecting and treating hypercoagulability and inflammatory induced myocardial ischemia and injury and cardiogenic shock is a reasonable strategy to decrease acute as well as chronic morbidity and mortality.

ECMO for Critically Ill COVID-19 with ARDS: A Case Series

Introduction

Veno-venous extracorporeal membrane oxygenation (VV-ECMO) as bridge to recovery in critically ill COVID-19 continues to be commonly utilized strategy in cases with persistent respiratory failure refractory to traditional ventilation support

Case Report

We report 5 cases of severe acute respiratory syndrome coronavirus-2 infection (SARS-CoV-2) who were treated with ECMO (Table 1). All 5 cases presented with fever, cough and shortness of breath and a positive nasopharyngeal swab for SARS-CoV-2 on admission. Case 1, 2, 3 and 5 patients were hypoxemic with saturation less than 90% on admission and decompensated rapidly, whereas Case 4 decompensated after day 14. Mechanical ventilation failed to provide adequate oxygenation in all 5 cases; case 2,3 and 5 were started on recruitment measures with proning while it was not possible for case 1 owing to morbid obesity. Proning was not possible in the case 4 as patient became severely hypoxemic while patient was undergoing mechanical thrombectomy. The case 1-4 remained on ECMO for 19, 17, 17 and 2 days respectively. All except case 2 had improvement in APACHEII and SOFA score after ECMO initiation. All 5 patients had elevated inflammatory markers of serum ferritin, D-dimer, Lactate dehydrogenase (LDH), C-reactive protein (CRP) which trended down after a few days of ECMO initiation All 5 patients received high dose steroids during their stay in the ICU. Case 4 and 5 passed away after compassionate extubation. Case 1-3 had prolonged hospital course with complication of hospital acquired pneumonia requiring multiple courses of broad-spectrum antibiotics.

Summary

Our observational report of 5 patients reports the use of ECMO in critically ill SARS-CoV-2 with ARDS and difficult to maintain saturation despite mechanical ventilation and proning with recovery for 3 patients. However, given the lack of ECMO centers; this is not a readily available option. Further studies are warranted to investigate the role of ECMO in SARRS-CoV-2 and careful identification of appropriate candidates.

Disparities in Ocular and Periocular Cancer Outcomes: Assessing Survival in Patients of Hispanic Origin

A nationwide cancer database was used to perform a retrospective cohort study to compare the overall survival and cause-specific survival in patients with ocular and periocular cancer from varying Hispanic origins. A total of 19,831 cases from the Surveillance, Epidemiology, and End Results (SEER) registries between 1973 and 2015 were obtained for analysis. All-cause and cause-specific mortality risk, with adjustment for age group, sex, race, tumor site, tumor histology, grade, summary stage, laterality, surgery status, radiotherapy status, and chemotherapy status, was examined using Cox proportional hazard models. Of the patients included 19,194 patients were non-Spanish-Hispanic-Latino, and 637 patients were Spanish-Hispanic Latino. The Spanish-Hispanic-Latino population was further subdivided as 398 of Mexican origin, 44 of Puerto Rican origin, 135 of South or Central American (excluding Brazil) origin, and 60 of other Spanish/Hispanic origin (including Europe origin). The mean (+/-SD) follow-up period was 98.57 (+/-93.23) months. In adjusted Cox regression, patients of Spanish-Hispanic-Latino origin demonstrated increased all-cause (HR, 1.173; 95% CI 1.022-1.347; P = 0.023) and cancer-specific mortality (HR, 1.328; 95% CI 1.099-1.604; P = 0.003) as compared to their non-Spanish-Hispanic-Latino counterparts. Upon subclassification by Hispanic origin, patients of Mexican origin had significantly increased all-cause (HR, 1.229; 95% CI 1.032-1.464; P = 0.021) and cancer-specific mortality (HR, 1.516; 95% CI 1.204-1.909; P < .001) and patients with other Hispanic/Spanish origin, including Europe, had significantly increased all-cause (HR, 1.627; 95% CI 1.16-2.28; P =0.005), but not cancer-specific (HR, 1.243; 95% CI 0.734-2.104; P = 0.418) mortality. Patients of Puerto Rican origin and South or Central American (excluding Brazil) origin had no significant difference in all-cause or cancer-specific mortality compared to those of non-Spanish-Hispanic-Latino origin. Mortality risk from ocular and periocular cancers varies extensively by specific Hispanic origin. A greater understanding of these disparities is essential to identify vulnerable populations and provide adequate treatment to optimize long-term outcomes.

Neuroinflammation Induces Neurodegeneration

Neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD), and Multiple Sclerosis (MS) are characterized by neuronal degeneration and neuronal death in specific regions of the central nervous system (CNS). In AD, neurons of the hippocampus and entorhinal cortex are the first to degenerate, whereas in PD, dopaminergic neurons in the substantia nigra degenerate. MS patients show destruction of the myelin sheath. Once the CNS neurons are damaged, they are unable to regenerate unlike any other tissue in the body. Neurodegeneration is mediated by inflammatory and neurotoxic mediators such as interleukin-1beta (IL-1β), IL-6, IL-8, IL-33, tumor necrosis factor-alpha (TNF-α), chemokine (C-C motif) ligand 2 (CCL2), CCL5, matrix metalloproteinase (MMPs), granulocyte macrophage colony-stimulating factor (GM-CSF), glia maturation factor (GMF), substance P, reactive oxygen species (ROS), reactive nitrogen species (RNS), mast cells-mediated histamine and proteases, protease activated receptor-2 (PAR-2), CD40, CD40L, CD88, intracellular Ca⁺ elevation, and activation of mitogen-activated protein kinases (MAPKs) and nuclear factor kappa-B (NF-kB). Activated microglia, astrocytes, neurons, T-cells and mast cells release these inflammatory mediators and mediate neuroinflammation and neurodegeneration in a vicious manner. Further, immune and inflammatory cells and inflammatory mediators from the periphery cross the defective blood-brain-barrier (BBB) and augment neuroinflammation. Though inflammation is crucial in the onset and the progression of neurodegenerative diseases, anti-inflammatory drugs do not provide significant therapeutic effects in these patients till date, as the disease pathogenesis is not yet clearly understood. In this review, we discuss the possible factors involved in neuroinflammation-mediated neurodegeneration.

Serous cystic neoplasm of the pancreas: a multinational study of 2622 patients under the auspices of the International Association of Pancreatology and European Pancreatic Club (European Study Group on Cystic Tumors of the Pancreas)

OBJECTIVES

Serous cystic neoplasm (SCN) is a cystic neoplasm of the pancreas whose natural history is poorly known. The purpose of the study was to attempt to describe the natural history of SCN, including the specific mortality.

DESIGN

Retrospective multinational study including SCN diagnosed between 1990 and 2014.

RESULTS

2622 patients were included. Seventy-four per cent were women, and median age at diagnosis was 58 years (16-99). Patients presented with non-specific abdominal pain (27%), pancreaticobiliary symptoms (9%), diabetes mellitus (5%), other symptoms (4%) and/or were asymptomatic (61%). Fifty-two per cent of patients were operated on during the first year after diagnosis (median size: 40 mm (2-200)), 9% had resection beyond 1 year of follow-up (3 years (1-20), size at diagnosis: 25 mm (4-140)) and 39% had no surgery (3.6 years (1-23), 25.5 mm (1-200)). Surgical indications were (not exclusive) uncertain diagnosis (60%), symptoms (23%), size increase (12%), large size (6%) and adjacent organ compression (5%). In patients followed beyond 1 year (n=1271), size increased in 37% (growth rate: 4 mm/year), was stable in 57% and decreased in 6%. Three serous cystadenocarcinomas were recorded. Postoperative mortality was 0.6% (n=10), and SCN's related mortality was 0.1% (n=1).

CONCLUSIONS

After a 3-year follow-up, clinical relevant symptoms occurred in a very small proportion of patients and size slowly increased in less than half. Surgical treatment should be proposed only for diagnosis remaining uncertain after complete workup, significant and related symptoms or exceptionally when exists concern with malignancy. This study supports an initial conservative management in the majority of patients with SCN.

TRIAL REGISTRATION NUMBER

IRB 00006477.

Suppression of glia maturation factor expression prevents 1-methyl-4-phenylpyridinium (MPP⁺)-induced loss of mesencephalic dopaminergic neurons

Inflammation mediated by glial activation appears to play a critical role in the pathogenesis of Parkinson disease (PD). Glia maturation factor (GMF), a proinflammatory protein predominantly localized in the central nervous system was isolated, sequenced and cloned in our laboratory. We have previously demonstrated immunomodulatory and proinflammatory functions of GMF, but its involvement in 1-methyl-4-phenylpyridinium (MPP(+)), active metabolite of classical parkinsonian toxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), inducing loss of dopaminergic (DA) neurons has not been studied. Here we show that altered expression of GMF has direct consequences on the production of reactive oxygen species (ROS) and nuclear factor-kappa B (NF-κB)- mediated production of inflammatory mediators by MPP(+). We examined MPP(+)-induced DA neuronal loss in primary cultures of mouse mesencephalic neurons/glia obtained from GMF-deficient (GMF knockout (GMF-KO)) and GMF-containing wild-type (Wt) mice. We demonstrate that deficiency of GMF in GMF-KO neurons/glia led to decreased production of ROS and downregulation of NF-κB-mediated production of tumor necrosis factor-alpha (TNF-α) and interleukin-1beta (IL-1β) as compared to Wt neurons/glia. Additionally, overexpression of GMF induced DA neurodegeneration, whereas GMF downregulation by GMF-specific shRNA protected DA neurons from MPP-induced toxicity. Subsequently, GMF deficiency ameliorates antioxidant balance, as evidenced by the decreased level of lipid peroxidation, less ROS production along with increased level of glutathione; and attenuated the DA neuronal loss via the downregulation of NF-κB-mediated inflammatory responses. In conclusion, our overall data indicate that GMF modulates oxidative stress and release of deleterious agents by MPP(+) leading to loss of DA neurons. Our study provides new insights into the potential role of GMF and identifies targets for therapeutic interventions in neurodegenerative diseases.

Double-balloon enteroscopy in Ireland in the capsule endoscopy era

BACKGROUND

The availability of double-balloon enteroscopy (DBE) and small bowel capsule endoscopy (SBCE) in Ireland has revolutionised our approach to the diagnosis and treatment of small bowel disorders.

AIMS

To evaluate the use of DBE in Ireland and to compare the diagnostic yield with and without prior SBCE in order to improve the efficiency of our resources for small bowel endoscopy.

METHODS

A retrospective comparison study of all DBEs performed between two centres, one with SBCE available, was undertaken. Information was obtained by review of endoscopy reports, referral letters, radiology reports and charts. A review of the SBCE database was undertaken to identify patients who had undergone SBCE prior to DBE.

RESULTS

A total of 242 DBE procedures were carried out between both centres. SBCE was performed prior to DBE in 20 % (n = 46). The overall diagnostic yield of DBE was 47 % (n = 115). There was a statistically significant difference in diagnostic yield between the DBE only and the DBE with prior SBCE groups 44 versus 61 %, respectively, p < 0.0001. There was also a significant difference in the DBE approach, with 73 % of procedures being anterograde in centre 1 versus 56 % in centre 2. A subgroup analysis of centre 1 data revealed a negative predictive value of 100 % and a positive predictive value of 74 % for SBCE when DBE findings were considered as a gold standard.

CONCLUSION

SBCE as a screening tool prior to DBE is extremely valuable and increases the diagnostic yield considerably as a consequence of a high negative predictive value.

Expression of glia maturation factor in neuropathological lesions of Alzheimer's disease

AIMS

The pathology of Alzheimer's disease (AD) is characterized by the presence of amyloid plaques (APs), neurofibrillary tangles (NFTs), degenerating neurones, and an abundance of reactive astrocytes and microglia. We aim to examine the association between glia maturation factor (GMF) expression, activated astrocytes/microglia, APs and NFTs in AD-affected brain regions.

METHODS

Brain sections were stained with Thioflavin-S to study AD pathology and sequentially immunolabeled with antibodies against GMF, glial fibrillary acidic protein (marker for reactive astrocytes), and Ionized calcium binding adaptor molecule 1 (Iba-1, marker for activated microglia) followed by visualization with avidin-biotin peroxidase complex.

RESULTS

Our double immunofluorescence labelling with cell-specific markers demonstrated the glial localization of GMF. The immunohistochemical data showed that APs and NFTs are associated with increased expression of GMF in reactive glia of AD brains compared with non-AD controls.

CONCLUSIONS

This is the first report that shows GMF, a mediator of central nervous system inflammation, is expressed in the brain regions affected in AD and that GMF is mainly localized in reactive astrocytes surrounding APs/NFTs. The distribution of GMF-immunoreactive cells in and around Thioflavin-S stained APs and NFTs suggests involvement of GMF in inflammatory responses through reactive glia and a role of GMF in AD pathology.

Augmented expression of glia maturation factor in Alzheimer's disease

We have previously demonstrated that glia maturation factor (GMF), a brain-specific protein, isolated, sequenced, and cloned in our laboratory, is a prominent mediator of inflammation in the CNS leading to the death of neurons. In the present study, we demonstrate, for the first time, a significant upregulation of the GMF protein in various regions of Alzheimer's disease (AD) brains compared with age-matched non-demented (ND) control brains. We analyzed AD and ND brain samples by quantitative enzyme-linked immunosorbent assay (ELISA) using a combination of highly specific monoclonal and polyclonal anti-GMF antibodies developed and characterized in our laboratory. For the comparison between ND controls and AD cases, we examined brain tissue from 12 ad cases (ages ranging from 78-92 years) and eight age-matched ND controls (ages ranging from 76-88 years). We observed a significant increase in GMF concentration in entorhinal cortex, parietal cortex, frontal cortex, occipital cortex, perirhinal cortex, and temporal cortex of AD patients. Our results clearly demonstrate that the GMF protein levels are significantly higher in all AD-affected brain regions than in ND controls. The immunohistochemistry analysis revealed co-localization of GMF with amyloid plaques (AP) and neurofibrillary tangles (NFTs) in AD brains. Our results imply that under conditions of neurodegeneration the expression of GMF is significantly upregulated.

Loss of nonphosphorylated neurofilament immunoreactivity in temporal cortical areas in Alzheimer's disease

The distribution of immunoreactive neurons with nonphosphorylated neurofilament protein (SMI32) was studied in temporal cortical areas in normal subjects and in patients with Alzheimer's disease (AD). SMI32 immunopositive neurons were localized mainly in cortical layers II, III, V and VI, and were medium to large-sized pyramidal neurons. Patients with AD had prominent degeneration of SMI32 positive neurons in layers III and V of Brodmann areas 38, 36, 35 and 20; in layers II and IV of the entorhinal cortex (Brodmann area 28); and hippocampal neurons. Neurofibrillary tangles (NFTs) were stained with Thioflavin-S and with an antibody (AT8) against hyperphosphorylated tau. The NFT distribution was compared to that of the neuronal cytoskeletal marker SMI32 in these temporal cortical regions. The results showed that the loss of SMI32 immunoreactivity in temporal cortical regions of AD brain is paralleled by an increase in NFTs and AT8 immunoreactivity in neurons. The SMI32 immunoreactivity was drastically reduced in the cortical layers where tangle-bearing neurons are localized. A strong SMI32 immunoreactivity was observed in numerous neurons containing NFTs by double-immunolabeling with SMI32 and AT8. However, few neurons were labeled by AT8 and SMI32. These results suggest that the development of NFTs in some neurons results from some alteration in SMI32 expression, but does not account for all, particularly, early NFT-related changes. Also, there is a clear correlation of NFTs with selective population of pyramidal neurons in the temporal cortical areas and these pyramidal cells are specifically prone to formation of paired helical filaments. Furthermore, these pyramidal neurons might represent a significant portion of the neurons of origin of long corticocortical connection, and consequently contribute to the destruction of memory-related input to the hippocampal formation.

Modular and laminar pathology of Brodmann's area 37 in Alzheimer's disease

Previous studies suggested a relationship between severity of symptoms and the degree of neurofibrillary tangles (NFTs) clustering in different areas of the cortex in Alzheimer's disease (AD). The posterior inferior temporal cortex or Brodmann's area (BA 37) is involved in object naming and recognition memory. But the cellular architecture and connectivity and the NFT pathology of this cortex in AD received inadequate attention. In this report, we describe the laminar distribution and topography of NFT pathology of BA 37 in brains of AD patients by using Thionin staining for Nissl substance, Thioflavin-S staining for NFTs, and phosphorylated tau (AT8) immunohistochemistry. NFTs mostly occurred in cortical layers II, III, V and VI in the area 37 of AD brain. Moreover, NFTs appeared like a patch or in cluster pattern along the cortical layers III and V and within the columns of pyramidal cell layers. The abnormal, intensely labeled AT8 immunoreactive cells were clustered mainly in layers III and V. Based on previously published clinical correlations between cognitive abnormalities in AD and the patterns of laminar distributed NFT cluster pathology in other areas of the brain, we conclude that a similar NFT pathology that severely affected BA 37, may indicate disruption of some forms of naming and object recognition-related circuits in human AD.

Posterior parahippocampal gyrus pathology in Alzheimer's disease

The posterior parahippocampal gyrus (PPHG) of the non-human primate brain has a distinct dual role in cortical neural systems. On the one hand, it is a critical link in providing the entorhinal cortex and hippocampal formation with cortical input, while on the other hand it receives output from these structures and projects widely by disseminating the medial temporal lobe output to the cortex. Layer III of TF and TH areas largely mediate the former (input) while layer V mediates the latter (output). We have examined areas TF and TH in the normal human brain and in Alzheimer's disease (AD) using pathological stains (Nissl, Thioflavin S) and phenotype specific stains non-phosphorylated neurofilament protein (SMI32) and parvalbumin (PV). Seven clinically and pathologically confirmed AD cases have been studied along with six age-compatible normal cases. Our observations reveal that neurofibrillary tangles (NFTs) heavily invest the area TF and TH neurons that form layers III and V. In both cortical areas, the large pyramids that form layer V contain a greater number of NFTs. These changes, and possibly, pyramidal cell loss, greatly alter the cytoarchitectural picture and diminish SMI32 staining patterns. Layer III of area TH loses the majority of SMI32 immunoreactivity, whereas this change is more conspicuous in layer V of area TF. PV-staining in both areas is largely unaffected. Normal cases contained no evidence of pathology or altered cytoarchitecture. These observations reveal a further disruption of memory-related temporal neural systems in AD where pathology selectively alters both the input to the hippocampal formation and its output to the cortex.

In vivo near-infrared fluorescence imaging of osteoblastic activity

In vertebrates, the development and integrity of the skeleton requires hydroxyapatite (HA) deposition by osteoblasts. HA deposition is also a marker of, or a participant in, processes as diverse as cancer and atherosclerosis. At present, sites of osteoblastic activity can only be imaged in vivo using gamma-emitting radioisotopes. The scan times required are long, and the resultant radioscintigraphic images suffer from relatively low resolution. We have synthesized a near-infrared (NIR) fluorescent bisphosphonate derivative that exhibits rapid and specific binding to HA in vitro and in vivo. We demonstrate NIR light-based detection of osteoblastic activity in the living animal, and discuss how this technology can be used to study skeletal development, osteoblastic metastasis, coronary atherosclerosis, and other human diseases.

Effects of glia maturation factor overexpression in primary astrocytes on MAP kinase activation, transcription factor activation, and neurotrophin secretion

Using the replication-defective adenovirus vector, we overexpressed rat glia maturation factor (GMF) in primary astrocyte cultures derived from embryonic rat brains. Among the three isoforms of MAP kinase, there was a big increase in the phosphorylation of p38, as detected with Western blotting using the phosphospecific antibody. Likewise, there was a substantial increase in the phosphorylation of the transcription factor CREB. Using the electrophoretic mobility shift assay (EMSA), we found a stimulation in the transcription factor NF-kappaB. The activations of CREB and NF-kappaB were blocked by inhibitors of either p38 (SB-203580) or MEK (PD-098059), suggesting that they were events downstream of MAK kinase. There was an increased secretion of BDNF and NGF into the conditioned medium, along with an increase in their messenger RNA. The inductions of BDNF and NGF were also blocked by inhibitors of p38 and MEK, as well as by the inhibition of NF-kappaB with a decoy DNA sequence. Taken together, the results suggest that GMF functions intracellularly in astrocytes as a modulator of MAP kinase signal transduction, leading to a series of downstream events including CREB and NF-kappaB activation, resulting in the induction and secretion of the neurotrophins.

Highly diffusion-sensitized MRI of brain: dissociation of gray and white matter

The brains of six healthy volunteers were scanned with a full tensor diffusion MRI technique to study the effect of a high b value on diffusion-weighted images (DWIs). The b values ranged from 500 to 5000 s/mm(2). Isotropic DWIs, trace apparent diffusion coefficient (ADC) maps, and fractional anisotropy (FA) maps were created for each b value. As the b value increased, ADC decreased in both the gray and white matter. Furthermore, ADC of the white matter became lower than that of the gray matter, and, as a result, the white matter became brighter than the gray matter in the isotropic DWIs. Quantitative analysis showed that these changes were due to nonmonoexponential diffusion signal decay of the brain tissue, which was more prominent in white matter than in gray matter. There was no significant change in relation to the b value in the FA maps. High b value appears to have a dissociating effect on gray and white matter in DWIs.

Magnetic resonance imaging of cerebral hemorrhagic stroke

Despite a traditional perception of reliance on computed tomography and lack of acceptance of magnetic resonance imaging (MRI) for detecting acute hemorrhage, MRI appears to be used increasingly in hemorrhagic stroke. This review addresses the MRI findings of acute hemorrhagic stroke obtained using relatively new imaging techniques. These new techniques have resulted in more acute stroke patients undergoing MRI examination. New information about the frequency and appearance of hemorrhage is emerging: for example, approximately 15-26% of cases of acute cerebral infarctions appear to be complicated by intracerebral hemorrhage. The MRI appearances of hemorrhagic transformation of ischemic infarction, as well as acute hypertensive intracerebral hemorrhage, are discussed based on clinical, biochemical, and technical aspects.

Transfection of C6 glioma cells with glia maturation factor upregulates brain-derived neurotrophic factor and nerve growth factor: trophic effects and protection against ethanol toxicity in cerebellar granule cells

Glial cells play active roles in neuronal survival, as well as neuroprotection against toxic insult. Recent studies suggest that the brain protein glia maturation factor (GMF) is involved in intracellular signaling in glia. This study investigated whether or not GMF plays a role in the survival-promoting and neuroprotective functions of glia. C6 glioma cells were transfected in vitro with GMF utilizing an adenovirus vector. The transfected cells overexpressed GMF intracellularly, but did not secrete the protein. The conditioned medium (CM) was obtained from the GMF-transfected cells (CM-GMF) and tested on primary neuronal cultures, consisting of cerebellar granule cells (CGC). The CGC cultures were utilized because these cultures have a background level of cell death, and the survival-promoting, i.e. neurotrophic effect, of the CM could be tested. In addition, since CGC cultures are ethanol-sensitive (ethanol enhances neuronal death), the neuroprotective effect of the CM against ethanol-induced cell death was tested also. We demonstrated that the CM-GMF had an enhanced neurotrophic effect as well as an increased neuroprotective effect against ethanol-induced cell death compared to control CM obtained from untransfected C6 cells (CM-Mock) or CM obtained from cells transfected with an unrelated gene (CM-LacZ). Because neurotrophins have trophic and protective effects, we investigated whether GMF-transfection upregulated the expression of neurotrophins in C6 cells. RT-PCR verified that GMF-transfected C6 cells had increased mRNA levels for BDNF and NGF. Immunoblotting corroborated the RT-PCR results and indicated that CM-GMF contained greater concentrations of BDNF and NGF protein compared to CM-Mock and CM-LacZ. A soluble TrkB-IgG fusion protein, which selectively binds BDNF and prevents its binding to the neuronal TrkB receptor, eliminated the neurotrophic effect of CM-GMF; whereas anti-NGF antibody was ineffective in preventing this effect, suggesting that the neurotrophic effect was due to BDNF. On the other hand, both the TrkB-IgG fusion protein and anti-NGF reduced neuroprotection, suggesting that BDNF and NGF both contribute to the neuroprotective effect of CM-GMF. In conclusion, GMF upregulates the expression of BDNF and NGF in C6 cells, and these factors exert neurotrophic and neuroprotective functions on primary neurons.

Activation of nuclear factor-kappaB in C6 rat glioma cells after transfection with glia maturation factor

The 17-kDa endogenous brain protein glia maturation factor (GMF) was transfected into C6 rat glioma cells using a replication-defective human adenovirus vector. The cells overexpressed GMF but did not secrete the protein into the medium. Transfection with GMF led to the activation of the transcription factor nuclear factor-kappaB (NF-kappaB), as evidenced by electrophoretic mobility shift assay of the nuclear extract, using a double-stranded oligonucleotide probe containing the consensus binding sequence for NF-kappaB. The specificity of binding was demonstrated by competition with unlabeled probe and by the nonbinding of the mutant probe. Binding was detectable as early as 3 h after transfection, peaked at 6 and 12 h, and gradually declined thereafter. The observed NF-kappaB activation was reduced by cotransfection with catalase and by the presence of high concentrations of pyruvate in the medium, suggesting the involvement of H2O2. The p38 mitogen-activated protein kinase inhibitor SB-203580 also suppressed the GMF-activated NF-kappaB, suggesting the involvement of the p38 signal transduction cascade. On the other hand, the phorbol ester phorbol 12-myristate 13-acetate activated NF-kappaB whether or not GMF was overexpressed. Along with NF-kappaB activation was an enhanced expression of superoxide dismutase (SOD), which was suppressed if NF-kappaB nuclear translocation was blocked by its specific decoy DNA, implicating NF-kappaB as an upstream mediator of this antioxidant enzyme. The p38 inhibitor SB-203580 also blocked the GMF-activated SOD. As NF-kappaB and SOD are both pro-survival signals, the results suggest a cytoprotective role for endogenous GMF in glial cells.

Enhanced expression of neurotrophic factors by C6 rat glioma cells after transfection with glia maturation factor

Glia maturation factor (GMF) is a 17-kDa protein unique to the nervous system. Although GMF was initially characterized as a growth/differentiation factor, the absence of a leader sequence and its intracellular localization in normal brain suggest an intracellularfunction as well. In this paper we transfected the C6 glioma cells with GMF cDNA by infecting the cells with a GMF/adenovirus construct. The transfected cells overexpressed GMF but did not secret the protein into the culture medium. However, the transfected cells showed an increased expression of the neurotrophic factors including nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF). The increase in neurotrophic activity of the C6 cell conditioned medium was demonstrable by its ability to promote neurite outgrowth in PC12 cells.

Overexpression of glia maturation factor in C6 cells promotes differentiation and activates superoxide dismutase

In order to evaluate the intracellular function of glia maturation factor (GMF), we overexpressed GMF in C6 rat glioma cells using two methods: stable transfection using the pcDNA3 plasmid, and transient transfection using replication-defective human adenovirus. With both methods, C6 cells transfected with GMF and overexpressing the protein exhibit a lower saturation density in culture compared to non-transfected or vector alone controls. Transfected cells also exhibit morphological differentiation as shown by the outgrowth of cell processes. When inoculated into nude mice, transfected cells are less tumorigenic than controls, and express the mature astrocytic marker glial fibrillary acidic protein. In tissue culture, transfected cells show a 3.5-fold increase in CuZn-dependent superoxide dismutase (CuZnSOD) activity. Western blot analysis reveals a 3.5-fold increase in CuZnSOD protein, suggesting an induction of the enzyme. In view of recent findings that reactive oxygen species (ROS) and the antioxidant enzymes are intricately involved in key physiologic processes such as proliferation, differentiation and apoptosis, the study raises the possibility that CuZnSOD may be a mediator of GMF function.

Overexpression of glia maturation factor (GMF) in PC12 pheochromocytoma cells activates p38 MAP kinase, MAPKAP kinase-2, and tyrosine hydroxylase

In order to study the intracellular regulatory function of glia maturation factor (GMF) in neuronal cells, we achieved a 10-fold overexpression of GMF in the rat pheochromocytoma cell line PC12 by infection with a replication-defective human adenovirus carrying a rat GMF cDNA insert. These cells showed a 3.6-fold increase in the activity of p38 MAP kinase, a 3.8-fold increase in the activity of MAPKAP-K2 (MAP kinase-activated protein kinase 2), and a 4.2-fold increase in the activity of tyrosine hydroxylase (TH). We also detected an increase in the phosphorylation of TH and the 25-kDa heat shock protein (Hsp25) without a concomitant increase in their corresponding protein levels, suggesting a posttranslational modification. It was previously established that in PC12 cells, MAPKAP-K2 is an immediate target of p38, and both TH and Hsp25 are immediate targets of MAPKAP-K2. The current in vivo results are in concordance with our earlier in vitro finding that GMF promotes the activity of p38, and they implicate the participation of GMF in stress-induced catecholamine synthesis.

Activation of JNK in the remote myocardium after large myocardial infarction in rats

A large myocardial infarction (MI) causes a chronic hemodynamic load on the uninjured remote myocardium (RM). This may lead to oxidative stress, activation of stress-induced cell signaling and increase in myocyte apoptosis. MI was produced in 6 rats (INF) while 4 rats underwent sham operation (CON). At four weeks, there was 128% increase in right ventricular hypertrophy in the hearts from INF vs. CON. Western blot analysis showed 3.8 fold increase in JNK phosphorylation within the RM from INF vs. CON, confirmed by a 4.2 fold increase in JNK kinase activity. There was a 52% increase in TBARS within the RM from INF vs. CON, suggesting increased lipid peroxidation. Furthermore, there was a twofold increase in myocyte apoptosis within the RM in INF vs. CON. We conclude that the RM from INF is associated with activation of JNK, increased oxidative stress and enhanced myocyte apoptosis.

Protein kinase A (PKA)- and protein kinase C-phosphorylated glia maturation factor promotes the catalytic activity of PKA

We observed previously that glia maturation factor (GMF), a 17-kDa brain protein, is rapidly phosphorylated in astrocytes following stimulation by phorbol ester, and that protein kinase A (PKA)-phosphorylated GMF is a potent inhibitor of extracellular signal-regulated kinase (ERK) and enhancer of p38; both are subfamilies of mitogen-activated protein (MAP) kinase, suggesting GMF as a bifunctional regulator of the MAP kinase cascades. In the current report, we present evidence that PKA-phosphorylated GMF also promotes (11-fold) the catalytic activity of PKA itself, resulting in a positive feedback loop. Furthermore, GMF phosphorylated by protein kinase C (PKC), but not by casein kinase II or p90 ribosomal S6 kinase, also activates PKA (7-fold). It appears that the mutual augmentation of GMF and PKA, and the stimulating effect of PKC, both serve to maximize the influence of PKA on the regulation of MAP kinase cascades by GMF. Using synthetic peptide fragments containing putative phosphorylation sites of GMF, we demonstrate that PKA is capable of phosphorylating threonine 26 and serine 82, whereas PKC, p90 ribosomal S6 kinase, and casein kinase II, can phosphorylate serine 71, threonine 26, and serine 52, respectively. The generation of various phospho-isoforms of GMF may explain its modulation of signal transduction at multiple locations.

In vitro enhancement of p38 mitogen-activated protein kinase activity by phosphorylated glia maturation factor

We previously demonstrated that glia maturation factor (GMF), a 17-kDa brain protein, can be phosphorylated in test tube by several protein kinases, and that endogenous GMF is rapidly phosphorylated upon stimulation of astrocytes by phorbol 12-myristate 13-acetate. We further observed that protein kinase A (PKA)-phosphorylated GMF is a potent inhibitor (IC50 = 3 nM) of the ERK1/ERK2 (p44/p42) subfamily of mitogen-activated protein (MAP) kinase. We now report that, by contrast, PKA-phosphorylated GMF strongly enhances the activity of a related but distinct subfamily of MAP kinase, the p38 MAP kinase, showing an increase of 60-fold over baseline and an EC50 of 7 nM. Non-phosphorylated GMF or GMF phosphorylated by other kinases exhibits only minimal effect. The intracellular interaction of PKA, GMF, and p38 is supported by the phosphorylation of GMF upon cellular stimulation by forskolin (blocked by PKA inhibitor) and by the co-immunoprecipitation of p38 with GMF from cell lysates. Withdrawal of nerve growth factor from PC12 leads to increased GMF phosphorylation with a time course similar to that reported for p38 activation. The results correlate well with a previous report that ERK and p38 carry out opposing functions and implicate GMF as a regulator of major cellular events.

In vitro inhibition of MAP kinase (ERK1/ERK2) activity by phosphorylated glia maturation factor (GMF)

We report that recombinant glia maturation factor (GMF), a 17-kDa brain protein, inhibits the activity of mitogen-activated protein (MAP) kinase in the test tube assay, in particular the ERK1/ERK2 isoforms. A preliminary phosphorylation of GMF by protein kinase A (PKA) dramatically increases its inhibitory effect by over 600-fold (Ki approximately 3 nM), making it the most potent MAP kinase inhibitor ever reported. Immunoprecipitation of GMF from cell extracts using its specific antibody coprecipitates ERK (and vice versa), suggesting the association of the two proteins in the cell. The inhibitory effect of PKA-phosphorylated GMF is specific, as it does not suppress the activity of cdc2 kinase, another proline-directed kinase. Nor does it inhibit MAP kinase kinase (MEK) and MAP kinase-activated protein (MAPKAP) kinase-2, the two enzymes immediately upstream and downstream, respectively, of ERK. Of the other three enzymes that can phosphorylate GMF, only p90 ribosomal S6 kinase (RSK) enhances the inhibitory function of GMF on ERK; protein kinase C (PKC) and casein kinase II (CKII) are without effect. The inhibition of ERK by PKA-phosphorylated GMF suggests that GMF could be one of the mediators of the suppressive effect of the PKA pathway on the MAP kinase pathway. On the other hand, that RSK-phosphorylated GMF also inhibits ERK implies a negative feedback loop in the regulation of MAP kinase activity.

Expression of mRNAs of multiple growth factors and receptors by neuronal cell lines: detection with RT-PCR

Neurons and glia are capable of both secreting and responding to a large variety of growth factors. However, information on multiple expression of growth factors and their receptors was usually obtained from uncorrelated observations, using cells from various animals of origin, developmental stages, growth phases, culture ages and culture conditions. Because of its specificity and extreme sensitivity, reverse transcription-polymerase chain reaction (RT-PCR) is uniquely suitable to study a large panel of growth factors and their receptors from a limited cell sample, free of these intervening variables. In this paper we evaluate the expression of mRNA of a total of 35 growth factor-related proteins by conducting RT-PCR on three neuronal cell lines: the PC12 rat pheochromocytoma line, the MAH rat sympathoadrenal progenitor line, and the N18 mouse neuroblastoma line. Three types of results are presented. The first confirms the existing knowledge such as the presence of Trk-A (NFG receptor) in PC12. The second consists of new information that expands and extends earlier observations, such as the presence of CNTF receptor complex in PC12, which explains our previous report that CNTF enhances the biological effects of NGF on these cells. The third consists of novel information that leads the way to further experimentation by the more conventional methods. These include the strong expression of Trk-B by MAH, predicting the biological responsiveness of MAH to BDNF and NT-4, and the expression of CNTF receptor in N18. Our results also suggest that CNTF is an autocrine factor for PC12 and MAH, since both lines express the growth factor as well as the receptor. Thus, RT-PCR is a valuable tool in growth factor research that can be used in complement to, and interactively with, other approaches such as bioassay, receptor binding, and immunochemical determination. It will be particularly useful for screening a large number of growth factors in minute areas of the brain in patients suffering from neurodegenerative diseases such as Parkinson's and Alzheimer's.

Phorbol ester stimulates rapid intracellular phosphorylation of glia maturation factor

We report that recombinant glia maturation factor (GMF), a 17-kD brain protein, can be phosphorylated in vitro at the serine residue by protein kinase C (PKC), protein kinase A (PKA), and casein kinase II (CKII), and at the threonine residue by p90 ribosomal S6 kinase (RSK). Endogenous GMF in astrocytes is phosphorylated at the serine (major) and threonine (minor) residues within 15 min after stimulation by phorbol 12-myristate 13-acetate (PMA). Phosphorylation gradually subsides over the next 24 h. The increased phosphorylation is not blocked by the protein synthesis inhibitor cycloheximide and is not accompanied by a rise in the mRNA for GMF and is therefore strictly a posttranslational regulatory phenomenon. The rapid and transient phosphorylation of GMF upon cellular activation suggests an intracellular role, possibly with involvement in signal transduction.

Expression of mRNAs of multiple growth factors and receptors by astrocytes and glioma cells: detection with reverse transcription-polymerase chain reaction

1. Although glial cells in culture are known to secrete growth factors and are also known to be responsive to some of them, detailed comparisons are difficult because the bulk of information was based on various animals of origin, developmental stages, growth properties, culture age, and culture conditions. 2. To present a unified picture of the growth factors and their receptors found in glial cells, we surveyed the expression of messenger RNAs of a panel of growth factors and receptors, using reverse transcription-polymerase chain reaction (RT-PCR), in three common glial cell types: rat astrocytes in primary culture, rat glioma line C6, and human glioma line A172. 3. We observed that normal and neoplastic glial cells in culture express multiple growth factors and also possess most of the receptors to the factors, suggesting multiple autocrine functions. In addition, glia produce growth factors known to be capable of acting on neurons, implicating paracrine function involving glia-neuron interaction. Glial cells also produce growth factors and receptors that are capable of communicating with hematopoietic cells, suggesting neuroimmunologic interaction. What is most interesting is that glial cells express receptors for growth factors previously thought to be acting on neurons only. 4. The current study demonstrates the feasibility of screening from a small sample a large number of growth factors and receptors. The method portends future clinical application to biopsy or necropsy samples from brain tumors or pathologic brains suffering from degenerative diseases such as Alzheimer's or Parkinson's disease.

Cancer in the Gizan province of Saudi Arabia: An eleven year study

The occurrence of histologically diagnosed primary malignant tumors in Saudi and Yemeni patients in Gizan Province over the 11 years from 1982 to 1992 was analyzed. During the study period, 1398 malignancies of known primary site were seen in males and 972 in females. In common with other parts of Saudi Arabia, the overall incidence of malignant disease was low by Western standards with lymphoreticular malignancies relatively common and tumors of lung, bowel, breast and the female genital system relatively uncommon. Some malignancies are more common in Gizan Province as compared to elsewhere in Saudi Arabia. Oral cancer was the most common malignancy in females and the most common overall, probably due to widespread use of oral tobacco preparations. Liver cancer was the most common malignancy in males, reflecting the endemic nature of hepatitis B in the area. The incidence of bladder cancer, and particularly of squamous carcinoma of the bladder, was also more, probably due to the high incidence of schistosomiasis in the area. No significant trends in incidence of specific malignancies were noted over the 11-year study period, even though the period has been marked by dramatic and unprecedented changes in lifestyle and public health.

Ciliary neurotrophic factor (CNTF) enhances the effects of nerve growth factor on PC12 cells

The rat pheochromocytoma cell line PC12 responds readily to nerve growth factor (NGF) but poorly to ciliary neurotrophic factor (CNTF). However, in a selected line derived from PC12 that normally responded weakly to NGF, CNTF potentiated the effect of NGF with respect to inhibition of proliferation, neurite outgrowth, and choline acetyltransferase (ChAT) induction. ChAT activity was assayed enzymatically, and an increase in the mRNA of ChAT was also detected by means of reverse transcription-polymerase chain reaction (RT-PCR). The PCR product was verified by sequencing and by Southern hybridization using a specific oligonucleotide probe. The presence of CNTF receptor in PC12 cells was confirmed by RT-PCR for its mRNA. The results indicate that PC12 responds to CNTF mainly when used in combination with NGF, and suggest an interaction between the two growth factors.

Expression of glia maturation factor beta mRNA and protein in rat organs and cells

Rat glia maturation factor beta (GMF-beta) cDNA was obtained by reverse transcription of rat brain mRNA followed by polymerase chain reaction amplification, using primers from the human sequence. The deduced amino acid sequence of rat GMF-beta differed from the human counterpart in only three places: His27 in place of Asn, Val51 in place of Ile, and Leu93 in place of Val. The high degree of evolutionary conservation suggests that GMF-beta plays an essential role in animal cell physiology. The expression of GMF-beta mRNA in the rat was studied by the northern blot technique, using a rat cRNA probe corresponding to the entire coding region. GMF-beta mRNA was predominantly expressed in the brain and spinal cord, although trace levels were found in other organs, including testis and ovary. In the brain GMF-beta mRNA was detectable at as early as embryonic day 10, and persisted through as late as postnatal month 14, with minor variations in between. On the other hand, GMF-beta protein exhibited more obvious developmental changes, with its level increasing slowly prenatally and plateauing at 1 week after birth. GMF-beta mRNA and protein were also observed in several cultured cells. Some cells of neural origin contained higher levels of GMF-beta protein compared with cells derived from other sources. Through demonstration of mRNA and confirmation by immunoblotting, we conclude that GMF-beta is synthesized by rat organs and that GMF-beta is predominantly a brain protein.

Polyclonal antibody localizes glia maturation factor beta-like immunoreactivity in neurons and glia

A rabbit polyclonal antibody (91-01) was raised against recombinant human glia maturation factor beta (r-hGMF-beta). The antibody did not cross-react with a number of other growth factors on ELISA test. When compared with the monoclonal antibody G2-09 previously obtained, 91-01 immunoblotted the same protein band in rat brain extract. However, unlike G2-09 which immunostained only astrocytes and Bergmann glia, 91-01 stained neurons as well. Many but not all neurons in the central and peripheral nervous system were positive for GMF-beta. The larger cell population stained by the polyclonal antibody was most likely due to its increased sensitivity, although other explanations are possible. The presence of GMF-beta-like immunoreactivity in both neurons and glia raises the possibility of a wider range of cell-cell interaction than was previously considered.

Glia maturation factor beta stimulates axon regeneration in transected rat sciatic nerve

Rat sciatic nerves were bilaterally transected and repaired with an entubulation technique. The nerve interstump gap was filled with either collagen gel or collagen gel mixed with a putative neurotrophic factor (leupeptin, 4-aminopyridine, lipid angiogenic factor or glia maturation factor beta (GMF-beta]. Six weeks after nerve transection, the myelinated distal stump axons were quantified for each nerve. Only the nerves treated with GMF-beta had significantly more axons than the control side.

Molecular cloning and expression of biologically active human glia maturation factor-beta

Glia maturation factor-beta, a protein found in the brains of all vertebrates thus far examined, appears to play a role in the differentiation, maintenance, and regeneration of the nervous system. Using oligonucleotide probes based on the sequences of three tryptic peptides derived from bovine glia maturation factor-beta, we screened a human brainstem cDNA library in lambda gt11. A 0.7-kb clone was isolated, sequenced in its entirety, and found to encode a polypeptide of 142 amino acids which contained regions identical to the three bovine peptides. This polypeptide, human recombinant glia maturation factor-beta, has been expressed in Escherichia coli and found to possess structural characteristics and biological activity indistinguishable from those of the native bovine protein.