Posterior lumbar interbody fusion: comparison of single intervertebral cage and single side pedicle screw fixation versus bilateral cages and screw fixation.

INTRODUCTION: The efficacy and economy of an alternative sparing method for posterior lumbar interbody fusion (PLIF) using a single cage fixed with pedicle screws placed on a single side (SS group, n=22) was compared to that of a standard bilateral protocol using two cages and pedicle screws placed bilaterally (BL group, n=15). METHODS: All PLIFs were non-compensation cases done at a single level by a single surgeon and were similar in most background characteristics. Significant differences were not found between the two groups in fusion rates, complications or in 2-year prospectively collected outcomes including percent improvement in back and leg pain (visual analog scales) and the Oswestry disability index. RESULTS: Perioperative results significantly favored the SS group: BL patients lost 81% more blood, used 74% more time for surgery, stayed in hospital 1.7 days longer, and the hospital-related cost per procedure was twice as high. Currently, the SS procedure typically averages less than 1 h and blood loss less than 50 mL. In summary, the BL and SS groups had similar outcomes while the SS procedure provided substantially superior efficiency and economy. CONCLUSION: In conclusion, the results of this retrospective comparative level III study warrant further studies on the SS protocol which may lead to the adoption of this minimally invasive protocol in the standard practice of PLIF in selected cases.

Cloning and characterization of ectopically expressed transcripts for the actin-binding protein MIPP in mouse mammary carcinomas.

Mipp is a kelch-related, placental-specific gene that is ectopically expressed in many BALB/c mouse mammary carcinomas of various etiologies. The Kelch family encompasses proteins that are emerging as key links between microfilaments and a variety of cellular structures and functions. Mouse mammary tumors express two mipp transcripts (2.2 and 5.6 kb). We cloned the 2.2 kb mipp mRNA and analysed the product of its 1.7 kb ORF. The 584 residue MIPP protein has an N-terminal BTB domain and six C-terminal tandem Kelch repeats. Despite expression of two mipp RNAs, only a single MIPP protein is expressed in mammary tumors. MIPP protein binds to microfilaments in vitro and co-immunoprecipitates with actin. MIPP co-localized with concanavalin A at the endoplasmic reticulum, suggesting that MIPP might mediate interactions between microtubules and actin filaments. Because MIPP expression is widespread in mouse mammary tumors, it might contribute to tumorigenesis. Although MIPP had little effect on the growth rate of human breast cell lines following transfection, it greatly reduced the formation of duct-like structures on reconstituted basement membrane. Our results suggest that MIPP could contribute to malignant progression in the mouse mammary epithelial cells by perverting their response to cues from the extracellular matrix.

Genes, chromatin, and breast cancer: an epigenetic tale.

The production of heritable changes in gene expression is the driving force in the development and progression of breast cancer. Such changes can result from mutations or from epigenetic events such as hypermethylation of DNA and hypoacetylation of histones. Histone acetylation and DNA methylation are major determinants of chromatin structure, and chromatin structure is a primary regulator of gene transcription. Cancer cells frequently contain both mutated genes and genes with altered expression due to one or more epigenetic mechanisms. This review describes the epigenetic changes that disrupt normal chromatin architecture and modify the expression of key genes in breast cancer cells. The structural integrity of the latter genes is usually intact, but their expression has been substantially altered due to methylation in their promoter region or deacetylation of histones that interact with their promoter region or both mechanisms. Genes affected by epigenetic changes in breast cancers include HoxA5, p21WAF, gelsolin, BRCA1, BRCA2, E-cadherin, steroid hormone receptors, and retinoic acid receptor II. Because these epigenetic modifications are usually reversible by treatment with certain drugs, they represent vulnerabilities in the cancer cell that can be exploited as novel targets for new prevention and therapeutic strategies.

Downregulation of gelsolin correlates with the progression to breast carcinoma.

The actin cytoskeleton underlies several normal cellular functions and is deranged during carcinogenesis. Gelsolin, a multifunctional actin-binding protein, is downregulated in several types of tumors and its abnormal expression is one of the most common defects noted in invasive breast carcinoma (ICA). This study utilizes immunohistochemistry to examine the expression of gelsolin in 95 ICA, 59 ductal carcinoma in situ (DCIS) and 36 benign lesions, including 17 atypical ductal hyperplasia (ADH). Cytoplasmic staining was scored as positive, reduced or negative. Gelsolin expression was then correlated with patient's age, tumor size, histologic grade and lymph node status. All unremarkable breast biopsies, 88% of ADH, 44% of DCIS and 28% of ICA were positive for gelsolin. This represents a significant difference among the groups (p = < 0.0001) and the trend towards reduced gelsolin with the progression to ICA is significantly linear (p = < 0.0001). For invasive carcinoma, patients older than 44 years were significantly more likely to have decreased expression of gelsolin than patients 44 years old and younger (p = 0.007). Bivariate analysis showed no correlation of gelsolin expression with lymph node status (p = 0.62), tumor size (p = 0.10), histologic grade (p = 0.42), estrogen receptor status (p = 1.0) or other clinicopathologic parameters. In clinical follow-up, there were 18 breast tumor related deaths within a median follow-up time of 4.2 years. Survival analysis indicated that the level of gelsolin expression may be associated with survival (p = 0.06). In summary, the frequency of gelsolin deficiency increases significantly with progression from ADH to DCIS to ICA. Additionally, gelsolin expression may be an independent marker of prognosis.

The mouse mammary gland requires the actin-binding protein gelsolin for proper ductal morphogenesis.

Gelsolin is an actin-binding/severing protein expressed in intracellular and secreted forms. It is a major regulator of the form and function of the actin cytoskeleton in most all cells. Here we demonstrate that female mice with a targeted deletion of the gelsolin gene (Gsn-/-) have defects in mammary gland morphogenesis. Two distinct defects were identified in the gelsolin-null mammary gland. First, the mammary anlage from Gsn-/- mice failed to elongate at the onset of puberty and remained rudimentary until approximately 9 weeks of age, early block (Gsn-/-(EB)). Second, after the mammary epithelium had filled the mammary fat pad, a complete lack of terminal branching, or late block, was observed (Gsn-/-(LB)). The Gsn-/-(EB) was seen in 70% of Gsn-/- mice and appeared to be dependent on a modifier gene(s) in addition to the loss of gelsolin. Gsn-/-(LB) was observed in all Gsn-/- mice. Terminal end buds (TEBs) were not evident in the mammary anlage from Gsn-/-(EB) mice until approximately 9 weeks of age. Cellular proliferation in the terminal ductal regions of Gsn-/-(EB) females was detected by bromodeoxyuridine incorporation, but was less than that found in the TEBs of age-matched controls. In mice deficient for gelsolin, mammary gland architecture was unaltered at the histological level. Lobuloalveolar development was delayed in response to pregnancy in mammary glands of Gsn-/- mice but was otherwise normal. Lactation and involution in the gelsolin-null animals were similar to those of wild-type mice. Transplantation of epithelium devoid of gelsolin into a wild-type (GsnWT) mammary fat pad resulted in proper arborization of the ductal tree. Transplantation of GsnWT epithelium into the Gsn-/- fat pad recapitulated the lack of terminal branching seen in Gsn-/- females. These results indicate that gelsolin is required in the mammary stroma for proper ductal morphogenesis. Our results provide the first evidence of an actin regulatory protein affecting mammary ductal growth through stromal-epithelial communication.

Down-regulation of gelsolin expression in human breast ductal carcinoma in situ with and without invasion.

Expression of gelsolin, an actin filament regulatory protein, in human breast ductal carcinoma in situ (DCIS) was analyzed by immunohistochemistry using a monoclonal antibody. Formalin-fixed paraffin-embedded tissues from 59 pure DCIS specimens and 33 DCIS specimens with associated invasive components were evaluated for gelsolin reactivity and compared to eight normal breast cases and 76 invasive breast cancers. The proportion of cases exhibiting negative/low expression of gelsolin in the epithelium was as follows -- normal, 0%; pure DCIS, 56%; DCIS associated with invasion, 58% in the DCIS component and 66% in the invasive component; invasive carcinoma, 70%. These data demonstrate that down-regulation of gelsolin expression in breast epithelium frequently parallels progression to malignancy. Testing gelsolin expression (normal vs. negative/low levels) in the DCIS lesions for associations with patient age or any of the following histopathologic parameters revealed no significant (95% probability level) correlations -- tumor size; pathologic (Van Nuys system) grade; nuclear grade; necrosis; presence of histologic calcifications; presence or type of adjacent benign lesions; architectural histologic pattern; and mammographic extent. Gelsolin loss was more commonly associated with mammographic soft tissue lesions as compared to calcified lesions (P = 0.009). A positive trend of borderline significance (P = 0.06) found in the DCIS with invasion group was a correlation between down-regulated gelsolin expression in the DCIS component and size (< versus > or = 15 mm) of the invasive tumor. In conclusion, reduced gelsolin protein is detectable in at least half of breast lesions which have progressed to DCIS. The trend between increasing gelsolin loss and malignant progression from normal epithelium to DCIS to invasive breast cancer (P < 0.0001) suggests additional investigation is needed to determine the potential of altered gelsolin expression as a marker for prognosis and for therapeutic interventions in breast cancer.

Concurrent deregulation of gelsolin and cyclin D1 in the majority of human and rodent breast cancers.

Decreased gelsolin and increased cyclin D1 are among the most common defects found in human and rodent breast cancers. Our purpose was to determine the frequency of concurrence of these 2 alterations in this malignancy. Our results demonstrate that gelsolin protein and mRNA were significantly reduced in 80-100% of rodent mammary carcinomas that developed spontaneously, following oncogene introduction, or after treatment with viral, chemical or hormonal agents. The reduction in gelsolin most likely occurs during the transition from preneoplasia to carcinoma because hyperplasias had normal levels of gelsolin whereas microtumors had reduced expression. Southern analysis revealed no major mutations in the gelsolin gene of tumors with low expression. Cyclin D1 mRNA was increased in 50-100% of these rodent mammary tumors, although the cyclin D1 gene was not amplified. By nuclear runon assay, downregulation of gelsolin in both human and mouse mammary cancer cells involved diminished transcription and, conversely, human breast cancer cells expressing high levels of cyclin D1 had increased initiation of cyclin D1 transcription compared with cyclin D1 low expressors. Thus, alteration in the rate of transcription appears to be an important factor underlying the dysfunction of these genes. According to our data, concurrent deregulation of gelsolin and cyclin D1 is highly prevalent among breast cancers of humans and rodents, with both defects present in 89% of the neoplasms analyzed in this study. In fact, most tumors in every rodent model of mammary tumorigenesis examined had the 2 alterations.

Epigenetic regulation of gelsolin expression in human breast cancer cells.

Gelsolin is a multifunctional, actin-binding protein that is greatly decreased in many transformed cell lines and tumor tissues, including breast cancers. Downregulation of gelsolin RNA occurs in most breast cancers of rats, mice, and humans, but gross mutations of the gelsolin gene have not been found. Here we demonstrate by PCR and RT-PCR analysis that there are no point mutations in putative regulatory regions or the entire coding region of the cytoplasmic isoform of the gelsolin gene in human breast cancer cells (BCC). To determine if epigenetic modification is involved in downregulating gelsolin expression in MDA-MB-231 (MDA231), MCF7, and T47D BCC, we have used Southern blot analysis, 5-azacytidine (5aza) treatment, and trichostatin A (TSA) treatment. Southern blot analysis performed on genomic DNA demonstrated altered CpG methylation within intron 1 in DNA from all BCC compared to normal, mortal human mammary epithelial cells (HMEC). Treatment of the BCC with 5aza converted the DNA restriction pattern to that seen in untreated HMEC genomic DNA and caused modest increases in gelsolin RNA and protein. Incubation with TSA, an inhibitor of histone deacetylase, induced a dramatic upregulation of gelsolin RNA and protein levels which preceded apoptotic death of all BCC within 48-60 h. Our data support a role for epigenetic changes in chromatin structure leading to downregulation of gelsolin expression in human breast cancer. To our knowledge, this is the first example of a tumor suppressor gene downregulated in human breast cancer by changes in histone acetylation.

Lumbar microdiscectomy in the elderly patient.

This study retrospectively analysed 60 patients who had undergone microsurgical lumbar discectomy at an age of > or = 60 years. The results were compared with those obtained in 44 discectomy patients who were operated on during the same study period, but not selected for age. Sixty-five operations were performed on the elderly group and 49 on the age comparison group. Patients were scored for pain relief in a short-term follow-up (2 months) using office visit records. Long-term follow-ups [mean 6.5 years (elderly) vs 8.8 (comparison) years], obtained by a mailed questionnaire, quantified leg and back pain and scored success in return to normal activities (RTA) and satisfaction with the results of surgery. In the short-term, overall pain relief was highly successful and not significantly different in both group [94% (elderly), 98% (comparison)]. Long-term follow-up yielded the following successful outcomes (elderly, comparison groups): leg pain relief (91%, 86%), back pain relief (76%, 76%), RTA (68%, 87%), and satisfaction (81%, 91%). As with other pre- and postoperative parameters, these differences were not statistically significant. As the proportion of older individuals continues to rise in developed countries, physicians are increasingly faced with geriatric patients whose symptoms are caused by herniated lumbar discs. The present study indicates that microsurgical discectomy for relief of this condition can be performed safely and effectively on these older patients.

Widespread loss of gelsolin in breast cancers of humans, mice, and rats.

Down-regulation of gelsolin, an actin-binding protein, is frequently found in several types of transformed cells and tumors. The present study demonstrates that gelsolin protein and RNA were absent or markedly reduced in human breast cancer cell lines relative to "normal" mortal human mammary epithelial cells and benign, immortalized cell lines. Moreover, actin filaments were usually attenuated coincident with the reduction in gelsolin. Gelsolin was also missing or greatly decreased in 70% of 30 human sporadic, invasive breast carcinomas examined by immunocytochemistry and in 100% of virally induced mouse and chemically induced rat mammary carcinomas evaluated by Northern analysis. Southern analysis revealed no major mutations in the gelsolin gene of human breast cancer cells. Our results show that partial or total loss of gelsolin expression is common to the majority of breast cancers of diverse etiologies in three animal species and point to gelsolin as a candidate suppressor of breast cancer.

Day surgery for cervical microdiscectomy: is it safe and effective?

The objective of this pilot study was to evaluate the safety and efficacy of cervical discectomy with fusion performed on an outpatient basis. The experimental group (50 consecutive patients) was studied prospectively and the outcomes were compared with 53 consecutive, retrospectively analyzed, admitted controls who underwent the same procedure. Outcomes for both groups were assessed by patient-response questionnaires and clinical examination. At follow-up times of 1.3 (outpatient) and 1.6 (inpatient) years, outcomes (outpatient/inpatient) expressed as percent successful were as follows: Relief of arm pain (80/70%); relief of neck pain (78/68%); relief of arm muscle weakness and atrophy (94/96%); return to normal activities (64/70%); return to work (65/68%); and satisfaction with the results of surgery (86/83%). No statistically significant differences between outpatients and inpatients were found for any of the outcome parameters studied. There was no mortality and the operative complication rate was 2% for each study group. The results indicate that conversion of cervical discectomy with fusion from an admitted to an ambulatory practice did not compromise the safety or efficacy of the surgical procedure. Potential economic savings to overall health costs of the United States that might result from such conversion could exceed $100 million annually.

Mutations involving the endogenous ecotropic murine leukemia virus in primary mammary carcinomas of BALB/c mice.

Endogenous murine leukemia virus-related elements (MLVEs) are often overexpressed in primary mammary carcinomas of BALB/c mice. We therefore searched for mutations associated with MLVEs and found amplified sequences of the ecotropic MLVE in hormonally and chemically induced mammary neoplasms. Restriction fragment length polymorphism (RFLP) analysis revealed DNA rearrangements consistent with 1-10 or more new copies of the ecotropic MLVE in the genome of these tumors. This is the first evidence of mutations involving an endogenous retrovirus other than mouse mammary tumor virus in mouse mammary carcinomas.

Comparative expression of the LINE-1 p40 protein in human breast carcinomas and normal breast tissues.

Human LINE-1 (L1Hs) retrotransposons can act as insertional mutagens and are expressed in a variety of tumors, including breast cancer. The purpose of the present study was to examine expression of the p40 protein encoded by the first open reading frame of a L1Hs element in normal human breast tissue of patients without malignant breast disease and in nontumor breast tissue adjacent to cancer and to compare it to expression in breast carcinomas. An antiserum specific for the L1Hs p40 protein was used to analyze its expression in 5 reduction mammoplasties, 16 primary breast cancers, 1 lymph node metastasis and 13 non-malignant breast tissues adjacent to matched primaries by western blotting and/or immunocytochemistry. The immunoreactive band observed on westerns consistently had a M(r) of approximately 46 kDa. Westerns detected some p40 protein expression in all malignant and nonmalignant tissues examined, although 4 of 5 reduction mammoplasties had very low or trace levels as compared with tumors. Nonmalignant breast tissues adjacent to cancers showed significant western band reactivity, and all 15 tumors were positive. Immunocytochemistry revealed staining specificity of the antibody for epithelial cells. Of 12 invasive carcinomas examined, 100% were positive for the p40 protein, whereas one reduction with benign proliferative disease was very weakly reactive, two histologically normal reductions were negative, and 4 of 6 nonmalignant tissues adjacent to cancers were negative. Our data indicated that expression of the L1Hs p40 protein was often elevated in tumor cells of human breast cancers compared to epithelium of normal mammary gland.

Lumbar disc excisions in patients under the age of 21 years.

STUDY DESIGN: This study retrospectively analyzed 15 patients in the rarely seen young (under 21 years) age group who had undergone discectomy without fusion for prolapsed (herniated) lumbar disc. OBJECTIVES: The results were analyzed for degree of success in several outcome parameters to relate the efficacy of this patient group/procedure pair to that of other studies. SUMMARY OF BACKGROUND DATA: Sixteen operations were performed on this patient group, including six by a conventional procedure and ten by a microsurgical technique. Although most previous studies tend to support the use of discectomy, some physicians have reportedly been reluctant to implement these procedures in young patients. METHODS: Patients were followed in a short-term (median 3.3 months) assessment using records of post-operative office visits. Long-term (median, 10.5 years) follow-up was done by a mailed, self-report questionnaire that quantified pain in leg and back and scored for degree of success in ability to return to normal activities and satisfaction with the results of surgery. RESULTS: The short-term results were excellent for all but one patient. Long-term follow-up yielded the following successful outcomes: relief of back pain, 77%; and relief of leg pain, return to normal activities, and satisfaction with surgery, each 85%. CONCLUSION: Despite some tendency to delay discectomy in children and young adults, physicians are urged to be aware of this rare condition and the excellent long-term outcomes and limited complications resulting from timely implementation of discectomy after a failed course of conservative therapy. Moreover, fusion should be avoided except in cases of vertebral instability.

Lumbar diskectomy for recurrent disk herniation.

Eighty-two patients who underwent reoperation using a lumbar microdiskectomy approach for recurrent back and leg pain were evaluated retrospectively. Patients were entered consecutively except for exclusion of those who had a spinal fusion in addition to the diskectomy or those where a diskectomy was performed as an adjunct to decompression for spinal stenosis. As a percentage of all diskectomies performed by us over the 13 years of the study, the overall rate of reoperation (including all patients who underwent more than one diskectomy procedure regardless of vertebral level and side) was 7.4%, with those having a reoperation on the same level and either the same or contralateral side as the initial procedure representing 4.5%. Long-term outcomes obtained from 68 questionnaire responses (83% compliance) included 56% who had successful leg pain relief, 54% who had successful back pain relief, 44% who successfully returned to work, 51% who successfully returned to normal activity, and 73% who were satisfied with the results of surgery. Poor outcomes correlated most significantly with reoperation on the same vertebral level, same side, and short (< or = 1 year) time interval between consecutive diskectomies. A major conclusion was that workers' compensation patients presenting within 1 year with recurrent complaints after diskectomy and whose radiologic findings indicate a same-level, same-side recurrence represent extremely poor outcome risks for repeat diskectomy.

Comparative expression of endogenous retrotransposons in adult mouse mammary gland during normal development and differentiation.

Amplified expression of the endogenous retrotransposons, intracisternal A particles (IAPs) and murine leukemia virus-related elements (MLVEs), along with decreased expression of VL30 elements frequently occurs during mouse mammary tumorigenesis. We have now analyzed the expression of these retroelements during the normal developmental and differentiation cycle of the mammary gland as found in virgin, pregnant, lactating, and postlactation adult female BALB/c mice. Retrotransposon expression was either unchanged or decreased during the progressive stages of the cycle compared to virgin tissue. Likewise, growth of mammary epithelial cells in primary culture had little or no effect on expression of IAPs, MLVEs and VL30 sequences. Thus, the dramatic changes involving these retrotransposons in many mouse mammary tumors appear unrelated to any normal state.

De-regulation of endogenous retrotransposons in mouse mammary carcinomas of diverse etiologies.

Of the several families of endogenous retrovirus-like elements present in the mouse genome, only mouse mammary tumor virus has been analyzed for its role in mammary carcinogenesis. Very little is known about the expression and activities of other retro-elements in normal and malignant mammary epithelium. We have begun investigating the possible involvement of the 3 retrotransposons, intracisternal A particles (IAPs), murine-leukemia-virus-related (MuLVr) elements, and VL30 sequences, in neoplastic progression of the mammary gland in BALB/c mice. The purpose of the present study was to determine which of these elements was active in primary mammary carcinomas induced by chemical, hormonal and viral agents. Each of these cancers had aberrant expression of at least one of the latter retrovirus-like components. IAP and/or MuLVr sequences were over-expressed 3 to 100-fold in most of the tumors as compared with normal mammary tissue, whereas VL30 expression was markedly decreased by 5- to 35-fold in almost all of the neoplasms. Our results thus demonstrate that substantial changes in the expression of one or more of these 3 families of endogenous retrotransposons are triggered during mouse mammary tumorigenesis, regardless of etiology. Direct involvement of IAPs and MuLVr elements in neoplastic progression by transposition and insertional mutagenesis in the genome of several hematopoietic cell types has already been demonstrated. Their elevated expression in many mammary carcinomas suggests that these retrotransposons may also be potential participants in some pathways of mouse mammary carcinogenesis.

Decompressive lumbar laminectomy for spinal stenosis.

A total of 258 consecutive decompressive lumbar laminectomies performed on 244 individuals presenting with spinal stenosis were analyzed retrospectively. Spinal fusion was avoided in all but two patients. Outcome in terms of pain relief and return to normal activity was evaluated in two stages, one derived from patient charts and having a relatively short-term follow-up time (mean 8.4 months) and a second derived from patient responses to a questionnaire (which also scored for satisfaction with the results of surgery), which had a longer follow-up time (mean 4.7 years). More than 20 clinical and operative parameters were analyzed. Overall, a high degree of success (93% pain relief, 95% return to normal activity) was achieved in the short term, which was supported by the longer-term follow-up data (64% pain relief, 56% activity return, 75% satisfaction). The following factors were not significantly correlated with outcome: patient age; sex; worker's compensation or no-fault insurance status; employed versus not employed; a history of back surgery prior to the laminectomy studied; existence of degenerative spondylolisthesis or scoliosis; complete versus incomplete myelographic block; or the level of the lumbar spine undergoing surgery. The major conclusions arising from these data are: 1) for all age groups through at least the eighth decade of life, decompressive lumbar laminectomy is a relatively safe operation having a high medium-to-long-term success rate; 2) lumbar instability following laminectomy is rare, even in individuals presenting prior to surgery with degenerative instability conditions; and 3) lumbar fusion in addition to the decompressive laminectomy procedure is rarely required for degenerative spinal stenosis.

Lipids covalently bound to keratins of mouse mammary epithelial cells.

Keratin polypeptides obtained from mouse mammary epithelial cells (MMEC) were found to be modified by covalent attachment of lipids. MMEC in primary culture were incubated in 3H-palmitate and treated with 1.5M KCl/1% Triton X-100 to obtain a cytoskeletal (CS) fraction containing primarily keratin and actin filaments. After exhaustive extraction to remove labeled lipids, the CS proteins were separated by gel electrophoresis, and the labeled 46 kD (K18) and 55 kD (K8) keratin polypeptides were excised, subjected to acid hydrolysis and the chloroform-soluble products were resolved on thin layer chromatography. For both keratins, covalently bound lipid included major peaks which co-chromatographed with fatty acid standards. Also, unlabeled lipid resolving with fatty acid standards was found covalently bound to both keratins. The results are discussed in terms of keratin-lipid-membrane interactions.