Combined monitoring of motor and somatosensory evoked potentials in orthopaedic spinal surgery

OBJECTIVES

To demonstrate possible advantages of combined (motor and sensory) versus single modality (either motor or sensory) intra-operative spinal cord monitoring and to investigate risk factors for post-operative neurological sequelae.

METHODS

Recordings of lower limb motor evoked potentials (MEPs) to multi-pulse transcranial electrical stimulation (TES), and tibial nerve somatosensory evoked potentials (SEPs), were attempted during 126 operations in 97 patients (79 with spinal deformity and 18 with miscellaneous spinal disorders).

RESULTS

Combined motor and sensory monitoring was successfully achieved in 104 of 126 (82%) operations. No response to either modality could be recorded in two patients with Friedreich' s ataxia. In 18 patients monitoring was possible in only one modality: SEPs could not be recorded in two patients and MEPs in 16. Significant intra-operative EP changes occurred in one or both modalities in 16 patients; in association with instrumentation in 10 cases, and with systemic changes in 6. After appropriate remedial measures, SEPs recovered either fully or partially in 8/8 patients and MEPs in only 67% (10/15 patients). New deficits were present post-operatively in 6 of the 16 patients with abnormal intra-operative EPs. Normal MEPs at the end of the operation correctly predicted the absence of new motor deficits in all cases. SEPs either remained unchanged or recovered fully after remedial measures in 3 patients with new post-operative motor deficits. Neurological complications were more frequent in patients with miscellaneous spinal disorders and/or pre-existing neurological deficits. No complications occurred in patients with idiopathic scoliosis.

CONCLUSIONS

Combined SEPs and multi-pulse TES-MEPs provide a safe, reliable and sensitive method of monitoring spinal cord function in orthopaedic surgery. This method is superior to single modality techniques, both for increasing the number of patients in whom satisfactory monitoring of spinal cord function can be achieved and, for improving the sensitivity and predictivity of monitoring. Combined SEP/MEP methods may enhance the impact of neuromonitoring on the intra-operative management of the patient and favourably influence neurological outcome.

Inhibitory effects of apoptotic cell ingestion upon endotoxin-driven myeloid dendritic cell maturation

Dendritic cells (DCs) are the sentinels of the immune system, able to interact with both naive and memory T cells. The recent observation that DCs can ingest cells dying by apoptosis has raised the possibility that DCs may, in fact, present self-derived Ags, initiating both autoimmunity and tumor-specific responses, especially if associated with appropriate danger signals. Although the process of ingestion of apoptotic cells has not been shown to induce DC maturation, the exact fate of these phagocytosing DCs remains unclear. In this paper we demonstrate that DCs that ingest apoptotic cells are able to produce TNF-alpha but have a diminished ability to produce IL-12 in response to external stimuli, a property that corresponds to a failure to up-regulate CD86. By single-cell analysis we demonstrate that these inhibitory effects are restricted to those DCs that have engulfed apoptotic cells, with bystander DCs remaining unaffected. These changes were independent of the production of anti-inflammatory cytokines TGF-beta1 and IL-10 and corresponded with a diminished capacity to stimulate naive T cells. Thus, the ingestion of apoptotic cells is not an immunologically null event but is capable of modulating DC maturation. These results have important implications for our understanding of the role of clearance of dying cells by DCs not only in the normal resolution of inflammation but also in control of subsequent immune responses to apoptotic cell-derived Ags.

Estimation and management of genetic diversity in small populations of plains zebra (Equus quagga) in KwaZulu-Natal, South Africa

Plains zebras (Equus quagga antiquorum) occur in few large, but many small, isolated populations in KwaZulu-Natal. Problems identified in small populations include reduced striping patterns on hind quarters, smaller size, elevated mortality rates and high number of still-births. Inbreeding may be implicated. Population viability analysis (PVA) was conducted with a computer model (VORTEX), and DNA and allozyme analyses were conducted to test the findings of the model. Using standard methods, DNA (PCR-RAPD) and allozyme diversity was assessed in blood samples from 72 plains zebra from four KwaZulu-Natal Nature Conservation Services (KZN-NCS) protected areas: Umfolozi Game Reserve (UGR), Albert Falls (AFNR), Vernon Crookes (VCNR) and Harold Johnson (HJNR) Nature Reserves. Populations of the latter three, small-sized (9-110 individuals) populations were seeded from the same source population (UGR: current population of 2000) during the past 25 years. Information from PCR-RAPD and allozyme analyses were compared with each other as well as to that predicted by population genetic modelling (using VORTEX). Allozyme heterozygosities were consistently high in all populations (12.1-12.9%), with no observable losses associated with reduced population size. On the other hand, percentage loss of polymorphism (20-39%) calculated from the PCR-RAPD study appeared to be positively correlated with the loss of heterozygosity predicted by population viability analysis (PVA), and negatively correlated with population size. On the basis of the above results, a policy of translocation was advocated for small, intensely managed populations of zebras, whereby a harem should be translocated every five years for a population size of nine (HJNR), while for a population size of 110 (VCNR) translocations should take place every 15 years if heterozygosity is to be maintained at more than 90% within each population over 100 years.

Adolescent research recruitment issues and strategies: application in a rural school setting

This report discusses adolescent research recruitment strategies in general and specifically, those developed by a research team for a rural school setting. Recruitment of adolescent subjects involves the consideration of several complex issues. These issues include adolescent development, ethical and legal guidelines, and access to school settings. Specific strategies are discussed regarding access and culture of the rural setting, collaboration, and recruitment procedures in relation to their use to recruit adolescent subjects from rural schools.

Regulation of the functional interaction between cyclin D1 and the estrogen receptor

We report that the functional interaction between cyclin D1 and the estrogen receptor (ER) is regulated by a signal transduction pathway involving the second messenger, cyclic AMP (cAMP). The cell-permeable cAMP analogue 8-bromo-cAMP caused a concentration-dependent enhancement of cyclin D1-ER complex formation, as judged both by coimmunoprecipitation and mammalian two-hybrid analysis. This effect was paralleled by increases in ligand-independent ER-mediated transcription from an estrogen response element containing reporter construct. These effects of 8-bromo-cAMP were antagonized by a specific protein kinase A (PKA) inhibitor, indicating that the signaling pathway involved was PKA dependent. Further, we show that culture of MCF-7 cells on a cellular substratum of murine preadipocytes also enhanced the functional interaction between cyclin D1 and ER in a PKA-dependent manner. These findings demonstrate a collaboration between cAMP signaling and cyclin D1 in the ligand-independent activation of ER-mediated transcription in mammary epithelial cells and show that the functional associations of cyclin D1 are regulated as a function of cellular context.

Single amino acid (arginine) deprivation: rapid and selective death of cultured transformed and malignant cells

The effects of arginine deprivation (-Arg) has been examined in 26 cell lines. Less than 10% of those with transformed or malignant phenotype survived for > 5 days, and many died more rapidly, notably leukaemic cells. Bivariate flow cytometry confirmed that vulnerable cell lines failed to move out of cell cycle into a quiescent state (G0), but reinitiated DNA synthesis. Many cells remained in S-phase, and/or had difficulty progressing through to G2 and M. Two tumour lines proved relatively 'resistant', A549 and MCF7. Although considerable cell loss occurred initially, both lines showed a 'cell cycle freeze', in which cells survived for > 10 days. These cells recovered their proliferative activity in +Arg medium, but behaved in the same manner to a second -Arg episode as they did to the first episode. In contrast, normal cells entered G0 and survived in -Arg medium for several weeks, with the majority of cells recovering with predictable kinetics in +Arg medium. In general, cells from a wide range of tumours and established lines die quickly in vitro following -Arg treatment, because of defective cell cycle checkpoint stringency, the efficacy of the treatment being most clearly demonstrated in co-cultures in which only the normal cells survived. The findings demonstrate a potentially simple, effective and non-genotoxic strategy for the treatment of a wide range of cancers.

A study of patient clues and physician responses in primary care and surgical settings

CONTEXT

Patients often present clues (direct or indirect comments about personal aspects of their lives or their emotions) during conversations with their physicians. These clues represent opportunities for physicians to demonstrate understanding and empathy and thus, to deepen the therapeutic alliance that is at the heart of clinical care. A paucity of information exists regarding how physicians address the psychological and social concerns of patients.

OBJECTIVES

To assess how patients present clues and how physicians respond to these clues in routine primary care and surgical settings.

DESIGN, SETTING, AND PARTICIPANTS

Descriptive, qualitative study of 116 randomly selected routine office visits to 54 primary care physicians and 62 surgeons in community-based practices in Oregon and Colorado, audiotaped and transcribed in 1994.

MAIN OUTCOME MEASURES

Frequency of presentation of clues by patients during office visits, nature (emotional vs social) and content of clues, and nature of physician responses to clues, coded as positive or missed opportunity.

RESULTS

Fifty-two percent and 53% of the visits in primary care and surgery, respectively, included 1 or more clues. During visits with clues, the mean number of clues per visit was 2.6 in primary care and 1.9 in surgery. Patients initiated approximately 70% of clues, and physicians initiated 30%. Seventy-six percent of patient-initiated clues in primary care settings and 60% in surgical settings were emotional in nature. In surgery, 70% of emotional clues related to patients' feelings about their biomedical condition, while in primary care, emotional clues more often related to psychological or social concerns (80%) in patients' lives. Physicians responded positively to patient emotions in 38% of cases in surgery and 21% in primary care, but more frequently they missed opportunities to adequately acknowledge patients' feelings. Visits with missed opportunities tended to be longer than visits with a positive response.

CONCLUSION

This study suggests that physicians in both primary care and surgery can improve their ability to respond to patient clues even in the context of their busy clinical practices. JAMA. 2000;284:1021-1027

Single amino acid (arginine) restriction: growth and death of cultured HeLa and human diploid fibroblasts

Requirements for arginine are different from leucine for the growth of HeLa cells in monolayer and suspension culture. Cells grow increasingly more slowly as arginine levels fall below millimolar. Most cells died at 10(-5) M in static cultures, but could be sustained in perfused cultures, but at 10(-6) M neither perfusion nor increased volume in static cultures compensated. Cell died within 3-4 days in 10(-6) M in the same manner as those in complete arginine deprivation, i.e. considerably faster than with leucine deprivation. Arginine restriction produced by arginase or arginine decarboxylase addition to culture medium gave similar results. Citrulline substituted for arginine, but ornithine and polyamines did not. Arginine was depleted 3-4 times faster from the medium than other amino acids, <5% being consumed in protein synthesis, and arginine released by protein turnover was less efficiently reutilised than leucine. Deprivation reduced protein and DNA syntheses, greatly extended S-phase and protracted the cell cycle in HeLa cells for more than leucine deprivation. The inability of the cells avoid reinitiation of S-phase resulted in their proliferative impetus driving them into an late cycle (premitotic) death. In contrast, normal human diploid fibroblasts reached quiescence with little delay and survived for >11 days. Arginine deprivation is discussed as a selectively means of tumour cell destruction.

Pathology characteristics that optimize outcome prediction of a breast screening trial

The ability of pathology characteristics to predict outcome was tested with the 1029 cancers accumulated in the Edinburgh Randomized Trial of breast screening after 14 years follow-up. The majority (55.7%) were in the screening arm, which also had more operable cases (81.3% vs 62.2%); the reduction in the proportion of inoperable breast cancers in a UK female population invited to mammographic screening is a notable effect of the trial. In the 691 operable invasive cases the size, histological type, grade, node status and node number group individually showed highly significant (P<0.001) association with survival. In multivariate analysis the Nottingham Prognostic Index (NPI) derived from these features showed highly significant association with survival (P<0.001). However, when first adjusted for NPI, combined addition of pathological size in 6 categories and histological type as special or not had an independent association with survival that was statistically firmly based (P<0.001). For operable breast cancer the gains are in smaller sizes, better histological features, and higher proportion node negative. The weighting factors applied to pathology indicators of survival in the NPI are not optimal for a population included in a trial of screening. In particular, a linear trend of the index with pathological size is not appropriate. Inclusion of histological type as special or not improves the index further.

Detection of Kaposi's sarcoma-associated herpesvirus in oral and genital secretions of Zimbabwean women

Kaposi's sarcoma-associated herpesvirus (KSHV) in oral and genital secretions of women may be involved in horizontal and vertical transmission in endemic regions. Nested polymerase chain reaction assays were used to detect KSHV DNA sequences in one-third of oral, vaginal, and cervical specimens and in 42% of peripheral blood mononuclear cell (PBMC) specimens collected from 41 women infected with human immunodeficiency virus type 1 who had Kaposi's sarcoma (KS). KSHV DNA was not detected in specimens from 100 women without KS, 9 of whom were seropositive for KSHV. A positive association was observed between KSHV DNA detection in oral and genital mucosa, neither of which was associated with KSHV DNA detection in PBMC. These data suggest that KSHV replicates in preferred anatomic sites at levels independent of PBMC viremia. Detection of genital-tract KSHV only among relatively immunosuppressed women may provide an explanation for infrequent perinatal transmission of KSHV.

Single amino acid (arginine) deprivation induces G1 arrest associated with inhibition of cdk4 expression in cultured human diploid fibroblasts

Withdrawal of a single amino acid (arginine) from freely cycling early passage primary human fibroblasts caused a halt to proliferation, characterized by an accumulation of cells in the G1 phase of the cell cycle. This arrest was accompanied by the suppression of cyclin D1- and cyclin E-associated kinase activities and the appearance of hypophosphorylated retinoblastoma protein. Arginine-deprived cells remained viable for in excess of 4 days and could be made to synchronously reenter the cell cycle by restoration of the amino acid, with kinetics characteristic of exit from a quiescent state. Stimulation of cells arrested by serum withdrawal did not result in S-phase entry when arginine was omitted from the culture medium. Although cyclin D1 accumulated on normal schedule, cdk4, which increased following restimulation in amino acid-replete medium, was not induced when arginine was absent. These results suggest that arginine deprivation-in common with other "suboptimal" conditions-inhibits the passage of normal human cells through the restriction point and implicate cdk4 as the key regulatory element in amino acid-sensitive cell cycle control.

Renal cell carcinoma with massive osseous metaplasia and bone marrow elements

Focal calcifications are frequently seen in renal masses and may be present in renal cell carcinomas. Metaplastic bone formation, on the other hand, is a rare event. We report a unique case of a large calcified renal cell carcinoma with massive osseous metaplasia and bone marrow elements. The clinical and pathologic differential diagnosis for this tumor is discussed along with a review of the literature on this unusual phenomenon.

Chromosome size-dependent control of meiotic reciprocal recombination in Saccharomyces cerevisiae: the role of crossover interference

In the yeast Saccharomyces cerevisiae, small chromosomes undergo meiotic reciprocal recombination (crossing over) at rates (centimorgans per kilobases) greater than those of large chromosomes, and recombination rates respond directly to changes in the total size of a chromosomal DNA molecule. This phenomenon, termed chromosome size-dependent control of meiotic reciprocal recombination, has been suggested to be important for ensuring that homologous chromosomes cross over during meiosis. The mechanism of this regulation was investigated by analyzing recombination in identical genetic intervals present on different size chromosomes. The results indicate that chromosome size-dependent control is due to different amounts of crossover interference. Large chromosomes have high levels of interference while small chromosomes have much lower levels of interference. A model for how crossover interference directly responds to chromosome size is presented. In addition, chromosome size-dependent control was shown to lower the frequency of homologous chromosomes that failed to undergo crossovers, suggesting that this control is an integral part of the mechanism for ensuring meiotic crossing over between homologous chromosomes.

Pain management. A patient's perspective

Improving pain management practices can decrease adverse complications and improve patient outcomes. This in turn will result in the more efficient use of health care resources. Clinicians who are constantly challenged to improve delivery of care are interested in the perceptions of patients. They often rely on their patients' reported levels of satisfaction as an outcome measure for success of a program. Most often, informal methods are used to gather information on satisfaction with care.

Health concerns and risk behaviors of rural adolescents

Although much has been written about the health status of adolescents, little is known about adolescents' perception of their own health. The purpose of this article is to describe the health concerns of rural adolescents. Two national studies, the Youth Risk Behavior Survey and the National Longitudinal Study of Adolescent Health (Add Health Project), are used as comparisons. Data from the rural survey represent 624 community adolescents attending 4 rural Pennsylvania schools. The students were in the 9th, 10th, and 11th grades. The Adolescent Health Inventory was used to report concerns related to general health, psychosocial issues, and risk behaviors. Overall, rural adolescents in the study reported an average of 6.5 (SD = 3.2) health concerns with frequencies of occurrence being always or often and reported an average involvement in 1 (SD = 1.3) risk behavior. Psychosocial issues were reported by 28%, and 23% worried about their general health. Frequently reported risk behaviors included alcohol use, drug use, and a lack of exercise. There was minimal concern expressed regarding venereal disease or AIDS, whereas 12% expressed concern about the possibility of pregnancy. These results suggest the likelihood that adolescents perceive health from a holistic perspective and that health promotion programs should consider involving adolescents in planning, both (a) to ensure congruence of the plan of care with adolescents' concerns and (b) to clarify the interpretation and meaning of their concerns. We present implications for the community health nurse.