Occupational lead exposure and survival with amyotrophic lateral sclerosis.

Objective: Lead exposure has been hypothesized to increase the risk of ALS, but only two studies have examined the association with ALS survival, and with inconsistent results. The use of occupational history to assess lead exposure can avoid reverse causation that may occur in epidemiologic analyses that use biomarkers of lead exposure collected after ALS onset.Methods: We evaluated the relationship of occupational lead exposure to ALS survival among 135 cases from an international ALS cohort that included deep phenotyping, careful follow-up, and questionnaires to quantify participants' occupation history. ALS patients were recruited in 2015-2019. We determined occupational lead exposure using a job-exposure matrix. We estimated hazard ratios (HR) and 95% confidence intervals (CI) for survival using Cox proportional hazard analysis with adjustment for covariates.Results: A total of 135 ALS patients completed the environmental questionnaires, among whom 38 reached a survival endpoint (death or permanent assisted ventilation). The median survival was 48.3 months (25th-75th percentile, 30.9-74.1). Older patients and those with initial symptom other than limb onset had shorter survival time. There were 36 ALS cases with occupational lead exposure. After adjusting for age, sex, site of onset, smoking, and military service, lead exposure was associated with an HR of 3.26 (95%CI 1.28-8.28). Results with adjustment for subsets of these covariates were similar.Conclusions: These results suggest that lead exposure prior to onset of ALS is associated with shorter survival following onset of ALS, and this association is independent of other prognostic factors.

[The effect of acupuncture and endogenous c-Fos, c-Jun on regeneration of neuronal dendrite of spared DRG in vitro following partial ganglionectomy].

OBJECTIVE: To explore the effect of acupuncture, endogenous c-Fos and c-Jun on the regeneration of neuronal dendrite of spared dorsal root ganglion (DRG) in vitro following partial ganglionectomy. METHODS: Five adult male cats were used in this experiment. Their bilateral L1-L5, L7-S2 DRG were removed, and L6 DRG were spared. Then unilaterally, two sets of acupoints (Zusanli(St. 36) and Xuanzhong(G. B. 39); Futu (St. 32) and Sanyinjiao (Sp. 6) located in the distribution area of spinal nerve L6) were electro-stimulated alternately 30 min everyday by electro-needling. Seven days after operation, bilateral L6 DRGs were taken out and were cultured respectively in vitro. Some cultured mediums of the acupuncture lateral wells were totally replaced by each corresponding antibody-cultured medium including respectively 100 ng/mL anti-c-Fos and anti-c-Jun antibody at the 24th hour and terminated after 7 days. The length of the neurite was measured by upside-down light microscopy. Then, cultured cells were stained by the immunohistochemistry ABC method. Data were analyzed by One-way ANOVA and q test. RESULTS: Immunocytochemical staining revealed that over 95% cells were NSE positive cells which were the typical neuron of DRG in vitro. On the 7th day, the average neurite length of the spared DRG group, the anti-c-Fos antibody and the anti-c-Jun antibody group were shorter than that of the acupuncture group (P < 0.05); the average neurite length of the two antibody groups were longer than that of the spared DRG group (P < 0.05). CONCLUSION: These results indicate that acupuncture, endogenous c-Fos and c-Jun probably promote regeneration of neuronal dendrite of spared DRG in vitro.

[Influence of acupunction on NT-4 expression in spared root ganglion and spinal cord].

OBJECTIVE: To explore the changes of the expression of NT-4 in spared dorsal root ganglia (DRG,L6) on both the operation/Acup side and the nonoperation/non-Acup side as well as in the spinal lamina II (L3, L5, L6) and Clarke' nucleus (L3) of the normal adult cats, partial dorsal rhizotomy cats, and Acup spared DRG cats so as to disclose the relation between NT-4 and the plasticity of spinal cord as well as the Acup promoting spinal cord plasticity. METHODS: Twenty-five adult cats were divided into 5 groups; normal control group; unilateral partial root rhizotomy 7 d and 14 d groups (unilateral L1-L5, L7-S2 DRG were transected, but L6 DRG was spared); Acup spared DRG 7 d and 14 d groups (electro-needle stimulation was performed following unilateral partial root rhizotomy). The cats survived for 7 or 14 days after operation respectively. Bilateral L6 dorsal root ganglia and L3, L5, L6 spinal cord of every group were made into 20 microm frozen sections. Then, sections were stained under the same condition using specific NT-4 (1 : 200) antibody by the immunohistochemistry ABC method. The distribution and the number of NT-4 immunoreactive neurons in bilateral spared DRG (L6) on the operation/Acup side and the nonoperation/Acup side as well as in the, spinal lamina II (L3, L5, L6) and Clarke' nucleus (L3) of each cat were oberserved and counted. All data were analyzed by one-way ANOVA, SNK-q test and paired-t test. RESULTS: Partial dorsal root rhizotomy led to continuous declination of total NT-4 immunoreactive neurons in spared ganglia, till the 14 d, while Acup reversed this tendency and made NT-4 immunoreactive neurons decrease firstly and then approach to normal level till the 14 d after Acup. In addition, Acup increased NT-4 expression in L5, L6 spinal lamina II. CONCLUSION: The above finding indicate that NT-4 plays an important role in the mechanism by which Acup promotes spinal cord plasticity. Partial dorsal root rhizotomy and Acup spared DRG may exert effects on the expression of NT-4 in the/non-operrtion non-Acup side of DRG.

[Effect of partial ganglionectomy and acupuncture on culturing spared DRG in vitro].

OBJECTIVE: To explore the effect of partial dorsal root rhizotomy and Acup on culturing dorsal root ganglion(DRG) in vitro. METHODS: Ten adult cats were divided into 2 groups: normal control group; Acup spared DRG 7 d group, in which bilateral L1-L5, L7-S2 DRG were removed; and L6DRG were spared; then unilaterally two sets of acupoints [Zusanlily (St. 36) and Xuanzhong (G. B. 39): Futu (St. 32) and Sanyinjiao (Sp. 6) located in the distribution area of spinal nerve L6] were electro-stimulated alternatively 30 min everyday by electro-needling. Five cats were used in every group. Bilateral L6 DRGs of every group were taken out on the condition of asepsis and were cultured respectively in vitro. Cultures were terminated after day 7. Then the cultured cells were stained under the same condition using specific NSE (1 : 200) antibody, a neuron-specific marker, by the immunohistochemistry ABC method. The neurite length was measured by micro-measured ruler in upside-down light microscope on the 1st, 3rd, 5th, 7th day. RESULTS: Immunocytochemical staining revealed that over 95% cells were NSE positive cells which were the typical neuron of DRG in vitro; on the 1st, 3rd, 5th, 7th day, the average neurite length of the normal group was shorter than that of the spared DRG group(P < 0. 05), and the spared DRG group's was shorter than the Acup group's at each time stage (P < 0.05). CONCLUSION: These results indicated that DRG had plasticity and acupuncture probably promoted the plasticity, which were probably in close relation with the spinal plasticity.

[The changes of NT-4 expression in spared root ganglion and spinal cord following partial dorsal root rhizotomy].

OBJECTIVE: This study was conducted to detect the expression levels of NT-4 in the spared dorsal root ganglia (DRG, L6) on the operated side and un-operated side, in the spinal lamina II (L3, L5, L6) and Clarke's nucleus (L3) of the normal adult cats and the cats submitted to partial dorsal rhizotomy. The aim was to illuminate the temporospatial changes of NT-4 expression and its possible relation to spinal cord plasticity. METHODS: Fifteen male adult cats were divided into three groups. The cats of two groups were submitted to unilateral partial dorsal root rhizotomy (L1-L5, L7-S2 DRG were sectioned, but L6 was spared) and animals were sacrificed at survived 7 days and 14 days after operation. The sections were stained by the immunohistochemistry ABC method under the same condition, using NT-4 (1:200, Santa Cruz) antibody. The distribution and the number of NT-4 positive neurons in bilateral spared DRG (L6) in the operated/un-operated side, spinal lamina II (L3, L5, L6) and Clarke's nucleus (L3) of each animal were observed and counted. All data were analyzed by one-way ANOVA, SNK-q test and paired-t test. RESULTS: (1) Seven days after partial dorsal root rhizotomy, the number of NT-4 positive neurons in spared DRG in the operated side was significantly less than that of normal group (P<0.05), but significantly more than that of L6 DRG in the unoperated side (P<0.05); the number of NT-4 positive neurons of L6 DRG on the 14th day after partial dorsal root rhizotomy was also less than that of normal group, 7-day group, and the un-operated side (P<0.05). (2) There was no difference in respect to the number of NT-4 positive neuron in L3, L5, L6 spinal lamina II and L3 Clarke's nucleus in the operated side between the normal group, 7-day operation group and 14-day operation group (P>0.05). CONCLUSION: Our results suggest that partial dorsal root rhizotomy can mainly lead to the change of NT-4 expression in the spared root ganglion, and NT-4 in the unoperated side DRG are involved in spinal cord plasticity.

[The neurotrophic effect of endogenous NT-3 from adult cat spared dorsal root ganglion on ganglionic neurons].

OBJECTIVE: To investigate the neurotrophic effect of endogenous NT-3 from adult cat dorsal root ganglion (DRG) on ganglionic neurons. METHODS: Rhizotomy of bilateral L1, L3, L5 and L7 dorsal roots of cats was performed, leaving L2, L4 and L6 DRG as spared DRGs. The separate neurons of normal (control) DRG, spared DRG and anti-NT-3 antibody blocking DRG were cultured in vitro respectively. The number of survival neurons and the length of neurites were measured and used for comparison in the control, spared DRG, and block groups. RESULTS: There were survival neurons and cell clusters in every group. The number of survival neurons and cell clusters of spared DRG group were much larger than those of the control and block groups. The neurite length of neurons, the neurite number and the length of cell clusters of spared DRG group were much greater than those of control and block groups. CONCLUSION: Endogenous NT-3 from spared DRG may act on ganglionic neurons to maintain survival of neuron and stimulate growth of neurite.

The effects of knowledge management on surgeon behavior.

Knowledge management is an important process for health care researchers and administrators. The way we manage and transfer knowledge in an organization can have a substantial impact on behavior and performance. In this article, we examine the behavioral effects of transferring performance-efficiency knowledge to a group of hospital-based surgeons. We observe the way the knowledge transfer impacts their sense of professional accountability and practice patterns for a limited set of diagnoses. We defined performance efficiency for a surgeon as the deviation from expected average length of inpatient hospital stay, and from expected average hospital charges (adjusted for risk and outcomes) for three of the most frequently performed and most costly surgical procedures in our subject hospital. We communicated knowledge of their performance efficiency to the group of hospital-based surgeons, along with benchmarked professional best practices, and included an identification of dimensions where performance could be improved. We then measured and compared their performance efficiency one year later. We did observe differences in performance efficiency, but not in consistent directions, and not in statistically significant magnitudes. Also, surgeons who initially had low levels of efficiency continued to have low levels of efficiency one year later. Within a professional accountability system, transfer of performance-efficiency knowledge alone did not provide sufficient motivation to induce consistent, significant change in practice behaviors among the group of surgeons. We conclude that medical opinion leaders and individualized strategies for surgeon motivation may have greater promise for improving performance efficiency if linked to the knowledge transfer system.