Differential action potentials and firing patterns in injured and uninjured small dorsal root ganglion neurons after nerve injury

The profile of tetrodotoxin sensitive (TTX-S) and resistant (TTX-R) Na(+) channels and their contribution to action potentials and firing patterns were studied in isolated small dorsal root ganglion (DRG) neurons after L5/L6 spinal nerve ligation (SNL). Total TTX-R Na(+) currents and Na(v) 1.8 mRNA were reduced in injured L5 DRG neurons 14 days after SNL. In contrast, TTX-R Na(+)currents and Na(v) 1.8 mRNA were upregulated in uninjured L4 DRG neurons after SNL. Voltage-dependent inactivation of TTX-R Na(+) channels in these neurons was shifted to hyperpolarized potentials by 4 mV. Two types of neurons were identified in injured L5 DRG neurons after SNL. Type I neurons (57%) had significantly lower threshold but exhibited normal resting membrane potential (RMP) and action potential amplitude. Type II neurons (43%) had significantly smaller action potential amplitude but retained similar RMP and threshold to those from sham rats. None of the injured neurons could generate repetitive firing. In the presence of TTX, only 26% of injured neurons could generate action potentials that had smaller amplitude, higher threshold, and higher rheobase compared with sham rats. In contrast, action potentials and firing patterns in uninjured L4 DRG neurons after SNL, in the presence or absence of TTX, were not affected. These results suggest that TTX-R Na(+) channels play important roles in regulating action potentials and firing patterns in small DRG neurons and that downregulation in injured neurons and upregulation in uninjured neurons confer differential roles in shaping electrogenesis, and perhaps pain transmission, in these neurons.     

Cytotoxic effects of Coptis chinensis and Epimedium sagittatum extracts and their major constituents (berberine, coptisine and icariin) on hepatoma and leukaemia cell growth

1. The present study was conducted to evaluate the cytotoxic effects of Coptis chinensis and Epimedium sagittatum extracts and their major constituents on hepatoma and leukaemia cells in vitro. 2. Four human liver cancer cell lines, namely HepG2, Hep3B, SK-Hep1 and PLC/PRF/5, and four leukaemia cell lines, namely K562, U937, P3H1 and Raji, were used in the present study. 3. Of the two crude drugs, C. chinensis exhibited the strongest activity against SK-Hep1 (IC50 = 7 microg/mL) and Raji (IC50 = 4 microg/mL) cell lines. The IC50 values for C. chinensis on HepG2, Hep3B and PLC/PRF/5 cell lines were 20, 55 and 35 microg/mL, respectively. The IC50 values for C. chinensis on K562, U937 and P3H1 cell lines were 29, 29 and 31 microg/mL, respectively. 4. With the exception of HepG2 and Hep3B, the E. sagittatum extract inhibited the proliferation of all cell lines (SK-Hep1, PLC/PRF/5, K562, U937, P3H1 and Raji), with IC50 values of 15, 57, 74, 221, 40 and 80 microg/mL, respectively. 5. Interestingly, the two major compounds of C. chinensis, berberine and coptisine, showed a strong inhibition on the proliferation of both hepatoma and leukaemia cell lines, with IC50 values varying from 1.4 to 15.2 microg/mL and from 0.6 to 14.1 microg/mL, respectively. However, icariin (the major compound of E. sagittatum) showed no inhibition of either the hepatoma or leukaemia cell lines. 6. The results of the present study suggest that the C. chinensis extract and its major constituents berberine and coptisine possess active antihepatoma and antileukaemia activities.     

Superoxide activates very late antigen-4 on an eosinophil cell line and increases cellular binding to vascular cell adhesion molecule-1

The recruitment of eosinophils to the airway is a key event in the pathogenesis of allergy. Very late antigen-4 (VLA-4), an integrin ligand for vascular cell adhesion molecule-1 (VCAM-1), is expressed on eosinophils. VLA-4-mediated adhesion of eosinophils to VCAM-1 may contribute to their selective recruitment to tissues in allergy. Reactive oxygen species (ROS), including nitric oxide (NO), are abundant in the airway of allergic patients, but their role in pathogenesis of allergy is unclear. In this investigation, we studied the effects of ROS on integrin-mediated eosinophil adhesion. Recombinant soluble VCAM-1 and ICAM-1 were used to test the effects of ROS on the integrin-mediated adhesion of an eosinophil cell line. We used phorbol 12-myristate 13-acetate-stimulated neutrophils and hypoxanthine to generate superoxide, NO donors as sources of NO, and a static cell-to-protein adhesion assay to analyze cellular adhesion. Stimulated neutrophils significantly increased eosinophil binding to VCAM-1, which was reversed in the presence of superoxide dismutase. Neutrophils from a chronic granulomatous disease patient lacked this activity in enhancing eosinophil adhesion. Our results suggest that the balance between ROS molecules in different tissue microenvironments may change the integrin-mediated leukocyte adhesion and is likely to be a key factor in leukocyte recruitment in allergic inflammation.     

Pain model and fuzzy logic patient-controlled analgesia in shock-wave lithotripsy

Pain control in conscious patients was investigated using a push-button, demand-driven supply of drugs. A fuzzy logic patient-controlled analgesia (PCA) algorithm was compared with a conventional algorithm, for alfentanil administration in extracorporeal shock-wave lithotripsy. The conventional PCA algorithm used an initial dose of 0.25 mg, a fixed infusion rate of 60 mg h⁻¹ and a fixed bolus size of 0.2 mg with a 1 min lockout. The fuzzy logic PCA algorithm used an initial dose of 0.25 mg, a changeable infusion rate and a bolus size of 0.1 or 0.05 mg. The infusion rate was adjusted according to a look-up table that accepted the button-pressing history over the last three lockout intervals. The look-up table was designed using fuzzy logic. The bolus size was adjusted according to the button-pressing history over the past two lockout intervals. Twelve patients were treated using conventional PCA, and thirteen were treated with PCA + fuzzy logic control (FLC). PCA+FLC patients consumed 45% less drug. Also, PCA-FLC patients had a mean delivery/demand ratio of 82%, compared with 60% in conventional PCA. When the pain intensity scale was analysed, PCA+FLC patients had acceptable pain intensity at 62%, compared with 44% in conventional PCA.     

Development of an automated immunoassay for advanced glycosylation end products in human serum

OBJECTIVE: Nonenzymatic reaction of protein and carbohydrate produce a series of brown fluorescent advanced glycosylation end products (AGEs). However, a convenient and rapid assay for serum AGEs level is currently unavailable.METHODS: We raised AGEs-specific polyclonal antibodies, which were used to develop a fully automated, noncompetitive, homogeneous, light-scattering immunoassay for serum AGEs.RESULTS: The assay requires a sample volume of 2 microL and takes a reaction time of 2 min. The coefficient of variation range from 1.8 to 6.1%, and the mean recovery rate was 98.6%. Comparative analysis shows moderate correlation with competitive ELISA (r = 0.8209, n = 52). The mean +/- SD concentration of AGEs in young and in older healthy subjects were 4.6 +/- 1.5 (n = 39) and 4.9 +/- 1.4 (n = 40), respectively. The level of AGEs was significantly higher in serum from patients with type II DM 7.8 +/- 4.8 (n = 89) than that from the normal subjects (p < 0.05).CONCLUSIONS: The automatic immunoassay for AGEs is appropriate for clinical use.     

Comparison of Medial-to-lateral versus Traditional Lateral-to-medial Laparoscopic Dissection Sequences for Resection of Rectosigmoid Cancers: Randomized Controlled Clinical Trial

This study aimed to compare medial-to-lateral versus lateral-to-medial laparoscopic dissection sequences for resecting rectosigmoid cancers. We hypothesized that the medial-to-lateral approach was a more efficient procedure and with potentially better oncologic results. Between January 1997 and June 1999, a total of 67 patients of rectosigmoid cancer treated by one surgeon using the laparoscopic approach were recruited for this prospective, randomized, double-blind clinical trial. Using the blocked randomization method, 36 patients were allocated to a medial-to-lateral (M) group and the other 31 to a lateral-to-medial (L) group; the groups were well matched in age, gender, symptoms, body mass index, American Society of Anesthesiology (ASA) class, tumor location, tumor distance above the anal verge, tumor gross morphology, TNM stage of the tumor, and accuracy of preoperative TNM staging (p > 0.05). All patients were followed up until June 2001. We found that the M group had a significantly shorter operating time and lower overall costs than the L group (p < 0.05). There was no significant difference between these two groups in terms of intraoperative complications, conversion rate, postoperative ileus, hospitalization, postoperative pain, postoperative complications, wound length, or disability (p > 0.05). The postoperative proinflammatory response, evaluated by the C-reactive protein level and the erythrocyte sedimentation rate, was significantly lower in the M group (p < 0.05). There was no significant difference between these two groups regarding postoperative immunosuppression, as evaluated by the alterations of total lymphocyte counts and the CD4(+)/CD8(+) ratio (p > 0.05). The extent of dissection of these two dissection approaches was similar, as the harvested lymph nodes were equivalent (p > 0.05). During the whole follow-up period (median 32 months, range 24-54 months), the tumor recurrence rate was similar for these two groups of patients (5.6% in the M group vs. 6.5% in the L group; p > 0.05). These findings indicated that the medial-to-lateral approach was quicker, less expensive and possibly less invasive; moreover, it gave oncologic results similar to those achieved with the traditional lateral-to-medial dissection sequence. We thus concluded that the medial-to-lateral dissection sequence may currently be the most appropriate procedure for laparoscopic resection of rectosigmoid cancers.     

Pathologic studies of fatal cases in outbreak of hand, foot, and mouth disease, Taiwan

In 1998, an outbreak of enterovirus 71-associated hand, foot, and mouth disease occurred in Taiwan. Pathologic studies of two fatal cases with similar clinical features revealed two different causative agents, emphasizing the need for postmortem examinations and modern pathologic techniques in an outbreak investigation.     

Afferent synaptic contacts on glycine-immunoreactive neurons in the rat cuneate nucleus

This study was aimed to clarify whether the primary afferent terminals (PATs), GABAergic terminals, and glutamatergic terminals made direct synaptic contacts with glycine-IR neurons in the cuneate nucleus of rats. In this connection, injection of the anterograde tracer WGA-HRP into brachial plexus, antiglycine preembedding immunoperoxidase, and anti-GABA, along with antiglutamate postembedding immunogold labeling, were used to identify the PATs, glycine-IR neurons, GABA-IR terminals, and glutamate-IR terminals, respectively. The present results showed that HRP-labeled PATs, immunoperoxidase-labeled glycine-IR terminals, immunogold-labeled GABA-IR, and glutamate-IR terminals made axodendritic synaptic contacts with immunoperoxidase-labeled glycine-IR neurons. The latter three presynaptic elements also formed axosomatic synapses with glycine-IR neurons. Statistical analysis has shown that the minimum diameter of the glycine-IR dendrites postsynaptic to the above-mentioned four presynaptic elements did not differ significantly. In addition, the synaptic ratio of the glutamate-IR terminals on the glycine-IR dendrites was higher than that of GABA-IR terminals. The synaptic ratio of the GABA-IR terminals on glycine-IR dendrite was in turn higher than that of the PATs and glycine-IR terminals. It is suggested that the PATs and glutamate-IR terminals on the glycine-IR neurons may be involved in subsequent postsynaptic inhibition for spatial precision of lateral inhibition. On the other hand, the GABA-IR and glycine-IR terminals which make synaptic contacts with the dendrites of glycine-IR neurons may provide a putative means for disinhibition or facilitation to maintain the baseline neuronal activity in the rat cuneate nucleus. The results of quantitative analysis suggest that glutamate act as the primary excitatory neurotransmitter, while GABA, when compared with glycine, may serve as a more powerful inhibitory neurotransmitter on glycine-IR neurons in the rat cuneate nucleus.     

What do we know about maternal-fetal attachment?

A review of the literature suggests that there are three critical attributes related to the concept of maternal-fetal attachment, including cognitive, affective, and altruistic attachment. Cognitive attachment is the desire to know the baby. Affective attachment is the pleasure associated with thoughts of or interaction with the fetus. Altruistic attachment refers to a desire to protect the unborn child. Existing measurements on maternal-fetal attachment are developed based on low-risk and white pregnant women and previous research has not yet resulted in a consistent theoretical model. Future research should focus on development of culturally sensitive instruments and combining qualitative and quantitative measures to broaden theoretical understanding of the concept. Nursing assessment of maternal-fetal attachment is an on-going process. The nurse's role is to reassure those who have developed attachment to their fetuses and to motivate those who are unaware of or unconcerned about their attachment to their fetuses. Collecting data from different attributes of attachment helps nurses identify each woman's attachment patterns and areas of concern.