Tooth movement and cytokines in gingival crevicular fluid and whole blood in growing and adult subjects.

INTRODUCTION: Tooth movement has been studied largely with respect to the force required for tipping when pressure distribution varies along the length of the periodontal ligament. But important factors for effective canine translation include the nature and magnitude of applied stress and the patient's cell biology. The purpose of this research was to test 3 hypotheses: (1) the velocity of tooth translation (v(t)) is related to applied stress and growth status, (2) a threshold of stress accounts for the lag phase, and (3) v(t) is correlated with the ratio (AI) of 2 cytokines (IL-1beta, IL-1RA) measured in gingival crevicular fluid (GCF) and stimulated whole blood (SWB). METHODS: Continuous maxillary canine retraction stresses of 13 kPa and 4, 26, or 52 kPa were applied bilaterally in 6 growing and 4 adult subjects for 84 days. Dental models and GCF samples were collected at 1- to 14-day intervals. Cytokines were measured in GCF and SWB cell cultures. RESULTS: V(t) was positively related to stress and was higher in growing subjects (P = .001). It was also related to AI(GCF) in growers (R2= 0.56) and nongrowers (R2= 0.72). Canines moved with 52 kPa showed a lag phase, and postlag phase AI(GCF) was twice that of lag phase AI(GCF). Mean v(t) and associated AI(GCF) during the postlag phase were nearly double the values for canines moved with 13 and 26 kPa. SWB production of cytokines was dose-dependent. For growing subjects, SWB IL-1RA was correlated with v(t) (R = 0.70-0.72), and AI(SWB) and IL-1beta concentrations were correlated with AI(GCF) (R = 0.73-0.78). CONCLUSIONS: V(t) varied with growth status and stresses < or = 52 kPa; stresses of < 52 kPa showed no lag phase; and equivalent stresses yielded subject-dependent differences in v(t), which correlated with cytokines in GCF and SWB.     

Inguinal hernia repair in Hospital Authority hospitals: The role of laparoscopic hernioplasty

Objective: Two major changes have occurred in inguinal hernia repair during the last two decades: (i) the use of tension‐free mesh repair; and (ii) the application of laparoscopic technique for repair. The aims of the present study were to study: (i) how inguinal hernia repair was carried out; and (ii) the outcome of inguinal hernia repair in Hospital Authority (HA) hospitals. Methodology: This was a retrospective analysis on 8311 elective inguinal hernia repairs performed in 16 HA hospitals from January 2001 to December 2003. The mean age was 63.9 ± 14.2 years, and the male to female ratio was 22.0 : 1.0. Among these, 869 (10.5%) repairs were performed with the laparoscopic approach and 7442 (89.5%) repairs with the open approach. The proportion of laparoscopic hernia repair increased from 8.7% to 12.6%. Results: For open repair, 39% of cases were carried out with regional anaesthesia, 32% with general anaesthesia and 29% with local anaesthesia (LA). Furthermore, mesh repair was used in 88% of the patients. For laparosocpic repair, 98.4% of cases were carried out under general anaesthesia, and all patients had mesh repair using the totally extraperitoneal approach. A significantly higher proportion of bilateral repair and recurrent hernia repair was performed with the laparoscopic approach (P = 0.000). For primary unilateral repair, there was no significant difference in the postoperative length of stay (LOS) and the total LOS between the laparoscopic and the open surgery groups. No difference in LOS was found in recurrent hernia repair between the two groups. With respect to bilateral repair, both the preoperative LOS (P = 0.036) and total LOS (P = 0.039) were shorter in the laparoscopic group. Furthermore, a significantly higher proportion of day‐surgery patients was observed in the laparoscopic group than the open surgery group (21.3%vs 16.9%, P = 0.001). Nevertheless, when only the results of 2003 were analyzed, the postoperative LOS (P = 0.000) and total LOS (P = 0.000) were significantly shorter in the laparoscopic group than the open surgery group. The LOS parameters were significantly shorter in the open surgery LA subgroup compared with the non‐LA subgroup (P = 0.000), and they were not different from those in the laparoscopic group. Conclusions: The open mesh repair is the predominant approach for inguinal hernia repair in HA hospitals. The originally described local anaesthetic approach was under utilized, although it resulted in good outcome. The use of laparoscopic hernia repair is increasing and a learning curve was recently observed with improved outcome.     

Surgical epicardial left ventricular lead versus coronary sinus lead placement in biventricular pacing.

OBJECTIVE: Biventricular pacing has demonstrated improvement in cardiac function in treating congestive heart failure (CHF). Two different operative strategies (coronary sinus vs. epicardial stimulation) for left ventricular (LV) pacing were compared. METHODS: Since April 1999, a total of 86 patients (pts, age: 63+/-10 years) with depressed systolic LV function (mean ejection fraction 24+/-9%), left bundle-branch-block (mean QRS 182+/-22 ms) and congestive heart failure NYHA III or higher were enrolled. For biventricular stimulation coronary sinus (CS) leads were placed in 79 pts. Nine of these devices were converted to surgical epicardial LV-leads, because of CS-lead failure. In 7 patients epicardial LV-leads were initially implanted surgically, accounting for a total of 16 pts with surgical placed epicardial steroid-eluting LV-leads. For these, a limited left-lateral thoracotomy (7+/-4 cm) was used. Thirty-three (38%) pts had an indication for a defibrillator. The mean follow-up time was 16.4+/-15.4 months (0.1-45 months), representing 107.1 patient-years. RESULTS: In the biventricular pacing mode, QRS duration decreased to 143+/-16 ms (P<0.001). Threshold capture of the CS-leads increased significantly compared to surgically placed epicardial leads (18 month control: 2.2+/-1.4V/0.5 ms vs. 0.7+/-0.3V/0.5 ms), which had no increase in threshold (P<0.001). At the 18 month follow-up 7 CS-leads had a threshold of >4V/0.5 ms vs. epicardial leads which were under 1.1V/0.5 ms, except for one (1.8V/0.5 ms). After CS-lead implantation 25 LV-lead related complications occurred, (failed implantation, CS-dissection, loss of pacing capture, diaphragm stimulation or lead dislodgment), vs. one dislodgement after surgical epicardial lead placement (P<0.05). Correct lead positioning (obtuse marginal branch area) was achieved in all surgical epicardial placements but only in 70% with CS-leads (P<0.03). In the follow up period, 9 pts died (4 cardiac related). Heart transplantation was necessary in 4 pts due to deterioration of the cardiomyopathy. CONCLUSIONS: Surgical epicardial lead placement revealed excellent long-term results and a lower LV-related complication rate compared to CS-leads. Although, the approach via limited thoracotomy for biventricular pacing is associated with 'more surgery', it is a safe and reliable technique and should be considered as an equal alternative.     

Elemental composition and water content of myelinated axons and glial cells in rat central nervous system

The distribution of elements (e.g. Na, Cl, K) and water in CNS cells is unknown. Therefore, electron probe X-ray microanalysis (EPMA) was used to measure water content and concentrations (mmol/kg dry or wet weight) of Na, Mg, P, S, Cl, K and Ca in morphological compartments of myelinated axons and glial cells from rat optic nerve and cervical spinal cord white matter. Axons in both CNS regions exhibited similar water content ( 90%), and relatively high concentrations (wet and dry weight) of K with low Na and Ca levels. The K content of axons was related to diameter, i.e. small axons in spinal cord and optic nerve had significantly less (25–50%) K than larger diameter axons from the same CNS region. The elemental composition of spinal cord mitochondria was similar to corresponding axoplasm, whereas the water content (75%) of these organelles was substantially lower than that of axoplasm. In glial cell cytoplasm of both CNS areas, P and K (wet and dry weight) were the most abundant elements and water content was approximately 75%. CNS myelin had predominantly high P levels and the lowest water content (33–55%) of any compartment measured. The results of this study demonstrate that each morphological compartment of CNS axons and glia exhibits a characteristic elemental composition and water content which might be related to the structure and function of that neuronal region.     

Inherited Neurodegenerative Disorders Caused by CAG/Polyglutamine Tract Expansions: Symposium Introduction

At the beginning of this decade, the American Association of Neurology decided that the 1990's should be labelled "the decade of the brain" for expected advances in our understanding of neurological disorders and neuroscience. By the end of this decade, clinicians and researchers who work in the field of inherited neurological disorders might well remember the 1990's as "the decade of the trinucleotide repeat". At the time of writing this introduction, eleven inherited neurological disorders have been found to be caused by expansions of trinucleotide repeats, and a twelfth trinucleotide repeat expansion mutation has been identified (6), although the gene containing this mutant triplet repeat has not been cloned to our knowledge (Table 1).