Dentistry as a possible route of hepatitis C transmission in Pakistan

AIMS AND OBJECTIVES: To identify the role of dental surgical procedures in contributing to the transmission of hepatitis C. DESIGN: Prospective observational pilot study. SETTING: Shaikh Zayed Federal Postgraduate Medical Institute Lahore, Pakistan. METHODS: Exposure to dental procedures, injections, tattooing, surgical intervention, blood transfusions, family history of hepatitis, diabetes mellitus and contact with jaundiced patients was evaluated in 78 consecutive adult patients of both sexes suffering from chronic hepatitis C. MAIN OUTCOME MEASURES: Distribution of risk factors for acquiring hepatitis C with emphasis on role of dentistry as a possible route of transmission. RESULTS: Dental procedures were the major source of exposure (39.7%) followed by injections (16.6%), surgical procedures (16.6%), diabetes (12.8%), family history of hepatitis (9%), blood transfusions (7%), tattooing (5.1%) and history of contact with a jaundiced patient (2.6%). There was a statistically significant difference in distribution of risk factors, with dental procedures being the commonest factor (p < 0.001). CONCLUSIONS: The high prevalence of dental procedures in patients with chronic hepatitis C stresses the importance of ineffective infection control methods practiced by dental surgeons as a risk factor for acquiring hepatitis C and which were probably the source of infection. Large epidemiological studies are needed to elucidate the role of dentistry in transmitting hepatitis C.     

Short- and intermediate-term follow-up results of percutaneous transluminal balloon valvuloplasty in adolescents and young adults with congenital pulmonary valve stenosis

Percutaneous pulmonary balloon valvuloplasty (PBV) is a well-established treatment alternative to surgery in many cardiology centers. We described our experience with PBV in 25 adolescent and young adult patients with isolated pulmonary valve stenosis (PVS). Among 20 successful PBVs, there was a significant immediate decrease in right ventricular systolic pressure from 116.9 32.4 mmHg to 60.5 18.7 mmHg (p < 0.0001) and a decrease in transpulmonary valve pressure gradient from 93.5 32.8 mmHg to 33.5 9.7 mmHg (p < 0.0001) was noted. The follow-up period was 1-5 years (mean = 3.2 1.2 years), during which patients were periodically assessed by Doppler echocardiogram. During follow-up, the transpulmonary valve pressure gradient further decreased from 33.5 9.7 mmHg to 18.6 3.4 mmHg (p < 0.0001) mainly due to regression of infundibular hypertrophy. Thus, the study showed excellent short-term and intermediate-term results of PBV.     

Outcome evaluation of early discharge from hospital with asthma

OBJECTIVE: The aim of the study was to determine whether it was safe to discharge children with asthma from hospital when stable on 3-hourly rather than 4-hourly doses of salbutamol. METHODOLOGY: A retrospective study of 419 individual admissions of 359 children with asthma was undertaken. We defined a theoretical 'time ready for discharge' (TRD) for asthmatic admissions based on: (i) at least two doses of 3-hourly salbutamol and due for the third dose, (ii) no oxygen supplementation, (iii) no intravenous fluid or therapy, and (iv) time of discharge should be either before 17:30 hours or after 07:30 hours. Each admission was analysed using appropriate parameters to assess for risks and benefits of using this theoretical TRD as a guide for discharging asthmatic children from hospital. RESULTS: A total of 116 (27.7%) children were discharged before our theoretical TRD, including 11 children who received salbutamol no less often than 2-hourly and 37 who had a single dose of 3-hourly salbutamol before discharge. Re-admission to hospital and representation to the Emergency Department without re-admission within 1 week of discharge were less common in the group who were discharged before they had achieved theoretical TRD than in those who were discharged at or after the theoretical TRD, although the numbers were too small to reach statistical significance. Between our theoretical TRD and actual time of discharge two children who received supplemental oxygen and more frequent salbutamol may have required re-admission. CONCLUSIONS: From the medical viewpoint discharge when the child is stable on 3-hourly rather than 4-hourly doses appears safe. This can be expected to shorten length of stay by an average of 5.5 h (P < 0.001).     

Myocardial stunning in man

Myocardial stunning refers to the contractile dysfunction that occurs following an episode of acute ischaemia, despite the return of normal blood flow. The phenomenon was initially identified in animal models, where it has been very well characterised, and there was initial doubt about whether a similar syndrome occurred in humans, and if it did, whether it was of any clinical relevance. This article outlines the conditions that must be met to diagnose myocardial stunning and why it has been difficult to confirm its presence in humans. The clinical scenarios where it has now been clearly identified and those others where it may also occur and be of clinical importance are also reviewed.     

High-resolution voxelation mapping of human and rodent brain gene expression

Voxelation allows high-throughput acquisition of multiple volumetric images of brain gene expression, similar to those obtained from biomedical imaging systems. To obtain these images, the method employs analysis of spatially registered voxels (cubes). For creation of high-resolution maps using voxelation, relatively small voxel sizes are necessary and instruments will be required for semiautomated harvesting of such voxels. Here, we describe two devices that allow spatially registered harvesting of voxels from the human and rodent brain, giving linear resolutions of 3.3 and 1 mm, respectively. Gene expression patterns obtained using these devices showed good agreement with known expression patterns. The voxelation instruments and their future iterations represent a valuable approach to the genome scale acquisition of gene expression patterns in the human and rodent brain.     

Bone morphogenetic proteins: relevance in spine surgery

Bone morphogenetic proteins (BMPs) are low molecular weight glycoproteins that play a vital role in the development and maturation of skeletal tissue. Bone morphogenetic protein-induced mesenchymal cell recruitment and differentiation leads to the formation of chondroblasts and osteoblasts leading to the formation of de novo bone. Overwhelming pre-clinical and clinical evidence has suggested a promising role for BMPs for anterior and posterolateral spinal fusion. Strength of this approach lies in the potential ability of these growth factors to reverse inhibitory conditions common in the clinical setting and enabling predictable fusion. However, several issues related to carriers, costs, and dosages still need to be consecutively addressed. Gene therapy techniques producing in vivo osteoinductive factors and utilizing minimally invasive approaches are attractive options being developed for the future.     

Distal nerve blocks at the wrist for outpatient carpal tunnel surgery offer intraoperative cardiovascular stability and reduce discharge time

Carpal tunnel release is often performed as an outpatient procedure. We designed this retrospective study to assess the effect of different anesthesia techniques on intraoperative cardiovascular stability and discharge time. According to the anesthesia technique received, 62 consecutive patients were categorized in Group BIER (IV regional anesthesia), Group BLOCK (distal nerve blocks), and Group GENERAL (general anesthesia). Incidences of intraoperative periods of tachycardia or bradycardia and hyper- or hypotension were studied, as were tourniquet, surgical, operating room, and discharge times. Cardiovascular stability was better achieved in Group BLOCK, as indicated by a significantly smaller incidence of periods of hypertension compared with Group BIER (5% vs 25%) and a significantly less frequent incidence of periods of hypotension compared with Group GENERAL (14% vs 42%). Patients in Group BLOCK spent significantly less time in the hospital after surgery than patients in Group BIER (65 vs 88 min) or patients in Group GENERAL (65 vs 133 min). We conclude that distal nerve blocks for outpatient carpal tunnel surgery are associated with greater intraoperative cardiovascular stability than general anesthesia. After surgery, patients in Group BLOCK could be discharged earlier than patients who received IV regional anesthesia or general anesthesia; this could be related to the superior postoperative analgesia provided by this technique. IMPLICATIONS: This retrospective analysis of three different anesthetic techniques for ambulatory carpal tunnel surgery shows that nerve blocks performed at the wrist provided excellent intraoperative cardiovascular stability and allowed for earlier discharge.     

N-phenylethyl amitriptyline in rat sciatic nerve blockade

BACKGROUND: The antidepressant amitriptyline is commonly used orally for the treatment of chronic pain, particularly neuropathic pain, which is thought to be caused by high-frequency ectopic discharge. Among its many properties, amitriptyline is a potent Na(+) channel blocker in vitro, has local anesthetic properties in vivo, and confers additional blockade at high stimulus-discharge rates (use-dependent blockade). As with other drug modifications, adding a phenylethyl group to obtain a permanently charged quaternary ammonium derivative may improve these advantageous properties. METHODS: The electrophysiologic properties of N-phenylethyl amitriptyline were assessed in cultured neuronal GH(3) cells with the whole cell mode of the patch clamp technique, and the therapeutic range and toxicity were evaluated in the rat sciatic nerve model. RESULTS: In vitro, N-phenylethyl amitriptyline at 10 microm elicits a greater block of Na(+) channels than amitriptyline (resting block of approximately 90% vs. approximately 15%). This derivative also retains the attribute of amitriptyline in evoking high-degree use-dependent blockade during repetitive pulses. In vivo, duration to full recovery of nociception in the sciatic nerve model was 1,932 +/- 72 min for N-phenylethyl amitriptyline at 2.5 mm (n = 7) versus 72 +/- 3 min for lidocaine at 37 mm (n = 4; mean +/- SEM). However, there was evidence of neurotoxicity at 5 mm. CONCLUSION: N-phenylethyl amitriptyline appears to have a narrow therapeutic range but is much more potent than lidocaine, providing a block duration several times longer than any clinically used local anesthetic. Further work in animal models of neuropathic pain will assess the potential use of this drug.