Puncture forces of solid organ surfaces

Background: In this experimental study, we measured the force needed to puncture the liver (low elastin) and the spleen (high elastin). The surface displacement preceding puncture was also measured. These data are relevant to an understanding of surgical technique and are essential to the development of electronic surgical simulators. Methods: Controlled puncture experiments were performed on intact organs harvested from pigs and sheep, as well as on their surface capsules following removal and suspension at zero strain and at three increasing levels of prestrain. The biomechanical data were compared with information obtained from histological studies. Results: The spleen has a higher puncture force than the liver and suffers greater displacement before puncture (p < 0.05). Prestrain decreases displacement before puncture (p < 0.05) but has no effect on puncture force. Conclusion: The higher puncture force and displacement of spleen, as compared with liver, is probably due to its higher elastin content. Received: 24 November 1999/Accepted: 24 February 2000/Online publication: 9 August 2000     

Ketamine anesthesia with or without diazepam premedication for bone marrow punctures in children with acute lymphoblastic leukemia

Ketamine is a drug widely used for analgesia and sedation of children for diagnostic and therapeutic procedures. The authors investigated in a randomized controlled clinical trial if diazepam premedication would have a beneficial effect on side effects related to ketamine anesthesia for bone marrow punctures (BMPs) in children with acute lymphoblastic leukemia (ALL). Sixteen children 4 years or older at the time of BMP were eligible. The first 2 BMPs after complete remission was obtained were studied. BMPs were performed under ketamine anesthesia (1.0-1.5 mg/kg iv), as usual. Patients were randomized to receive 1 h before the first BMP blinded, either diazepam or placebo orally and before the second BMP the other way round. Blood pressure, heart rate, and oxygen saturation were monitored, and patients were observed for signs of anxiety, pain, and other side effects. The patients were interviewed after each BMP and asked for their preference 1 week after the second BMP. Ketamine anesthesia appeared as safe and effective after diazepam premedication as after placebo premedication. From the interviews and questionnaires, it was clear that half of the children preferred diazepam premedication because of less awful dreaming and more gradual falling asleep and waking up. Diazepam premedication may be useful for selected children with ALL receiving ketamine anesthesia for BMPs.     

Submental intubation for cancrum oris: a case report

Cancrum oris (Noma) is a devastating gangrenous disease that leads to severe tissue destruction in the face. We describe the anesthetic management of a 12-year-old girl with cancrum oris sequelae in a Rural Secondary level Hospital in Central India (Padhar Hospital). She presented with a large defect in her upper lip on the left side that extended into the columella and the floor of the left nostril. She was scheduled to undergo reconstructive surgery and the surgeons planned to use an Abbé flap based on the lower lip. For this, access to both the mouth and the nose was required. We considered a tracheostomy but decided to attempt the submental route for orotracheal intubation. Following intravenous induction the patient's trachea was intubated with a cuffed oral tracheal tube. This was passed through the submental incision and then reconnected. The surgery proceeded uneventfully and the patient was extubated before transfer. She made a satisfactory recovery and the submental scar healed without complication or scarring. We describe briefly the features of cancrum oris and review the technique of submental intubation (described in adults with midfacial trauma). The use of submental intubation in children and for cancrum oris sequelae has not been previously reported.     

Single-dose oral ciprofloxacin compared with single-dose intravenous cefazolin for prophylaxis in inguinal hernia repair: a controlled randomized clinical study

The aim of this study was to compare the efficacy of single-dose intravenous cefazolin prophylaxis with single-dose oral ciprofloxacin prophylaxis in patients undergoing tension-free inguinal hernia repair with polypropylene mesh. In a prospective and randomized setting, 395 patients received either a single dose of 500 mg of ciprofloxacin orally, 1--2h before the operation, or a single dose of 1g cefazolin intravenously on induction of anaesthesia. The primary outcome was to determine the wound infection rate within one year. The overall infection among the entire study population was 2% (eight of 395) including 2% (four of 199) of those receiving intravenous cefazolin and 2% (four of 196) of those treated with oral ciprofloxacin. There was no statistically significant difference between groups (P=0.59). All the infections were superficial incisional surgical site infections, and none progressed to a deep infection. Escherichia coli was the most commonly isolated bacterium. None of the infected patients developed recurrence of hernia. The rate of recurrence was 1.3% (five of 395) at one year including 2% (four of 199) of those receiving cefazolin and 0.5% (one of 196) of those receiving ciprofloxacin. Oral ciprofloxacin prophylaxis was found to be an attractive option with its wide antibacterial spectrum, low cost and ease of administration in patients undergoing tension-free inguinal hernia repair with polypropylene mesh.     

Methadone disposition following oral versus parenteral dose administration in rats during chronic treatment

A single radiolabeled dose of dl-methadone was administered by the oral, subcutaneous and intravenous routes to rats that had been chronically treated with dl-methadone. Radiolabeled compound (methadone and metabolites) was found in all organs at all time points studied after 30 minutes to 24 hours. Thin-layer chromatographic analysis showed that approximately 30–40 per cent of this compound is unchanged methadone at the 1-hour time point in the liver of rats receiving an oral or intravenous dose and in the brain of rats receiving an oral dose. Ninety-four per cent of compounds in brain is unchanged methadone at 1 hour after intravenous dose administration. Twenty-four hours following dose administration, levels of methadone within any organ are found to be similar irrespective of route of administration. The liver was found to contain the largest amounts of methadone in all animals studied with whole blood, lungs, and kidneys also containing large total amounts of methadone and metabolites. The liver and adrenals contained the highest concentrations of radiolabeled compounds.     

Effect of granulocyte-macrophage colony-stimulating factor on post-weaning multisystemic wasting syndrome in porcine circovirus type-2-transfected piglets

Post-weaning multisystemic wasting syndrome (PMWS) is a complex disease syndrome in swine, affecting nursery and fattening pigs. Although ongoing evidence suggests that porcine circovirus type-2 (PCV2) is the causal agent of PMWS, the host immune system appears to have a crucial role in the PMWS pathogenesis of PCV2-affected pigs. Owing to difficulties in producing a biologically pure form of PCV2 devoid of the other viral agents commonly present in swine tissues, we decided to use a tandem-cloned PCV2 DNA providing highly pure grade reagent in order to monitor the virulence of PCV2 alone or with an immunostimulating co-factor, granulocyte-macrophage colony-stimulating factor (GM-CSF). A single intramuscular injection of tandem-cloned PCV2 DNA into 5-week-old piglets produced plasmid to viral genome progeny and infectious particles as early as 8 days post-injection in all the organs tested (the lung, the tonsil and the inguinal, mesenteric, bronchial and upper-right axial lymph nodes). The initial plasmid load was not detected with the help of primers designed to specifically detect the acceptor plasmid, thus confirming the replication of the viral genome. Despite the presence of a high level of PCV2 genome copies in the lymphoid organs--the tonsil and the lung--and the presence of infectious particles, no detectable clinical manifestations or pathological lesions were observed in the transfected pigs over the period of observation, regardless of whether they had been co-injected with plasmid containing GM-CSF DNA or had received plasmid containing PCV2 DNA alone. GM-CSF encoding DNA injection had no significant effect on viral replication or on the production of viral particles and appearance of the disease.     

Dialogues on complex analgesic strategies for difficult pain syndromes

Although the use of oral analgesics for the control of cancer pain has been demonstrated to be successful in most patients, some patients will fail to respond to pharmacological therapy or will suffer unacceptable adverse effects. Experience is accumulating that when adverse effects prevail with oral opioid administration, the analgesic response may be improved by changing the drug and/or the route of administration. Switching to an alternative opioid may further improve the balance between analgesia and adverse effects Despite optimal systemic opioid treatment, in some complicated circumstances it is necessary to find different solutions, including the neuraxial administration of multiple drugs with different characteristics, which are difficult to manage. Three case reports illustrate how complex could be the analgesic approach using multiple analgesic regimens and different routes of administration to effectively manage complex pain syndromes commonly defined as unresponsive.     

Sedation in children undergoing CT scan or MRI: effect of time-course and tolerance of rectal chloral hydrate

The aim of this paper was to describe the time-course of the sedative effect of rectal chloral hydrate (75 mg/kg) in children undergoing CT scan or MRI. Twenty children (2.13 +/- 1.43 years old) were administered 75 mg/kg chloral hydrate rectally (chloralhydrat-rectiole rectal formulation, Dr Mann-Pharma Lab, Berlin, Germany), before a CT scan or an NMR imaging. Sedation was measured at specific times using a sedation score of 1-6. Patients were continuously monitored for respiratory and heart rate, systolic and diastolic blood pressures, and oxygen saturation. About 82.35 and 94.11% of the patients had a score of sedation > or = 3 within 15 and 30 min, respectively. The mean time to effective sedation (score > or = 3) was of 0.30 +/- 0.14 h (median time, 0.25 h). The mean duration of effective sedation (score > or = 3) was 1.29 +/- 1.05 h (median duration, 0.75 h). A total of 93.1% of the X-ray sections were obtained without artifact and sedation was considered by radiologists to be efficient for 83.3% of the procedures. This sedation procedure appeared efficient and safe during ambulatory CT scan and NMR imaging. The long-term effect of chloral hydrate, however, remains to be evaluated.     

Pattern of Salmonella excretion in amphibians and reptiles in a vivarium

During a period of about three years the faeces of five species of amphibians (35 individuals) and of 23 species of reptiles (103 individuals) living in one vivarium with terrariums imitating different types of ecosystems were examined for salmonellae. From 54 out of 376 faecal samples Salmonella spp. was isolated (= 14%). Twenty-one different Salmonella strains were found. Salmonellae could be isolated about twice as often from animals kept under arid or mesic conditions than from animals living in humid or aquatic environments although this was not statistically significant. Statistically significant for the rate of Salmonella excretion was the animals' diet and the class the animals are belonging to. Animals feeding on mice (p = 0.04) and reptiles in general (p = 0.04) were more commonly excreting Salmonella. Duration of stay was also a significant factor (p = 0.0005), whereby the relative risk for Salmonella excretion increased with the factor 2.91 per year during the investigation period. Salmonella strains were not necessarily transferred among animals living in the same terrarium or among the inhabitants of different terrariums. The pattern of Salmonella excretion was generally fragmentary. The outsides as well as the insides of the walls of the terrariums were also tested for salmonellae several times, but salmonellae have never been isolated.     

Relation between choice of ethanol concentration and response rates under progressive- and fixed-ratio schedules: studies with rhesus monkeys

Rationale A fundamental problem in the study of drugs as reinforcers is the evaluation of a drug's relative reinforcing effects and changes in such effects. Relative reinforcing effects can be measured by determining the preference for one drug dose relative to another drug dose. However, in IV drug self-administration studies technical limitations make direct comparisons between drug doses difficult. An alternative procedure is to measure the relative persistence of behavior across increases in schedule size.Objective To develop a more rapid method to measure the relative persistence of behavior. Instead of increasing the schedule size across sessions, schedule size was increased within sessions by use of a progressive-ratio schedule (PR).Methods Male rhesus monkeys orally self-administered ethanol during daily 3-h sessions. At each concentration responding was measured with fixed-ratio (FR) 8 schedules to obtain baseline values. Subsequently behavior was studied with a PR schedule. Relative persistence of behavior was calculated by dividing the mean response rate under the PR schedule by the mean response rate under the FR8 schedules. To compare these findings with results of choice between concentrations, monkeys were given concurrent access to pairs of ethanol concentrations.Results The relative persistence of behavior increased with increases in drug concentration. When two concentrations were concurrently available, the higher concentration maintained higher response rates.Conclusions The relative persistence of behavior can be efficiently measured by dividing the response rate under the PR schedule by the response rate under the FR schedule. Measures of relative persistence corresponded well with measures of choice and show that relative reinforcing effects increase as dose increases.