Multiplex polymerase chain reaction.

The polymerase chain reaction (PCR) is a widely utilized assay for specifically amplifying small fragments of DNA. Multiplex PCR is the amplification of more than one DNA fragment per reaction and has many potential uses. When more than one primer set per reaction tube is utilized, the total number of tubes in any one experiment may be reduced, conserving expensive reagents and decreasing possible contamination. Multiplex PCR allows for an assay of the gene of interest and assures that the amplification process proceeds as expected with the use of a companion control genome primer set. Multiplex PCR is useful in assaying DNA extracted from samples of immunocompromised patients in which more than one infectious agent may be suspected such as simultaneous EBV and CMV detection. Multiplex PCR offers many advantages over single reaction PCR and has been found to be an useful adjunct in our laboratory.     

Rapid rise in plasma glucagon induced by acute cold exposure in man and rat

The effect of acute cold exposure on the concentration of glucagon in the blood was investigated in man and in intact and adrenalectomized rats.In man fasted overnight acute cold exposure, which caused a twofold increase in O₂-consumption resulted in a rapid rise in plasma glucagon. The levels of insulin and blood glucose remained unaltered, while the concentration of serum free fatty acids and -hydroxybutyrate increased.In fasted intact rats acute cold exposure lead to similar effects. A close parallelism between the rise in plasma glucagon and the concentration of hepatic cycloAMP was observed. Adrenalectomy did not impair the cold induced rise in plasma glucagon and hepatic cycloAMP.It is concluded that acute cold exposure caused a rapid rise in the concentration of plasma glucagon leading to an increase in the concentration of hepatic cycloAMP, thus enhancing the rate of hepatic gluconeogenesis and ketogenesis. As these alterations were similar in the absence of glucocorticoids and medulla-derived catecholamines, it is suggested that glucagon may play a role in the metabolic adaptation to acute cold exposure.     

Effect of dynamization on gap healing of diaphyseal fractures under external fixation

We asked whether dynamization of externally fixed diaphyseal fractures could improve bone healing in comparison to rigid fixation of fractures having similar remaining gap sizes. To answer this question we evaluated metatarsal osteotomies in 12 sheep. The osteotomy with a 0.6-mm gap was stabilized with a specially designed high bending and torsional stiffness external ring fixator. Osteotomies in six sheep were stabilized rigidly (axial movement < 0.06 mm) or dynamically (axial movement 0.15-0.34 mm). The cyclical axial interfragmentary movement was caused by the load-bearing of the operated limb. With increasing healing time, the initially allowed movement was decreased by callus formation around the osteotomy. The reduction in interfragmentary movement was measured and monitored by a linear variable displacement transducer at the external fixator and a telemetry system. After 9 weeks the sheep were sacrificed and the healed bones were investigated biomechanically and histomorphologically. Compared to the rigidly fixed osteotomies, the dynamized osteotomies showed significantly (P < 0.05) greater (+41%) callus formation and 45% greater tensile strength of the newly formed bone in the cortical osteotomy gap. Histological analysis indicated that the effect of dynamization occurred mainly after the 5th week. RELEVANCE: From these results we conclude that dynamic fixation of diaphyseal gaps is advantageous in comparison to stable external fixation.     

Prevalence of hypovitaminosis a in children of peripheral districts of Campinas São Paulo, Brazil

The prevalence of hypovitaminosis A among children of the peripheral districts of the city of Campinas, S o Paulo, Brazil, was estimated by determining serum retinol levels by High Performance Liquid Chromatography (HPLC) in a sample of 131 children aged between three and ten years, between April 1991 and February 1992. A prevalence of 17.6% and retinol concentrations in the range of 0.35 to 0.70 micromol/L were found (CI=11.1-24.1; 95%), indicating the existence of public health risk Ophthalmological examinations, however, failed to detect any cases of xerophthalmy. Additional characterization of the sample was obtained from 341 children. The per capita income of the average household was surprisingly high for low-income areas. According to FAO-WHO standards, food consumption was adequate only for protein (133.96%). Adequacy levels were low for energy (87.76%) and particularly for vitamin A (66.13%) and iron (42.14%). Height for-age and weight-for-height anthropometric indices revealed that many children were located below -1 standard deviation.     

Effects of specimen length on the monosegmental motion behavior of the lumbar spine

STUDY DESIGN: An in vitro biomechanical analysis of the segmental motion behavior of the same segments in polysegmental (five segments), bisegmental, and monosegmental specimens using sheep lumbosacral spines. OBJECTIVES: To investigate the effect of specimen length on monosegmental motion behavior. These data may be helpful in planning in vitro tests and in comparing results of studies using specimens of different lengths. SUMMARY OF BACKGROUND DATA: The length of spinal specimens used for in vitro stability tests varies greatly, depending on the purpose of the study. Some investigators prefer testing specimens with one adjacent segment on either end of the region of interest. Others favor specimens as short as possible. METHODS: In a first step, seven sheep spine specimens, L3-S1 (note that sheep spines normally have seven lumbar vertebrae), each were tested without preload in a spine-loading apparatus. Alternating sequences of pure lateral bending, flexion/extension, and axial rotation moments (+/-3.75 Nm) were applied continuously. The motion in each single segment was measured simultaneously. Then, these polysegmental specimens were cut into two bisegmental specimens, L3-L5 and L6-S1, and tested in the same way. Finally, another vertebra was removed to obtain two monosegmental specimens, L3-L4 and L7-S1, and to test them as described. RESULTS: In general, the range of motion at L3-L4 and L7-S1 was smaller when tested in polysegmental than in monosegmental specimens. In polysegmental specimens (five segments), the range of motion at L3-L4 and L7-S1 was approximately 80% (range, 70.6-92.5%) and in bisegmental specimens approximately 95% (range, 66.7-100%) of their range of motion measured in monosegmental specimens. Neutral zone and coupled motions showed the inverse behavior. Significant differences were found. However, they were not consistent with either the loading direction or with the specimen length. CONCLUSIONS: For comparison of results, the specimen length should be kept constant within one experiment. Segmental motion behavior of specimens with different lengths should be compared only qualitatively.     

Modulation of 5-fluorouracil with methotrexate and low-dose N-(phosphon-acetyl)-L-aspartate (PALA) is inactive in advanced pancreatic carcinoma

Purpose: To evaluate the effect of biochemical modulation by PALA and methotrexate on the therapeutic activity of 5-fluorouracil (5-FU) in patients with advanced pancreatic adenocarcinoma.Patients and methods: The treatment protocol consisted of phosphonacetyl-L-aspartate (PALA) 250 mg/m² i.v. 15-minute infusion followed by methotrexate 200 mg/m² i.v. 30-minute infusion on day 1 and 5-FU 600 mg/m² i.v. push on day 2. Folinic acid was given at 15 mg/m² p.o. every six hours for eight doses, starting 24 hours after methotrexate infusion. Cycles were repeated every two weeks.Results: Thirty patients with advanced chemotherapy-naive pancreatic cancer were included; 26 had measurable disease. Median age 56 years (27–72); median PS 1 (0–2). One PR (3.9%) was achieved; nine patients had stable disease. Median time to progression was 91 days. Median survival was 177 days and one year survival was 13.3% (4 of 30 patients). Treatment was well tolerated; diarrhea WHO grade 2 or 3 occurred in six patients; stomatitis WHO grade 2 and 3 in nine patients.Conclusions: Modulation of 5-FU by PALA and MTX given in this dose and schedule appears to be ineffective in patients with advanced pancreatic adenocarcinoma.     

Paclitaxel in combination with weekly 24-hour infusional 5-fluorouracil plus leucovorin in the second-line treatment of metastatic breast cancer: Results of a phase II study

Purpose: To evaluate the antitumor activity in terms of response rate (RR), time to progression (TTP) and survival of paclitaxel in combination with weekly 24-hour infusional 5-fluorouracil (5-FU)/leucovorin in pretreated metastatic breast cancer (MBC).Patients and methods: Fifty-four patients with bidimensionally measureable disease were included during phase II. Thirty-two had anthracycline resistant disease. Treatment consisted of 5-FU (24-hour i.v. infusion) 2.0 g/m², leucovorin (two-hour i.v. infusion prior to 5-FU) 500 mg/m², weekly for six weeks (day 1, 8, 15, 22, 29, 36) and paclitaxel (three-hour i.v. infusion) 175 mg/m² was administered additionally on days 1 and 22, q 50 days.Results: We observed complete remissions in 4% of patients (2 of 54), partial remissions in 55% (30 of 54), stable disease in 37% (20 of 54) and progressive disease in 4% (2 of 54). The overall RR was 59% (95% CI 48%–72%). The RR in 32 patients with anthracycline resistant disease was 59% (19 of 32). The median duration of response was 12 months (3–22), median TTP eight months (2–22) and median survival time 15 months (2–28). Neutropenia was common, but of CTC grade 2 or 3 in most patients. Nonhematologic toxicities mostly consisted of CTC grade 1 and 2 myalgia, diarrhea, mucosits, nausea and vomiting.Conclusions: Paclitaxel combined with weekly 24-hour infusional 5-FU/leucovorin is well tolerated in the second line treatment of MBC. High efficacy was documented even in the treatment of anthracycline resistant disease, which warrants further evaluation.     

Recovery and pharmacokinetic parameters of desflurane, sevoflurane, and isoflurane in patients undergoing urologic procedures.

STUDY OBJECTIVE: To compare the pharmacokinetics and the speed of recovery after inhalation anesthesia with desflurane, sevoflurane, and isoflurane in elective surgery. DESIGN: Prospective, randomized study. SETTING: University medical center. PATIENTS: 30 ASA physical status I and II adults presenting for elective surgery. INTERVENTIONS: Anesthesia was induced with etomidate and maintained with desflurane (n = 10), sevoflurane (n = 10), or isoflurane (n = 10) and nitrous oxide. The inhalation drugs were titrated until an adequate clinical depth of anesthesia was reached. At the end of anesthesia, the patients breathed oxygen via the endotracheal tube and after extubation via a face mask. MEASUREMENTS AND MAIN RESULTS: The groups were similar with respect to age, weight, duration of anesthesia, and mean arterial pressure. Mean end-tidal concentration (FA = FA0) at the end of anesthesia was 6.34 +/- 1.15% after desflurane, 1.85 +/- 0.42% after sevoflurane, and 1.10 +/- 0.24% after isoflurane. FA/FA0 decreased significantly faster with desflurane than with isoflurane, while there was little difference between desflurane and sevoflurane. As for the terminal half-life (t1/2), there were no differences among the groups (8.16 +/- 3.15 min after desflurane, 9.47 +/- 4.46 min after sevoflurane, and 10.0 +/- 5.57 min after isoflurane). The time until a command was followed for the first time was the same in all three groups (13.0 +/- 4.7 min after desflurane, 13.4 +/- 4.4 min after sevoflurane, and 13.6 +/- 3.4 min after isoflurane). There was no significant correlation between duration of anesthesia and the time until recovery. CONCLUSIONS: There are only minor differences with regard to the recovery phase in premedicated patients who receive clinically titrated inhalation anesthesia with desflurane, sevoflurane, or isoflurane.     

In vitro low-speed side collisions cause injury to the lower cervical spine but do not damage alar ligaments

Whether injuries to the alar ligaments could be responsible for complaints of patients having whiplash injury in the upper cervical spine is still controversially discussed. It is known that these ligaments protect the upper cervical spine against excessive lateral bending and axial rotation movements. The objective of the present in vitro study was therefore to examine whether the alar ligaments or any other structures of the cervical spine are damaged in side collisions. In a specially designed acceleration apparatus, six human osteoligamentous cervical spine specimens were subjected to incremental 90° side collisions from the right (1 g, 2 g, 3 g, etc.) until structural failure occurred. A damped pivot table accounted for the passive movements of the trunk during collision, and a dummy head (4.5 kg) ensured almost physiological loading of the specimens. For quantification of functional injuries, the three-dimensional flexibility of the specimens was tested in a spine tester before and after each acceleration. In all six specimens, structural failure always occurred in the lower cervical spine and always affected the facet joint capsules and the intervertebral discs. In four specimens, this damage occurred during the 2 g collision, while in the other two it occurred during the 3 g and 4 g collision, respectively. The flexibility mainly increased in the lower cervical spine (especially in lateral bending to both sides) and, to a minor extent, in axial rotation. In vitro low-speed side collisions caused functional and structural injury to discoligamentous structures of the lower cervical spine, but did not damage the alar ligaments. Since the effects of muscle forces were not taken into account, the present in vitro study reflects a worst-case scenario. Injury thresholds should therefore not be transferred to reality.     

Thoracolumbar fracture stabilization: comparative biomechanical evaluation of a new video-assisted implantable system

Minimally invasive techniques for spinal surgery are becoming more widespread as improved technologies are developed. Stabilization plays an important role in fracture treatment, but appropriate instrumentation systems for endoscopic circumstances are lacking. Therefore a new thoracoscopically implantable stabilization system for thoracolumbar fracture treatment was developed and its biomechanical in vitro properties were compared. In a biomechanical in vitro study, burst fracture stabilization was simulated and anterior short fixation devices were tested under load with pure moments to evaluate the biomechanical stabilizing characteristics of the new system in comparison with a currently available system. With interbody graft and fixation the new system demonstrated higher stabilizing effects in flexion/extension and lateral bending and restored axial stability beyond the intact spine, as well as having comparable or improved effects compared with the current system. Because of this biomechanical characterization a clinical trial is warranted; the usefulness of the new system has already been demonstrated in 45 patients in our department and more than 300 cases in a multicenter study which is currently under way.