Quantitative gas chromatographic determination of perfluorooctanoic acid as the benzyl ester in plasma and urine

A method is presented for the quantitative determination of perfluorooctanoic acid in plasma and urine. The acid was esterified by an extractive alkylation method using tetrabutylammonium ion as the counter ion and benzyl bromide as the alkylating agent. Quantitation was made by gas chromatography. Typical values for precision obtained in the determination of 5 g/ml of perfluorooctanoic acid in plasma and urine were 3.3% (S.D. N=6) and 3.0% (S.D. N=6), respectively. The limit of detection was 1 ng (2.4 pmol).     

The role of lipid antigen presentation, cytokine balance, and major histocompatibility complex in a novel murine model of adoptive transfer of insulitis

After adoptive transfer of insulitis from nonobese diabetic (NOD) mice, leukocytes accumulate in the pancreas of SCID/SCID and NOD/SCID mice. These cells express classical antigen-presenting molecules and costimulators of T-cell activation and adhesion molecules involved in homing. The aim of the present study was to study the expression of cytokines involved in regulation of the T(H1)/T(H2) balance by these cells, the role of lipid antigen presentation in the local immune system activation in the pancreas during onset of insulitis, and the role of major histocompatibility complex in this process. Splenocytes from NOD and BALB/c mice were injected intraperitoneally to SCID/SCID and NOD/SCID mice. Sections from the pancreata of these injected mice were stained for cytokines (tumor necrosis factor alpha [TNF-alpha], interferon gamma [IFN-gamma], CD1d, interleukin 2 [IL-2], IL-4, IL-6, IL-10, and IL-12). Some SCID/SCID and NOD/SCID mice injected with NOD splenocytes developed a severe disease. IL-10 was expressed in almost all the animals: in exocrine pancreas, large groups of infiltrating lymphocytes, endothelia of blood vessels, pancreatic islets, and interstitial tissue. CD1d was found in most of the mice: in the endothelia of collecting ducts and blood vessels of the pancreas, lymphocytic infiltrates, interstitial tissue, septae, islets, and a pancreatic lymph node. TNF-alpha was expressed notably more often in the pancreata of NOD/SCID than SCID/SCID mice. It was found between pancreatic lobules, in the epithelia of collecting ducts, endothelia of blood vessels, islets, capillaries, infiltrates, and septae. IL-6 was expressed more in the SCID/SCID than in the NOD/SCID mice. It was seen in infiltrates, walls of blood vessels, around islets, and in connective tissue. IFN-gamma was found only in the pancreata of SCID/SCID and NOD/SCID mice injected with NOD splenocytes. The expression of IL-2 and IL-12 was very scarce. IL-4 was not expressed at all. The present study clearly shows that antigen presentation has a role in the development of autoimmune diseases after adoptive transfer of splenocytes from diseased mice to intact ones and that IL-10 may have a central role in the control of the disease process.     

Cementless total hip arthroplasty in patients with severely dysplastic hips and a previous Schanz osteotomy of the femur: Techniques, pitfalls, and long-term outcome

Background and purpose Historically, a Schanz osteotomy of the femur has been used to reduce limp in patients with severely dysplastic hips. In such hips, total hip arthroplasty is a technically demanding operation. We report the long-term results of cementless total hip arthroplasty in a group of patients who had all undergone a Schanz osteotomy earlier.Patients and methods From 1988 through 1995, 68 total hip replacements were performed in 59 consecutive patients previously treated with a Schanz osteotomy. With the cup placed at the level of the true acetabulum, a shortening osteotomy of the proximal part of the femur and distal advancement of the greater trochanter were performed in 56 hips. At a mean of 13 (9–18) years postoperatively, we evaluated these patients clinically and radiographically.Results The mean Harris hip score had increased from 51 points preoperatively to 93 points. Trendelenburg sign was negative and there was good or slightly reduced abduction strength in 23 of 25 hips that had not been revised. There were 12 perioperative complications. Only 1 cementless press-fit porous-coated cup was revised for aseptic loosening. However, the 12-year survival rate of these cups was only 64%, as 18 cups underwent revision for excessive wear of the polyethylene liner and/or osteolysis. 6 CDH femoral components had to be revised due to technical errors.Interpretation Our results suggest that cementless total hip arthroplasty combined with a shortening osteotomy of the femur and distal advancement of the greater trochanter can be recommended for most patients with a previous Schanz osteotomy of the femur. Because of the high incidence of liner wear and osteolysÍs of modular cementless cups in this series, nowadays we use hard-on-hard articulations in these patients.     

Modulating apoptosis as a target for effective therapy

Alterations in cell proliferation and cell death are essential determinants in the pathogenesis and progression of several diseases such as cancer, neurodegenerative disorders or autoimmune diseases among others. Complex networks of regulatory factors determine whether cells proliferate or die. Recent progress in understanding the molecular changes offer the possibility of specifically targeting molecules and pathways to achieve more effective and rational therapies. Drugs that target molecules involved in apoptosis are used as treatment against several diseases. Candidates such as TNF death receptor family, caspase inhibitors, antagonists of the p53-MDM2 interaction, NF-kappaB and PI3K pathways and Bcl-2 family members have been targeted as cancer cell killing agents. Moreover, apoptosis of tumor cells can also be achieved by targeting the inhibitor of apoptosis proteins, IAPs, in addition to the classical antiproliferative approach. Disruption of STAT activation and interferon beta therapy have been used as a treatment to prevent the progression of some autoimmune diseases. In models of Parkinson's, Alzheimer's and amyotrophic lateral sclerosis, blocking of Par-4 expression or function, as well as caspase activation, prevents neuronal cell death. Finally, it has been shown that gene therapy may be an encouraging approach for treatment of neurodegenerative disorders.     

Repeatability of a computerized muscle tonometer and the effect of tissue thickness on the estimation of muscle tone

The aim of the present study was to assess the intrarater repeatability of the computerized muscle tonometer (CMT), which is a computer-driven device designed to measure and register the tone of connective tissues. The second aim was to evaluate the effect of muscle thickness on results and repeatability as well as sensitivity, which was done by comparison to a mechanical hand-held tonometer (HHT). Participants were ten healthy male volunteers. The thickness of soft tissues was measured with ultrasound and the CMT was used to evaluate the muscle tone of thigh muscles 10, 15 and 20 cm and the HHT 15 cm above the patella on both sides. Great individual variability in muscle thickness and tone was noted. Muscle thickness increased proximally on the thigh and thus the mean distance travelled by the indenter of the CMT also increased from distal to proximal from 22 to 26 mm and the work done increased from 116 to 161 mJ. Intraclass correlation (ICC) for travel and work ranged from 0.85 to 0.92 and 0.94 to 0.98, respectively. Repeatability coefficients increased somewhat at proximal measurement sites. ICC for the HHT was 0.78. The CMT also showed a considerably higher range of results, indicating greater resolution power. Despite the twofold pressure used with the HHT the distance measured was on average 60% lower compared to the CMT. In conclusion, the repeatability of the CMT was found to be good. Muscle thickness greatly affected the results and should therefore be taken into consideration when measuring muscle tone. Work was a more reliable unit of measurement than travel, which has been commonly used to describe muscle tone.     

A novel and efficient regimen for producing chronic relapsing experimental autoimmune encephalomyelitis (CR-EAE) in SJL mice.

We report that SJL mice developed chronic relapsing experimental autoimmune encephalomyelitis (CR-EAE) when injected with a mixture of mouse spinal cord homogenate (MSCH), killed mycobacteria tuberculosis (M. tb), and mycobacteria butyricum (M. b) in PBS 2 months before a conventional acute experimental autoimmune encephalomyelitis (EAE) induction injection. The altered progression of the disease involved an accelerated but less severe acute attack and development of a chronic course with relapsing-remitting episodes. Histological examination revealed inflammatory cell infiltration and demyelination in the brain. The dose of neuroantigen as well as the anatomical sites of injections were found to be crucial for the development of the disease.     

Phoneme quality and quantity are processed independently in the human brain

In speech perception, the primary cue of phoneme recognition is typically the spectral quality of the speech sound. In some languages, however, even speech-sound duration may serve as a phonological cue. This distinction is called quantity. We used a component of event-related potential, the mismatch negativity, to determine whether phoneme quality and quantity are processed independently in the human brain. We found that the mismatch negativity responses to phoneme quality and quantity changes are additive, indicating that the analysis of these features is independent of each other. This suggests that phoneme quality and quantity are processed by separate neural processes that, in a system model, may be regarded as different levels in the phonological system.     

Use of hydroxylapatite/ polymer-composite in facial bone augmentation. An experimental study

On purpose to achieve better and more controlled alveolar ridge augmentation, biodegradable polyglycolide (PGA) curved implants with porous, particulate hydroxylapatite (HA) were developed to be used in an experimental augmentation in sheep mandible. Prior to surgery curved PGA implants were loaded with particulate HA with help of a rather fast degrading adhesive, polyglycolide/polylactide (PGA/PLA) copolymer. This augmentation device was inserted into the ridge using a slight modification of the tunnelling technique. Macroscopically, a dehiscence with loss of HA particles was observed in 3 of the 16 augmentations. Bone ingrowth was seen in a noticeable degree in one sheep at 24 weeks. Instead, foreign body-type cells were shown at the interface of mandibular bone and hydroxylapatite deposit, as well as abundant connective tissue reaction inside HA deposits. The results of the study give rise to concern about bony integration in the presence of biodegradable polyglycolide substances in HA augmentation. The findings call in question even their use as a carrier for bone forming agents in combination with HA.     

Modifying effects of epidural analgesia or general anesthesia on the stress hormone response to laparoscopy for in vitro fertilization

Modifying effects of epidural analgesia and general anesthesia on stress hormone release was studied during laparoscopy for in vitro fertilization (IVF). In 24 women follicle development was stimulated by clomiphene and gonadotropin treatment, and oocytes were collected by laparoscopy under epidural analgesia in 11 women and under fentanyl-supplemented nitrous oxide-oxygen anesthesia in 13. The plasma levels of immunoreactive -endorphin (ir -E), cortisol, and prolactin (PRL) did not change under epidural analgesia per se, but after the start of laparoscopy, increased release of all these stress hormones was observed. General anesthesia per se increased the release of PRL, whereas the release of cortisol and ir -E decreased, probably due to the effects of fentanyl and thiopentone. During the stress attributed to laparoscopy, significantly more ir -E and cortisol was released under epidural than under general anesthesia, whereas the release of PRL was more significant under general anesthesia. These results show that neither mode of anesthesia prevented the stress response to laparoscopy. In the subsequent midluteal phase, the mean plasma level of progesterone and the mean progesterone-estradiol ratio were significantly greater in the epidural than in the general anesthesia group, suggesting that the mode of anesthesia may have an effect on the luteal phase. The significance of this difference on the conception rate remained unsolved, however.