A polyhydroxybutyrate biodegradable stent: preliminary experience in the rabbit

PURPOSE

The lifelong persistence of foreign bodies within the arteries may contribute to restenosis. Thus, biodegradable devices might decrease recurrence rates.

METHODS

Eleven polyhydroxybutyrate biodegradable stents and 13 tantalum stents were implanted into the iliac arteries of New Zealand white rabbits for up to 30 weeks. After killing the animals, the specimens were harvested, fixed in formalin, processed in paraffin, and stained.

RESULTS

Polyhydroxybutyrate instigated intense inflammatory and proliferative reactions with an increase in collagen (2.4- to 8-fold vs native segments), thrombosis and in-stent lumen narrowing (375.5-606.6 mm vs 655.6 +/- 268.8 mm in native segments). The elastic membranes were destroyed in all specimens. The tantalum stents increased the in-stent lumen progressively (769.7 +/- 366.6 mm vs 1309.9 +/- 695.3 mm), penetrated the external elastic membrane, and increased mural collagen content (6- to 8.6-fold vs native segments). Neither restenoses nor thromboses occurred.

CONCLUSIONS

In the rabbit iliac artery, polyhydroxybutyrate stents caused intensive inflammatory vascular reactions which ban them from clinical use.

Combination of microplate and miniplate for osteosynthesis of mandibular fractures: an experimental study

Because of the limited space available in the mandible, especially in the mental foramen and apical region, miniature osteosynthesis material is desirable. Recently, metal deposition in the direct neighbourhood of osteosynthesis plates made of titanium or even in peripheral organs have been reported in the literature with increasing frequency. The size and amount of osteosynthesis material used should therefore be kept to a minimum. In an experimental study on 60 models, we examined load-carrying stability and in a second series, torsional strength of two-piece plastic models connected by either a single miniplate, two miniplates, or a titanium microplate plus a miniplate. In our test arrangement, the average loading capacity of the combination miniplate/miniplate was 470 N: that of the combination microplate/miniplate was only 267 N. The test group with the single miniplate had an average loading capacity of only 225 N. Masticatory loads on the plates exceeding 200 N occur only 3 months after osteosynthesis. At that time the fracture has largely consolidated. The torsional strength of the microplate/miniplate combination was similar to that of the miniplate/miniplate combination (1,000 Nmm resulting in a width of the gap measuring 0.8 mm and 0.5 mm, respectively). The single miniplate was considerably less stable (0.8 mm gap width as early as with 300 Nmm). According to Champy, rotational forces in the anterior region of the mandible amount to approximately 1,000 Nmm and need to be withstood by the osteosynthesis material. Our results suggest that treatment of fractures in the interforaminal region with a combination of microplate and miniplate will be stable enough for early mobilization.

The cannabinoid agonist WIN 55,212-2 reduces sensorimotor gating and recognition memory in rats

Cannabinoids can disrupt short-term memory in humans and animals and induce learning deficits and other cognitive impairments. In the present study we examined the role of a full cannabinoid agonist in short-term memory, sensorimotor gating, and the acquisition and expression of an operant learning paradigm in rats. We tested the effects of the synthetic cannabinoid WIN 55,212-2 (0.6 and 1.2 mg/kg) on short-term memory in social and object recognition tests, on prepulse inhibition (PPI) of startle, as well as on lever pressing for palatable food. Injections of 0.6 and 1.2 mg/kg WIN 55,212-2 impaired recognition memory and PPI in a dose-dependent manner, but had no effect on lever-pressing acquisition or expression, or on food preference. The PPI deficit was reversed by the administration of 0.1 mg/kg haloperidol. These data suggest that the synthetic cannabinoid WIN 55,212-2 does not lead to a general impairment of learning in an appetitive instrumental task, but significantly affects short-term memory and sensorimotor integration. The impairment in recognition and PPI might be due to deficits in attention-based short-term information processing.

Clinical prognostic factors for patients with recurrent head and neck cancer: implications for randomized trials

The purpose of our study was to determine the clinical prognostic factors for the duration of the overall survival from recurrence (OSR) in patients with recurrent head and neck squamous-cell carcinoma. We performed a retrospective analysis on 496 patients treated between 1982 and 1993 at the Antoine Lacassagne Center. The significant favorable prognostic factors for the OSR were: initial T(1-2) (p = 0.008), no initial nodal involvement (p = 0.002), no initial chemotherapy exposure (p = 0.002), induction chemotherapy response (p = 0.001), duration of disease-free interval (DFI; p = 0.0001), performance status (PS) 0-1 (p = 0.004) and local-regional recurrence (p = 0.001). In the multivariate analysis, the apparent nonsignificance of all factors apart from the DFI suggested that relevant prognostic factors could be embedded in the DFI. Multivariate analysis was performed after excluding the DFI. The results indicated that local-regional recurrence, PS 0-1 and no initial chemotherapy exposure remained significant favorable prognostic factors for the OSR. The advantages of taking into account such prognostic factors are to eliminate the patient selection bias and to ensure a fairer comparative evaluation of new or already existing agents in recurrent head and neck cancer.

Intolerance to neuroleptics and susceptibility for malignant hyperthermia in a patient with proximal myotonic myopathy (PROMM) and schizophrenia

We report a patient with proximal myotonic myopathy who was treated with neuroleptics because of exacerbating schizophrenia. Under therapy with fluanxol, the patient developed muscle stiffness and oculogyric cramps. Treatment with both amisulpride and olanzapine lead to markedly elevated serum creatine kinase levels. An in-vitro contracture test was positive for halothane. Thus, in patients with all kinds of multisystemic myotonic myopathies, a susceptibility for malignant hyperthermia and intolerance towards neuroleptics should be taken into account.

Drosophila Stardust is a partner of Crumbs in the control of epithelial cell polarity

The polarized architecture of epithelial cells depends on the highly stereotypic distribution of cellular junctions and other membrane-associated protein complexes. In epithelial cells of the Drosophila embryo, three distinct domains subdivide the lateral plasma membrane. The most apical one comprises the subapical complex (SAC). It is followed by the zonula adherens (ZA) and, further basally, by the septate junction. A core component of the SAC is the transmembrane protein Crumbs, the cytoplasmic domain of which recruits the PDZ-protein Discs Lost into the complex. Cells lacking crumbs or the functionally related gene stardust fail to organize a continuous ZA and to maintain cell polarity. Here we show that stardust provides an essential component of the SAC. Stardust proteins colocalize with Crumbs and bind to the carboxy-terminal amino acids of its cytoplasmic tail. We introduce two different Stardust proteins here: one MAGUK protein, characterized by a PDZ domain, an SH3 domain and a guanylate kinase domain; and a second isoform comprising only the guanylate kinase domain. The Stardust proteins represent versatile candidates as structural and possibly regulatory constituents of the SAC, a crucial element in the control of epithelial cell polarity.

Immediate versus delayed outpatient flexible cystoscopy: final report of a randomized study

PURPOSE

To evaluate discomfort experienced by men undergoing an immediate versus delayed outpatient flexible cystoscopy after topical local anesthesia.

PATIENTS AND METHODS

Two hundred eighty eight consecutive men with superficial bladder tumors were randomized to undergo immediate or delayed surveillance flexible cystoscopy after intraurethral instillation of lidocaine jelly. The patients recorded their level of pain experienced during cystoscopy on a 4-point pain scale and on a 10-point visual analogue (VAS) scale.

RESULTS

Of the 288 patients, 145 underwent immediate cystoscopy and 143 had a delayed cystoscopy. The mean pain score on a scale of 1 (no pain) to 4 (severe pain) was 1.6 after immediate cystoscopy compared with 1.5 after delayed cystoscopy (p=7). The mean VAS score on a scale of 1 (no pain) to 10 (most painful) was 1.8 after immediate cystoscopy versus 1.7 after delayed cystoscopy (p=5).

CONCLUSION

There was no difference in pain perception among men undergoing an immediate or a delayed outpatient flexible cystoscopy using the same local anesthetic.

Influence of transplantation regimen on prognostic significance of high-level minimal residual disease before allogeneic stem cell transplantation in children with ALL

High MRD levels before transplantation in children receiving T cell-depleted unrelated grafts for relapsed ALL were associated with a 100% relapse risk. We report on two children with relapsed ALL who underwent non T cell-depleted BMT from unrelated donors. Despite a high residual tumor load pre- transplant and the occurrence of only aGVHD grade I, they are still in second complete remission 2.7 and 5.2 years after transplantation, respectively. Thus, we propose that the transplant regimens influence the prognostic significance of high MRD levels pre-BMT.

Result of two randomized trials comparing nolatrexed (Thymitaq) versus methotrexate in patients with recurrent head and neck cancer

We report on two randomized trials performed in the USA and Europe, which compared methotrexate and nolatrexed as treatment for patients with recurrent head and neck cancer. Eligibility criteria included: histologically confirmed squamous-cell carcinoma, measurable disease, adequate hematological, renal and hepatic functions, failure of a first-line chemotherapy, and informed consent. Methotrexate 40 mg/m2 was weekly given by short infusion, and nolatrexed 725 mg/m2 per day was administered as a five-day continuous infusion, every three weeks. A total of 139 patients (63 in the USA. 76 in Europe) were randomized based on a ratio of 2/1: 93 and 46 received nolatrexed and methotrexate, respectively. Patient characteristics included 115 males and 24 females; median age 60 years. In the nolatrexed arm, the following grade 3-4 toxicities occurred: neutropenia (29.9%) with 3.1% of febrile neutropenia, mucositis (33.3%), and vomiting (10.3%). In the MTX arm, the grade 3-4 toxicities were neutropenia (7.1%) and mucositis (6.9%). There was no difference in activity between the nolatrexed and the methotrexate treatment: 3.3% and 10.8% of objective responses, 1.9 versus 1.5 months of disease-free progression and 3.5 versus 3.7 months of overall survival, respectively. Nolatrexed has demonstrated a similar activity to methotrexate.

Carbohydrate-deficient transferrin is elevated in catabolic female patients

Serum carbohydrate-deficient transferrin (CDT) is currently widely used as a biochemical marker of alcohol misuse. However, various recent studies have questioned the diagnostic value of this parameter and reported low levels of both specificity and sensitivity, especially in women. Thus, we sought to identify sub-groups of female individuals in which CDT is elevated independently of alcohol consumption. Significantly increased CDT levels were found in catabolic disease states due to psychiatric disorders distinct from alcoholism. None of those patients reported frequent alcohol consumption. CDT therefore appears also to be increased by metabolic processes distinct from alcohol degradation. Possible biochemical mechanisms of this phenomenon are discussed. As a consequence of these findings, the measurement of CDT alone is not suitable to screen for alcohol misuse in catabolic subjects.

The type 2 iodothyronine deiodinase is essential for adaptive thermogenesis in brown adipose tissue

Type 2 iodothyronine deiodinase (D2) is a selenoenzyme, the product of the recently cloned cAMP-dependent Dio2 gene, which increases 10- to 50-fold during cold stress only in brown adipose tissue (BAT). Here we report that despite a normal plasma 3,5,3'-triiodothyronine (T3) concentration, cold-exposed mice with targeted disruption of the Dio2 gene (Dio2(-/-)) become hypothermic due to impaired BAT thermogenesis and survive by compensatory shivering with consequent acute weight loss. This occurs despite normal basal mitochondrial uncoupling protein 1 (UCP1) concentration. In Dio2(-/-) brown adipocytes, the acute norepinephrine-, CL316,243-, or forskolin-induced increases in lipolysis, UCP1 mRNA, and O(2) consumption are all reduced due to impaired cAMP generation. These hypothyroid-like abnormalities are completely reversed by a single injection of T3 14 hours earlier. Recent studies suggest that UCP1 is primarily dependent on thyroid hormone receptor beta (TR beta) while the normal sympathetic response of brown adipocytes requires TR alpha. Intracellularly generated T3 may be required to saturate the TR alpha, which has an approximately fourfold lower T3-binding affinity than does TR beta. Thus, D2 is an essential component in the thyroid-sympathetic synergism required for thermal homeostasis in small mammals.

Cytogenetic analysis of human zygotes displaying three pronuclei and one polar body after intracytoplasmic sperm injection

BACKGROUND

Digynic zygotes with three pronuclei and one polar body obtained after intracytoplasmic sperm injection (ICSI) were studied cytogenetically to elucidate the frequency and origin of chromosomal abnormalities at the earliest stage of conception.

METHODS

Uncleaved, single-cell zygotes were incubated with podophyllotoxin and vinblastine and fixed by a gradual fixation air drying method. The chromosomes were stained with Giemsa.

RESULTS

Twenty-two (50%) out of 44 informative zygotes revealed cytogenetic alterations, including aneuploidy (six cells, 13.6%), structural aberrations (10 cells, 22.7%) and combinations of numerical and structural abnormalities (two cells, 4.5%). In one case (2.3%), double aneuploidy or an effect of chromosomal translocation could not be distinguished and one zygote (2.3%) turned out tetraploid due to injection of a diploid spermatozoon. Two zygotes (4.5%) showed an irregular chromatid segregation between the two maternal complements. In completely analysable cells, the sex chromosome ratio XXX:XXY was 17:15.

CONCLUSIONS

Digynic ICSI zygotes carry a high rate of cytogenetic abnormalities that obviously have been transmitted by the participating oocytes and spermatozoa. We also confirmed the previously reported, possibly ICSI-induced irregular oocyte chromatid segregation. The results suggest that aneuploidy in the oocytes must have been caused by predivision instead of non-disjunction.

Factor V(LEIDEN) and cardiopulmonary bypass: investigation of haemostatic parameters and the effect of aprotinin using an ex vivo model

It has been suggested that aprotinin results in significantly increased risk for perioperative thrombotic complications in patients with Factor V(LEIDEN) (F5L) due to its ability to competitively inhibit activated protein C (APC) function in vitro. No clinical studies have been performed to assess the effect of aprotinin on APC function of F5L in vivo. We developed an ex vivo model to mimic the effects of cardiopulmonary bypass with the exclusion of the patient in order to assess APC function. Blood from normal (n = 2) and F5L heterozygous donors (n = 2) was treated with aprotinin or placebo (saline). The blood was heparinized, added to the prime and circulated at 2 l/min through a modified cardiopulmonary bypass circuit. After 60 min of circulation, the heparin was neutralized with protamine sulfate. Blood samples, drawn at specific time points, were analysed for APC ratio. Results showed a decrease in APC ratio for both F5L and normal bloods with the addition of aprotinin (18% and 40%, respectively). APC ratios also decreased with the commencement of extracorporeal circulation for all bloods, resulting in an APC ratio of 1.35 in normal placebo-treated blood and 0.67 in F5L placebo-treated blood. The combined effect of aprotinin and extracorporeal circulation resulted in APC ratios of 0.90 for normal blood and 0.63 for F5L blood, corresponding to a severe dysfunction of APC intraoperatively (reference range 1.9-4.0). The data from this model predict an increased risk of perioperative thrombosis due to inhibition of APC function in cardiac surgical patients heterozygous for the F5L mutation. Aprotinin further compounds the severity of APC dysfunction, though the effect is more severe in normal blood. The ex vivo model employed was an effective tool for the investigation of the haemostatic effect of aprotinin. This model may be exploited for other applications such as the investigation of novel or emerging haemostatic agents prior to clinical trial.

The relationship of epidermal growth factor receptor levels to the prognosis of unresectable pharyngeal cancer patients treated by chemo-radiotherapy

The aim of this study was to analyse prognostic factors for time to treatment failure (TTF) and overall survival (OS) in patients with unresectable cancer of the pharynx. A twice daily (b.i.d.) radiotherapy with concomitant cisplatin-5-fluorouracil chemotherapy was administered to 77 consecutive patients (68 males, 9 females; median age: 56 years). The studied factors were: age, gender, tumour differentiation, tumour volume, initial hemoglobin level, karnofsky index (KI), primary tumour location, T, N, epidermal growth factor receptor (EGFR) level in the tumour (fmol/mg protein). KI and EGFR level were significant predictors in a multivariate analysis for TTF (P=0.004 and P=0.0001) and OS (P=0.004 and P=0.0001). In order to select subgroups with different outcomes, a stratification of patients was performed based on the EGFR value: patients with tumour EGFR levels <35 fmol/mg protein, between 35 and 275 fmol/mg protein and >275 fmol/mg protein had 95%, 51% and 16% 3 year OS rates, respectively (log rank test; P=0.0001). Interestingly, for patients exhibiting a complete response (CR) after concomitant b.i.d. chemo-radiotherapy, patients with EGFR levels <35 fmol/mg protein were all alive at 3 years; in contrast, there was only 70 and 13% 3 year survival rates for patients with EGFR tumour levels between 35 and 275 fmol/mg protein and above 275 fmol/mg protein, respectively. EGFR determination appears to be a powerful prognostic parameter in unresectable pharyngeal cancer patients treated by concomitant chemo-radiotherapy.

Magnetic resonance imaging and miniarthroscopy of metacarpophalangeal joints: sensitive detection of morphologic changes in rheumatoid arthritis

OBJECTIVE

To evaluate and characterize magnetic resonance imaging (MRI) findings in the metacarpophalangeal (MCP) joints of rheumatoid arthritis (RA) patients macroscopically, using miniarthroscopy (MA; needle arthroscopy).

METHODS

The second MCP joint of the dominant hand of 22 RA patients (13 with various RA activities/stages; 9 with early RA [< or = 1.5 years' duration]) was examined by MRI followed by MA. Findings were evaluated by standardized semiquantitative measures of synovial and bony pathologic changes of the MCP joint, and were compared with the clinical and conventional radiologic findings.

RESULTS

Erosions and pre-erosions were detected in 17 of 22 patients by MRI; 2 of the other 5 patients (all early RA) displayed bony changes on MA. All 10 joints with pre-erosions on MRI (grade I bony alterations on MRI) exhibited significant cartilaginous and bony pathology on MA. Synovial membrane pathology was detected in all but 1 patient by MRI and in all patients by MA, although findings of plain radiography were normal in 6 of the 22 patients and another 9 patients had a Larsen score of 1. Semiquantitative analysis of synovial findings of MRI revealed gadolinium diethylenetriaminepentaacetic acid enhancement as a significant marker of macroscopically varied synovial vascularity and hyperemia, both of which strongly correlated with clinical activity (as measured by the Disease Activity Score). The extent of synovitis/synovial proliferation shown by MA and MRI were significantly correlated with each other, but not with any other activity or damage parameter analyzed.

CONCLUSION

In RA, both MRI and MA findings support early detection and staging of synovial changes. Ongoing longitudinal studies are aimed at evaluating the value of synovial proliferation as visualized by both methods.

[MR-morphological changes of the metacarpophalangeal joints in patients with rheumatoid arthritis: Comparison of early and chronical stages]

MR-morphological changes of the metacarpophalangeal joints in patients with rheumatoid arthritis: Comparison of early and chronical stages.

PURPOSE

Evaluation of MRI findings in the metacarpophalangeal (MCP) joints in patients with early (eRA) and chronical rheumatoid arthritis (cRA).

MATERIAL AND METHODS

In 22 RA patients (9 with disease duration </= 1.5 years = eRA) the dominant hands were examined by MRI in coronal T(2) weighted turbo-spin-echo (TSE). T(1) weighted spin-echo (SE) sequences before and after injection of Gd-DTPA and fat-suppressed short tau inversion recovery (STIR) sequences, followed by miniarthroscopy (MA) of the MCP II joint after an interval of 24 hours. MRI and MA findings were assessed using standardised semiquantitative items of synovial and bony pathologies and a statistical comparison between eRA and cRA patients was performed.

RESULTS

In MRI synovial proliferation was detected in 13/13 cRA and 8/9 eRA patients. It was statistically not significant; the degree of synovial proliferation was however lower in the eRA group. All eRA patients with synovial changes showed enhancement after administration of contrast medium, a marker which correlated with the clinical activity. In 2/13 cRA patients no uptake of contrast medium was evident. Bony erosions and strongly narrowing joint space correlated with disease duration and were documented significantly rarer in the eRA patients (1/9, 2/9) than in the cRA patients (9/13, 10/13).

CONCLUSION

In RA patients, MRI of the metacarpophalangeal joints can detect specific pathological changes which are observed significantly more often in either early or chronic stages and which are associated with disease activity and duration.

[Bone density and 25-OH vitamin D serum level in patients with systemic lupus erythematosus]

OBJECTIVE

To clarify the influence of vitamin D metabolism on bone mineral density (BMD) or bone metabolism in patients with systemic lupus erythematosus (SLE).

METHODS

57 consecutive patients in our department (mean age 33.9 years, 44 female, 13 male) were studied. BMD was measured with dual-X-ray absorptiometry at the lumbar spine and femoral neck. Biochemical investigation of bone metabolism included measurement of vitamin D metabolites, intact parathyroid hormone (PTH), serum osteocalcin und urinary pyridinoline-crosslink excretion.

RESULTS

25 patients had 25-OH cholecalciferol serum values below the normal range after adjustment for seasonal changes; 9 patients were severely vitamin D depleted with 25-OH vitamin D serum values below 5 ng/ml. Low 25-OH-vitamin D was significantly associated with high disease activity. Mean 1.25 (OH)2-vitamin D, PTH, osteocalcin and crosslink excretion were in the normal range. Thirty-six patients had normal BMD; 5 patients had osteoporosis according to WHO diagnosis criteria. No correlation of biochemical parameters of bone metabolism with BMD was found.

CONCLUSION

Severe vitamin D depletion was common in this group of patients with SLE even after adjustment for seasonal variations, especially in patients with high disease activity. Therefore, D-hypovitaminosis should be included in the differential diagnosis in patients with SLE presenting with low bone mass.

Differential infectivity of two Pseudomonas species and the immune response in the milkweed bug, Oncopeltus fasciatus (Insecta: Hemiptera)

Pseudomonas aeruginosa and Pseudomonas putida show a profound differential infectivity after inoculation in Oncopeltus fasciatus. Whereas P. putida has no significant impact on nymphs, P. aeruginosa kills all experimental animals within 48 h. Both Pseudomonas species, however, induce the same four hemolymph peptides in O. fasciatus. Also injection of saline solution and injury induced these peptides. In general peptide induction was stronger in nymphs than in adult males. A significantly higher number of nymphs survived a challenge with P. aeruginosa when an immunization with P. putida preceded. The antibacterial properties of the hemolymph were demonstrated in inhibition experiments with P. putida. Two of the four inducible peptides (peptides 1 and 4) could be partially sequenced after Edman degradation and were compared with known antibacterial peptides. Peptide 1, of 15 kDa, showed 47.1% identity with the glycine-rich hemiptericin of Pyrrhocoris apterus. Peptide 4, of 2 kDa, had a 77.8% identity with the proline-rich pyrrhocoricin of P. apterus and a 76.9% identity with metalnikowin 1 of Palomena prasina. Peptides 2 and 3 are also small, with molecular weights of 8 and 5 kDa.