Complication rate with prosthodontic reconstructions on ITI and IMZ dental implants. Internationales Team für Implantologie

The aim of this study was to compare the complication rate of two implant systems with different prosthodontic concepts: rigid conical or resilient support of the suprastructure. In 66 patients, 138 ITI implants were inserted whereas 31 patients received a total of 50 IMZ implants. Over an average observation period of 3.5 years (range from 0.5 to 8 years), not only was implant survival recorded, but also prosthodontic complications such as screw loosening, fractures of screws, inserts (intramobile elements, intramobile connectors) and abutments, as well as fractures of metal framework and veneers. With the ITI system, 28.8% of all devices placed exhibited such problems during the observation period. With the IMZ system, this rate was significantly higher (P < 0.05), in that 77.4% of all reconstructions required a repair at some point. The various complications were divided into those occurrences which affected only the suprastructure, i.e., failures of frameworks, veneers, bar devices or other retentive elements, and those which involved implant components per se, such as screws and abutment components. In the first category, adverse effects occurred more frequently with ITI-supported prostheses (15.1%) versus IMZ suprastructures (6.4%). Regarding complications with implant components, the rate with IMZ components was considerably higher (71%) compared with ITI (13.5%). This was mainly due to the presence of intramobile elements (IME) and connectors (IMC) in the IMZ system. In this retrospective study, precise fitting, non-resilient abutment components leading to rigid connections of suprastructures, proved to be clinically more successful than resilient anchoring components.

Differential expression of chemokine receptors and chemotactic responsiveness of type 1 T helper cells (Th1s) and Th2s

T helper cells type 1 (Th1s) that produce interferon-gamma predominantly mediate cellular immune responses and are involved in the development of chronic inflammatory conditions, whereas Th2s which produce large amounts of IL-4 and IL-5 upregulate IgE production and are prominent in the pathogenesis of allergic diseases. The precise factors determining whether Th1- or Th2-mediated immune responses preferentially occur at a peripheral site of antigen exposure are largely unknown. Chemokines, a superfamily of polypeptide mediators, are a key component of the leukocyte recruitment process. Here we report that among four CXC (CXCR1-4) and five CC (CCR1-5) chemokine receptors analyzed, CXCR3 and CCR5 are preferentially expressed in human Th1s. In contrast, Th2s preferentially express CCR4 and, to a lesser extent, CCR3. In agreement with the differential chemokine receptor expression, Th1s and Th2s selectively migrate in response to the corresponding chemokines. The differential expression of chemokine receptors may dictate, to a large extent, the migration and tissue homing of Th1s and Th2s. It may also determine different susceptibility of Th1s and Th2s to human immunodeficiency virus strains using different fusion coreceptors.

Inhibition of IL-12 production by 1,25-dihydroxyvitamin D3. Involvement of NF-kappaB downregulation in transcriptional repression of the p40 gene

Interleukin 12 (IL-12), produced by myelomonocytic cells, plays a pivotal role in the development of T helper 1 (Th1) cells, which are involved in the pathogenesis of chronic inflammatory autoimmune disorders. 1,25-Dihydroxyvitamin D3 [1,25(OH)2D3] inhibits IL-12 production by activated macrophages and dendritic cells, thus providing a novel interpretation to its immunosuppressive properties. 1,25(OH)2D3 significantly inhibits mRNA expression for both IL-12 p35 and p40 subunits acting at the transcriptional level. The effect of 1,25(OH)2D3 on p40 promoter activation was analyzed by cotransfecting monocytic RAW264.7 cells with p40 promoter/reporter constructs and expression vectors for vitamin D3 receptor (VDR) and/or retinoid X receptor (RXRalpha). We observed transcriptional repression of the p40 gene by 1,25(OH)2D3, which required coexpression of VDR with RXR and an intact VDR DNA-binding domain. The repressive effect maps to a region in the p40 promoter containing a binding site for NF-kappaB (p40-kappaB). Deletion of the p40-kappaB site abrogates part of the inhibitory effect on the p40 promoter, confirming the functional relevance of this site. Activation of monocytic THP-1 cells in the presence of 1,25(OH)2D3 results in reduced binding to the p40-kappaB site. Thus, 1,25(OH)2D3 may negatively regulate IL-12 production by downregulation of NF-kappaB activation and binding to the p40-kappaB sequence.

Bacteriologic response to oral cephalosporins: are established susceptibility breakpoints appropriate in the case of acute otitis media?

Bacteriologic response to cefuroxime axetil and cefaclor administered for 10 days was evaluated in acute otitis media (AOM) in patients aged 6-36 months. Middle ear fluid culture was obtained by tympanocentesis before treatment, on day 4 or 5 after initiation of treatment, and if clinical relapse occurred before day 17. Bacteriologic failure was observed in 32% of patients receiving cefaclor versus 15% of patients receiving cefuroxime axetil (P = .009). Failure rates increased with increasing MIC: For Streptococcus pneumoniae, 0.5 microg/mL (established as cutoff value for cefuroxime by the National Committee for Clinical Laboratory Standards [NCCLS]) discriminated between success and failure. For Haemophilus influenzae, high failure rates were observed for cefaclor, even with low MICs (< or = 1.0 microg/mL), and with both drugs they tended to increase with increasing MIC, even for values below the cutoff suggested by the NCCLS (8.0 and 4.0 microg/mL for cefaclor and cefuroxime, respectively). Thus, for AOM caused by H. influenzae, lower susceptibility cutoff levels for MICs should be established.

Cardiovascular complications of malignant carcinoid disease

Carcinoid tumors are endocrinologic malignancies often associated with a characteristic syndrome-the malignant carcinoid syndrome. Cardiovascular manifestations of this rare illness result from unique pathophysiologic characteristics, are associated with poor prognosis, and are difficult to treat medically. The hemodynamic consequences of this disease present unique management problems perioperatively. New pharmacologic and surgical therapies for malignant carcinoids have improved quality of life for patients to the extent that carcinoid heart disease now has more impact on morbidity and mortality rates. Cardiologists may be called on to diagnose and treat this rare cardiac disease. We review, for consulting cardiologists, the pathophysiologic characteristics, cardiovascular manifestations, and management of this disease.

Beta2-agonists prevent Th1 development by selective inhibition of interleukin 12

Interleukin 12 (IL-12) plays a central role in the immune system by skewing the immune response towards T helper 1 (Th1) type responses which are characterized by high interferon-gamma and low IL-4 production. In this report we present evidence that beta2-agonists inhibit IL-12 production by both human monocytes in response to lipopolysaccharide (LPS) and dendritic cells stimulated via CD40. Inhibition of IL-12 production is selective, as other cytokines produced by monocytes are unaffected. IL-12 inhibition is dependent on beta2-adrenoceptor stimulation and correlates with increased levels of intracellular cAMP. In conjunction with their ability to suppress IL-12 production, when beta2-agonists are added at priming of neonatal T lymphocytes, they inhibit the development of Th1-type cells, while promoting T helper 2 (Th2) cell differentiation. Further, the in vivo administration of a therapeutic dose of salbutamol results in the selective inhibition of IL-12 production by whole blood lymphocytes stimulated in vitro with LPS. These findings provide new insight into the immunological consequences of the clinical use of beta2-agonists and may suggest new approaches for the treatment of Th1-mediated diseases.

Colour stability of visible light-curing hybrid composites

The colour stability of six visible light-curing fine hybrid composites was evaluated after 24 and 120 hours of irradiation using a xenon lamp. Discoloration of four shades of each material (A1, A2, A3.5 and B2- Vita shade guide) was measured using a reflection spectrophotometer with the CIE-L*a*b* system. The discoloration after 24 hours of irradiation had values of between 0.7 and 3.8 DE*, and was therefore, with the exception of Z 100 (colours A1 and B2), clinically acceptable. The results showed that the differences in colour of all shades of Pekafill NF and Tetric tested were significantly less than those of the other products. All samples, with the exception of Pekafill NF (A3.5 and B2), showed increased discoloration to values of 3.7 to 7.8 DE* after 120 hours of exposure to UV light. In general, all the composites tended to become more yellow (b*), darker (L*) and slightly greener (a*).

A rapid method for semiquantitative analysis of the human V beta-repertoire using TaqManR PCR

Analysis of the V beta-repertoire of antigen-reactive T cell populations can be approached using either flow-cytometry or PCR-based techniques. While the former method requires a complete set of V beta-specific monoclonal antibodies (mAbs) and large cell numbers for analysis, the latter is both time-consuming and labour-intensive. To circumvent the drawbacks of both these methods we have employed the recently developed technique of TaqManR PCR to analyse the V beta-usage of human T cell populations. TaqManR PCR is based on the 5'-->3' nuclease activity of Taq polymerase. During PCR amplification an internal oligonucleotide probe, that is labelled with a fluorescent reporter and a quencher dye, is cleaved by Taq polymerase. After cleavage, quenching of the reporter dye is lost and reporter fluorescence can be detected with a fluorescence plate reader. Using one C beta-specific fluorogenic probe and a panel of V beta-specific primers, we show that fluorescence-detected amplification of TCR beta cDNA is V beta-specific and linear within a 2-3-log range of template concentration. The sensitivity of TaqManR PCR is comparable to conventional detection of PCR-products by agarose gel staining, while processing time is reduced. Furthermore, superantigen-induced skewing of the V beta-repertoire of human T cells is readily detected with this method. Thus TaqManR PCR is a reliable and fast method for semiquantitative analysis of the V beta-repertoire of human T cell populations.

A relationship between apoptosis and flow during programmed capillary regression is revealed by vital analysis

Previous analyses of developmentally programmed capillary regression suggested two distinct causes of vascular endothelial cell (VEC) death. The first appeared to be macrophage-dependent (Lang, R. A. and Bishop, M. J. (1993) Cell 74, 453–462) while the second was proposed to result from cessation of blood flow (Lang, R. A., Lustig, M., Francois, F., Sellinger, M. and Plesken, H. (1994). Development 120, 3395–3403). Combined, these analyses suggested a model in which initial, macrophage-mediated endothelial cell apoptosis blocked blood flow within a capillary segment and, as a consequence, caused apoptosis of all remaining cells in the affected segment. In the current study, we have tested this model using a new method that combines vital and histological analyses as a means of determining the fate of whole capillary segments and individual cells in vivo. This technique revealed that one of the first events in regression was the apoptosis of a single VEC in otherwise normal, flowing capillary segments (initiating apoptosis). These isolated, dying VECs projected into and restricted the capillary lumen, imposing either a temporary or permanent block to blood flow. Following cessation of flow, synchronous apoptosis of VECs occurred (secondary apoptosis). In addition, a quantitative analysis revealed a reciprocal relationship between plasma flow and VEC apoptosis. These observations are consistent with a model for capillary regression in which macrophages induce apoptosis in a limited number of VECs and, as a consequence of a block to blood flow, also cause apoptosis in those remaining.

Impaired bacteriologic response to oral cephalosporins in acute otitis media caused by pneumococci with intermediate resistance to penicillin

BACKGROUND

Penicillin resistance of Streptococcus pneumoniae, one of the most common causes of acute otitis media, has recently increased and is now highly prevalent in many regions. However, its contribution to clinical failure still must be proved. Because the role of antibiotics in acute otitis media is to eradicate the pathogens present in the middle ear fluid, we conducted a randomized controlled study to determine bacterial eradication of pathogens in acute otitis media by two commonly used oral cephalosporins, cefuroxime axetil (30 mg/kg/day) and cefaclor (40 mg/kg/day).

METHODS

Patients 6 to 36 months old with pneumococcal otitis media seen in the Pediatrics Emergency Room were studied. An initial middle ear fluid culture was obtained at enrollment, and a second culture was obtained on Day 4 or 5 during treatment. Follow-up was done also on Days 10, 17 and 42 after initiation of treatment. In cases of clinical relapse a third culture was obtained.

RESULTS

In total 78 patients were enrolled, 41 in the cefuroxime axetil group and 37 in the cefaclor group. Of the 78 S. pneumoniae isolates 31 (40%) were intermediately penicillin-resistant (MIC 0.125 to 1.0 microgram/ml). Of the 47 patients with penicillin-susceptible organisms 3 (6%) had bacteriologic failure vs. 4 of 19 (21%) and 7 of 11 (64%) of those with MIC of 0.125 to 0.25 microgram/ml and 0.38 to 1.0 microgram/ml, respectively (P < 0.001). For intermediately resistant pneumococci, in 7 of 12 (58%) of those receiving cefaclor the isolate was not eradicated vs. only 4 of 19 (21%) of those receiving cefuroxime axetil (P = 0.084). MIC to the administered cephalosporin of > 0.5 microgram/ml was associated with bacteriologic failure. Clinical failure was observed in 9 of 14 (64%) patients with bacteriologic failure vs. 10 of 52 (19%) patients with bacteriologic eradication (P = 0.003).

CONCLUSION

Intermediately penicillin-resistant S. pneumoniae is associated with an impaired bacteriologic and clinical response of acute otitis media to cefaclor and cefuroxime axetil. This effect was more pronounced with cefaclor than with cefuroxime axetil.

Childhood brucellosis in Israel

BACKGROUND

Brucellosis has become a major medical problem in Israel particularly in the Muslim Arab population.

METHODS

Eighty-eight children with acute brucellosis are described. Sixty-seven were studied retrospectively during 1987 through 1988, and 21 children were studied prospectively during 1989 through 1992. Epidemiologic, clinical and laboratory features were evaluated, and the outcome of 4 antimicrobial regimens are compared.

RESULTS

Although the clinical manifestation varied, the classical triad of fever (91%), arthralgia or arthritis (83%) and hepato- and/or splenomegaly (63%) characterized most patients. Sixty-one percent of the children had elevated liver enzymes. Brucella melitensis was isolated from 61% of blood cultures. The relapse rate in patients who were treated with monotherapy (doxycycline) was 43% compared with 14% with regimens of combined therapy with rifampin and doxycycline, streptomycin and doxycycline or rifampin and trimethoprim-sulfamethoxazole (P < 0.049). Eleven children (33%) who were treated for 3 weeks had relapse compared with 1 patient (3.5%) treated for 4 weeks or longer. The total relapse or reinfection rate was 20%. All patients with relapse recovered after a second course of antibiotic therapy. During the 2 years of follow-up one child progressed to chronic osteomyelitis.

CONCLUSIONS

Combination therapy and extending treatment for 4 weeks or longer gave significantly better results than monotherapy or shorter courses of therapy and resulted in fewer relapses.

Fine needle aspiration biopsy in patients with diffusely enlarged spleens

OBJECTIVE

To evaluate the diagnostic value and potential risk of fine needle aspiration biopsy (FNAB) of the spleen in patients with diffuse splenomegaly due to an undetermined cause.

STUDY DESIGN

Retrospective evaluation of the medical records and cytologic material from 58 patients on whom FNAB was performed between 1967 and 1993.

RESULTS

Sixty-five FNABs were performed on 58 patients. Lymphoproliferative diseases were found in six; in four additional cases, metastatic adenocarcinoma, sarcoidosis, Candida albicans and enterococcal infection were demonstrated. The remaining 55 biopsies either showed normal splenic tissue or were nondiagnostic. No complications were recorded.

CONCLUSION

Splenic FNAB may be useful in some patients with diffuse splenomegaly. The diagnostic yield is rather low. The procedure, however, is simple, safe and well tolerated.

Long-term renoprotective effect of angiotensin-converting enzyme inhibition in non-insulin-dependent diabetes mellitus. A 7-year follow-up study

BACKGROUND

Diabetic nephropathy is the leading cause of end-stage renal disease in developed countries. Duration of diabetes, blood pressure values, and metabolic status are the major determinants of the course of nephropathy, and microalbuminuria is the hallmark of its onset. Angiotensin-converting enzyme inhibitors offer important renoprotection to hypertensive and normotensive patients with insulin-dependent diabetes mellitus and non-insulin-dependent diabetes mellitus. Our study extends previous observations for duration and the effect of angiotensin-converting enzyme inhibition on advanced nephropathy.

METHODS

Double-blinded (first phase) and open (second phase) randomized controlled study of 7 years. Ninety-four normotensive patients with non-insulin-dependent diabetes mellitus whose serum creatinine levels were lower than 123.76 mumol/L (1.4 mg/dL) and who had microalbuminuria (30 to 300 mg/24 h) were given enalapril maleate, 10 mg/d, or placebo, for 5 years. For 2 more years they were followed up openly and given the choice to receive enalapril or no treatment.

RESULTS

In the enalapril-treated patients, albuminuria remained stable for 7 years. An increase from (mean +/- SD) 123 +/- 58 to 310 +/- 167 mg/24 h occurred in the untreated group after 5 years, and a further increase to (mean +/- SD) 393 +/- 223 mg/24 h occurred after 7 years. Reciprocal creatinine was unchanged in treated patients for 7 years; in the untreated patients, the mean decline was 13% at 5 years and 16% at 7 years. Treatment with enalapril resulted in an absolute risk reduction of 42% for nephropathy to develop during 7 years (95% confidence interval, 15% to 69%; P < .001, Student's t test). Glycosylated hemoglobin and body mass index remained unchanged.

CONCLUSIONS

Angiotensin-converting enzyme inhibition offers long-term protection against the development of nephropathy in normotensive patients with noninsulin-dependent diabetes mellitus who have microalbuminuria, and it stabilizes renal function in previously untreated patients with impaired renal function. Discontinuation of treatment results in renewed progression of nephropathy.

Studies for a genotoxic potential of some endogenous and exogenous sex steroids. II. Communication: examination for the induction of cytogenetic damage using the chromosomal aberration assay on human lymphocytes in vitro and the mouse bone marrow micronucleus test in vivo

The cytogenetic potential of 10 sex steroids (cyproterone acetate, drospirenone, gestodene, cyclodiol, cyclotriol, ethinylestradiol, atamestane, lilopristone, onapristone and propylmesterolone) with various medical indications was determined using the chromosomal aberration test in human lymphocytes in vitro and the mouse bone marrow micronucleus test in vivo. Nine of these sex steroids (gestodene was omitted) were investigated in the human lymphocyte assay and found to be negative with respect to the induction of chromosomal aberrations either with or without metabolic activation. In all assays the highest concentration evaluated was either clearly cytotoxic or, in case of noncytotoxicity, resulted in visible precipitates in the culture medium. Evaluation of the data from the mouse bone marrow micronucleus test indicated that the seven steroids (cyproterone acetate, drospirenone, gestodene, ethinylestradiol, atamestane, onapristone and propylmesterolone) investigated failed to induce enhanced frequencies of micronucleated polychromatic erythrocytes in male and female mice. The steroids were tested up to dose levels which induced signs of toxicity in the experimental animals or, in the case of non toxic compounds, the animals were treated up to the maximum recommended dose of 2 g/kg body weight. Evaluation of all data indicates that the investigated estrogens, progestins and other sex steroids had no genotoxic potential detectable with the chromosomal aberration assay on cultured human lymphocytes or the mouse bone marrow micronucleus test.