Current Biotechnological Approaches to the Prevention of Restenosis

No systemic pharmacological treatment has been convincingly shown to reduce the incidence of restenosis after angioplasty in patients. The lack of success of many pharmaceutical agents in reducing restenosis rates post-angioplasty and following stent implantation, as documented in dozens of clinical trials, has encouraged the development of new biotechnological approaches to the treatment of restenosis. Gene therapy and other agents, including antibodies, fusion toxins and ribozymes, have the potential to prevent some of the sequelae after arterial injury, particularly cell proliferation. Mechanical methods of preventing restenosis, for example sophisticated local drug delivery strategies and biodegradable stents using new materials, in combination with novel therapeutic agents or radiation, may also be of use.     

Remote unaffiliated presurgical psychosocial evaluations: a qualitative assessment of the attitudes of ASMBS members

BackgroundA psychosocial evaluation is an important component of the preoperative assessment process for people seeking metabolic and bariatric surgery (MBS), and is required for accreditation of MBS programs. Recently, independent companies without affiliations with MBS programs have been marketing remotely administered, unaffiliated psychosocial evaluations for MBS (RUS), and American Society for Metabolic and Bariatric Surgery (ASMBS) members have raised concerns about these evaluations.ObjectivesTo explore ASMBS members’ beliefs about RUS.SettingOnline survey.MethodsWe developed a survey to evaluate ASMBS members’ opinions, experiences, and/or concerns about in-person and RUS psychosocial evaluations for MBS.ResultsIn total, 635 ASMBS members responded to the online survey and 156 responded to an open-ended question on RUS. Responses were coded based on a manual developed for this study, yielding themes of concerns about the quality of RUS, lack of ongoing relationships in RUS, and conditions under which/reasons why RUS evaluations could be acceptable.ConclusionRespondents expressed both interest in and concerns about RUS in pre-MBS psychosocial evaluations. Use of RUS has the potential to improve access to MBS by providing a convenient and efficient means of completing the psychosocial evaluation. Conversely, respondents expressed concerns about the background and training of RUS providers, the quality of the reports, and the limited relationships between the RUS provider and both the MBS patient and the MBS team. We discuss the clinical and research implications of response themes, particularly for patients in rural areas or those who have other barriers to care.     

Involvement of nitric oxide synthase in the physiology and pathophysiology of facial nerve function and dysfunction

To date few reports have discussed the presence and function of nitric oxide (NO) in structures of the facial nerve. We performed nicotinamide adenine dinucleotide phosphate (NADPH-d)-diaphorase-histochemistry and immunohistochemistry on the intratemporal portion of the facial nerve, including the geniculate ganglion, of guinea pigs using specific antibodies to the three known isoforms of NO synthase and soluble guanylyl-cyclase (sGC). Normal facial nerves were compared to those treated intratympanically with bacterial lipopolysaccharides (LPS) and tumor necrosis factor-α (TNF-α). Both constitutive NOS isoforms and sGC could be detected in the bipolar ganglion cells of normal animals, while the inducible isoform (iNOS or NOS II) was not found. Endothelial NOS (NOS III) and sGC were present in blood vessels and were predominantly found in the perineurial sheath and less in the endoneurium. sGC could be detected in all fibers in a cross section of the facial nerve. LPS and TNF treatment led to the detection of iNOS in the perikaryia of the geniculate ganglion and the perineural sheath. These findings imply that NO may be involved in neurotransmission at least in the visceroafferent system. NO regulates vascular tone of nutrient blood vessels in the perineural sheath and endoneurium. The presence of sGC indicates that NO acts via its second messenger cGMP. NOS II expression may be a contributing factor to facial nerve palsy via two different mechanisms: NOS II-generated NO may lead to an overstimulation of the visceroefferent nerve fibers and motor fibers of the facial nerve. Dysregulation in facial nerve blood vessels could lead to edema and elevated pressure on the nerve within its osseous canal. Received: 13 April 1999 / Accepted: 12 August 1999     

Value of German Hospital Diagnosis Statistics in epidemiology-- an analysis with subarachnoid hemorrhage as an example

Due to the Hospital Statistics Regulations of the 10th April 1990, the German Hospital Diagnosis Statistics were introduced in 1993 with the intention to serve as a database of health care decisions. This purpose requires a high-quality collection of epidemiologically relevant data. From 1993 to 1996 we analysed the datasets obtainable for subarachnoid haemorrhage which is coded with ICD 430. A subset concerning the data of 1996 and the Saarland region was compared to the data of the Saarland medical school at Homburg/Saar. Cases treated in the neurosurgical department were critically reviewed. About 20% of the cases coded with ICD 430 showed no subarachnoid haemorrhage. On the other hand, again about 20% of subarachnoid haemorrhage cases were not coded with ICD 430. The statistics comprise duplicates due to transfers between hospitals. The calculation of incidence is not possible because new bleeding cases cannot be outlined. In the present form the German Hospital Diagnosis Statistics are not suitable as a reliable base of health care decisions. This is partly caused by the inadequacy of the ICD-classification but, also, by the criteria for collecting data. We propose several modifications which can improve data quality in order to meet the intended requirements.     

How frequent is glomerulonephritis in diabetes mellitus type II?

A high frequency of glomerulonephritis (GN) in diabetics, or coexistence of GN with diabetic glomerulosclerosis, has been reported by previous authors, but the true prevalence of GN in diabetics remains to be established. In the Department of Pathology, Heidelberg, from 1.1.1987 to 31.12.1989 we examined all consecutive patients (89 male, 121 female, median age 74 years; 47-98) who came to autopsy with the diagnosis of "diabetes mellitus" to assess this issue in an unbiased sample. Five patients had known type I diabetes, the others type II diabetes or diabetes of unknown classification. In 61/159 patients, proteinuria had been present (no information in 51 patients) and in 99/169 patients renal failure, i.e. serum creatinine above 1.4 mg/dl (no information in 41 patients). Paraffin-embedded kidney specimens from the upper pole of the left kidney were examined by immunohistochemistry (PAP technique; rabbit antihuman IgG; IgM; IgAab). 166/210 of the patients had glomerulosclerosis by light microscopy (129 diffuse, 37 nodular GS). Concomitant glomerulonephritis, i.e. typical mesangial IgA (and IgG) deposits, with mesangial enlargement by light microscopy were detected in only one case. Membranous GN was not found. These findings must be interpreted against the observation of mesangial immune deposits in 6 of 250 consecutive non-diabetic patients who had come to autopsy [Waldherr et al. 1989]. The findings show that an excessive prevalence of undiagnosed glomerulonephritis in our cohort of elderly type II diabetics was not to be found.     

Divalent Cations Modulate the Inhibitory Substrate Properties of Murine Glia-derived J1-160 and J1-180 Extracellular Matrix Glycoproteins for Neuronal Adhesion

J1-160 and J1-180 are developmentally late appearing J1 extracellular matrix glycoproteins derived from oligodendrocytes. They prevent adhesion of neurons (but not of astrocytes or fibroblasts) when offered as a substrate in mixture with laminin (Pesheva et al., J. Cell Biol., 109, 1765 - 1778, 1989). In the present study we have examined the influence of divalent cations on the inhibitory substrate properties of J1-160/180 glycoproteins towards adhesion of neurons. By metal chelate affinity chromatography, we show that J1-180, but not J1-160, binds Ca2+, while both J1 components are capable of binding Zn2+ and other divalent metal ions. Divalent cation binding was observed by gel filtration, aggregation assays with coated latex beads and electron microscopic examination to elicit aggregation of the molecules. Divalent cation binding also affects their non-permissive substrate properties towards neurons from early postnatal mouse cerebellum. Without divalent cations, J1-160 and J1-180 are inhibitory for substrate adhesion of neurons independently of the adhesive substrate present (laminin or poly-l-lysine). This effect is neutralized when J1-180 is preincubated with Ca2+ or Zn2+ prior to coating as substrate. In contrast, preincubation with Ca2+ ions does not affect the inhibitory substrate properties of J1-160 under these conditions. These observations show that J1-160/180 molecules may undergo self-aggregation in a divalent cation-dependent mechanism, which correlates with the neutralization of their inhibitory effect on neuronal adhesion. The aggregation state of the molecules may thus influence the process of myelination by a homophilic binding mechanism and determine the effectiveness of neurite extension during central nervous system development and under traumatic conditions in the adult.     

Interaction of phenylbutazone with racemic phenprocoumon and its enantiomers in rats

The interaction of phenylbutazone with the enantiomers and racemic [ ³ H]phenprocoumon was studied in male inbred Wistar-Lewis rats following a single i.v. dose of the three forms of phenprocoumon and chronic oral treatment with phenylbutazone (average plasma concentration of about 60 g/ml). Phenylbutazone augmented the anticoagulant effect of R(+), S(–), and R, S (±) phenprocoumon to a similar extent. The free fraction of drug in the plasma of the enantiomers and racemic phenprocoumon increased in the presence of phenylbutazone. However, the rate of elimination of total drug from plasma and liver and the distribution between liver and plasma of all three forms of phenprocoumon remained nearly unaffected by phenylbutazone. Thus there is no evidence for a stereoselective drug interaction between phenprocoumon and phenyl-butazone. For racemic [ ³ H]phenprocoumon it was possible to follow the kinetics of free drug in plasma and liver along with the time course of anticoagulant activity. In these studies, free drug concentrations in plasma and liver increased during treatment with phenylbutazone, but the elimination rate constant of free racemic phenprocoumon in plasma and liver remained essentially unchanged. Phenylbutazone markedly decreased the volume of distribution referenced to free drug and the clearance of free phenprocoumon (i.e., intrinsic metabolic clearance). Whereas the total (bound and unbound) drug concentration-effect relationship in plasma and liver was shifted to the left in rats treated with phenylbutazone, such shift was not seen in the free drug concentration-response relationship. In conclusion, the increase in the free concentration of phenprocoumon in plasma and liver and the concomitant decrease in the clearance of free drug are the mechanisms responsible for the marked and sustained enhancement of the anticoagulant effect which follows treatment with phenbutazone.This work was supported by the Deutsche Forschungsgemeinschaft.