Application of Piagetian measures of cognition in severe Alzheimer's disease

Conventional psychometric measures uniformly yield zero or near zero scores (i.e., "bottom-out") as patients with Alzheimer's disease (AD) progress to the more severe stages of the illness. Consequently, there are no psychometric measures which objectively assess the mental abilities of AD patients with very severe cognitive impairment. We explored the hypothesis that mental function in AD patients with very severe cognitive impairment can be effectively assessed using test measures developed to assess the earliest stage of cognitive development as proposed by Piaget. We also investigated the relationship between decline on these experimental cognitive measures and progressive functional disability in patients with severe cognitive impairment. The results indicate that modified instruments derived from measures developed to assess Piaget's sensorimotor stage of cognitive development provide useful information about the cognitive abilities of very severely impaired AD patients. These modified instruments provide a measure of cognition in these extremely impaired patients that has acceptable validity and demonstrable reliability.     

Topical diclofenac sodium, dexamethasone and placebo compared in a model of immunogenic uveitis in rabbits

Unacceptable side effects involved in topical steroid usage for uveitis have prompted the search for alternative antiinflammatory drugs for the treatment of ocular inflammation. Cyclooxygenase inhibitors have been widely used for systemic inflammatory conditions over the last two decades and are therefore natural candidates to be studied for uveitis therapy. Previous studies of cyclooxygenase inhibitors in uveitis models yielded inconclusive and sometimes contradicting results. The authors compared the clinical effect of topical dexamethasone, diclofenac and placebo in an immunogenic uveitis model produced in ovalbumin immunized NZW rabbits challenged with ovalbumin in the vitreous. Nine clinical parameters of inflammation were compared employing a double blind placebo controlled protocol. Three groups of 16 eyes each, were assigned for each preparation and were followed for nine days with biomicroscopic examinations. Diclofenac was superior or equal to dexamethasone for iris hyperemia (p=0.059) and conjunctival injection (p=0.02), equal for corneal haziness and AC fibrin, yet inferior for corneal endothelial debris, iris fibrin and AC cells and flare (p<0.05). Placebo was inferior (p<0.05) to the other groups for the above mentioned parameters excluding fibrin precipitation on the iris that was greater in diclofenac treated eyes. While some clinical criteria of inflammation responded better to steroids than to diclofenac, the results of this study show that others responded better or equal to diclofenac. The authors hypothesize that although diclofenac reduces prostaglandin levels it may induce high levels of leukotrienes that maintain cellular exudation.     

Percutaneous endoscopic lumbar discectomy (PELD)

Percutaneous endoscopic lumbar discectomy (PELD) is a new technique for the decompression of the lumbar disc space and removal of nucleus pulposus via a posterolateral approach. The technique was introduced in Germany by the authors in April 1987. The method is indicated in patients with non-equestrated lumbar disc herniation with an intact lorsal longitudinal ligament. In local anesthesia, a working cannula (OD 5 mm) is placed at the dorsal lateral border of the disc. The disc space is opened with anulus trephines and the nucleus pulposus is removed with rigid and flexible forceps as well as with automated shaver systems under intermittent endoscopic control (discoscopy). The procedure is performed in local anesthesia. The results of the first thirty patients with a follow-up time between 6 months and 17 months could be graded as excellent in 13 cases, as good in 9 cases, as fair in 6 cases, and as bad in 2 cases. The relief of symptoms as judged by the patients was between 70–100 percent in the majority of the cases. Three patients had to be reoperated at the same level and site, because of either persistent or recurrent sciatica. The performance in local anesthesia, the atraumatic extraspinal approach, the reduced time of hospitalization and post-operative morbidity as well as the reduced time of work incapability are the main advantages of this new method.     

Sampling clinicians' activities using electronic pagers

Pager-based activity sampling (PAS) is described as a cost-effective and unobtrusive method for sampling residents' activities in clinical settings. A sample program evaluation is presented using residents in an urban children's hospital resident-training program. The purposes of the program evaluation were: (a) to establish a behavioral baseline that would help clinical faculty understand how residents were using their time, and (b) to determine whether alterations in the way residents were assigned within the hospital resulted in desired changes to time spent. The primary rationale for changing resident-assignment policies were: (a) to decrease the time residents were spending in transit between various locations within the hospital, and (b) to increase the time spent by residents in educational activities and in direct contact with patients and their families. This PAS application demonstrates that the technique can produce statistically supportable conclusions, at minimal cost, without unduly disrupting either the residents or their patients. PAS is compared with other time-sampling methods, its limitations are discussed, and suggestions for future applications are provided.     

Growth factor antagonists for the treatment of diabetic vascular complications

Diabetic vascular disease is characterised by altered vascular reactivity and blood flow, hyperpermeability, hyperproliferative responses, and increased extracellular matrix deposition in tissues that are sites of complications. These vascular functional and structural changes have been linked to excessive glucose metabolism in target organs via at least three pathophysiological mechanisms, including increased sorbitol (polyol) pathway activity, increased nonenzymatic glycation of vascular wall proteins, and increased protein kinase C (PKC) activity. These potential mechanisms of glucose toxicity remain the subject of intense scientific investigation, and therapies targeting each of them are being evaluated in clinical trials. It is becoming increasingly clear that excessive production of growth factors provides a common denominator linking these diverse mechanisms of glucose toxicity to the functional and structural vascular alterations associated with diabetes. Increased expression of vascular endothelial growth factor (VEGF) has been linked to increased metabolism of glucose via the sorbitol pathway, to nonenzymatic glycation, and to increased PKC activity, and appears to modulate the hyperpermeability and hyperproliferative responses of diabetes. Consequently, because of the unmet medical need and market size, numerous pharmaceutical and biotechnology companies have initiated research programmes evaluating growth factor antagonists as a potential therapeutic approach for treating complications associated with diabetic vascular disease. However, before growth factor antagonists can enter clinical testing, a number of important issues must be clarified, including the physiological effect of chronic growth factor inhibition, which appears to be necessary for ameliorating chronic vascular deterioration of diabetes, and administration routes, especially for protein-based therapies.     

Histological and immunopathological analysis of T-cells mediating murine HSV-1 keratitis

Background: Thymusderived lymphocytes play a critical role in the development of herpes simplex keratitis (HSK). T-cell subsets defined by their expression of various T-cell receptor (TCR) Vß segments were studied following corneal HSV-1 infection (p.i.). Methods: Conjunctiva, corneal limbus and corneal stroma of two inbred BALB/c congenic mouse strains which differ only in the gene products closely linked to the Igh-1 locus on chromosome 12 were analyzed. Results: While C.B-17 mice (Igh-1^b) were resistant to HSK, C.AL-20 mice (Igh-1^d) clinically developed severe necrotizing keratitis by day 11 p.i. The corneal stroma of C.B-17 mice remained clear, while it was increasingly infiltrated by mononuclear cells and neutrophils in C.AL-20 mice by day 11 p.i. In C.B-17 mice, Thy1.2+ cells were found in the conjunctiva between days 2 to 4 p.i., and subsequently decreased. Only a few Thyl.2+ cells were found in the limbus, and no such cells were found in the stroma. In contrast, in C.AL-20 mice the numbers of Thyl.2+ cells (activated CD4+, Vß8+ T cells) profoundly increased in the conjunctiva by day 4 p.i. These cells infiltrated the limbus between days 7 and 11 p.i. and eventually entered the stromal tissue by day 11 p.i. Conclusions: Our data suggest that the HSV-1-induced corneal tissue destruction is mediated by mononuclear cells and neutrophils and that these cells are probably attracted into the cornea by cytokines elaborated by activated CD4+, Vß8+ T cells.Presented as a paper at the ECORA Meeting, 4–7 October 1993, Bonn     

Atopic keratoconjunctivitis

Atopic keratoconjunctivitis (AKC) is a potentially blinding disease characterized by a bilateral chronic keratoconjunctivitis associated with atopic dermatitis. The disease usually manifests as severe itching and burning, excessive tearing, foreign body sensation, and mucoid discharge. The clinical characteristics of AKC show a broad spectrum including lid dermatitis, chronic blepharitis, cicatrizing conjunctivitis with fornix foreshortening and symblepharon formation, punctate epithelial keratitis, persistent epithelial defects, corneal scarring and neovascularization, lipid keratopathy, conjunctivalization of peripheral cornea, and peripheral ulcerative keratitis. The underlying pathophysiologic mechanism in AKC involves a combination of type-I IgE-mediated, and type-IV delayed hypersensitivity reactions. The immunoregulatory defect responsible for the overproduction of allergen-specific IgE antibody, the key component responsible for antigen binding, and subsequent mast cell degranulation, is probably multifactorial. The histopathologic characteristics of the conjunctiva in AKC include a mast cell and eosinophil invasion of the epithelium, epithelial pseudotubule formation, and prominent mast cell and mononuclear cell infiltration of the substantia propria. A number of ocular conditions have been reported to be associated with AKC, including keratoconus, herpes simplex keratitis, and cataracts. Successful long-term control of this potentially blinding disease requires a multidisciplinary approach involving systemic and environmental aspects. Scrupulous long-term environmental control of allergens is the single most important aspect in the management of patients with AKC. Systemic anti-histamine therapy, and long-term topical mast cell stabilizing therapy are also mandatory. Topical steroids should be reserved for exacerbations of the disease.     

Dose and Load Studies for Subcutaneous and Oral Delivery of Poly(lactide-co-glycolide) Microspheres Containing Ovalbumin

Poly(lactide-co-glycolide) microspheres containing different loads of OVA (0.05, 0.1, 0.5 and 1.0% w/w) were manufactured by a w/o/w emulsion/solvent evaporation method. Low load efficiencies of less than 20% were observed. Normal size distributions with mean volume diameters ranging from 3.7 to 4.7 µm were obtained for different batches. The in vitro release of OVA from different loaded microspheres showed an expected burst release with all batches. The in vivo dose study (1, 10, 25, 50 µg of OVA) was performed by subcutaneous and oral inoculation in mice by single (0 week) or double (0 and 3 weeks) administration of PLGA 50/50 microspheres containing 0.1% OVA. Subcutaneous administration showed an immune response (serum Ig levels by ELISA) statistically (Fishers paired t-test; P < 0.05) above OVA saline negative controls at 3, 6 and 12 weeks after administration. Oral administration of microspheres produced statistically higher systemic immune responses at the higher doses. Single and double inoculation orally and subcutaneously produced similar serum antibody levels. The in vivo load study was performed by subcutaneous and oral administration to mice of 25 µg OVA contained in various loaded (0.05, 0.1, 0.5 and 1.0% w/w) microspheres. Serum immune responses at 3, 6, and 12 weeks after inoculation were statistically above OVA saline controls and were inversely proportional to the OVA load using either route. This observation suggested a relationship between the number of microspheres delivered and the in vivo serum response. Single subcutaneous administration of 0.05 or 0.1% OVA loaded PLGA 50/50 microspheres induced larger immune responses compared with complete Freunds adjuvant.     

Response of multicellular tumor spheroids to liposomes containing TNF-α

Summary This publication describes a new model to investigate the influence of tumor necrosis factor- (TNF-) on a three-dimensional glial cell aggregate under defined, standardized, reproducible conditions using the glioma cell line A 172.The cells are initially grown as normal monolayer culture until they reach a cell density of up to 1×10⁶. Subsequently they are grown as spheroids by the liquid overlay technique. Spheroids grown in this way were divided into ten groups of more than 50 cell aggregates. Three groups were coincubated with free TNF- in increasing dosages (100 ng/ml, 200 ng/ml and 1000 ng/ml); three groups were incubated with empty liposomes (0.2 mg/ml, 0.4 mg/ml and 2 mg/ml); three groups received liposomes which had been loaded with TNF-, and one group, which received no treatment, served as control.The diameter of the spheroids ranged from 80 m to 350 m. There was no significant difference in growth between the 3 groups treated with free TNF-. Comparing spheroids treated with TNF- with those which had been coincubated with empty liposomes, there was a significant difference (p<0.001) in growth, which correlated with the amount of liposomes. Similarly, free TNF- had a significantly (P<0.001) stronger growth-inhibiting effect as compared to liposomes loaded with TNF-. Comparing the groups treated with liposomes only to those treated with liposomes loaded with TNF-, the latter exhibited a more marked (although not significantly) growth-inhibiting effect.The preliminary conclusion is that the major growth-inhibiting effect seems to be mediated by the liposomes. This phenomenon is in agreement with results obtained in monolayer cultures.     

Human liver mitochondrial carnitine palmitoyltransferase I: characterization of its cDNA and chromosomal localization and partial analysis of the gene.

Using the cDNA for rat liver mitochondrial carnitine palmitoyltransferase I (CPT I; EC 2.3.1.21) as a probe, we isolated its counterpart as three overlapping clones from a human liver cDNA library. Both the nucleotide sequence of the human cDNA and the predicted primary structure of the protein (773 aa) proved to be very similar to those of the rat enzyme (82% and 88% identity, respectively). The CPT I mRNA size was also found to be the same (approximately 4.7 kb) in both species. Screening of a human genomic library with the newly obtained cDNA yielded a positive clone of approximately 6.5 kb which, upon partial analysis, was found to contain at least two complete exons linked by a 2.3-kb intron. Oligonucleotide primers specific to upstream and downstream regions of one of the exon/intron junctions were tested in PCRs with DNA from a panel of somatic cell hybrids, each containing a single human chromosome. The results allowed unambiguous assignment of the human liver CPT I gene to the q (long) arm of chromosome 11. Additional experiments established that liver and fibroblasts express the same isoform of mitochondrial CPT I, legitimizing the use of fibroblast assays in the differential diagnosis of the "muscle" and "hepatic" forms of CPT deficiency. The data provide insights into the structure of a human CPT I isoform and its corresponding gene and establish unequivocally that CPT I and CPT II are distinct gene products. Availability of the human CPT I cDNA should open the way to an understanding of the genetic basis of inherited CPT I deficiency syndromes, how the liver CPT I gene is regulated, and which tissues other than liver express this particular variant of the enzyme.