A novel assay for lysosomal pepstatin-insensitive proteinase and its application for the diagnosis of late-infantile neuronal ceroid lipofuscinosis

A highly sensitive assay for mammalian lysosomal pepstatin-insensitive proteinase (LPIP) is described using a synthetic peptide substrate coupled to aminotrifluoromethyl coumarin (AFC). LPIP is an endocarboxyl proteinase which has specific sequence requirements of Phe-Phe around the carboxyl terminal. This HPLC based assay can detect patients suffering from late-infantile neuronal ceroid lipofuscinosis (LINCL) and also heterozygote carriers in cultured lymphoid cells and skin fibroblasts. None of the patients analyzed had detectable enzyme activity confirming the defective gene product, while carriers had about 50% activity when compared with the normal controls. Neurological controls comprised of patients with other neurodegenerative disorders have LPIP activities similar to normal controls. LPIP activity is also detectable in amniocytes and chorionic villi. Thus the assay reported can also be used for prenatal diagnosis of LINCL.     

Mechanical thrombectomy in acute venous thrombosis using an Amplatz thrombectomy device

Three cases of percutaneous mechanical thrombectomy using the Amplatz thrombectomy device are presented. All cases involve the application of the device in a major thoracic or abdominal vein in situations in which chemothrombolysis was contraindicated. The method of operation of the Amplatz thrombectomy device, as well as a brief overview of its clinical applications, are presented.     

Anabolic-androgenic steroid administration causes hypertrophy of immobilized and nonimmobilized skeletal muscle in a sedentary rabbit model

Although the use of anabolic agents in athletics has generated extensive publicity and controversy, the potential therapeutic benefits of these drugs have not been fully investigated. This randomized, blinded experimental study investigated whether short-term administration of an anabolic-androgenic steroid can limit immobilization-induced muscle atrophy in a rabbit model. We casted one hindlimb each in 48 New Zealand White rabbits and randomly assigned the rabbits to two groups. The treated group received weekly intramuscular injections of the anabolic-androgenic steroid, nandrolone decanoate (15 mg/kg). Immobilization significantly decreased muscle weights in both the treated rabbits and controls. Compared with controls, the body weights of the treated rabbits increased significantly at 2, 4, and 8 weeks. At 4 and 8 weeks, wet weights, dry weights, and contractile forces were significantly greater in both the casted and noncasted tibialis anterior muscle-tendon units of the treated group. Dry weights and casted contractile forces of the extensor digitorum longus muscle unit at 4 weeks and all measures at 8 weeks were greater in the treated rabbits than in controls. These results are contrary to previously accepted views that anabolic-androgenic steroid use leads to muscle hypertrophy only in conjunction with strength training. This study adds to the growing evidence that anabolic-androgenic steroids can produce significant skeletal muscle hypertrophy in sedentary populations.     

Radiolabelled 5'-iodo-2'-deoxyuridine: a promising alternative to [18F]-2-fluoro-2-deoxy-D-glucose for PET studies of early response to anticancer treatment

We investigated the potential of radiolabelled 5-iodo-2'-deoxyuridine (IUdR) as a pharmacodynamic probe for use with positron emission tomography (PET) in studies of early proliferative response to anticancer treatment. Using the hormone-responsive rat mammary carcinoma OES.HR1, we used a multiple radiotracer method to examine treatment-induced changes in 24 h tumour retention of [131I]IUdR, uptake of [3H]2-deoxy-D-glucose ([3H]DG) together with [99mTc]hexylmethylpropylene amineoxine ([99mTc]HMPAO) uptake as a measure of blood flow. Radiotracer data were compared with macroscopic changes in tumour growth, and cell proliferation as determined by DNA histogram flow cytometry. From 4 days after tumour growth arrest induced by oestrogen ablation, a sustained fall in tumour cell proliferation was demonstrated, which was associated with reduced tumour uptake of each tracer. Whereas reduced levels of tumour [3H]DG could be accounted for by changes in blood flow, this was not the case for [131I]IUdR, which was found to be closely related to percentage S-phase cells within tumour (r = 0.73, p < 0.002). It was also estimated that residual levels of radioiodide may contribute significantly, to the low levels of retained radioactivity associated with responding tumours at 24 h following IUdR administration, suggesting that metabolite correction methods should be implemented as part of IUdR PET imaging protocols. We conclude that [124I]IUdR is a promising alternative to [18F]fluorodeoxyglucose ([18F]FDG) for the early assessment by PET of tumour response to treatments directed at targets associated with cell proliferation.     

Bone morphogenetic protein but not transforming growth factor-beta enhances bone formation in canine diaphyseal nonunions implanted with a biodegradable composite polymer

BACKGROUND: The purpose of the present study was to create an effective bone-graft substitute for the treatment of a diaphyseal nonunion. METHODS: A standardized nonunion was established in the midportion of the radial diaphysis in thirty mongrel dogs by creating a three-millimeter segmental bone defect (at least 2 percent of the total length of the bone). The nonunion was treated with implantation of a carrier comprised of poly(DL-lactic acid) and polyglycolic acid copolymer (50:50 polylactic acid-polyglycolic acid [PLG50]) containing canine purified bone morphogenetic protein (BMP) or recombinant human transforming growth factor-beta (TGF-beta1), or both, or the carrier without BMP or TGF-beta1. Five groups, consisting of six dogs each, were treated with implantation of the carrier alone, implantation of the carrier with fifteen milligrams of BMP, implantation of the carrier with 1.5 milligrams of BMP, implantation of the carrier with fifteen milligrams of BMP and ten nanograms of TGF-beta1, or implantation of the carrier with ten nanograms of TGF-beta1. At twelve weeks after implantation, the radii were examined radiographically and the sites of nonunion were examined histomorphometrically. RESULTS: We found that implantation of the polylactic acid-polyglycolic acid carrier alone or in combination with ten nanograms of TGF-beta1 failed to induce significant radiographic or histomorphometric evidence of healing at the site of the nonunion. The radii treated with the carrier enriched with either 1.5 or fifteen milligrams of BMP showed significantly increased periosteal and endosteal bone formation on histomorphometric (p < 0.05) and radiographic (p < 0.02) analysis. CONCLUSIONS: Bone formation in a persistent osseous defect that is similar to an ununited diaphyseal fracture is increased when species-specific BMP incorporated into a polylactic acid-polyglycolic acid carrier is implanted at the site of the nonunion. TGF-beta1 at a dose of ten nanograms per implant did not induce a similar degree of bone formation or potentiate the effect of BMP in this model. CLINICAL RELEVANCE: The biodegradable implant containing BMP that was used in the present study to treat diaphyseal nonunion is an effective bone-graft substitute.     

Calibrating space: exploration is important for allothetic and idiothetic navigation

Allothetic and idiothetic navigation strategies rely on very different cues and computational procedures. Allothetic navigation uses the relationships between external cues (visual, auditory, and olfactory) and mapping or geometrical calculations to locate places. Idiothetic navigation relies on cues generated by self-movement (proprioceptive cues or cues from optic, auditory, and olfactory flow, or efference copy of motor commands) and path integration to locate a present location and/or a starting point. Whereas it is theorized that exploratory behavior is used by animals to create a central representation of allothetic cues, it is unclear whether exploration plays a role in idiothetic navigation. Computational models suggest that either a reference frame, calibrated by exploration, or vector addition, without reference to exploration, could support path integration. The present study evaluated the contribution of exploration in these navigation strategies by comparing its contribution to the solution of both allothetic and idiothetic navigation problems. In two experiments, rats were trained to forage on an open table for large food pellets, which they then carried to a refuge to eat. Once trained, they were given probe trials from novel locations in either normal light, which permits the use of allothetic cues, or in infrared light, which requires the use of idiothetic cues. When faced with a new problem in either lighting condition, the rats first explored the foraging table before navigating directly home with the food. That exploration is equally important for allothetic and idiothetic navigation, suggests that both navigation strategies require a calibrated representation of the environment.     

Focal hippocampal gain of NGF function elicits specific septal cholinergic reorganization

The influence of NGF on the neuroanatomic substrate(s) subserving learning and memory was probed by somatic mosaic analysis. NGF XAT mice underwent unilateral hippocampal delivery of virus vector expressing cre recombinase to produce focal NGF gain of function mosaics. Activated mice expressing increased NGF, but not control mice transduced with the lacZ gene showed reorganization of the septohippocampal projection assessed by retrograde labeling with Fluorogold (FG). Mice mosaic for NGF function demonstrated in ipsilateral medial septum and diagonal band significant increases in FG-labeled cell bodies (94%), ChAT-labeled cells (55%), double-positive cells (190%) and increased somal size of double-positive cells (56%) than did non-activated mice. These results indicate that reorganization of the cholinergic septal input to a specific hippocampal region is promoted by gain of NGF function.     

Paediatric Nosocomial Urinary Tract Infection at a Regional Hospital

From a total of 26,603 admissions to the paediatric wards, 1360 paediatric nosocomial urinary tract infections (PNUTI) were identified during a 5-year retrospective chart review at the SFGH. The ages ranged from 3 days to 13 years, with 46% boys and 54% girls. The highest rates of PNUTI per service per 100 admissions were seen in the nursery (11.28) followed by paediatric surgery (2.89) and paediatric medicine (2.86). Although the greatest number of PNUTI occurred in the nursery, comparison between the years was not statistically significant. About 90% (1218 of 1360) of PNUTI occurred in catheterized patients. No documentation was found specifying the type of catheterization (intermittent or continuous). About 90% (1210 of 1360) of isolates were single organisms with Escherichia coli, Proteus mirabilis, Klebsiella spp. and Group B streptococci accounting for a total of 70% of all pathogens. However, the composition of the most common isolate in each service differed. The most common isolate in the nursery was E. coli, in the paediatric medical and surgical services the most common isolates were Klebsiella spp. and Proteus mirabilis, respectively. Proteus mirabilis was isolated predominantly from boys with structural abnormality of the urethral tract. No PNUTIs were complicated by bacteraemia. The antibiotics with least effectiveness (in increasing order) for UTIs were cephalexin, ampicillin, trimethoprim, co-trimoxazole and tetracycline. The most effective antibiotics were nalidixic acid, gentamicin and amoxicillin-clavulanic acid.     

A clinical trial to selectively change dietary fat and/or energy intake in women: the Women's Diet Study.

Dietary fat and energy intake have been implicated in breast cancer etiology. To examine the relative importance of these dietary factors on markers of cancer risk in women, we designed an intervention trial to selectively decrease fat and/or energy intake in free-living, premenopausal women who were somewhat overweight. The study used a 2 x 2 factorial design to evaluate the independent and interactive effects of dietary fat and energy. The diets were nonintervention, low fat (15% of energy from fat, maintenance of energy intake), low energy (25% energy reduction), and combination low fat and low energy. We utilized an individualized counseling approach with self-selection of foods. Women on the low-fat and combination diets were asked to meet given daily goals for fat grams and food group exchanges, while women on the low-energy diet used only food group exchanges. Of the 113 premenopausal women randomized who were eligible for analysis, 43% were African-American. A total of 88 women completed the 12-week program, and adherence to the dietary goals was similar in both racial groups. Women on the low-fat diet were able to reduce dietary fat intake to 19% of energy by 4 weeks and to 17% by 12 weeks with a slight decrease in energy intake. Women on the low-energy diet met their energy reduction goals by four weeks while maintaining percentage of energy from fat. Women on the combination diet largely met their goals by four weeks as well. These data indicate that it is possible to selectively manipulate dietary fat and energy intake in women over a short period of time, which makes clinical studies on the relative effects of these two dietary variables on cancer risk biomarkers readily feasible.