Low dose preoperative radiotherapy for carcinoma of the oesophagus: results of a randomized clinical trial.

One-hundred-and-seventy-six patients with potentially operable squamous cell carcinoma or adenocarcinoma of the middle or lower thirds of the oesophagus were randomly assigned to preoperative radiotherapy or surgery alone. Patients assigned to the radiotherapy arm received 20 Gy in 10 treatments over 2 weeks, using parallel opposed 4 MV beams. The preoperative radiotherapy was not associated with any significant acute morbidity or any increase in operative complications. The median survival of the overall group of 176 patients was 8 months, and the 5-year survival was 13%. There was no significant difference in the survival of the 90 patients who received preoperative radiotherapy and the 86 who were managed by surgery alone. Proportional hazards analysis identified lymph node involvement, high tumour grade and male sex as significant adverse prognostic features, but the treatment option assigned had no prognostic significance. It was concluded that low dose preoperative radiotherapy offered no advantage over surgery alone.     

The effects of acute and repeated doses of moclobemide on psychomotor performance and cognitive function in healthy elderly volunteers

The effects of moclobemide, a new selective and reversible MAO-A inhibitor, on cognitive function and psychomotor performance were measured in 12 healthy elderly male volunteers (with a mean age of 72.5 years). Subjects received moclobemide 200 mg, amitriptyline (positive internal control) 25 mg or placebo twice daily and were assessed on a battery of psychometric tests on the mornings following the first (acute) day and seventh (sub-chronic) day. The tests were: Choice Reaction Time; Tracking; Critical Flicker Fusion Threshold; Memory Scanning; Continuous Attention Task; the Leeds Sleep Evaluation Questionnaire and a Visual Line Analogue Rating Scale. The results show that amitriptyline produced impairment of cognitive and psychomotor functions. Moclobemide, however, did not disrupt sleep or cause daytime sedation, and remained neutral in the assessment of behavioural toxicity.     

Highly water-soluble lipophilic prodrugs of the anti-HIV nucleoside analogue 2',3'-dideoxycytidine and its 3'-fluoro derivative.

The synthesis of a novel series of lipophilic prodrug derivatives of the anti-HIV drugs 2',3'-dideoxycytidine (ddC, 1) and 3'-fluoro-ddC (2), involving N4-substitution with (N,N-dialkylamino)methylene side chains, is described. The increase in the partition coefficients for the prodrug series, compared to those of the parent drugs 1 and 2, ranged from 1.5- to 122-fold and from 1.6- to 175-fold, respectively. At pH 7.4, 37 degrees C, the hydrolytic t1/2 values ranged from 2 to 52 h, the diisopropyl derivatives (3d and 4d) being most stable in the series. 3d and 4d were greater than or equal to 4-fold and 1.7-fold more soluble in water than 1 and 2, respectively. The in vitro antiretroviral activities of 3d, 4a, and 4d were evaluated; the results indicate efficient prodrug-to-drug conversion under the assay conditions. The results of this investigation demonstrate that it is indeed feasible to chemically modify certain nucleoside analogues with inferior solubility properties to simultaneously achieve significantly enhanced lipid and water solubility.     

Carboplatin as opposed to cisplatin does not stimulate the expression of the human immunodeficiency virus long terminal repeat sequences.

The recombinant plasmid pBHIV1 carrying the long terminal repeat (LTR) of the human immunodeficiency virus 1 (HIV-1), linked to the chloramphenicol acetyl transferase (CAT) gene, was introduced into human and rat fibroblasts. Stable transfectants resistant to geneticin expressed CAT activity from the HIV-1 LTR. It was found that the cytotoxic drug cis-diammine(1,1-cyclobutanedicarboxylato)platinum(II) (carboplatin) at concentrations from 1 x 10(-6) to 1 x 10(-4) M does not stimulate the expression of CAT from the HIV-1 LTR. These results differ from previous studies with the related drug cis-diamminedichloroplatinum(II) which showed stimulation of gene expression from the HIV-1 LTR and suggest that carboplatin could be used in the treatment of cancer patients with Acquired Immune Deficiency Syndrome.     

A novel keratanase-generated keratan sulfate antibody and its application to structural analysis of skeletal and corneal keratan sulfate

Introduction The objective of this study was to make monoclonal antibodies specific for keratanase‐generated neoepitopes in keratan sulfate (KS) and to use them along with existing KS monoclonal antibodies (e.g. 5D4, IB4) to investigate KS sulfation pattern motifs in connective tissue proteoglycans during development, ageing and disease. Methods Bovine nasal cartilage aggrecan (BNC A1D1) was trypsin digested, generating a range of GAG‐peptide fragments. The sample was then subjected to anion‐exchange and size exclusion chromatography to separate KS peptides from CS attachment domain fragments. Fractions were analysed by Western blotting for positive immunoreactivity for KS, then pooled and keratanase digested to generate ‘KS stub’ antigens. Immunization and fusions were carried out as previously described ( Caterson et al. 1983 ; Hughes et al. 1992 ). Screenings involved the use of a range of antigens; including keratanase vs. keratanase II‐digested bovine cartilage aggrecan and bovine corneal KS‐PGs. A new monoclonal antibody, BKS‐I, was identified that specifically recognized a keratanase‐generated neoepitope on both skeletal and corneal KS. This novel monoclonal antibody was used along with existing KS monoclonal antibodies 5D4 and 1B4 to investigate KS structure. Results and discussion Bovine trypsin‐generated aggrecan KS‐peptides were chondroitinase ABC treated and either keratanase or keratanase II treated. The digests were run on SDS‐PAGE and immunolocated with monoclonal antibody 5D4 (that recognizes linear disulfated N‐acetyl lactosamine disaccharide‐containing segments in KS) and the new ‘KS‐stub’ monoclonal antibody BKS‐I. Our results indicated that there was reduced monoclonal antibody 5D4 immunostaining after keratanase pretreatment. However, keratanase II digestion completely removed all 5D4 structural epitopes. In contrast, BKS‐I showed no immunostaining on the untreated KS‐peptides but strong staining on keratanase treated samples and no staining after keratanase II digestion. Similar patterns of immunoreactivity were observed with Western blot analysis of untreated, keratanase treated and keratanase II treated corneal KS‐PGs. Conclusion These data indicate that monoclonal antibody BKS‐I recognizes a nonreducing terminal neoepitope‐containing sulfated N‐acetylglucosamine adjacent to a nonsulfated lactosamine disaccharide. We also conclude that skeletal KS must have a structure with four possible variations opposed to the generic structures, proposed as being made of disulfated disaccharides at the nonreducing end, followed by a series of monosulfated disaccharides at the middle and nonsulfated disaccharides nearer the linkage region. 5D4 staining, observed after keratanase digestion, indicates that there must be a minimum structure of a pentasulfated hexasaccharide remaining on the KS chain ‘stubs’ near the linkage region of skeletal and corneal KS. The BKS‐I monoclonal antibody can be used to demonstrate differential substitution of KS GAG chains in the CS attachment region of cartilage aggrecan with ageing. It has also proven useful for immunohistochemical analyses identifying the sites of KS–PG association with collagen lamellae of cornea.     

The striatal-enriched protein tyrosine phosphatase gates long-term potentiation and fear memory in the lateral amygdala.

BACKGROUND: Formation of long-term memories is critically dependent on extracellular-regulated kinase (ERK) signaling. Activation of the ERK pathway by the sequential recruitment of mitogen-activated protein kinases is well understood. In contrast, the proteins that inactivate this pathway are not as well characterized. METHODS: Here we tested the hypothesis that the brain-specific striatal-enriched protein tyrosine phosphatase (STEP) plays a key role in neuroplasticity and fear memory formation by its ability to regulate ERK1/2 activation. RESULTS: STEP co-localizes with the ERKs within neurons of the lateral amygdala. A substrate-trapping STEP protein binds to the ERKs and prevents their nuclear translocation after glutamate stimulation in primary cell cultures. Administration of TAT-STEP into the lateral amygdala (LA) disrupts long-term potentiation (LTP) and selectively disrupts fear memory consolidation. Fear conditioning induces a biphasic activation of ERK1/2 in the LA with an initial activation within 5 minutes of training, a return to baseline levels by 15 minutes, and an increase again at 1 hour. In addition, fear conditioning results in the de novo translation of STEP. Inhibitors of ERK1/2 activation or of protein translation block the synthesis of STEP within the LA after fear conditioning. CONCLUSIONS: Together, these data imply a role for STEP in experience-dependent plasticity and suggest that STEP modulates the activation of ERK1/2 during amygdala-dependent memory formation. The regulation of emotional memory by modulating STEP activity may represent a target for the treatment of psychiatric disorders such as posttraumatic stress disorder (PTSD), panic, and anxiety disorders.     

Caffeine restores regional brain activation in acute hypoglycaemia in healthy volunteers.

AIMS: Caffeine enhances counterregulatory responses to acute hypoglycaemia. Our aim was to explore its effects on cortical function, which are not known at present. METHODS: Regional brain activation during performance of the four-choice reaction time (4CRT) at different levels of complexity was measured using functional magnetic resonance imaging (fMRI) at euglycaemia (5 mmol/l) and hypoglycaemia (2.6 mmol/l) in the presence and absence of caffeine in six healthy right-handed men. RESULTS: During hypoglycaemia, caffeine enhanced adrenaline responses to hypoglycaemia (2.5 +/- 0.7 nmol/l to 4.0 +/- 1.0 nmol/l, P = 0.01) and restored the brain activation response to the non-cued 4CRT, the linear increases in regional brain activation associated with increased task complexity and the ability to respond to a cue that were lost in hypoglycaemia alone. CONCLUSIONS: Caffeine can sustain regional brain activation patterns lost in acute hypoglycaemia, with some restoration of cortical function and enhanced adrenaline responsiveness. A methodology has been established that may help in the development of therapies to protect against severe hypoglycaemia in insulin therapy for patients with diabetes and problematic hypoglycaemia.     

Asymptomatic renal thoracic ectopia, pulmonary hypoplasia, and Bochdalek hernia

Right sided intrathoracic kidney associated with ipsilateral pulmonary hypoplasia and Bochdalek hernia in a 13 year old girl was diagnosed by computed tomography.