Identification of an early endosomal protein regulated by phosphatidylinositol 3-kinase

Phosphatidylinositol 3-kinases (PI 3-kinases) have been implicated in membrane trafficking in the secretory and endocytic pathways of yeast and mammalian cells, but the molecular mechanisms by which these lipid kinases operate are not known. Here we identify a protein of 170 kDa that is rapidly released from cell membranes in response to wortmannin, a potent inhibitor of mammalian PI 3-kinases. The amino acid sequence of peptides from p170 reveal its identity to early endosomal antigen (EEA) 1, an endosomal antigen with homology to several yeast proteins genetically implicated in membrane trafficking. Immunofluorescence analysis of 3T3-L1 adipocytes with antisera against p170/EEA1 reveal a punctate peripheral pattern that becomes diffuse in response to wortmannin. In vitro, p170/EEA1 binds specifically to liposomes containing PIns(3)P, suggesting that the effect of wortmannin on cells is due to inhibition of PIns(3)P production. Thus, p170/EEA1 may define a family of proteins that mediate the regulatory effects of 3′-phosphoinositides on membrane trafficking in yeast and mammalian cells.     

The Prospective Assessment of Autonomic Nerve Function by Pupillometry in Adolescents with Type 1 Diabetes Mellitus

The study aimed to compare the longitudinal assessment of autonomic nerve function by computerized infrared pupillometry and standard cardiovascular tests in adolescents with diabetes. Adolescents (n = 150) were assessed at two time points (T1 and T2). The median time interval between assessments was 1.5 (range 0.9–3) years. At T1 the median age was 14.5 (range 8.3–19.5) years and the median duration was 6.5 (range 1.1–16) years. The pupillary variables assessed included the resting pupil diameter, the maximum constriction velocity, and the reflex amplitude of constriction. Heart rate reflexes were assessed in response to deep breathing, the Valsalva manoeuvre, and on standing from a lying position (30/15 ratio). Between visits there was a significant decrease in maximum constriction velocity (6.0 mm s^?1 vs 6.3 mm s^?1, p = 0.0001) and resting pupil diameter (6.2 mm vs 6.3 mm, p = 0.001). At reassessment pupillary abnormalities increased from 32 (21 %) to 45 (30%), with 17 (54 %) of the initial abnormalities persisting. Adolescents with abnormally slow maximum constriction velocity compared to those with normal maximum constriction velocity had a higher glycated haemoglobin (HbA_1c%) at T2 (p = 0.02) and between assessments (p = 0.01). Cardiovascular test abnormalities did not increase between visits and the persistence of initial abnormalities was low (21 %). In summary, pupillometry appears a more sensitive test of autonomic nerve dysfunction in adolescents with diabetes than assessment of cardiovascular reflexes.     

Benign intracranial hypertension and recombinant growth hormone therapy in Australia and New Zealand

Benign intracranial hypertension (BIH) is reported in three children from Australia and one from New Zealand, who were being treated with recombinant human growth hormone (rhGH). Three males and one female, aged between 10.5 and 14.2 y, developed intracranial hypertension within 2 weeks to 3 months of starting treatment. A national database, OZGROW, has been prospectively collecting data on all 3332 children treated with rhGH in Australia and New Zealand from January 1986 to 1996. The incidence of BIH in children treated with growth hormone (GH) is small, 1.2 per 1000 cases overall, but appears to be greater with biochemical GHD (<10IUml ^-1), i.e. 6.5/1000 (3 in 465 cases), relative risk 18.4, 95% confidence interval 1.9-176.1, than in all other children on the database. The incidence in patients with Turner's syndrome was 2.3/1000 (1 in 428 cases). No cases in patients with partial GHD (10–20 IUml ^-1) or chronic renal failure were identified. Possible causative mechanisms are discussed. The authors'practice is now to start GH replacement at less than the usual recommended dose of 14IUm-² week^-1 in those children considered to be at high risk of developing BIH. Ophthalmological evaluation is recommended for children before and during the first few months following commencement of rhGH therapy and is mandatory in the event of peripheral or facial oedema, persistent headaches, vomiting or visual symptoms. The absence of papilledema does not exclude the diagnosis.     

The effect of phencyclidine and DL-2-amino-5-phosphonovaleric acid on N-methyl-D-aspartic acid induced changes in extracellular concentration of dopamine and DOPAC in the rat neostriatum.

The effects of N-methyl-D-aspartic acid (NMDA) and phencyclidine (PCP) on extracellular levels of dopamine (DA) and dihydroxyphenylacetic acid (DOPAC) in the striatum of the rat were studied using in vivo microdialysis. Intrastriatal infusion of NMDA produced a significant dose-dependent increase in extracellular DA and a decrease in concentrations of DOPAC. Whereas both 2-amino-5-phosphonovalerate (APV) and PCP antagonized the NMDA-induced increase in extracellular levels of DA, the effect on NMDA-induced changes in extracellular concentrations of DOPAC were different for the two compounds. The APV significantly attenuated the decrease in extracellular DOPAC produced by smaller concentrations of NMDA, whereas PCP did not prevent decrease in DOPAC produced by any concentrations of NMDA. Phencyclidine alone produced a dose-dependent increase in extracellular DA but had no effect on the extracellular concentration of DOPAC. This study demonstrated that PCP, at concentrations which did not produce an increase in extracellular DA, antagonized the effect of the NMDA on DA. The data also indicated that both APV and PCP antagonized the NMDA-evoked release of DA over a range of concentrations of NMDA, even though they did so by different mechanisms.     

Unrelated donor marrow transplantation between 1977 and 1987 at four centers in the United Kingdom

Retrospectively we analyzed the histocompatibility data and clinical results of bone marrow transplantation in 51 patients who received marrow from unrelated donors (UD) from 1977 to 1987 at one of four UK BMT centers. We compared the results with those obtained in 51 transplants carried out at the same centers using HLA-identical (ID) sibling donors. Of the UD/recipient pairs 32 (63%) were serologically identical for HLA A, B, and DR antigens, and 37% showed varying degrees of mismatch. UD-BMT primary diagnoses were: severe aplastic anemia or Fanconi's anemia (n = 17), acute leukemia (n = 11), chronic myeloid leukemia (n = 21), and other conditions (n = 2). T cell depletion of the graft was associated with a significant improvement in survival in both UD and ID-BMT. Graft failure was more common in recipients of UD than of ID transplants (13 [25%] vs. 5 [10%] P = 0.05) but there was no significant difference in the frequency of acute or chronic graft-versus-host disease. Actuarial survival was superior for recipients of ID transplants (UD vs. ID: 49% vs. 78%, respectively, at 3 months; 32% vs. 63% at one year). Reduced survival for recipients of UD-BMT was confirmed in case control regression analysis (relative risk 3.0, P = 0.01). Nevertheless in patients whose only alternative is a partially mismatched family donor we think that UD-BMT is justified.     

Circulating Pancreatic Polypeptide in Patients with Adenocarcinoma of the Bile Duct

Using radioimmunoassay methods, the blood of patients with pancreatic tumors was screened for circulating polypeptide hormones. This screening discovered pancreatic polypeptide in abnormally high concentration in the serum of six of seven patients with adenocarcinomas of the bile duct. the assay appears to be very sensitive finding excessive residual pancreatic polypeptide production after palliative resections. Serum pancreatic polypeptide assays warrant evaluation as an aid in the diagnosis and management of patients with bile duct tumors.     

Treatment of essential tremor with the barbiturate T2000 (1,3-dimethoxymethyl-5,5-diphenyl-barbituric acid).

The effect of the barbiturate T2000 (1,3-dimethoxymethyl-5,5-diphenyl-barbituric acid; DMMDPB) on essential tremor, given in twice daily doses of 400 and 300 mg, was assessed in two brief, randomized, placebo-controlled, parallel-group, double-blinded, single-center trials in 12 and 22 patients, respectively. These trials represent the first clinical use of T2000 for a specific indication. The primary endpoint was the change in the mean scores of the treated and control groups based on the Fahn-Tolosa-Marin tremor scale. In the first study of 12 patients treated with 400 mg or placebo twice daily for 14 days, the mean change from baseline at day 14 was 19.3 (P < 0.0001) in the treated group and 9.0 (P = 0.0121) in the control group. Using a two-factor mixed ANOVA model to evaluate within group and between group changes, the effect of T2000 was significantly different from that of the placebo group (P = 0.03). In the second study of 22 patients treated with 300 mg of T2000 or placebo twice daily for 20 days, statistically significant changes were seen in treated patients compared to baseline, but the ANOVA model did not demonstrate a significant treatment effect of T2000 compared to placebo. When the treated groups from each study are compared, the 800-mg daily group is significantly different from the 600-mg daily group (P = 0.02). Some treated patients in each study, but no placebo patients, experienced marked improvement. These results support further evaluation of T2000 in the treatment of essential tremor.