Involvement of protein synthesis in the development of thermotolerance using a CHO temperature-sensitive mutant

A Chinese hamster ovary temperature-sensitive mutant (CHO-tsH1) with defective leucyl-tRNA synthetase at temperatures greater than 39 degrees C was used to examine the importance of protein synthesis in the development of thermotolerance. Its wild-type parent CHO-SC1 was used as the control. At temperatures of 41.5 degrees C, 42 degrees C and 42.5 degrees C, SC1 showed the classical biphasic thermotolerant response while tsH1 showed no thermotolerance. When both cell lines were heated for 15 min at 45 degrees C, then allowed to incubate at the permissive temperature of 35 degrees C and finally challenged with another 25 min treatment at 45 degrees C, tolerance was expressed in both cell lines. When the development incubation temperature was raised from 35 degrees C to the non-permissive temperature of 40 degrees C, tolerance was also observed. Although both cell lines expressed tolerance under these conditions, the magnitude and duration of response of the mutant cell line were reduced. Heat-shock protein analysis using one-dimensional gel electrophoresis showed that, under permissive conditions, the mutant cell was able to express the full spectrum of heat-shock proteins as seen in the wild-type cells. Under non-permissive conditions, little or no detectable proteins were synthesized in the mutant cell. We therefore postulate that the synthesis of new cytosol proteins is not required for the initial onset of thermotolerance but is necessary for the sustenance of tolerance.     

Low-level echogenicity in intraventricular hemorrhage versus ventriculitis

Serial cranial sonograms of 55 neonates with large perinatal intraventricular/intraparenchymal hemorrhages and moderate-to-severe posthemorrhagic hydrocephalus were reviewed. In all 55 patients, the ventricles were initially enlarged and filled with anechoic cerebrospinal fluid, which contained discrete hyperechoic fragments of hematoma. Between 7 and 25 days after the initial hemorrhagic episode, however, diffuse, low-level echogenicity appeared in the ventricles of 34 patients. The low-level echogenicity was transient and persisted for 7-59 days (average, 18 days). In 32 patients, low-level echogenicity was a benign finding associated with prior intraventricular hemorrhage. In two patients, the low-level echogenicity was associated with ventriculitis. Low-level echogenicity appeared, increased, then cleared, but reappeared with the onset of ventriculitis in these two patients. Thickening of the ependyma and abnormal periventricular echogenicity, signs of inflammation, were also present. Although low-level echogenicity may commonly be a benign finding, the possibility of ventriculitis should not be ignored.     

Developing novel treatments for mood disorders: accelerating discovery.

This review was generated from discussions by the Pharmacologic and Somatic Treatments Section of the National Institute of Mental Health Strategic Plan for Mood Disorders Committee on advancing novel pharmacologic and somatic treatments for mood disorders. The opening section of the article summarizes in broad strokes, current pharmacologic treatments, and new directions in the field. Thereafter the topics focus on specific research initiatives that could advance the current therapeutics for mood disorders including new basic and clinical research in vivo human imaging procedures, somatic therapeutics, and the vast new area of pharmacogenetics. New scientific and technical opportunities exist today based on advances in basic neuroscience, opportunities in clinical testing, industry interest in advancing central nervous system therapeutics, and on active consumer advocacy groups. The question of how to bring all of these positive forces together to accelerate discovery in mood disorder thera-peutics is the topic of this article.     

Regulation of choline transporter surface expression and phosphorylation by protein kinase C and protein phosphatase 1/2A

The Na(+)/Cl(-)-dependent, hemicholinium-3-sensitive choline transporter (CHT) provides choline for acetylcholine biosynthesis. Recent studies show that CHT contains canonical protein kinase C (PKC) serine and threonine residues. We examined the ability of PKC and serine/threonine protein phosphatase 1/2A (PP1/PP2A) to regulate CHT function, surface expression, and phosphorylation. In mouse crude striatal and hippocampal synaptosomes, PKC activators beta-phorbol 12-myristate 13-acetate (beta-PMA) and beta-phorbol 12,13-dibutyrate produced time- and concentration-dependent reductions in CHT function. PP1/PP2A inhibitors okadaic acid (OKA) and calyculin A (CL-A) produced a time- and concentration-dependent decrease in CHT function. However, tautomycin (PP1 inhibitor) and cyclosporin A (PP2B inhibitor) failed to alter CHT-mediated choline uptake. Choline transport kinetic studies following beta-PMA, OKA, and CL-A treatment revealed a reduction in the maximal choline transport velocity (V(max)) with no change in K(m) for choline. These modulators also produced no change in the total levels of CHT protein in the crude hippocampal and striatal synaptosomes; however, surface biotinylation studies using the membrane-impermeant N-hydroxysuccinimide-biotin in crude synaptosomes following treatment with beta-PMA, OKA, and CL-A indicate significant reductions of CHT levels in biotinylated fractions. Pretreatment with OKA alone, but not beta-PMA, significantly augmented the phosphorylation level of CHT proteins. Our findings suggest that neuronal PKC and PP1/PP2A activity may establish the level of function and surface expression of CHT. These studies also provide the first evidence that CHT is a phosphoprotein and that the basal PP1/PP2A activity may have a dominant role in controlling the levels of CHT phosphorylation.     

PRIMARY MENINGOCOCCAL CONJUNCTIVITIS IN CHILDREN

SUMMARY Four cases of primary meningococcal conjunctivitis in children are reported. This represents an incidence of 2% of patients presenting with conjunctivitis to a paediatric A&E department. All were initially treated with topical chloramphenicol, followed by systemic rifampicin once the diagnosis had been established. No ocular or systemic complications developed, nor recolonisation of the conjunctiva or colonisation of the nasopharynx at follow-up (1–2 years).     

Simultaneous confirmation and differentiation of human T-lymphotropic virus types I and II infection by modified western blot containing recombinant envelope glycoproteins

A modified Western blot (WB) that includes both shared (r21e) and unique recombinant envelope proteins from human T-lymphotropic virus (HTLV) type I (rgp46I) and type II (rgp46II) was compared to conventional HTLV serologic tests in 379 United States blood donors and individuals residing in diverse geographic regions, and the specimens were categorized as positive (n = 158), indeterminate (n = 158), or negative (n = 63) for HTLV infection. Of the 158 HTLV-I/II-positive specimens (66 requiring radioimmunoprecipitation assay [RIPA] for confirmation), 156 reacted concordantly with r21e, gag, and either rgp46I or rgp46II, thus eliminating the need for RIPA in all but two specimens and yielding a test sensitivity of 98.7 percent. Of the 158 indeterminate and 63 negative specimens, none reacted with r21e and rgp46I or rgp46II, yielding a test specificity of 100 percent. Furthermore, analysis of an additional 184 consecutive specimens from a retrovirology reference laboratory demonstrated that the modified WB correctly identified 27 of 28 HTLV-I specimens and all 13 HTLV-II specimens, with a test sensitivity of 97.6 percent. None of specimens that were indeterminate or nonreactive in conventional WB and/or RIPA and none of the screening enzyme immunoassay-negative specimens reacted with r21e and either rgp46I or rgp46II, for a test specificity of 100 percent. Thus, the modified WB appears to be highly sensitive and specific for simultaneous detection and discrimination of HTLV-I from HTLV-II and has the advantage of being a one-step assay that is easily performed in all types of laboratory settings and allows rapid, reliable, and standardized testing for HTLV-I/II infection.     

USE OF SOLVENTS TO DISPERSE EAR WAX

SUMMARY In this test a course of 4 drops twice a day for 5 days of ear wax solvents, a cerumenolytic, sodium bicarbonate, or sterile water significantly increased the clearance of wax from ears by natural expulsion and eliminated the requirement for ear syringing in 50% of cases.     

Creutzfeldt--Jakob Disease in Recipients of Human Growth Hormone in the United Kingdom: A Clinical and Radiographic Study

In the past 3 years there have been five further cases, in additionto one case reported in 1985, of Creutzfeldt-Jakob disease inrecipients of human growth hormone in the United Kingdom. Theclinical findings of two of these cases are described, demonstratinga typical presentation with a predominantly cerebellar syndromeat onset which is not commonly a presenting feature of sporadicCreutzfeldt-Jakob disease. In one case a ^99mTc hexamethylpropylenaminesingle photon emission tomographic scan showed marked impairmentof tracer uptake in the basal ganglia and cerebral cortex ata time when the clinical picture was predominantly cerebellar.This technique may be useful in early diagnosis. In the othercase post mortem examination of the brain showed prominent amyloiddeposition in the cerebellum, which has not been described previouslyin pituitary-hormone related Creutzfeldt-Jakob disease. Thepreviously published cases of growth hormone-related Creutzfeldt-Jakobdisease are reviewed and reasons for the particular clinicalpattern seen are discussed.