Effect of home-based light treatment on persons with dementia and their caregivers.

Sleep disorders are problematic for persons with dementia and their family caregivers. This randomized controlled trial with crossover evaluated the effects of an innovative blue-white light therapy on 17 pairs of home-dwelling persons with dementia and their caregivers. Subjects with dementia received blue-white light and control ('red-yellow' light) for six weeks separated by a four-week washout. Neither actigraphic nor most self-reported sleep measures significantly differed for subjects with dementia. For caregivers, both sleep and role strain improved. No evidence of retinal light toxicity was observed. Six weeks of modest doses of blue-white light appear to improve sleep in caregivers but not in persons with dementia. Greater or prolonged circadian stimulation may be needed to determine if light is an effective treatment for persons with dementia.

Hybribox: a device for processing numbers of radioactively labeled hybridization filters with a minimum of personal exposure.

The device described permits the rapid and efficient processing of large numbers of filter hybridizations while virtually eliminating exposure to radioactive emission from the labeled probe. The filters are annealed and washed without being transferred from the holder. Throughout the process, the Plexiglas composition of the device absorbs the beta particles and exposure to the hands and arms is essentially zero. Since the hybridization solution can be reused several times, the cost involved approximates that of the conventional methods for hybridization.

Synthesis of papain in Escherichia coli.

We have transferred the cloned papain genetic information into an expression vector (pT7-7) regulated by the T7-promoter and have obtained in vitro expression as well as expression in Escherichia coli. In Western blots the proteins produced are immunologically recognizable as papain. Multiple forms of specific but differing sizes are detected, suggesting either that initiation can occur at more than one of the upstream methionines, or that the enzyme is processed after synthesis.

Transhiatal blunt esophagectomy for carcinoma of the esophagus.

Transhiatal blunt esophagectomy has been reported as a safe and effective procedure for the palliation of carcinoma of the esophagus. Avoidance of a thoracotomy eliminates the morbidity associated with this procedure, and creation of a cervical esophagogastric anastomosis avoids the catastrophic sequelae of an intrathoracic anastomotic leak. Moreover, use of the procedure for palliation does not preclude excellent 1-year survival rates. We report early results in five consecutive patients with esophageal carcinoma who underwent transhiatal blunt esophagectomy. Five patients had 22 complications, including one with a fascial dehiscence, pyloroplasty leak, and localized mediastinal abscess requiring a second laparotomy. One patient died in the hospital postoperatively of massive aspiration pneumonitis. Our results compare favorably with those reported in the literature. We believe that transhiatal blunt esophagectomy avoids the morbidity and mortality of a thoracotomy and an intrathoracic anastomosis, yet remains a major gastrointestinal operative procedure with all of its attendant risks.

Cloning and sequencing of papain-encoding cDNA.

Messenger RNA extracted from Carica papaya fruit was converted to cDNA and cloned into the PstI restriction site of plasmid pBR322. Subclones of the approximately 1.4-kb fragment were sequenced. The nucleotide sequence matched that expected, based on the amino acid (aa) sequence for papain, with the following exceptions: at aa positions 47, 118 and 135 the codon for glutamate was found instead of glutamine; at aa position 169 the codon for asparagine was found instead of glycine; at aa positions 86-88, a difference in the order of the aa codons was observed, namely tyr-pro-tyr instead of the published pro-tyr-tyr. The upstream sequence revealed that papain is probably synthesized with a 133-aa prosegment, suggesting that the enzyme is synthesized as an inactive zymogen. The downstream segment revealed an unusual (AT)9AGAA sequence beginning 26 bp from the double TGA stop codon.

Oligonucleotide-directed mutagenesis as a general and powerful method for studies of protein function.

We have used oligonucleotide-directed mutagenesis to make a specific change in the beta-lactamase (EC 3.5.2.6) (ampicillin resistance) gene of the plasmid pBR322. Evidence suggests that the active site for this enzyme may include a serine-threonine dyad (residues 70 and 71). By priming in vitro DNA synthesis with a chemically synthesized 16-base oligodeoxyribonucleotide, we have inverted the Ser-Thr dyad to Thr-Ser and thereby generated a mutant with an ampicillin-sensitive phenotype. This "double-mismatch" method is relatively simple and also very general because detection of mutants is at the level of DNA and involves only colony hybridization. Accordingly, the procedure can be applied to any DNA sequence and does not depend on the phenotype of the mutant.

Two-dimensional gel electrophoresis of 125I-labeled surface proteins of human fibroblasts.

Human fibroblasts were labeled by the 125I-lactoperoxidase technique and the sodium dodecyl sulfate soluble proteins examined by two-dimensional gel electrophoresis to determine the charge heterogeneity of the surface proteins and test for differences in surface proteins in several hereditary disorders. Approximately 80 polypeptides were observed. Those below 65 000 daltons tended to occur as single spots, while those of higher molecular weight were often present as a series of polypeptides of similar molecular weight (charge isomers). The possible role of these proteins in cell-cell recognition is discussed.

Delayed lysis with a mutant of salmonella bacteriophage p22.

A mutant of bacteriophage P22 (Lys(-)) was isolated which shows a plaque morphology on mixed plates comparable to the r(+) plaques of the T-even phages. When Lys(-) and normal Lys(+) plaques are juxtaposed on a petri dish, the Lys(+) plaque exhibits a flat side adjacent to the Lys(-) plaque. The mutant is identical to P22 under an electron microscope, is inactivated at the same rate by antiserum and heat, and has the same kinetics of attachment. It does not plate on Salmonella lysogenic for phage P22 nor on strain St/22. In liquid culture, the lysis of mutant infections in M9CAA medium is delayed between 20 and 40 min. Cells mixedly infected in M9CAA with Lys(-) and Lys(+) phage lyse later than Lys(+)-infected cells and even later than Lys(-)-infected cells. In unsupplemented M9 medium, however, mixedly infected cells again lyse later than Lys(+)-infected cells, but Lys(-)-infected cells require more than 3 hr to lyse. In supplemented and unsupplemented M9 media, intracellular phage development and endolysin synthesis proceed in Lys(-) infections at least as rapidly as in Lys(+)-infected cells. In diluted infections, the latent and eclipse periods of Lys(-) and Lys(+) infections are indistinguishable. The possible mechanisms involved in the control and timing of lysis are discussed.

Delayed lysis with salmonella bacteriophage p22: induction of lysis by addition of cysteine or histidine to the growth medium.

A mutant (Lys(-)) of Salmonella bacteriophage P22 showed a delay in lysis of more than 3 hr in infections in unsupplemented M9 medium. The infected cells were induced to lyse during that interval by addition of histidine or sulfhydryl compounds cysteine, mercaptoethanol, glutathione, or ergothioneine. Urocanic acid, the first intermediate in the catabolic histidine pathway, did not induce lysis, nor did histamine, imidazolelactate, or carnosine. None of the other amino acids common to protein had any inductive effect. Both the d and l forms of histidine were effective in inducing lysis, suggesting that the incorporation of the histidine into protein is not involved. Chloramphenicol inhibited lysis when added at 60 min with or without histidine, but did not inhibit the induction of lysis when added with cysteine. Bacterial cells infected with Lys(+) phage were induced to lyse prematurely when cysteine was added at 30 min but not at 20 min of infection. Iodoacetate inhibited lysis of Lys(+)-infected cells when added at 20 min but not at 30 min.