A chronic high alcohol intake was induced in rats through the use of two procedures: the schedule-induced polydipsia technique and the liquid diet technique. Rats consumed 11-12 g of ethanol per kilogram body weight per day for 16 to 18 weeks. Morphologic evidence of a mild distal axonal neuropathy in the ventral caudal nerve was proposed. The red blood cell transketolase levels were normal, indicating that the rats were not deficient in thiamine and suggesting that the axonal degeneration was due to the direct toxic effect of alcohol. Axonal transport studies demonstrated a significant increase in the amount of acetylcholinesterase transported in an orthograde direction in the sciatic nerves of alcohol-exposed rats, and indicated no change in the transport of choline acetyltransferase or in the specific binding of colchicine by neurotubulin.

Acetylcholinesterase↗

PubMedDate not supplied

Dexamethasone modulation of gestation length and parturition in rats.

Dexamethasone blocks aromatase and phospholipase A2 enzyme activities that are essentially involved in the formation of oestrogens and prostaglandins, the key chemicals to initiate parturition. The present study was undertaken to determine whether dexamethasone, a potent glucocorticoid, could prolong gestation and/or delay parturition in rats. Dexamethasone at 0.5 mg/rat/day from Day 19 through Day 21 of pregnancy consistently prolonged gestation. Only 36% of the pregnant rats had labour with an extended parturition time. Foetal mortality rate was also high. The remaining 64% pregnant rats that did not deliver showed intrauterine foetal death and resorption. Concomitant injection of oestradiol cyclopentylpropionate or prostaglandin F2 alpha on Day 19 effectively reversed the deleterious effects of dexamethasone. 100% of the pregnant rats had successful labour at term. The parturition time and foetal mortality rate were not different from controls. The results, therefore, indicate that an excess glucocorticoid that initiates parturition in sheep conversely prolongs gestation and delays parturition in rats.

Animals↗

PubMedDate not supplied

Optimal chemostat cascades for periplasmic protein production.

This theoretical work predicts the optimal system design for the steady-state production of secreted protein in a chemostat cascade, using bakers' yeast (Saccharomyces cerevisiae) as the host organism. The protein of interest, mutant invertase, is secreted to the periplasmic space instead of the culture medium on account of its large size. This work uses the secretion model developed and tested by Park and Ramirez (1988). It is shown that the highest productivity is achieved when the chemostat cascade contains two stages, although the improvement over the single-stage productivity is small. When no recycle is used, the advantage of two stages results from the tradeoff between maximizing the cell concentration and maximizing the rate of protein production per cell. When recycle is used, the cell concentration and protein productivity are increased, and the advantage of two stages results from the tradeoff between maximizing the specific protein production rate and maximizing the specific protein secretion rate. Cascades with three stages were also investigated, but these were found to have no improvement over the corresponding two-stage cascades.

Cloning, Molecular↗

PubMedDate not supplied

Characterization of a novel regulatory gene aepA that controls extracellular enzyme production in the phytopathogenic bacterium Erwinia carotovora subsp. carotovora.

Erwinia carotovora subsp. carotovora strain Ecc71 produces an array of extracellular enzymes including pectate lyase (Pel), polygalacturonase, cellulase, and protease. In strain Ecc71, these enzymes are coregulated by aepA, which encodes an activator of extracellular protein production (H. Murata, J. L. McEvoy, A. Chatterjee, A. Collmer, and A. K. Chatterjee, Mol. Plant-Microbe Interact, 4:239-246, 1991). The nucleotide sequence of a 2.7-kb aepA+ DNA segment revealed an open reading frame (ORF) of 1,395 bp which matches with the size of the aepA transcript determined by Northern blot analysis. aepA is predicted to encode a protein of 465 amino acid residues with a molecular mass of approximately 51 kDa and a pI of 6.52. The occurrence of a putative signal sequence and several hydrophobic domains suggest membrane localization of AepA. An aepA-lacZ operon fusion was constitutively expressed in E. coli (DH5 alpha) but inducible by pectate and celery extract in E. c. subsp. carotovora (AC5006). These findings suggest that aepA expression may be negatively regulated in E. c. subsp. carotovora. By assaying for the transcript of pel-1, which species a major secreted Pel species in strain Ecc71, and by following the expression of a pel1-lacZ operon fusion we determined that AepA activates pel-1 transcription. The characteristics of aepA including the lack of homology with other prokaryotic regulatory genes indicate that aepA encodes a novel regulatory protein required for extracellular protein production. Whereas homologs of Ecc71 aepA occur in E. c. subsp. carotovora and E. c. subsp. atroseptica strains, activation of exoenzyme production is markedly stimulated by aepA in E. c. subsp. carotovora than in E. c. subsp. atroseptica.

Amino Acid Sequence↗

PubMedDate not supplied

Nucleotide sequence of a pectate lyase structural gene, pel1 of Erwinia carotovora subsp. carotovora strain 71 and structural relationship of pel1 with other pel genes of Erwinia species.

Of the various exoproteins secreted by Erwinia carotovora subsp. carotovora strain 71, Pel1 is the major pectate lyase species with tissue macerating activity. Nucleotide sequencing of a 2.2-kb pel1+ DNA segment revealed a 1,122 base pair open reading frame which could encode pre-Pel1 of 374 amino acid residues. A signal peptide of 22 amino acid residues is present within the NH2-terminal region of pre-Pel1. Transcription of pel1 was initiated at the guanine residue 111 base pairs upstream of the start codon. Consensus sequences for the binding of KdgR, a negative regulatory factor known to control some of the E. chrysanthemi pectinases, flank the promoter of pel1. Although pel1 belongs to the pelBC family, it is more closely related to the pel genes of E. carotovora than to the pelBC genes of E. chrysanthemi.

Amino Acid Sequence↗

PubMedDate not supplied

The Severe Mini-Mental State Examination: a new neuropsychologic instrument for the bedside assessment of severely impaired patients with Alzheimer disease.

The bedside and office assessment of cognitive abilities in moderately to severely impaired patients with Alzheimer disease could be enhanced by a well-standardized instrument. The authors' group has developed such an instrument (i.e., Severe Mini-Mental State Examination; SMMSE) to assess this population. Based on the Folstein Mini-Mental State Examination (MMSE), the SMMSE, which totals 30 points, was designed to briefly assess cognitive domains relatively preserved in moderate to severe Alzheimer disease. One hundred eighty-two patients with possible or probable Alzheimer disease were administered both the MMSE and SMMSE. Performances on the SMMSE and MMSE were found to correlate significantly only when MMSE fell below 9 points (p < 0.0001). However, as performance on the MMSE approached floor levels, patients continued to score at half maximal levels on the SMMSE. Functional staging with the Clinical Dementia Rating Scale and the Global Deterioration Scale also were found to significantly correlate with performance on the SMMSE (p < 0.001). Test-retest performance on both the SMMSE and MMSE was relatively stable over a period of 5 months. Inter-rater reliability of the SMMSE was excellent. These results suggest that the SMMSE has both construct and criterion validity for assessing severely impaired Alzheimer disease patients. Our results also suggest that the SMMSE may be a useful instrument for assessing severely impaired patients at the bedside and in the office.

Aged↗

PubMedDate not supplied

Suitable bases for patch testing in tropical countries.

Patients suspected of having contact dermatitis due to topical medicaments were patch tested with various bases to evaluate the most suitable base for tropical countries. Plastibase and polyethylene glycol 400 produced the least positive reactions. Both were therefore found to be suitable bases, although polyethylene glycol had more positive results than plastibase.

Dermatitis, Contact↗