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Biomedical subjects

J Cole

Publications and source records attributed to J Cole.

At least 91 records · Page 5Linked to original sources
PubMed1996

Escherichia coli K-12 genes essential for the synthesis of c-type cytochromes and a third nitrate reductase located in the periplasm.

The 'aeg46.5' operon was originally detected as an 'anaerobically expressed gene' located at minute 46.5 on the Escherichia coli linkage map. Subsequent results from the E. coli Genome Sequencing Project revealed that the 'aeg46.5' promoter was located in the centisome 49 (minute 47) region. Downstream from this promoter are 15 genes, seven of which are predicted to encode a periplasmic nitrate reductase and eight encode proteins homologous to proteins essential for cytochrome c assembly in other bacteria. All of these genes, together with the 'aeg46.5' promoter, have been subcloned on a 20kb EcoRI fragment from Kohara phage 19D1. Evidence is presented that, as predicted, the region includes structural genes for two c-type cytochromes of mass 16kDa and 24 kDa, which are transcribed from the previously described 'aeg46.5' promoter, and that the first seven genes encode a functional nitrate reductase. We, therefore, propose that they should be designated nap (nitrate reductase in the periplasm) genes. Plasmids encoding the entire 20kb region, or only the downstream eight genes, complemented five mutations resulting in total absence of all five known c-type cytochromes in E coli, providing biochemical evidence that these are ccm (for cytochrome c maturation) genes. The ccm region was transcribed both from the FNR-dependent, NarL- and NarP-regulated nap promoter (formerly the 'aeg46.5' promoter) and from constitutive or weakly regulated promoters apparently located within the downstream nap and ccm genes.

Amino Acid Sequence↗
PubMed1996

Immune responsiveness in a rat model for type II diabetes (Zucker rat, fa/fa): susceptibility to Candida albicans infection and leucocyte function.

There is a causal relationship between obesity-associated diabetes and an increased risk of infection. The ability of obese (fa/fa) Zucker rats, a model for non-insulin-dependent diabetes mellitus (NIDDM), to clear Candida albicans from the circulation and tissues was compared to that of lean (Fa/fa, Fa/Fa) Zucker rat controls as a measure of immune function. The ID50 necessary to establish tissue colonisation in lean Zucker rats was 1.18 log10 times greater than that determined for the obese Zucker rats. Nine days after intravenous (i.v.) injection of a yeast suspension, the organs of obese rats had a 10-fold greater yeast/g organ burden than did lean rats. The kidney was determined to be the primary target organ for colonisation. Germ-tube formation by C. albicans occurred at a rate 1.5 times faster in serum from obese rats than in serum from lean rats. Peritoneal polymorphonuclear leucocytes, resident macrophages and thioglycollate-elicited macrophages from lean Zucker rats displayed a significantly higher ability to kill ingested yeast cells than analogous cell populations from obese Zucker rats.

Animals↗
PubMed1996

Carpal tunnel syndrome: evaluation of a new method of assessing median nerve conduction at the wrist.

OBJECTIVE: To compare median nerve conduction velocity measured using a new, portable electroneurometer with measurements made using conventional hospital nerve conduction apparatus. METHODS: Twenty five patients were studied who were consecutively referred to a hospital neurophysiology department with a clinical diagnosis of carpal tunnel syndrome. Sensory and motor latencies for the median nerve at the wrist were measured bilaterally using the portable electroneurometer and a Medilec MS 92 hospital apparatus operated by a trained technician. RESULTS: There was strong agreement between motor latency values obtained by the two techniques (r = 0.89, p < 0.001; mean difference -0.03 ms, limits of agreement -0.33 to 0.27 ms). Sensory latencies were less easy to detect with the electroneurometer, and correlated less well with the hospital apparatus (r = 0.78, p < 0.001; mean difference -0.16 ms, limits of agreement -0.50 to 0.18 ms). CONCLUSION: The portable electroneurometer provides a convenient, rapid, and inexpensive means of assessing median nerve conduction velocity at the wrist. Measurements of motor latency obtained with this new instrument agree more strongly with those made by conventional apparatus than do measurements of sensory latency. Although the utility of the instrument in clinical practice will be limited, it provides a helpful tool in epidemiological studies of carpal tunnel syndrome.

Adult↗
PubMed1996

Local anaesthesia for major general surgical procedures. A review of 116 cases over 12 years.

Between 1980 and 1992, 116 patients had either a simple mastectomy (32) or intra-abdominal procedures (84) under local anaesthesia (0.5-1% lignocaine with 1:200 000 adrenaline). A wide variety of general surgical procedures were feasible using only supplementary intravenous sedation (54%). Complications were uncommon and related to surgical procedure (three incorrect diagnoses, three procedures impossible) rather than the anaesthetic technique. There were no anaesthetic toxicity or postoperative problems. Local anaesthesia is extremely safe and facilitates larger surgical procedures than is generally appreciated.

Abdomen↗
PubMed1996

Self-moved target eye tracking in control and deafferented subjects: roles of arm motor command and proprioception in arm-eye coordination.

1. When a visual target is moved by the subject's hand (self-moved target tracking), smooth pursuit (SP) characteristics differ from eye-alone tracking: SP latency is shorter and maximal eye velocity is higher in self-moved target tracking than in eye-alone tracking. The aim of this study was to determine which signals (motor command and/or proprioception) generated during arm motion are responsible for the decreased time interval between arm and eye motion onsets in self-moved target tracking. 2. Six control subjects tracked a visual target whose motion was generated by active or passive movements of the observer's arm in order to determine the role played by arm proprioception in the arm-eye coordination. In a second experiment, the participation of two subjects suffering complete loss of proprioception allowed us to assess the contribution of arm motor command signals. 3. In control subjects, passive movement of the arm led to eye latencies significantly longer (130 ms) than when the arm was actively self-moved (-5 ms:negative values meaning that the eyes actually started to move before the target) but slightly shorter than in eye-alone tracking (150 ms). These observations indicate that active movement of the arm is necessary to trigger short-latency SP of self-moved targets. 4. Despite the lack of proprioceptive information about arm motion, the two deafferented subjects produced early SP (-8 ms on average) when they actively moved their arms. In this respect they did not differ from control subjects. Active control of the arm is thus sufficient to trigger short-latency SP. However, in contrast with control subjects, in deafferented subjects SP gain declined with increasing target motion frequency more rapidly in self-moved target tracking than in eye-alone tracking. 5. The deafferented subjects also tracked a self-moved target while the relationship between arm and target motions was altered either by introducing a delay between arm motion and target motion or by reversing target motion relative to arm motion. As with control subjects, delayed target motion did not affect SP latency. Furthermore, the deafferented subjects adapted to the reversed arm-target relationship faster than control subjects. 6. The results suggest that arm motor command is necessary for the eye-to-arm motion onset synchronization, because eye tracking of the passively moved arm was performed by control subjects with a latency comparable with that of eye-alone tracking of an external target. On the other hand, as evidenced by the data from the deafferented subjects, afferent information does not appear to be necessary for reducing the time between arm motion and SP onsets. However, afferent information appears to contribute to the parametric adjustment between arm motor command and visual information about arm motion.

Adult↗
PubMed1996

"A sudden and terrible revelation": motherhood and infant mortality in France, 1858-1874.

In 1874, legislators in France passed a law regulating the wet-nursing industry. Citing recent medical research into the causes and social costs of high infant mortality, the law's supporters met little opposition, despite the fact that the law challenged the tradition of paternal authority and familial autonomy that had been inscribed in French law since the promulgation of the Civil Code of 1804. Extending state power into the familial realm required a concerted effort by reformers, who concentrated on two issues: maternal responsibility for newborn infants and the social costs of early death. Because working women in urban areas used wet-nurses to preserve their wage-earning capacity, reformers capitalized on widespread opposition to women's labor outside the home. The law met little opposition in part because the issues of paternal authority had already been thoroughly debated several months earlier in the child labor law of 1874.

Breast Feeding↗
PubMed1996

Lack of evidence for an association between the frequency of mutants or translocations in circulating lymphocytes and exposure to radon gas in the home.

Radon measurements in the living room and main bedroom of 41 houses in the town of Street, Somerset, England have been made. Exposure levels, weighted using the formula of the UK National Radiological Protection Board, of 19-484 Bq m-3 (about half > 100 Bq m-3) were found. Blood samples were obtained from a total of 66 occupants in these homes, and the frequency of genetic alterations in lymphocytes was estimated using two different end points. Gene mutations at the hypoxanthine guanine phosphoribosyl transferase locus were determined in T lymphocytes for 65 subjects using a clonal assay, and the frequency of the BCL-2 t(14;18) translocation, a chromosomal event associated with leukemia/lymphoma, was estimated in lymphocytes using a polymerase chain reaction-based technique for 64 subjects. In neither case was a significant correlation with radon levels in the home found, in contrast to our earlier observation with a smaller series.

Adult↗
PubMed1996

Healthy People 2000 Goal 1.12: primary care physicians and exercise counseling.

The Healthy People 2000 Goal 1.12 was designed to increase to 50% the number of primary care physicians who regularly counsel their patients concerning the appropriate frequency, duration, type and intensity of exercise. To assess the overall progress in relation to this goal, a survey of 212 physicians was conducted in an eight county region of northern Mississippi. Fifty-nine physicians completed and returned the survey. The findings indicate that 90% of the physicians perceive exercise to be important and that they are discussing exercise with approximately 50% of their patients aged 40 and older. However, the average length of the counseling segment is two minutes or less. It is therefore probable that the appropriate frequency, duration, type and intensity of exercise may not be adequately discussed during physician-based exercise counseling.

Adult↗
PubMed1995

Analysis of TYA protein regions necessary for formation of the Ty1 virus-like particle structure.

The yeast retrotransposon, Ty1, produces a macromolecular structure known as a virus-like particle (VLP) as an essential part of its replication cycle. The Ty1 Gag-like structural protein TYA, p1-440, alone is capable of directing assembly of the VLP. In order to determine the TYA sequences required for assembly, we have produced a series of truncated and deleted TYA forms and assessed their ability to assemble into particles. Removal of 100 amino acids from the C-terminus renders the TYA protein, p1-340, incapable of particle assembly; however, p1-363 with 77 residues missing from the C-terminus is capable of assembly. Removal of 40 amino acids from the N-terminus (p41-440 and p41-381) does not affect particle formation but more severely N-truncated forms, p71-381 and p100-381, are present as large aggregates within the cells and are therefore either incapable of or unavailable for VLP formation. Analysis of an internally deleted TYA, p1-381 delta 62-114, has identified this as a possible region of the TYA protein important for subunit:subunit interactions during the particle assembly.

Fungal Proteins↗
PubMed1995

Reporter genes and fluorescent probes for studying the colonisation of biofilms in a drinking water supply line by enteric bacteria.

Biofilms containing diverse microflora were developed on bitumen-painted steel and glass tiles suspended in a chemostat model of a water distribution system. Escherichia coli, taken from a naturally occurring biofilm, was transformed with a plasmid containing the anaerobically induced nirB promoter fused to the lacZ reporter gene. The resulting transformant, PRB1, was introduced into the chemostat. After 7 and 13 days, an E. coli strain with an anaerobically induced Lac+ phenotype was present in the biofilm. Development of an episcopic differential interference contrast technique combined with UV fluorescence microscopy enabled the simultaneous visualization of E. coli in the biofilm using a fluorescent probe to detect expression of the gusA reporter gene and a lacZ fluorescent probe to monitor anaerobic expression of beta-galactosidase from pnirB.

Biofilms↗
PubMed1995

U.v.-hypermutability of xeroderma pigmentosum cells demonstrated with a DNA-based mutation system.

We have developed a DNA-based system, to detect mutations at restriction sites without any selection in culture. DNA is exhaustively digested with a restriction enzyme. Primers flanking a chosen site for this enzyme are used in the polymerase chain reaction (PCR). Only DNA molecules mutated at the chosen site are resistant to digestion and can serve as templates for the PCR. We have initially used this system to demonstrate the generation of mutations by ethyl methanesulphonate (EMS) at a TaqI site in the aprt gene of Chinese hamster cells, and by u.v.-C irradiation at a TaqI site in the hprt gene of human fibroblasts. In repair-deficient xeroderma pigmentosum (XP) cells the u.v.-induced mutant frequency was greatly enhanced. We have been able to detect and analyse mutations in XP cells at TaqI sites in three different genes, hprt, p53 and c-Ha-ras1. Both u.v.-C and u.v.-B irradiation have been used as mutagenic agents with both lymphoblastoid and fibroblast cells from XP patients from complementation group G. The mutant DNA molecules have been sequenced. Following u.v.-C-irradiation, the majority of mutations analysed were GC-->AT transitions, but several double and tandem mutations were also found.

Animals↗
PubMed1995

Determination of hprt mutant and mutation frequencies and the molecular characterization of human derived in vivo T-lymphocyte mutants.

Using a T-lymphocyte clonal assay, 73 6-thioguanine resistant T-lymphocytes were isolated from two blood samples obtained 4 months apart from a 50-year-old male subject. Sixty-six of these mutants were characterized at the DNA sequence level using cDNA. One particular single base substitution was recovered a total of 23 times. The majority of T-cell receptors (TCR) of these mutants all share a common gamma-TCR rearrangement, and thus likely represent a single mutational event that underwent clonal expansion in vivo. Siblings of this clone were recovered in both collections. Three other single base substitutions were also recovered more than once. In two of the three cases, the mutants were also found to be clonally related, while in one case they were not. A number of identical exon loss events were also recovered, yet none of these were clonally related. This probably reflects the multiple pathways by which these mutations can arise. The TCR data was used to correct the observed mutant frequency to produce an estimate of the actual mutation frequency. The two mutant frequencies, 18 x 10(-6) and 19 x 10(-6), obtained from the first and second sampling periods, respectively, can thus be corrected to yield true mutation frequency's of 12 x 10(-6) each.

Base Composition↗
PubMed1995

An essential role for DsbA in cytochrome c synthesis and formate-dependent nitrite reduction by Escherichia coli K-12.

An Escherichia coli K-12 mutant, isolated on the basis of its inability to catalyze formate-dependent nitrite reduction, was characterized. The mutant was defective in the synthesis of all known c-type cytochromes during anaerobic growth. The mutation was localized by conjugation, transduction, and Southern blotting experiments to the dsbA gene at minute 87 on the E. coli chromosome and was complemented by the wild-type allele. Both DsbA and the recently described DipZ protein were shown to be essential for cytochrome c synthesis, suggesting that they act sequentially in a pathway for cytochrome c assembly in the E. coli periplasm.

Bacterial Proteins↗
PubMed1995

Suggestions concerning the relationship between mutant frequency and mutation rate at the hprt locus in human peripheral T-lymphocytes.

Mutant frequency is defined as the proportion of mutant cells in a population and is readily estimated. It should be distinguished from mutation rate, which relates to the rate at which mutation events arise, and is generally expressed as events per cell division. Since one mutation event may give rise to one or many mutant cells, depending on the generation in which it has arisen, the relationship of mutant frequency to the underlying mutation rate is complex. A large number of estimates of mutant frequency at the hprt locus in human lymphocytes are available, from our two laboratories among others. From our two extensive data sets, we have determined median hprt mutant frequencies of different age groups and used the method of Lea and Coulson (J. Genet., 49, 1949, 264-285) to attempt to estimate the underlying mutation rate at this locus. It is in principle possible to obtain estimates of mutation rate from the mutant frequency in newborns, from the increase in mutant frequency with age, and from the difference between the upper and lower quartile mutant frequencies. We discuss reasons for the discrepancies between these estimates and argue that the best estimate can probably be obtained from the increase in mutant frequency with age. We arrive at an estimate of mutation rate to 6-thioguanine resistance at the hprt locus of about 5 x 10(-7) mutation events per nominal cell division.

Adolescent↗
PubMed1995

A serum-sensitive, sialyltransferase-deficient mutant of Neisseria gonorrhoeae defective in conversion to serum resistance by CMP-NANA or blood cell extracts.

A stable, sialyltransferase-deficient mutant of Neisseria gonorrhoeae strain F62 totally defective in CMP-NANA-dependent lipopolysaccharide (LPS) sialylation was isolated by insertion mutagenesis with transposon Tn 1545-delta 3 and screened for unlabelled colonies following incubation with CMP-14C-NANA. In contrast to the parental strain which became serum resistant on incubation with CMP-NANA or blood cell extracts, the mutant, JB1, remained serum sensitive. French press extracts of strain F62 catalysed LPS sialylation, but corresponding extracts of the mutant were inactive. Five LPS components were detected by SDS-PAGE in the parental strain. Five components of the same Mr were also found in the mutant. Three identical components were detected by Western blotting using MAb 3F11, which recognizes the Gal beta 1-4GlcNAc groups in the conserved LPS components of F62 which can be sialylated. The mutant, JB1, is therefore deficient in the sialyltransferase that is essential for both LPS sialylation and conversion of serum-sensitive gonococci to serum resistance by either CMP-NANA or blood cell extracts. No evidence was obtained for an LPS sialylation pathway by blood cell extracts that is independent of CMP-NANA.

Antibodies, Monoclonal↗
PubMed1995

The Birmingham mummy: the first torticollis in history.

The Birmingham Mummy is of a warrior, 25-35 years of age, from the Graeco-Roman period. He was struck from the front by an arrow, which penetrated the soft tissues of the neck to some depth and lodged in the right infratemporal fossa. It is suggested that the wound became infected and that muscle spasm induced the torticollis which was not fully corrected on mummification.

Egypt↗