Assessment of a new Goldmann applanation tonometer.

BACKGROUND/AIMS: The classic Goldmann applanation tonometer (GAT) has been further developed by Haag-Streit International. The applanation principle has been retained, while the internal force transmission and the pressure gauging have been optimised, the display of results digitised. The authors compared the GAT standard with the new GAT digital. METHODS: Four fixed tonometer pairs were used. The protocol included: non-contact pachymetry, slit-lamp examination, three consecutive measurements with each tonometer with a 5 min interval in between, check for side effects in 15 min. Three groups (intraocular pressure (IOP) levels) were defined: (1) IOP ≤ 16; (2) IOP>16 and <23; (3) IOP ≥ 23 mm Hg. RESULTS: 125 Patients (250 eyes) were evaluated. IOP (mm Hg), GAT standard versus GAT digital, for the rights eyes was: Group 1: 12.94 ± 0.55 versus 13.11 ± 0.53, p=0.71. Group 2: 18.26 ± 0.59 versus 18.03 ± 0.52, p=0.53; Group 3: 30.28 ± 0.48 versus 30.42 ± 0.41, p=0.97; all right eyes: 17.48 ± 7.48 versus 17.73 ± 7.4, p=0.99. For the left eyes, there was no significant difference, either. The correlation was very good and was not influenced by the IOP level. The Pearson coefficient for the right eye was 0.985, and for the left eye 0.994. In the Bland-Altman analysis, although there were two single readings that differed by as much as 5 mm Hg, GAT digital measures showed almost no skew, and the mean difference was 0.03 ± 1.23 mm Hg (n=250). A multiple regression analysis showed no influence of order of measurement, eyeside or pachymetry. CONCLUSIONS: The new GAT digital is as reliable and safe as GAT standard. IOP values correlate well. It offers a digitised display and a wireless transfer of data. The display of values up to the first decimal digit is not necessarily associated with a more precise measurement, but may offer an additional comfort compared with the 2 mm Hg scale of the classic GAT.

Genetic analysis of long-term Barrett's esophagus epithelial cultures exhibiting cytogenetic and ploidy abnormalities.

BACKGROUND & AIMS: Progression to cancer in Barrett's esophagus occurs through an accumulation of cell cycle and genetic abnormalities that have been documented in vivo. To better study neoplastic evolution in Barrett's esophagus, the aim of this study was to establish in vitro cultures from preneoplastic tissues. METHODS: Mechanical and enzymatic dissociation methods were used to initiate Barrett's epithelial cultures from endoscopic biopsy specimens, and the cells were characterized using flow-cytometric, cytogenetic, and molecular genetic analyses. RESULTS: Four long-term cultures were established from 39 attempts. All cultures contain cytogenetic abnormalities and elevated flow-cytometric 4N DNA content fractions. Molecular genetic abnormalities detected include the following: 9p and/or CDKN2/p16 abnormalities in 4 of 4 cultures, 17p loss of heterozygosity and p53 mutation in 3 of 4 cultures, and 5q loss of heterozygosity in 1 of 4 cultures. Inactivation of p53 was statistically associated with successful long-term culture. CONCLUSIONS: These cultures contain cell cycle and molecular genetic abnormalities that closely parallel those previously documented to occur early in cancer development in Barrett's esophagus in vivo. These alterations also appear to be associated with successful growth in vitro. The cultures may provide a premalignant in vitro system in which to test potential therapies for Barrett's esophagus as well as to examine etiologic factors and genetic intermediates important in neoplastic progression.

TnrA, a transcription factor required for global nitrogen regulation in Bacillus subtilis.

Expression of the Bacillus subtilis nrgAB operon is derepressed during nitrogen-limited growth. We have identified a gene, tnrA, that is required for the activation of nrgAB expression under these growth conditions. Analysis of the DNA sequence of the tnrA gene revealed that it encodes a protein with sequence similarity to GlnR, the repressor of the B. subtilis glutamine synthetase operon. The tnrA mutant has a pleiotropic phenotype. Compared with wild-type cells, the tnrA mutant is impaired in its ability to utilize allantoin, gamma-aminobutyrate, isoleucine, nitrate, urea, and valine as nitrogen sources. During nitrogen-limited growth, transcription of the nrgAB, nasB, gabP, and ure genes is significantly reduced in the tnrA mutant compared with the levels seen in wild-type cells. In contrast, the level of glnRA expression is 4-fold higher in the, tnrA mutant than in wild-type cells during nitrogen restriction. The phenotype of the tnrA mutant indicates that a global nitrogen regulatory system is present in B. subtilis and that this system is distinct from the Ntr regulatory system found in enteric bacteria.

Role of CodY in regulation of the Bacillus subtilis hut operon.

Bacillus subtilis mutants deficient in amino acid repression of the histidine utilization (hut) operon were isolated by transposon mutagenesis. Genetic characterization of these mutants indicated that they most likely contained transposon insertions within the codVWXY operon. The codY gene is required for nutritional regulation of the dipeptide permease (dpp) operon. An examination of hut expression in a delta codY mutant demonstrated that amino acid repression exerted at the hutOA operator, which lies immediately downstream of the hut promoter, was defective in a delta codY mutant. The codY gene product was not required for amino acid regulation of either hut induction or the expression of proline oxidase, the first enzyme in proline degradation. This indicates that more than one mechanism of amino acid repression is present in B. subtilis. An examination of dpp and hut expression in cells during exponential growth in various media revealed that the level of CodY-dependent regulation appeared to be related to the growth rate of the culture.

A Streptococcus mutans mutant that synthesizes elevated levels of intracellular polysaccharide is hypercariogenic in vivo.

We used the streptococcal transposon, Tn916 to identify and isolate mutants of Streptococcus mutans with altered intracellular polysaccharide (IPS) accumulation. We report on the isolation and characterization of S. mutans SMS202, a transposon mutant which accumulated the glycogen-like IPS in excess of wild-type levels. Southern blot analysis confirmed a single Tn916 insertion into the SMS202 chromosome. Moreover, quantitative ultrastructural analysis revealed significantly increased concentrations of IPS in SMS202 relative to those of the wild-type progenitor strain, UA130. The activities of ADPglucose pyrophosphorylase (GlgC) and glycogen synthase (GlgA), enzymes required for the biosynthesis of bacterial IPS, were also elevated in the IPS excess mutant. Furthermore, SMS202 was significantly more cariogenic on the molar surfaces of germ-free rats than the wild type (P < 0.01), thus confirming a central role for IPS in S. mutants-induced caries formation. We propose that the increased cariogenic potential of SMS202 is due to constitutive expression of genes which encode glycogen biosynthesis in this oral pathogen. The coordinate expression of GlgC and GlgA along with the results of ongoing nucleotide sequence analysis and Northern hybridization experiments support an operon-like arrangement for the glg genes of this oral pathogen.

Fluorescein angiography complication survey.

This is a report on the results of a national survey designed to study the nature and frequency of moderate and severe complications of intravenous fluorescein angiography. In this survey, 2434 responding ophthalmologists reported on 221,781 fluorescein angiograms performed in the year 1984. Adverse reactions were classified as mild, moderate, severe, and death, depending on the duration of the effect, the necessity for medical intervention, the time required for its resolution, and the final outcome. The frequency rate for a moderate reaction was (1:63), for a severe reaction (1:1900), and for death (1:222,000). A review of previous studies on adverse reactions to the drug, a compilation of suggested methods for the amelioration and prevention of the complications, and a comparison of the responses of the general ophthalmic public to the members of The Macula Society are also reported.

The atherosclerotic ascending aorta and transverse arch: a new technique to prevent cerebral injury during bypass: experience with 13 patients.

Calcification of the ascending aorta and transverse arch significantly increases morbidity and may compromise the completeness of cardiac surgical procedures. Several stratagems have been suggested to reduce the risk, but for some patients this finding is still associated with a devastating outcome, irrespective of the technique employed. Thirteen patients (7 men and 6 women with a mean age of 66 years) with extensive calcification in the ascending aorta and transverse arch underwent cardiopulmonary bypass (CPB). The presence of calcification was known prior to CPB in 12 patients and noted after cross-clamping of the aorta in 1 patient. Special techniques for cannulation of the ascending aorta or arch were undertaken in 12 patients; 1 patient required groin cannulation. In 12 patients CPB with gradual core cooling to 18 degrees C was done, during which time no manipulation of the aorta was allowed. Circulatory arrest was then initiated for 3.5 to 12 minutes. The aorta was opened widely during this time to remove ulcerated plaques and friable debris, and to locate a safe place for aortic occlusion. All patients recovered without neurological complications. In 1 patient, in whom occipital lobe infarcts developed, calcification was discovered after the aorta had been cross-clamped and necessitated subsequent endarterectomy of the ascending aorta and transverse arch.(ABSTRACT TRUNCATED AT 250 WORDS)

Rehabilitation in spinal cord injury: use of a patient-family group.

A 1-day group meeting for spinal cord injured individuals and their families was initiated approximately 3 years ago with emphasis on providing information and sharing mutual concerns and feelings. From the results of tests administered before and after the program and of evaluation forms filled out by all participants, the Family Group has been found to be a useful adjunct to the rehabilitation program. Family members are effectively and meaningfully involved in the total rehabilitation process with the added benefit of decreasing their feelings of anxiety, helplessness and isolation. Evaluation suggests that the Family Group increases the individual's knowledge and awareness of a disability and its implications. It has introduced important topics of discussion within the family unit and has aided in more open communication among family members surrounding these issues. All of these benefits, combined, have resulted in more effective, realistic and appropriate discharge planning for patients.