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Biomedical subjects

J L Pearce

Publications and source records attributed to J L Pearce.

At least 19 recordsLinked to original sources
PubMed2003

Serotypes of Escherichia coli isolated from healthy infants in Berlin, Germany and Melbourne, Australia.

The characterization of Escherichia coli strains isolated from healthy infants under one year of age with respect to O:H serotype, K1 and K5 antigens in two disparate parts of the developed world was the purpose of this investigation. A total of 450 strains were examined, 264 from Berlin and 186 from Melbourne. Of all the 220 different O:H serotypes found, 179 were only isolated once, 90 in Berlin and 89 in Melbourne. However, 30 of the 41 O:H serotypes (73.2%) found more than once were isolated in both centers. The most commonly identified serotypes were found in both centers and included O1:H-; O1:H7; O2:H2; O2:H4; O2:H7; O4:H5; O6:H-; O6:H1; O15:H1; O18:H7; O25:H1; and 075:H-. Potentially pathogenic serotypes were found in both cities. Enteropathogenic E. coli (EPEC)-associated serotypes (O18:H7; O26:H-; O44:H34; O86:H-; O128:H2) were present in 11 cases and enterohaemorrhagic E. coli (EHEC)-associated types including O26:H11; O128:H2) were present in four cases. The distributions of serotypes found were similar in the two cities, strongly suggesting the wider applicability of these results.

Berlin↗
PubMed1999

Sudden infant death syndrome: what questions should we ask?

A limited historical perspective can affect the questions we pose about the sudden infant death syndrome (SIDS) issue. Evidence is presented from the literature that the SIDS rate in Western countries was low prior to World War II and peaked in the 1980s. An analogy is drawn with the trends in the prevalence of some infectious diseases, and questions are posed from the perspective of a bacterial toxin hypothesis of SIDS causation.

Bacterial Toxins↗
PubMed1999

Extraintestinal Escherichia coli isolations from SIDS cases and other cases of sudden death in Victoria, Australia.

This investigation is an extension of previous studies on the possible role of intestinal Escherichia coli in sudden infant death syndrome (SIDS) to include the isolation of extraintestinal E. coli. The lungs of 52 and the blood of 144 SIDS infants were cultured and isolates were investigated. E. coli was isolated from about a quarter of post-mortem lung samples and about 15% of blood samples from SIDS infants. The isolates were subjected to microbiological studies, including serotyping and haemolysin assays. The majority were found to belong to serogroups commonly associated with bacteraemia. These results may indicate that extraintestinal E. coli plays a role in SIDS.

Autopsy↗
PubMed1997

Multifocal intraocular lenses.

It has been 10 years since I implanted the first multifocal intraocular lens (IOL). Unfortunately, there has been a gradual lessening of commitment to this modality by the ophthalmic community. The most important single factor for this lack of interest despite the more than adequate available clinical data is the repeated moving of "goal posts" by the American FDA when a multifocal lens style nears premarket approval. The refractive multifocal lens styles of iolab (Claremont, CA), Stortz Ophthalmics (St. Louis, MO), Domilens (Lyon, France), and Amo with the diffractive multifocals of 3M (St. Louis, MO), and Pharmacia (Kalamazoo, MI) and their recent modifications are reviewed. Reports show that they generally give excellent visual results depending on whether a near or distance dominant lens is indicated. The foldable Amo Array SA40N provides a good distance dominant foldable lens for the surgeon performing small incisions and has a small but dedicated surgical following. Loss of contrast sensitivity at low-light levels remains a source of concern in certain professions and with certain lifestyles, and a report suggesting that many monofocal and multifocal patients do not achieve the standards set for night driving by the German Ophthalmic Society warrants further consideration. Development of a new accommodative IOL for small incision surgery is the only really new concept, and it will be interesting to see the results of independent reports. Spectacle dependence is considerably reduced with all the current multifocals when compared to monofocals, and for patients there are ample multifocal lens styles from which to choose. It is the author's opinion that more than 60% of the cataract population is currently suitable for multifocals if small incision surgery is performed. More multifocals would be used if price disparity with monofocals was reduced.

Humans↗
PubMed1996

Phacoemulsification versus endocapsular cataract extraction in a unique cohort of patients.

The visual recovery and refractive results of 33 consecutive patients (66 eyes) undergoing standard endocapsular cataract extraction in one eye and simultaneous phacoemulsification in the fellow eye are reported. One surgeon performed all the operations. Surgically induced astigmatism was evaluated for the two techniques in terms of: (1) the proportion of eyes with a refractive cylinder of 1.5 dioptres (D) or less; (2) the interocular difference in post-operative astigmatism. Eyes undergoing phacoemulsification had a significantly lower mean induced cylinder (paired Student's t-test: t = 3.729; p < 0.001) and were more likely to exhibit a cylinder of 1.5 D or less (chi-squared test with Yates' correction: chi 2 = 7.88; p < 0.01) than the nuclear expression group. For paired eyes less post-operative astigmatism (Wilcoxon's signed rank test: T = 92; p < 0.01) was seen in the phacoemulsification eye. At the time of the last post-operative assessment a significantly higher proportion of phacoemulsified eyes achieved a corrected Snellen visual acuity of 6/6 or better than their fellow eyes (McNemar's test: p < 0.01). The results of this unique cohort of patients confirm the beneficial effects of phacoemulsification on astigmatism and visual outcome in the early post-operative period.

Aged↗
PubMed1996

Multifocal intraocular lenses.

Since the publication of my last article in Current Opinion in Ophthalmology in 1991 (2:33-34), the use of multifocal intraocular lenses (IOLs) has not gained general acceptance among ophthalmologists. Despite this situation, major IOL companies have continued to invest in clinical trials of new designs. Recently, large optic multifocal lenses used mainly with extracapsular extraction provided good results, with 94% to 100% of best-corrected cases having distance correction of 20/40 vision or better; 77% to 100% similarly had J3 near vision or better, and approximately 52% to 63% of patients became eyeglass independent. Between 50% to 80% of eyes in which 20/40 vision or better was obtained and in which J2 or better resulted were unaided. However, all multifocal lens designs showed some reduction in contrast sensitivity compared with monofocal designs using Regan charts and Vistech 6500 tests. Contrast sensitivity loss was probably only significant when reading very small print or in low-contrast light. Small-incision surgery with phacoemulsification and more accurate IOL power calculations have made the goal of emmetropia more possible. Also, less eyeglass dependence with the use of multifocal IOLs is a more realistic expectation.

Humans↗
PubMed1995

Virulence factors associated with strains of Escherichia coli from cases of sudden infant death syndrome (SIDS).

Strains of Escherichia coli isolated from cases of Sudden Infant Death Syndrome, healthy infants and infants that died of other causes were subjected to a series of tests with particular reference to serotyping, toxigenicity and adherence factors. E. coli from SIDS infants tended to have a low hydrophobicity and high toxigenicity, compared to those from healthy infants, while no notable differences in haemagglutination patterns were observed between these two groups of strains.

Animals↗
PubMed1995

Simultaneous bilateral cataract extraction in the UK.

AIMS/BACKGROUND: Simultaneous bilateral extracapsular cataract extraction (SBCE) is not routinely performed in the developed world. This study investigated the safety and efficacy of this procedure as performed in the UK. METHODS: A review of 319 consecutive patients (638 eyes) who underwent SBCE with posterior chamber intraocular lens implantation is presented. RESULTS: The incidence of intraoperative complications was 7.7%. These included posterior capsule rupture (0.8%) and vitreous loss (0.3%). Postoperative complications were seen in 8.7% of operated eyes and included iris prolapse (0.3%) and raised intraocular pressure (3.0%). Endophthalmitis occurred in one eye (0.15%). There were no major bilateral complications, and, in particular, no cases of bilateral endophthalmitis. Final visual acuities compared favourably with reports for unilateral surgery. Eighty two per cent achieved a final visual acuity of 6/12 or better, and 41% tested 6/6 or better. CONCLUSION: This study illustrates that SBCE is not associated with an increased incidence of complications and that the visual results are good. Where indicated, and under strict surgical protocol, this procedure is safe.

Aged↗
PubMed1993

The isolation of cytotoxic necrotizing factor (CNF)-producing Escherichia coli from the intestinal contents of babies who died of sudden infant death syndrome (SIDS) and other causes as well as from the faeces of healthy babies.

Strains of Escherichia coli producing cytotoxic necrotizing factor (CNF) have been isolated from intestinal contents of 16.8% of babies who died of Sudden Infant Death Syndrome (SIDS) and 16.5% of faeces from healthy babies. While no difference in CNF carriage was seen, it is noteworthy that these CNF-producing E. coli are present in such specimens. Some of the CNF-producing E. coli belonged to serotypes associated with this factor in other parts of the world.

Bacterial Toxins↗
PubMed1992

Distribution of toxigenic Escherichia coli serotypes in the intestines of infants.

As part of an ongoing study into the pathogenesis of sudden infant death syndrome (SIDS), the distribution of serotypes of toxigenic and non-toxigenic Escherichia coli within the gastrointestinal tract of babies who had died was investigated. Escherichia coli isolates from the mid-ileum, colon and rectum of six SIDS cases and one case which had died suddenly and unexpectedly but had underlying cardiac pathology were "O" serogrouped and examined for verocytoxic activity and production of heat-labile enterotoxin. In addition, the effect of storage of gut specimens and rectal swabs at 4 degrees C on isolation of toxigenic strains was studied in three of the cases. A diversity of serogroups and toxigenicity was a general finding, however, strains found in the proximal gut were also cultured from the rectum, indicating that faecal specimens would be a valid tool in investigating the role of these organisms in SIDS cases compared with healthy controls. Storage for up to 5 days at 4 degrees C had no appreciable effect on isolation rates of toxigenic bacteria.

Animals↗
PubMed1992

Intraocular lenses.

I have again reviewed the current state of the art in intraocular lens design in what has been a year of consolidation rather than dramatic discoveries. In foldable lenses, silicone reigns supreme, but there is the promising development of high-refractive-index foldable acrylic lenses. Heparin surface modification is now accepted as valuable in high-risk eyes, but there remains a question mark over surface passivation value. Small-incision lenses continue to proliferate with the design of new haptics to facilitate insertion after circular tear capsulorhexis. Some doubt has been raised concerning the optical qualities of ovoid lenses. Anterior-chamber myopic lenses for phakic myopic patients remain controversial. However, an increasing volume of data concerning their advantages and disadvantages is now available.

Biocompatible Materials↗
PubMed1992

Recessively determined chylous ascites--a case report and possible mouse model.

A male infant, whose parents were first cousins, was born with tense chylous ascites, mild generalized oedema and facial dysmorphism. The baby initially seemed well but subsequently probably aspirated, developed septicaemia and finally died at 26 days from a bleeding diathesis, possibly secondary to liver dysfunction. No cause for the chylous ascites was found at post mortem. This case is presumed to represent an example of recessively determined chylous ascites. The mouse mutant Chy may be an homologous condition.

Animals↗
PubMed1991

Review of a series of disc lens implants.

A consecutive series of 380 patients (431 eyes) implanted with the Pearce Lasadisc Lens are reviewed, of which 225 patients (255 eyes) underwent detailed assessment. The operative technique for implanting the disc lens is described and the importance of superior capsular bag fixation is discussed. Postoperatively 89.9% of eyes achieved a best corrected visual acuity of 6/12 or better. Five (1.2%) of the implants were removed; three due to lens decentration causing visual problems, one after dislocating into the anterior chamber, and one after causing pupil block glaucoma. One implant dislocated into the vitreous.

Adolescent↗
PubMed1991

Intraocular lenses.

In reviewing the 1990 literature on intraocular lenses, it is evident that the increased popularity of phacoemulsification in North America has stimulated interest in lens designs that can be inserted through small incisions, and various methods for folding soft lenses. Critical evaluation of various multifocal lenses has now resulted in greater understanding of their advantages and drawbacks, and it is becoming apparent that there are guidelines of suitable candidates for such lenses. Use of multifocals has stimulated interest in contrast sensitivity testing, and new more accurate lens power formulas. Heparin surface modification of polymethylmethacrylate lenses now seems to be accepted as having value in reducing pigment deposits after surgery. Clinical trials of lenses for patients suffering from age-related macular degeneration hold some promise for this large group of unhappy patients. However, the use of anterior chamber lenses to correct high myopia in phakic eyes is now on hold because of reports of progressive endothelial cell loss in some eyes. More reports are available on the technique and results of suturing posterior chamber lenses to the sclera where there is absent or insufficient capsule to support a conventional sulcus fixated posterior chamber lens. Intraocular lenses remain alive and well in 1990 with increased usage worldwide.

Astigmatism↗