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Biomedical subjects

A Kerr

Publications and source records attributed to A Kerr.

At least 19 recordsLinked to original sources
PubMed1997

Feeding ability in Rett syndrome.

Feeding abilities in 20 individuals with Rett syndrome aged 1 1/2 to 33 years were investigated by history and clinical assessment during a meal, followed by videofluoroscopy of feeding. All were shown to have reduced movements of the mid and posterior tongue, with premature spillover of food and liquid from the mouth into the pharynx. They also showed delayed pharyngeal swallow, but otherwise pharyngeal problems were minimal. These findings were noted to be similar to those in Parkinson's disease. Those individuals with the most general neurological impairment tended to have the worst feeding problems and were smaller and malnourished.

Activities of Daily Living↗
PubMed1996

Studies of liver repopulation using the dipeptidyl peptidase IV-deficient rat and other rodent recipients: cell size and structure relationships regulate capacity for increased transplanted hepatocyte mass in the liver lobule.

The feasibility of liver repopulation with hepatocytes has been shown, although clinical applications demand significant hepatic replacement. To show whether portal vascular bed in large animals could accomodate a greater cell number, we analyzed liver repopulation in syngeneic Fischer 344 rats deficient in dipeptidyl peptidase IV. This system allowed localization of transplanted normal hepatocytes in liver or various ectopic sites, as well as dual studies for analysis of gene expression. Interestingly, the product of a dipeptidyl peptidase IV substrate inactivated bile canalicular adenosine triphosphatase (ATPase) activity in normal but not in dipeptidyl peptidase IV-deficient rats, which allowed localization of dipeptidyl peptidase IV-deficient hepatocytes in normal rat liver for additional reversed transplantation systems. Further studies with genetically marked cells showed that because of the size difference between hepatocytes and portal vein radicles, intrasplenically transplanted cells were distributed in periportal areas (zone 1) in mice, whereas in larger animals (rats or rabbits) cells were also distributed downstream to midlobular (zone 2) or perivenous (zone 3) areas. Transplantation of an escalating number of hepatocytes showed that adult rats tolerated intrasplenic injection of a large cell number in single sessions (up to 1 X 10(8), approximately 10% to 15% of the host hepatocyte mass). Morphometric analysis of recipient livers showed survival of a significantly greater cell number with incorporation in host liver plates. At 4 weeks, transplantation of 2 x 10(7) hepatocytes into adult rats led to a survival of 1.4 +/- 1.0 x 10(6) transplanted cells/cm3 liver, whereas after transplantation of 5 x 10(7) cells or 7.5 x 10(7) cells, the number of surviving transplanted cells in the liver significantly increased to 4.1 +/- 1.4 x 10(6) transplanted cells/cm3 liver (mean, 2.9-fold; P<.003) and 5.5 +/- 1.3 x 10(6) transplanted cells/cm3 liver (mean, 3.9-fold; P<.003), respectively. When cells were injected in greater numbers, transplanted hepatocytes retained normal function and produced more serum albumin or hepatitis B surface antigen in deficient hosts. These data indicate the feasibility in larger animals of significant liver repopulation with hepatocyte transplantation. Use of dipeptidyl peptidase IV-deficient rats should help further analysis of mechanisms in liver repopulation.

Alanine Transaminase↗
PubMed1996

Efficacy and safety of repeated hepatocyte transplantation for significant liver repopulation in rodents.

BACKGROUND & AIMS: Significant liver repopulation by hepatocyte transplantation will advance clinical applications. The aim of this study was to test the hypothesis that translocation of transplanted cells into liver plates will allow repeated cell transplantation for increasing the transplanted hepatocyte mass. METHODS: Hepatocytes were transplanted via spleen from either F344 rats into syngeneic recipients deficient in dipeptidyl peptidase IV or from transgenic hepatitis B surface antigen-producing G26 mice with hepatitis B virus into nontransgenic congeneic recipients. Portosystemic shunting was shown by radiological methods. RESULTS: Repeated hepatocyte transplantation led to progressively increased liver repopulation. Transplantation of 1.75 x 10(8) hepatocytes in three divided doses repopulated more than an estimated 5% of the host rat liver, with 3.8 x 10(6) +/- 0.1 x 10(6) transplanted cells/cm3 liver. This was a tenfold or threefold mean increase in transplanted cell number compared with recipients of 2.0 x 10(7) or 7.5 x 10(7) cells transplanted in single sessions, respectively (P < 0.001). Repeated hepatocyte transplantation interfered with neither cell integrations in liver parenchyma nor secretory function of transplanted cells. Portal hypertension, portasystemic collaterals, or intrahepatic shunting were not observed in cell recipients. CONCLUSIONS: Repeated transplantation of hepatocytes in large numbers is safe and effective and should advance strategies for liver repopulation.

Animals↗
PubMed1996

Vision care requirements among intellectually disabled adults: a residence-based pilot study.

Intellectually disabled adults have an high incidence of visual problems and they are often unable to communicate their visual difficulties. At Lennox Castle and Waverley Park Hospitals, vision care is through referral by medical and nursing staff to designated optometrists and ophthalmologists. This practice has provided a good service when visual difficulties are noticed. The vision care requirements of all residents had not been comprehensively assessed and a new interdisciplinary procedure developed at Waverley Park Hospital had drawn attention to the fact that only 11% had been offered vision assessment within the previous 5 years. In this study, 63 residents without specific referral received a comprehensive visual and medical assessment. The residents ranged from age 20 to 85 years and included the full range of disabilities. Objective assessments, ophthalmoscopy and retinoscopy were generally successful for all levels of disability. Visual acuity and visual fields were tested using methods suitable for nonverbal subjects. Success rates for these subjects were generally good, except in the profoundly disabled group where less than 30% were able to respond. A high prevalence of visual impairment, refractive error, squint and other ocular conditions was found. Visual impairment was most common in the severe and profoundly disabled groups because of optic nerve or cortical dysfunction. New spectacles were recommended for 23 residents (seven others had adequate correction). Nine residents were referred for ophthalmologic consultation, mainly for cataract. Three required monitoring for visual conditions. Thirty-one residents (49%) required no immediate action beyond documentation of the visual status. This study has shown a high prevalence of visual difficulties which were not previously detected. Routine biennial vision assessment of all residents is recommended to allow timely intervention to correct vision problems, and also to provide the necessary information about vision to plan appropriate programmes of activity.

Adult↗
PubMed1996

Endolymphatic sac surgery: why we do not do it. The non-specific effect of sac surgery.

Three of the present authors described a trial in 1981 which showed that cortical mastoidectomy was as effective as an endolymphatic sac shunt in controlling vertigo in patients with Ménière's disease both on a short-term as well as a long-term basis. The hearing was not influenced by the treatment and any change was considered to be the result of time, rather than the effect of the surgery. Upon perusal of the literature only two other studies exist resembling our study, and they both reached the same conclusion, that sac surgery is at best non-specific and at worst of no value. None of the numerous other studies published have convinced the authors that sac decompression is specific in nature. We have also looked at ECoG as a means of proving the specificity of sac operations and come to the same conclusion that the existing information is conflicting and confusing, and cannot be used to prove anything about sac surgery. The present conclusion is therefore that in treating patients with Ménière's disease anything goes, even sac surgery.

Audiometry, Evoked Response↗
PubMed1996

Accuracy of four commercial systems for identification of Burkholderia cepacia and other gram-negative nonfermenting bacilli recovered from patients with cystic fibrosis.

Burkholderia cepacia has recently been recognized as an important pathogen in chronic lung disease in patients with cystic fibrosis (CF). Because of the social, psychological, and medical implications of the isolation of B. cepacia from CF patients, accurate identification of this organism is essential. We compared the accuracies of four commercial systems developed for the identification of nonfermenting, gram-negative bacilli with that of conventional biochemical testing for 150 nonfermenters including 58 isolates of B. cepacia recovered from respiratory secretions from CF patients. The accuracies of the four systems for identifying all nonfermenters ranged from 57 to 80%, with the RapID NF Plus system being most accurate. The accuracies of these systems for identifying B. cepacia ranged from 43 to 86%, with the Remel system being most accurate. Depending on the commercial system, from two to seven isolates were misidentified as B. cepacia. The relatively poor performance of the commercial systems requires that identification of certain nonfermenters be confirmed by conventional biochemical testing. These organisms include B. cepacia, Burkholderia sp. other than B. cepacia, and infrequently encountered environmental species (Pseudomonas and Flavobacterium species). In addition, conventional biochemical testing should be done if a commercial system fails to assign an identification to an organism. Confirmatory testing should preferably be performed by a reference laboratory with experience in working organisms isolated from CF patients.

Bacteriological Techniques↗
PubMed1996

Endovascular graft repair of penetrating subclavian artery injuries.

PURPOSE: Penetrating subclavian arterial injuries are often difficult to treat. Standard surgical techniques require wide exposure and dissection in traumatized areas, which is often challenging. This report summarizes the early results of endovascularly placed stented grafts for the treatment of penetrating subclavian arterial trauma. METHODS: Six patients with penetrating injuries of the subclavian artery had stented grafts inserted to repair five pseudoaneurysms and one arteriovenous fistula. The stented grafts consisted of a polytetrafluoroethylene graft sutured over a balloon-expandable Palmaz stent. The devices were inserted from an ipsilateral brachial arteriotomy and deployed using fluoroscopic guidance in the operating room. RESULTS: Immediate success was obtained in all procedures (100%). All patients continue to have patent grafts with a follow-up ranging from 7 to 30 months (mean 19 months). The only procedure-related complication was the need for a brachial artery patch angioplasty at the site of device insertion in the first patient. There was one other patient who developed a stent fracture at 8 months; a second stent was inserted. Duplex studies up to 24 months later show no recurrence in this patient. CONCLUSIONS: Endovascular stented grafts offer an effective, less invasive alternative to standard techniques in treating traumatic arterial lesions. Early results are encouraging, but long-term follow-up will be necessary to fully delineate the effectiveness of this technique.

Adult↗
PubMed1995

Comparison of antimicrobial susceptibility methods for detection of penicillin-resistant Streptococcus pneumoniae.

We sought to determine if commercially available susceptibility tests were accurate in detecting penicillin resistance and relative resistance in Streptococcus pneumoniae. We compared the reference MIC method with oxacillin disk screening and three commercial tests, E-test (AB Biodisk), JustOne (Radiometer America), and MicroScan Pos MIC Panel Type 6 (Baxter Diagnostics), with 80 selected clinical isolates. Thirty-three additional isolates were tested by the reference method and the E-test to further validate the latter method. Oxacillin screening was effective in detecting all penicillin-resistant and relatively resistant strains of S. pneumoniae. The MicroScan method was not effective in detecting penicillin resistance or relative resistance. The JustOne system classified only 6 (35%) of 17 resistant strains correctly, with 11 resistant strains classified as relatively resistant. The E-test correctly classified 30 (83%) of 36 resistant isolates, with 6 resistant isolates interpreted as relatively resistant. For determining penicillin MICs for S. pneumoniae, the E-test was the most accurate of the commercial systems that we studied.

Humans↗
PubMed1995

The association between tuberous sclerosis and insulinoma.

We describe a patient with tuberous sclerosis and an insulinoma. The neurologic abnormalities typically present in patients with tuberous sclerosis may, in rare cases, be manifestations of hypoglycemia. We discussed a possible association between tuberous sclerosis and multiple endocrine neoplasia type I.

Adult↗
PubMed1994

Platelet bacterial contamination and the use of a chemiluminescence-linked universal bacterial ribosomal RNA gene probe.

BACKGROUND: Currently, the maximum outdate for platelets is 5 days, because of the increasing chance of bacterial growth over time. Various methods for rapid detection of bacterial contamination of blood components have been described, with mixed results and no general acceptance. A recently described, molecular biologic approach for the detection of bacterial contamination involves a chemiluminescence-linked universal DNA bacterial probe to a highly conserved bacterial region of ribosomal RNA (rRNA). STUDY DESIGN AND METHODS: A multicenter trial of a chemiluminescence-linked universal bacterial rRNA probe for the detection of bacterial contamination in platelet concentrates is described. At each of five sites, platelet concentrates (no older than 1 day from date of phlebotomy) were inoculated in triplicate with isolates of four bacterial species (Pseudomonas aeruginosa, Bacillus cereus, Staphylococcus epidermidis, and Staphylococcus aureus) to a final concentration of 10 to 50 colony-forming units (CFUs) per mL and in triplicate to a final concentration of 1000 CFUs per mL. At one site, an additional 6 platelet concentrates were inoculated with sterile saline to serve as controls. Inoculated units were then subjected periodically to quantitative cultures and probe analyses. A total of 126 platelet concentrates were studied over a period of 7 days (120 inoculated with bacteria and 6 with sterile saline). RESULTS: This assay was, in some cases, able to detect S. aureus bacterial contamination in the range of 100 to 1000 CFUs per mL; the majority of samples (B. cereus, P. aeruginosa, S. aureus, and S. epidermidis) with contamination exceeding 10(4) CFUs per mL; and all samples with contamination of 2.1 x 10(5) CFUs per mL or greater. Increasing the sample size from the recommended 0.4 mL to 1.0 mL resulted in an unacceptable loss of specificity (83.3%). CONCLUSION: The routine use of this assay would be expected to result in a decreased risk of septic platelet transfusion reactions and could lead to a lengthening of the current 5 day storage period for platelets. Further, the pooling of random-donor platelet concentrates before storage instead of immediately before transfusion may be possible if this rRNA probe is employed to detect bacteria in the pool.

Bacillus cereus↗
PubMed1993

Agrobacterium conjugation and gene regulation by N-acyl-L-homoserine lactones.

Conjugal opines secreted by crown gall tumours induce strains of Agrobacterium tumefaciens that are donors of Ti plasmids to produce a diffusible conjugation factor. This enhances the conjugal transfer efficiency of the Ti plasmid in other strains of A. tumefaciens. This factor behaves as a secondary messenger, transmitting the environmental information to tra genes. Here we report the use of spectrometry to show that this factor is identical to synthetic N-(beta-oxo-octan-1-oyl)-L-homoserine lactone and confirm that the synthetic compound is biologically active. N-(Hexan-1-oyl)-L-homoserine lactone has also been detected. A closely related molecule, N-(beta-oxo-hexan-1-oyl)-L-homoserine lactone, autoinduces bioluminescence in the distantly related bacterium, Vibrio fischeri. N-Acyl-homoserine lactones thus seem to be conserved molecules in which the length and nature of the lipophilic acyl chain determines the biological function to be regulated. Mutants that do not produce the factor fail to conjugate unless supplied with it in the induction medium (our unpublished data). These data indicate that the conjugation factor is an autoinducer and a key signal molecule in the conjugation system of A. tumefaciens. It is, to our knowledge, the first example of a second messenger molecule in a bacterial conjugation system.

Agrobacterium tumefaciens↗
PubMed1993

Clinical features of individuals with cystic fibrosis in New Zealand.

AIMS: To determine the status of cystic fibrosis patients, their mode of diagnosis and source of medical care in New Zealand. METHODS: A database was established in 1988 to record clinical information on individuals with cystic fibrosis in New Zealand. Three hundred and two cystic fibrosis patients were identified and clinical information on 248 obtained. RESULTS: Thirty five per cent of patients at diagnosis had gastrointestinal and pulmonary and 33% had gastrointestinal symptoms alone. Ninety three infants were diagnosed after a positive screening test and confirmatory sweat test. The mean age at diagnosis overall was 1.8 years, while 61% of children were diagnosed before one year of age. 74.2% of patients were said to be pancreatic insufficient, 4% pancreatic sufficient and in 22% the results were unavailable or unknown. Medical care was provided by 28 sources comprising paediatricians, physicians or combined clinics. One cystic fibrosis clinic cared for more than 40 patients. Sixty-one per cent of cystic fibrosis subjects were colonised with Staphylococcus aureus at some time, and 44% were reported to be colonised with Pseudomonas aeruginosa. CONCLUSIONS: Common clinical features of cystic fibrosis have been characterised for New Zealand patients. It is unknown to what extent the clinical features of the disease and source of medical care in New Zealand are responsible for previously reported survival for the condition but it is planned to examine serial measurements of growth, nutrition, pulmonary function and survival and it is hoped that these measurements will be the subject of a further report.

Adolescent↗
PubMed1993

The use of a chemiluminescence-linked universal bacterial ribosomal RNA gene probe and blood gas analysis for the rapid detection of bacterial contamination in white cell-reduced and nonreduced platelets.

Because of the rising incidence of bacterial growth and septic platelet transfusions in aging units, platelet storage is currently limited in the United States to 5 days. This approved shelf life of platelets might be altered if methods were devised to rapidly detect infected units and/or to decrease the incidence of bacterially contaminated platelets. An investigation was conducted on the effect of a prototype blood collection system with an in-line filter for the production of white cell-reduced platelet-rich plasma on the growth of bacteria in platelets prepared from whole blood that had been inoculated with Staphylococcus epidermidis. Additional studies were conducted with a chemiluminescence-linked ribosomal RNA (rRNA) gene probe and with blood gas analysis to identify possible methods for the rapid detection of bacterial contamination. All units were followed for 9 days of storage. The filtration of the platelet-rich plasma resulted in an approximate 2 log10 reduction in white cells with an average loss of 6.7 percent of platelets. Filtration did not appear to alter bacterial growth. In all platelet units that supported growth, pO2 dropped to negligible values and pCO2 rose relative to culture-negative units. The changes were most sensitive and specific beyond 5 days of storage. The universal bacterial rRNA probe assay was able to detect S. epidermidis in concentrations as low as 1 x 10(3) colony-forming units per mL in some cases and reliably detected all units contaminated at a concentration of 1 x 10(4) colony-forming units per mL.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Gas Analysis↗