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Biomedical subjects

A Jones

Publications and source records attributed to A Jones.

At least 217 records · Page 12Linked to original sources
PubMed1999

Segmentation of confocal microscope images of cell nuclei in thick tissue sections.

Segmentation of intact cell nuclei from three-dimensional (3D) images of thick tissue sections is an important basic capability necessary for many biological research studies. However, segmentation is often difficult because of the tight clustering of nuclei in many specimen types. We present a 3D segmentation approach that combines the recognition capabilities of the human visual system with the efficiency of automatic image analysis algorithms. The approach first uses automatic algorithms to separate the 3D image into regions of fluorescence-stained nuclei and unstained background. This includes a novel step, based on the Hough transform and an automatic focusing algorithm to estimate the size of nuclei. Then, using an interactive display, each nuclear region is shown to the analyst, who classifies it as either an individual nucleus, a cluster of multiple nuclei, partial nucleus or debris. Next, automatic image analysis based on morphological reconstruction and the watershed algorithm divides clusters into smaller objects, which are reclassified by the analyst. Once no more clusters remain, the analyst indicates which partial nuclei should be joined to form complete nuclei. The approach was assessed by calculating the fraction of correctly segmented nuclei for a variety of tissue types: Caenorhabditis elegans embryos (839 correct out of a total of 848), normal human skin (343/362), benign human breast tissue (492/525), a human breast cancer cell line grown as a xenograft in mice (425/479) and invasive human breast carcinoma (260/335). Furthermore, due to the analyst's involvement in the segmentation process, it is always known which nuclei in a population are correctly segmented and which not, assuming that the analyst's visual judgement is correct.

Animals↗
PubMed1999

A modernized mental health service: the role of care pathways.

AIM: This paper reviews the impact of the UK governments' strategy and structures to improve the quality of mental health care. The possible role of care pathways within this modernization agenda is discussed. BACKGROUND: The governments' emphasis upon reducing clinical variation and cost effective treatments complements both the historical and structural elements of care pathways. This paper is a reflection on some of the issues within this debate. METHODS: The paper reviews the latest publications from government sources and draws on the authors' research and critical analysis of the care pathway literature. FINDINGS: The government has made an explicit movement towards structuring care processes within the newly formed National Service Framework. However, there are many problems in following standardized care processes such as professional antagonism and a relative dearth of evidence-based practice. CONCLUSION: Further research is required to examine the wider impact of government initiatives on the work force. Care pathways may provide the structure for this research and development activity.

Critical Pathways↗
PubMed1999

Is surveillance for stage 1 germ cell tumours of the testis appropriate outside a specialist centre?

OBJECTIVE: To assess the results of treatment for stage 1 germ cell tumours of the testis, outside a specialist centre. PATIENTS AND METHODS: From May 1984 until March 1996, 123 patients with stage 1 disease were treated at our institution. Sixty patients with seminoma and 31 with teratoma were treated with orchidectomy only and surveillance; 32 patients with stage 1 seminoma elected for orchidectomy and adjuvant radiotherapy. The mean ages were 40, 31 and 35 years, and the median follow-up 52, 47 and 49 months, respectively. RESULTS: There were no disease- or treatment-related deaths. However, 18 (30%) patients with seminoma treated by orchidectomy only relapsed (median time 8 months, range 3-19); 14 of these responded to radiotherapy, three to radiotherapy and chemotherapy for second relapses outside the irradiated fields, and one to chemotherapy initially, for large-volume relapse. Fifteen (48%) patients with teratoma relapsed (median time 3 months, range 1-12); all responded to 4-6 courses of bleomycin/etoposide/cisplatin chemotherapy. One patient had a second relapse and is currently disease-free 3 years after surgical excision of a lung metastasis. CONCLUSION: These results show that stage 1 testis tumours can be managed successfully in a district general hospital. However, we are concerned about the high relapse rates and are now attempting to identify patients at greater risk of recurrence, to consider adjuvant therapy in this group.

Adult↗
PubMed1999

Effect of positioning on recorded lung sound intensities in subjects without pulmonary dysfunction.

BACKGROUND AND PURPOSE: Physical therapists often use positioning to assist in the reexpansion of collapsed lung segments. An increase in lung sound intensity on auscultation is considered indicative of lung expansion. This study was designed to examine whether clinical interpretation of auscultatory findings is warranted. SUBJECTS: The subjects (5 male, 6 female) were young physical therapist students without pulmonary dysfunction (mean age=20.4 years, mean height=166.3 cm, mean weight=57.5 kg). Subjects with lung disease were excluded because pulmonary pathology is difficult to standardize. METHODS: Lung sounds electronically recorded over the posterior chest wall of subjects in sitting and side-lying positions were compared. Measures included peak intensity, frequency at maximum power, and median frequency. RESULTS: In the sitting position, inspiratory sounds recorded over the left posterior chest wall were louder than those recorded on the right side. In the side-lying positions, the sound intensity recorded from the dependent chest wall was louder than that recorded from the nondependent chest wall. In side-lying positions, the upper hemithorax is "nondependent," and the side in contact with the bed is "dependent." Sound intensities recorded over both posterior chest walls in the sitting position were louder than those recorded over the same lung area in the nondependent side-lying position. There was no difference in the sound intensity recorded between the sitting and dependent side-lying postures. CONCLUSION AND DISCUSSION: When comparative auscultation of the chest wall is used by physical therapists to assess the adequacy of pulmonary ventilation, patient posture and regional differences in breath sound intensity can influence clinical interpretation.

Adult↗
PubMed1999

Are endoscopic biopsies of small bowel as good as suction biopsies for diagnosis of enteropathy?

BACKGROUND: Endoscopy is increasingly used in paediatric practice for diagnosis of enteropathy, although the quality of grasp forceps-obtained biopsy specimens required for reliable diagnosis has been questioned in comparison with suction capsule biopsy specimens. This study prospectively compared the diagnostic suitability of grasp forceps biopsy versus suction biopsy in the same patient during the same procedure. METHODS: A double-port paediatric suction biopsy capsule was front-loaded onto an endoscope and directed to the fourth part duodenum-proximal jejunum for biopsy sampling. Subsequently, three grasp biopsy specimens were taken from the same region. All biopsies were coded, photographed, and measured for area, using computed morphometry. A single blinded histopathologist assessed sample adequacy for diagnosis. Twenty-nine patients were enrolled (age range, 8-185 months). RESULTS: On three occasions the suction capsule failed to fire, and on four occasions only one sample was obtained. Three grasp biopsy specimens were obtained on each occasion by endoscopy, and the first two were used for comparison with suction biopsy samples. Median total area of individual biopsy samples obtained by the two procedures was not different (21.3 vs. 22.5 mm2; P = 0.027). Muscularis mucosae was obtained more commonly with grasp biopsies (P<0.001), and no difference was observed for the presence of three or more villus-crypt units, degree of haemorrhage, or optimal orientation. Two suction biopsy procedures and one grasp biopsy procedure were inadequate for diagnosis. CONCLUSIONS: Endoscopic grasp biopsies are perfectly adequate for the assessment of small intestinal histology. In addition, endoscopy affords advantage in diagnosis of other upper gastrointestinal disease with avoidance of radiologic screening involved with the suction capsule technique.

Adolescent↗
PubMed1999

IncC of broad-host-range plasmid RK2 modulates KorB transcriptional repressor activity In vivo and operator binding in vitro.

The korAB operon of broad-host-range plasmid RK2 encodes five genes, two of which, incC and korB, belong to the parA and parB families, respectively, of genome partitioning functions. Both korB and a third gene, korA, are responsible for coordinate regulation of operons encoding replication, transfer, and stable inheritance functions. Overexpression of incC alone caused rapid displacement of RK2. Using two different reporter systems, we show that incC modulates the action of KorB. Using promoter fusions to the reporter gene xylE, we show that incC potentiates the repression of transcription by korB. This modulation of korB activity was only observed with incC1, which encodes the full-length IncC (364 amino acids [aa]), whereas no effect was observed with incC2, which encodes a polypeptide of 259 aa that lacks the N-terminal 105 aa. Using bacterial extracts with IncC1 and IncC2 or IncC1 purified through the use of a His6 tail and Ni-agarose chromatography, we showed that IncC1 potentiates the binding of KorB to DNA at representative KorB operators. The ability of IncC to stabilize KorB-DNA complexes suggests that these two proteins work together in the global regulation of many operons on the IncP-1 genomes, as well in plasmid partitioning.

Bacterial Proteins↗
PubMed1999

Interferon alpha treatment of molluscum contagiosum in immunodeficiency.

A sister (aged 6 years) and brother (aged 8 years) presented four months apart with severe molluscum contagiosum. Both children demonstrated clinical and laboratory evidence of combined immunodeficiency. The extent of skin involvement by molluscum contagiosum precluded conventional treatment as well as intralesional interferon alpha (IFN alpha). Both subjects responded well to subcutaneous IFN alpha.

Antiviral Agents↗
PubMed1999

Primary antibody deficiency and Crohn's disease.

Five patients with primary antibody deficiency were investigated because of intermittent but persistent diarrhoea of several years duration despite immunoglobulin replacement therapy. We found no evidence of Giardia lambia or other intestinal pathogens to explain their gastrointestinal symptoms. All five had definite radiological evidence of small bowel Crohn's disease and three had histological specimens available with abnormalities consistent with Crohn's disease. One patient had a non-caseating granuloma in an oral ulcer. A second patient with stricturing disease in the small bowel had a mucosal inflammatory infiltrate with non-caseating granulomas. A third had transmural inflammation but no granulomas. All five patents were diagnosed as having Crohn's disease and have responded symptomatically to steroid therapy.

Adult↗
PubMed1999

A confidential inquiry into asthma deaths in Wales.

BACKGROUND: Death from asthma is regarded as preventable in principle, especially under the age of 65 years. METHODS: In 1994 a confidential inquiry was set up to investigate deaths attributable to asthma in residents of Wales under the age of 65 years. During the period of the inquiry 92 cases were notified as being ascribed to asthma, or (in 1996) having a mention of asthma on the death certificate. Of these, 80 were investigated further with the help of general practitioners, hospital notes, and relatives. The details were then considered by a small panel of doctors who endeavoured to identify factors that may have contributed to the deaths. RESULTS: Asthma was considered to be the underlying cause of 52 deaths. Although disease severity was usually a major factor, some aspect of the patient's behaviour or circumstances seemed to have contributed to 31 deaths, while in 15 cases there was probably a deficiency in medical care. CONCLUSIONS: Some preventable asthma deaths still occur, particularly in relation to inadequate treatment. Factors associated with patients' behaviour and circumstances are more difficult to tackle but, if doctors are aware of high risk patients, increased vigilance may prevent some deaths.

Adolescent↗
PubMed1999

Incremental cost-effectiveness analysis of intravenous ganciclovir versus oral ganciclovir in the maintenance treatment of newly diagnosed cytomegalovirus retinitis in patients with AIDS.

OBJECTIVE: To evaluate the cost effectiveness of a new product, oral ganciclovir, in comparison to a current therapy, intravenous (i.v.) ganciclovir, in the maintenance treatment of newly diagnosed cytomegalovirus (CMV) retinitis in patients with AIDS. DESIGN: This was a retrospective economic study of a prospective non-blinded randomised clinical trial. The model included i.v. ganciclovir induction, i.v. or oral ganciclovir maintenance and i.v. ganciclovir reinduction for patients whose CMV retinitis progressed. Safety and efficacy data were derived from the trial. A panel of Canadian infectious disease physicians and family physicians estimated the following in relation to i.v. ganciclovir treatment for CMV retinitis and related adverse events: healthcare resource utilisation, clinical practice patterns, patient out-of-pocket expenses and time loss from work. The incremental cost-effectiveness analysis is reported from a societal and a Ministry of Health perspective. SETTING: The trial was conducted in Canada (2 centres) and the US (13 centres) between March 1991 and November 1992. The model assumed that patients received either inpatient or outpatient care, or both. The model provided an analysis in a Canadian setting. PATIENTS AND PARTICIPANTS: Participants were patients with AIDS and newly diagnosed CMV retinitis. INTERVENTIONS: All patients received induction therapy with i.v. ganciclovir 5 mg/kg, twice daily for 14 days then once daily for 7 days. Patients whose CMV retinitis stabilised were randomised to maintenance therapy with either i.v. ganciclovir (5 mg/kg/day; n = 57) or oral ganciclovir (3000 mg/day; n = 60) and were followed for up to 140 days after the start of maintenance therapy. MAIN OUTCOME MEASURES AND RESULTS: The trial demonstrated that the mean time to progression of CMV retinitis was 57 days for oral ganciclovir compared with 62 days for i.v. ganciclovir maintenance therapy, as measured by masked fundus photography, and 96 days with i.v. ganciclovir compared with 68 days with oral ganciclovir according to the funduscopy results. There were more adverse events in the i.v. ganciclovir group compared with the oral ganciclovir group. The cost-effectiveness results provide the dollar amount expended in order to continue to provide additional benefit using i.v. ganciclovir compared with oral ganciclovir. The incremental cost-effectiveness (C/E) ratio was 482 Canadian dollars ($Can: 1993 to 1995 values) per progression-free day gained with i.v. ganciclovir. Sensitivity analysis using funduscopy, rather than fundus photography, to document progression of CMV retinitis resulted in a C/E ratio of $Can42. CONCLUSIONS: This analysis found that i.v. ganciclovir provided additional days free of progression of CMV retinitis when compared with oral ganciclovir, but the costs were higher.

Administration, Oral↗
PubMed1999

Resistance properties of Thera-Band tubing during shoulder abduction exercise.

STUDY DESIGN: Single-group, repeated measures. OBJECTIVES: To investigate the relationship between tubing length and tubing tension for 6 colors of Thera-Band tubing (each color representing a different level of resistance) and to estimate the resistive shoulder torque provided during shoulder abduction exercise. BACKGROUND: Thera-Band tubing is popular for providing resistance in rehabilitation strengthening programs. Unfortunately, it is difficult to compare use of elastic tubing with other resistance training methods because no published data exist on how much resistance is being provided during exercise. METHODS AND MEASURES: Nine male and 6 female subjects (age, 25.9 +/- 3.6 years; height, 173 +/- 10 cm) performed shoulder abduction, using 6 colors of tubing. A strain gauge attached at the fixed end of the tubing directly measured the tension generated during stretch. For each color of tubing, each subject momentarily held a position at 30 degrees, 60 degrees, 90 degrees, 120 degrees, and 150 degrees of abduction. Shoulder joint abduction, limb segment position, and tubing length were analyzed by means of the Peak Motion Measurement System. Simple linear regression equations predicted tubing tension from percent change in tubing length at the joint angle positions. A 2-way (5 x 6) repeated-measures ANOVA determined the mean differences in tubing tension across tubing colors at the shoulder abduction positions. RESULTS: Strong linear relationships were found for each tubing tension when referenced according to changes in tubing length. Significant differences in tension were found for the various colors of tubing. The resistive torque curves for each color tubing were similar to isotonic exercise. CONCLUSIONS: Thera-Band tubing provides linear resistance during shoulder abduction, but the resistive torque provided by the tubing mimics isotonic exercise.

Adult↗
PubMed1999

Effects of bovine serum albumin on function of cryopreserved stallion spermatozoa during medium culture and uterine tube epithelial cell coculture.

OBJECTIVE: To compare function of cultured cryopreserved stallion spermatozoa in a modified Tyrode's medium (TM), with or without bovine serum albumin (BSA), or in uterine tube (oviduct) epithelial cell (OEC) coculture in TM, with or without BSA. SAMPLE POPULATION: Cryopreserved spermatozoa from 6 proven stallions and OEC from bovine reproductive tracts in follicular phase. PROCEDURE: Thawed spermatozoa were cultured in TM, with or without BSA, or cocultured with OEC monolayers in TM, with or without BSA. Percentages of capacitated and acrosome-reacted spermatozoa were measured at 5 hours for TM cultures. Spermatozoal survival and motility characteristics were observed over time for all culture methods. Number of spermatozoa attaching to OEC were compared for cocultures. RESULTS: Use of TM without BSA altered spermatozoal function in cell-free medium culture and OEC coculture. A higher percentage of spermatozoa were acrosome reacted in TM with BSA, although percentages of capacitated spermatozoa did not differ. Spermatozoa survived longer and maintained superior motion in TM culture without BSA and in OEC cocultures. More spermatozoa were able to attach to OEC in TM without BSA. CONCLUSIONS: Incubation of cryopreserved spermatozoa in media with BSA resulted in rapid decrease in percentage of intact, motile spermatozoa and limited their ability to interact with OEC. CLINICAL RELEVANCE: Current culture media used for assisted reproduction techniques in horses do not provide functionally capacitated spermatozoa. Removal of BSA from such media improves spermatozoal quality and survival.

Animals↗