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Biomedical subjects

M Birch

Publications and source records attributed to M Birch.

At least 37 records · Page 2Linked to original sources
PubMed1998

Variation in morphotype, karyotype and DNA type of fluconazole resistant Candida albicans from an AIDS patient.

Azole-resistant oropharyngeal and oesophageal candidiasis is a recent phenomenon observed in patients with AIDS usually previously treated with fluconazole. Some variation has been observed in antifungal susceptibility testing among separate colonies of Candida albicans from the same patient. This raises the question of whether there are multiple clones present or simply phenotypic variation in expression of azole resistance. To address this question we took 18 isolates grown from multiple swabs taken before and after experimental azole therapy from a single HIV-positive individual with fluconazole-resistant oral candidiasis and compared morphotype, karyotype, PCR-based DNA typing and azole susceptibility. Ten of the isolates were from a single 2-day period. Amongst these 10 there were seven morphotypes, five karyotypes and four polymerase chain reaction (PCR) types. Three further morphotypes, one karyotype and two PCR types were found amongst the eight isolates obtained during the subsequent 4 months. Limited variation in susceptibility to two azoles--fluconazole and D0870--was also seen. This work emphasizes both the large genotype and phenotypic variability of C. albicans isolates in the mouth of AIDS patients with fluconazole resistance, and the difficulties in interpretation of present typing methods.

AIDS-Related Opportunistic Infections↗
PubMed1998

Polar lipids of Aspergillus fumigatus, A. niger, A. nidulans, A. flavus and A. terreus.

Little is known of the phospholipid composition of Aspergillus species. The aim of this study was to determine individual phospholipid analogues in Aspergillus. Twenty-nine clinical and environmental isolates from five Aspergillus species were analysed. Fast atom bombardment mass spectrometric data were considered in two ranges, m/z 190-500 and m/z 500-1000, to facilitate the recognition of major fatty acyl groups and phospholipids. Quantitative comparison of major anions in both m/z ranges was undertaken. Confirmation of major phospholipid anions from eight representative isolates was achieved by tandem mass spectrometry. The major phospholipid families were phosphatidic acid (PA), phosphatidylethanolamine (PE), phosphatidylinositol (PI), and phosphatidylserine (PS). Anions were detected consistent with the presence of specific phospholipid moieties, such as palmitoyl-linolenoyl phosphatidic acid, palmitoyl-oleoylphosphatidylethenolamine, oleoyl-linoleoyl-phophatidylserine and palmitoyl-linoleoyl-phosphatidylinositol. It appears that there is some commonality of sn1 or sn2 fatty acyl substituents, frequently C18:2 at sn1 accompanied by C16:0 at sn2, with differing molecular weights being attributable to analogues with differing head groups. Differences in certain phospholipids (e.g. minor peak with m/z 933) were detected between A. fumigatus, A. nidulans and other species examined which could have diagnostic value.

Aspergillus↗
PubMed1997

In the land of counterpane. Travels in the realm of play.

Using illustrations from the treatment of a three-year-old girl, a case is made that imaginative play between therapist and young child is not only a legitimate but often a preferable medium for therapeutic intervention. The displacement and magical thinking characteristic of the child's play are seen as creative and developmentally appropriate modes of thought, rather than as primarily defensive. By making her person available to be played with, the therapist facilitates a rich intersubjective exchange which permits the child to explore otherwise anxiety-provoking feelings, roles, and relationships.

Child, Preschool↗
PubMed1997

The three-dimensional structure of the connective tissue in the lamina cribrosa of the human optic nerve head.

Comprehensive understanding of the three-dimensional structure of the extracellular matrix (ECM) of the lamina cribrosa is central to understanding its role in health and disease, particularly how changes in configuration might precipitate nerve fibre death in glaucoma. Research until recently has relied almost entirely on light and scanning electron microscopy (SEM) to investigate the ECM of the lamina cribrosa. In this paper, we review the contribution of these methods to current understanding of the three-dimensional structure of the lamina ECM, highlight their potential weaknesses and emphasise that there is still much to be revealed about the structure of the lamina ECM. We then describe our development of confocal microscopy and computer reconstruction as a new and alternative method of investigating the three-dimensional structure of the lamina ECM. We show how optical sectioning allows the confocal microscope to acquire three-dimensional images of the lamina ECM without the degree of tissue disruption associated with preparation for SEM and demonstrate the versatility of analysis of these images by computer reconstructive software. A case is made for confocal microscopy and computer reconstruction contributing to our understanding of this important but complex and delicate structure.

Connective Tissue↗
PubMed1996

RT-PCR detection of cytokine transcripts in a series of cultured human meningiomas.

The expression of cytokine transcripts has been investigated in a series of cultured human meningiomas using reverse transcriptase linked polymerase chain reaction (RT-PCR), which allowed simultaneous analysis of a range of cytokines. The main histological subgroups of meningioma were investigated; these included transitional, fibroblastic, and syncytial as well as atypical meningiomas. Meningiomas from each of the different histological subgroups were subjected to a standard tissue culture regime. Total RNA was extracted from representative cultures and reverse-transcribed to yield cDNA. PCR was performed using oligonucleotide primers designed to detect interleukin (IL)-1 alpha/beta to IL-8, transforming growth factor (TGF)beta 1-3, tumour necrosis factor (TNF)alpha/beta, and interferon (IFN)gamma. Transcripts for IL-3, IL-6, IL-8, and TGF beta 3 were detected in all cultures. Transcripts for the three isomers of TGF beta were expressed in the transitional and fibroblastic meningioma cells. TGF beta 2 and TGF beta 3 transcripts were expressed in the syncytial and TGF beta 1 and TGF beta 3 in the atypical meningioma cells. IL-1 beta transcripts were expressed in fibroblastic and atypical cultures and TNF beta transcripts were expressed in syncytial and transitional cultures only. Transcripts for IL-1 alpha, IL-2, IL-4, IL-5, IL-7, TNF alpha, or IFN gamma were not detected in any of the meningioma cultures. This investigation using cells cultured from a small number of tumours from each of the classic histological subtypes suggests that there is a distinct pattern of cytokine mRNA expression linked with histological classification.

Cytokines↗
PubMed1996

Rapid genotyping of Escherichia coli O157 isolates by random amplification of polymorphic DNA.

Although several typing methods have been described for Shiga-like toxin-producing Escherichia coli O157, the methods are somewhat cumbersome. Using 22 isolates of Escherichia coli O157 and five other Escherichia coli isolates, two primers (M13 core sequence and 970-11) were found to give excellent differentiation between isolates using random amplified polymorphic DNA (RAPD). Using only the presence or absence of variable bands, a matrix of 20 variable characters was identified. From these characters, similarity coefficients were calculated and a phenogram constructed. All of the Escherichia coli O157 isolates were easily distinguished from the non-O157 Escherichia coli isolates. Using a 95% similarity cutoff, we found 13 RAPD types among the 22 Escherichia coli O157 isolates. Isolates thought to be identical by toxin and phage typing as well as by epidemiological association were distinguished, and others thought to be distinct by lack of epidemiological association were identical. RAPD using M13 and 970-11 primers is a potentially useful typing tool for Escherichia coli isolates of serotype O157 and possibly other Escherichia coli isolates.

Bacteriophage Typing↗
PubMed1996

Aspergillus wound infection following laparostomy.

Wound infections with Aspergillus are surprisingly rare given the quantity of spores in hospital air. We report the first case of infection of abdominal viscera due to Aspergillus in a patient with a laparostomy for Crohn's disease. Amphotericin B effected a cure. Sampling of air from the patient's environment yielded one isolated of Aspergillus fumigatus that matched the patient's isolates. Other examples of surgical wounds being contaminated by Aspergillus are reviewed.

Adult↗
PubMed1996

PCR phenotyping of cytokines, growth factors and their receptors and bone matrix proteins in human osteoblast-like cell lines.

The expression of a total of 58 cytokines, growth factors, and their corresponding receptors and bone matrix proteins was assessed using reverse transcription-linked polymerase chain reaction (RT-PCR) analysis to determine the similarity in the expression profile between clonal osteosarcoma-derived human osteoblast-like cell lines and primary human osteoblast-like cell cultures derived from human trabecular bone explants. The spectrum of cytokines, growth factors, and bone-related proteins expressed by three human osteosarcoma-derived cell lines, TE-85, MG-63, SaOS-2, and primary human osteoblast-like cells was found to be highly comparable and for the first time the expression of EGF, ECGF, FGF beta, oncostatin M, TNF beta, and SCF by human osteoblast-like cells was detected. Also the expression of several receptor types including IL-4R, IL-7R, IFN alpha/beta R, and SCFR was detected that has not been previously described for human osteoblast-like cells. For the factors examined, no qualitative variations in the expression profile were observed in the six primary human osteoblast-like cell cultures used in this study. Of the 58 factors examined, only 13 showed some degree of nonuniformity of expression between all of the three cell lines and primary cell cultures. These differences were seen especially in the expression of cytokine receptor mRNA and to a lesser extent with some cytokines. Differences in receptor expression would suggest that the possible spectrum of response to exogenously added factors, or even autocrine/ paracrine networks would be determined by the repertoire of receptors expressed by each cell type. Whether the differences are related to the status of cell maturation within the osteoblast development lineage or to their abberant regulation of expression cannot be concluded at this stage. However, this PCR-phenotyping approach rapidly provides a resource of information, which can be subsequently used for further in depth studies to facilitate the analysis of the molecular mechanisms, whereby the target gene of interest is modulated in a model cell line. In addition, this study indicates that at least based on the transcript expression profile of the factors analyzed, human osteosarcoma-derived osteoblast-like cells are useful as models for their nontransformed counterparts.

Base Sequence↗
PubMed1996

Evidence of multiple extracellular phospholipase activities of Aspergillus fumigatus.

Extracellular phospholipase activity has been implicated in the pathogenesis of several bacterial infections. Recently, extracellular phospholipase activity has been proposed as a virulence factor in the opportunistic yeast Candida albicans. Aspergillus fumigatus is the most pathogenic member of its genus, responsible for > 90% of infections. Previously, no specific virulence factors have been determined. We investigated the ability of A. fumigatus to produce extracellular phospholipases at 37 degrees C. Fast atom bombardment was used to compare lipid-containing media before and at 5-h intervals during shaking culture of A. fumigatus. Lipids were extracted and analyzed. Many anions corresponding to phospholipid breakdown products were identified. Specific anion species identified indicated phospholipase A, B, C (PLC), and D activities. PLC activity was further investigated by using the synthetic substrate p-nitrophenylphosphorylcholine. PLC activity was initially observed after 30 h of growth and accumulated in broth cultures up to 50 h. At 55 h, there was a sharp increase in PLC activity which coincided with cultures reaching the stationary phase. Activity of the PLC was measured at different temperatures, with greater activity occurring at 37 degrees C than at lower temperatures. Phospholipases could represent a virulence determinant in A. fumigatus.

Aspergillus fumigatus↗
PubMed1995

Molecular typing of Aspergillus species.

In the last four years, several molecular typing methods have been applied to various Aspergillus species, primarily A. fumigatus and A. niger. Many 'clones' or DNA types exist in the environment and in patients. The most discriminatory methods appear to be restriction fragment length polymorphism analysis with or without specific probes and random amplification of polymorphic DNA analysis. Insufficient work on interlaboratory reproducibility has been done. Most patients are infected by single DNA types, although occasionally multiple isolates are detected. Little work has been done with regard to detailed hospital epidemiology using molecular typing methods.

Aspergillus↗
PubMed1995

DNA typing of epidemiologically-related isolates of Aspergillus fumigatus.

Invasive aspergillosis is often nosocomially acquired and carries a high mortality. Molecular typing methods to discriminate isolates have now been developed. Using simple restriction endonuclease (Sal1 and Xho1) digestion of total genomic DNA, we have typed 25 epidemiologically-related isolates of A. fumigatus from six hospital episodes of invasive aspergillosis. Eight DNA types were found and in each case the DNA type matched precisely the epidemiological data. Thus DNA typing of A. fumigatus can provide the means to match isolates from linked sources and distinguish isolates from diverse origins.

Aspergillosis↗
PubMed1994

Image analysis of lateral velopharyngeal closure in repaired cleft palates and normal palates.

We have undertaken the design and testing of a system for making measurements of velopharyngeal function from lateral videofluoroscopic images based upon standard equipment found in any cleft clinic. The uncertainties in the measurements have been found to be acceptably low and, in conjunction with other measurement techniques, the system has made a valuable contribution to the assessment of velopharyngeal function. Additional measurements using this system are presently being developed.

Cleft Lip↗
PubMed1994

Cleft palate re-repair--a clinical and radiographic study of 32 consecutive cases.

The results of clinical and radiographic assessment of palate re-repair (by a single operator) in 32 patients are presented. This has shown that radical muscle correction as a secondary procedure (following limited or no muscle correction in primary repair) has produced measurable improvement in velar function and should be considered as the first option in many patients with velopharyngeal incompetence. The results also support the concept of muscle dissection and retropositioning in primary cleft palate repair.

Adolescent↗
PubMed1994

Randomized trial of long-term diuretic therapy for infants with oxygen-dependent bronchopulmonary dysplasia.

STUDY OBJECTIVE: To determine whether long-term oral diuretic therapy would improve the pulmonary function of preterm infants with bronchopulmonary dysplasia. DESIGN: Randomized, double-blind, placebo-controlled study. SETTING: Level III intensive care nursery. INTERVENTION: We randomly selected 43 stable patients with oxygen-dependent bronchopulmonary dysplasia to receive either orally administered spironolactone and chlorothiazide or placebo. These drugs were continued until the patients no longer required supplemental oxygen. Both groups received furosemide as needed. MEASUREMENTS AND RESULTS: Each infant had pulmonary function tests at study entry, 4 weeks after study entry, 1 week and 8 weeks after being weaned to room air and off study drugs, and at 1 year of corrected age. Pulmonary function tests include dynamic pulmonary compliance, airway resistance, thoracic gas volume, and maximal expiratory flow at functional residual capacity; most of the infants had functional residual capacity measured. Between the first and second pulmonary function tests (while the infants were receiving diuretic or placebo), the infants in the diuretic group had a significant improvement in dynamic pulmonary compliance (46%; p < 0.001) and airway resistance (31%; p < 0.05); there were no changes in compliance or resistance in the placebo group. Although patients in both the diuretic and the placebo groups required progressively less supplemental oxygen, by 4 weeks after study entry the patients in the diuretic group needed less supplemental oxygen than did those in the placebo group (p < 0.01). There were no significant differences in results of serial pulmonary function tests in either group after discontinuation of diuretic therapy. Despite the significant differences in pulmonary function between the two groups, there was no significant difference between them in the total number of days that supplemental oxygen was required. Significantly more infantsin the placebo group received more than 10 doses of furosemide on an as-needed basis. CONCLUSIONS: Long-term diuretic therapy in stable infants with oxygen-dependent bronchopulmonary dysplasia, after extubation, improves their pulmonary function and decreases their fractional inspired oxygen requirement, but does not decrease the number of days that they require supplemental oxygen. The improvement in pulmonary function associated with diuretic therapy is not maintained after treatment is discontinued.

Analysis of Variance↗
PubMed1994

Postpartum amenorrhoea and breast-feeding in a Danish sample.

The duration of postpartum amenorrhoea was studied in a Danish sample of 361 women. The median duration of amenorrhoea was 17 weeks. The 25th and 75th percentiles were 10 and 30 weeks, respectively. A significant correlation was found between the duration of postpartum amenorrhoea and of breast-feeding. However, lactation for more than 9 months did not extend the duration of amenorrhoea. Menstruation before weaning occurred in 57% of the women, and 43% terminated breast-feeding before the first menstruation. Four weeks after weaning menstruation had returned in 79% and by 8 weeks after in 93% of the mothers. At 6 months postpartum, frequency of breast-feeding, and of night-time feeding were determinants of amenorrhoea.

Adolescent↗
PubMed1993

[Utilization of the right to maternity leave and resumption of work after delivery. A longitudinal prospective study].

A longitudinal interview study of 360 mothers was carried out to investigate: 1) utilization of maternity leave by the parents, 2) mothers' resumption of occupation after delivery and 3) duration of breast feeding seen in correlation with the mothers' resumption of work. 1) 95% of the families utilized the entire maternity leave. In 92% of the families, the mothers utilized all 24 weeks and, in 3% of the families, the fathers took part in the maternity leave. Only 46% of the fathers utilized the right to take leave in connection with delivery and 14% employed their holiday but were at home for a significantly shorter period. 2) Only one fourth of the mothers had resumed work 24 weeks after the delivery. 44% of the mothers prolonged the maternity leave with their holiday and 32% prolonged the maternity leave even longer. One year after delivery, significantly more mothers were housewives than previously. 3) A significantly positive correlation was found between the time for maternal return to work and the duration of breast feeding. We conclude that almost all of the families utilized the maternity leave and that prolongation of maternity leave (which is 24 weeks after delivery at present) might be necessary.

Denmark↗
PubMed1993

Retrobulbar phenol injection in blind painful eyes.

Retrobulbar phenol injection was used as a neurolytic to manage blind chronically painful eyes in ten patients. The cause of the blind painful eye was absolute glaucoma in eight of the ten eyes. We used 1.5mL of 1:15 (6.7%) aqueous phenol solution in each case. None of the patients experienced any pain from the injection. Seven patients obtained complete pain relief after the procedure, and one patient had some improvement. We found a range of duration of pain relief of 4.5 to 48 months (mean, 15 months), which compares favorably with retrobulbar alcohol injection. We believe retrobulbar phenol injection is preferable to alcohol. It has the advantage of being less painful during injection because of its local anesthetic properties.

Adult↗