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Biomedical subjects

J Birch

Publications and source records attributed to J Birch.

At least 19 recordsLinked to original sources
PubMed1995

The choroid plexus carcinomas of childhood: histopathology, immunocytochemistry and clinicopathological correlations.

Anaplastic choroid plexus carcinoma is a tumour with a predilection for the posterior fossa of infants and can be difficult to distinguish histologically from medulloblastoma without the aid of immunocytochemistry using a panel of antibodies. Of a series of 17 choroid plexus carcinomas (five of which were classed as moderately differentiated and 12 as anaplastic) 17 expressed antigens to transthyretin, transferrin and cathepsin and 16 expressed carbonic anhydrase II. Eleven expressed at least one epithelial marker (cytokeratin or epithelial membrane antigen). In contrast, none of six medulloblastomas expressed epithelial markers, transrythetin, carbonic anhydrase II or transferrin, though three were positive with antibodies to cathepsin.

Carbonic Anhydrases↗
PubMed1994

A suitable study to evaluate colour vision requirements for firefighters?

A recent paper by Rees (Occup. Med. 1994; 44: 253-256) has proposed a study to evaluate the performance of both clinical and trade tests on firefighter recruits. The paper suggests that a new trade test using painted gas cylinders and/or the BOC cylinder identification chart may be appropriate in the selection of firefighter recruits. Evaluation of pass/fail standards on these tests would be achieved by comparing the results with those obtained from the Ishihara test, the City University test and the Holmes-Wright lantern test. In this paper, we argue that the proposed battery of tests does not allow an accurate evaluation of the new trade tests. Indeed,the new trade tests are likely to result in a false sense of obvious fairness' that ultimately be an unsound means of assessing the colour vision requirements of firefighter recruits.

Color Perception Tests↗
PubMed1992

New method based on random luminance masking for measuring isochromatic zones using high resolution colour displays.

A new method of measuring normal hue discrimination ellipses and dichromatic zones using a high resolution colour monitor is described. The test involves the detection of chromatic bars on a grey background (x = 0.305, y = 0.323) having a luminance of 34 cd m-2. Elements of the background matrix of square checks are varied randomly in luminance in space and time to provide random luminance masking (RLM) which compensates for differences in the relative luminous efficiency of different observers. The measurement technique provides a rapid and comprehensive colour vision test. Typical results are presented for normal trichromats, protanopes and deuteranopes without RLM and with the RLM set of 25%. The size of the discrimination ellipse in normal observers is the same in both viewing conditions, but the use of the RLM technique reveals the extent of the isochromatic zones in colour deficient observers.

Color Perception Tests↗
PubMed1991

Family intervention.

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Combined Modality Therapy↗
PubMed1990

Concurrent visual conversion reaction and simulated colour vision defects in a 12-year-old child.

Visual conversion reaction (VCR) is a psychosomatic anomaly which occasionally manifests in children, most commonly in the form of reduced vision and visual field defects. Malingering or conscious simulation for secondary gain would appear to be rare in children but occasionally VCR and simulation coexist. A case history is presented of a 12-year-old child with behavioural and reading difficulties who manifested reduced vision most probably attributable to VCR and severe colour deficiency, which was best explained in terms of simulation or malingering.

Child↗
PubMed1989

Serum bioactive lactogenic hormone levels in women with familial breast cancer and their relatives.

Serum levels of bioactive lactogenic hormone (BLH), immunoreactive prolactin and growth hormone (ir-PRL and ir-GH) were measured in a group of familial breast cancer patients and their first degree female relatives and compared to those found in normal healthy women. The ratio of BLH to the sum of ir-PRL and ir-GH was slightly but significantly decreased in the familial breast cancer group (P = 0.018 by the Mann-Whitney U test) although there were no significant differences in the levels of BLH, ir-PRL and ir-GH between the two groups. No differences in the levels of the lactogenic hormones could be detected when the pre-menopausal women were considered separately or when 20 women from the familial group were compared to normal controls matched for age, parity, weight and menopausal status. The levels of BLH were highly correlated with the sum of ir-PRL and ir-GH in both the familial breast cancer group and the controls (P less than 0.001 for both groups by Spearman's rank correlation test). These findings are not indicative of the presence of an additional species of bioactive, but not immunoreactive, lactogen in the sera of women with or at high risk of breast cancer. However, the presence of different, but equipotent, forms of lactogen cannot be excluded in these women.

Adolescent↗
PubMed1989

Use of the Farnsworth-Munsell 100-Hue test in the examination of congenital colour vision defects.

Results for the Farnsworth-Munsell 100-Hue test are reported for 238 male subjects with congenital colour vision defects (47 protanopes, 17 protanomalous trichromats, 57 deuteranopes and 117 deuteranomalous trichromats). The results are analysed in terms of the error score and the presence of an axis of confusion. A wide range of results is obtained in each diagnostic group and the error score cannot be used to distinguish between dichromats and anomalous trichromats. Approximately 50% of subjects with anomalous trichromatism obtain error scores less than 100 without an axis of confusion. These subjects could be mistakenly identified as having normal colour vision if pseudoisochromatic and colour matching tests are not employed. The prime use of the F-M 100 Hue test is in vocational guidance.

Adolescent↗
PubMed1989

Anorexia nervosa and food avoidance emotional disorder.

A retrospective and longitudinal study was carried out on all children and adolescents who presented to a child psychiatry service over a period of 26 years to identify the nature, course, and outcome of cases meeting criteria for anorexia nervosa (n = 27). Two groups of the same age were identified for comparison, firstly those with food avoidance and emotional disorders (n = 23), and secondly those with emotional disorders but no symptoms associated with eating (n = 22). The results confirm previous reports that early onset anorexia nervosa shows a similar nature, course, and outcome to the adult disease. Being tall at presentation seems to be associated with a poor outcome. Self starvation of early onset may result in short stature in some cases. There seem to be more boys among the group in whom the disease was of early onset than would be predicted from the sex ratio among adult patients. In addition boys with anorexia nervosa may have a better prognosis than girls. Children with food avoidance emotional disorders seem to have a worse prognosis than expected for childhood emotional disorders. They may represent a middle group between those with anorexia nervosa and those with emotional disorders but no symptoms associated with eating.

Adolescent↗
PubMed1988

Identification of polarity in FM 100-Hue plots: a comparison of methods.

Several methods which have been proposed to aid the identification of polarity in Farnsworth-Munsell (FM) 100-Hue test plots are described. The assumptions which underlie one type of method are discussed and problems identified. Two methods are taken as representative of the two types of analysis and their performance compared on plots from congenital and acquired color defectives. The key difference between the two methods and the types of method which they represent lies in the imposition of symmetry on the plot. From the performance of 200 diabetic subjects, the problems created by the presence of monopolar plots, plots with unequal magnitudes of errors in the two poles of bipolar plots, and plots in which the two poles are not diametrically opposite are highlighted. It is concluded that the simpler type of analysis is sufficient and retains more information.

Color Perception↗
PubMed1988

Studies in the guinea-pig with ICI 185,282: a thromboxane A2 receptor antagonist.

The effects of ICI 185,282 (5(Z)-7-([ 2,4,5-cis]-4-O-hydroxyphenyl-2-trifluoromethyl-1, 3-dioxan-5-yl)heptenoic acid) have been studied on guinea-pig platelets and pulmonary smooth muscle in-vitro and in-vivo. When tested on guinea-pig lung parenchyma in-vitro. ICI 185,282 (1 x 10(-7) M) produced a significant shift in U-46619 response curves (concentration ratio of 13:3); the antagonist (1 x 10(-5) M) did not modify histamine responses. When tested on guinea-pig trachea in-vitro ICI 185,282 (1 x 10(-7) M) caused significant inhibition of U-46619 and PGD2 responses (concentration ratios of 8.3 and 14.1, respectively); the antagonist (1 x 10(-5) M proved less effective against contractions of PGF2 alpha, LTD4 and histamine (concentration ratios of 7.0, 1.5 and 1.6). When added to guinea-pig platelet rich plasma in-vitro, ICI 185,282 (x 10(-6), 1 x 10(-5) M) caused concentration-dependent parallel shifts to the right of U-46619 aggregation curves, yielding concentration ratios of 13.6 and 141.9, respectively. In-vitro, addition of ICI 185,282 (x 10(-5) M) to indomethacin-treated pulmonary smooth muscle did not modify resting tone, neither did it induce aggregation or swelling in platelet-rich plasma preparations. When administered orally to guinea-pigs ICI 185,282 (0.1, 0.5 mg kg-1) caused a significant inhibition of U-46619-induced platelet aggregation ex-vivo which persisted greater than or equal to 8 h. In-vivo, a single oral dose of ICI 185,282 (1 mg kg-1) inhibited bronchospasm induced by U-46619, PGD2, PGF2 alpha, arachidonic acid, LTD4 and PAF; responses to histamine were unaffected.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Evaluation of desmin as a diagnostic and prognostic marker of childhood rhabdomyosarcomas and embryonal sarcomas.

The diagnostic and prognostic relevance of desmin expression in 80 rhabdomyosarcomas (RMS) and 5 embryonal sarcomas (ES) was examined using a peroxidase anti-peroxidase staining procedure. Fifty-nine RMS but only one ES stained for desmin (P less than 0.05). The maximum percentage of desmin containing cells was 49 in RMS compared with only 1% in ES. Desmin positivity correlated inversely with survival (P less than 0.02) in that RMS with high proportions of desmin positive cells were associated with poorer prognoses than those containing fewer desmin positive cells. If the degree of expression of desmin is related to myogenic differentiation, then our results indicate that poorly differentiated RMS tend to have a better prognosis than the well differentiated tumours. One possible explanation is that the poorly differentiated RMS respond better to chemotherapy than to well differentiated RMS. A multivariant analysis incorporating desmin staining, treatment, histology, age and gender revealed that the two most significant independent prognostic factors were treatment and histology.

Desmin↗
PubMed1987

Leukemia after therapy with alkylating agents for childhood cancer.

The risk of leukemia was evaluated in 9,170 2-or-more-year survivors of childhood cancer in the 13 institutions of the Late Effects Study Group. Secondary leukemia occurred in 22 nonreferred individuals compared to 1.52 expected, based on general population rates [relative risk (RR) = 14; 95% confidence interval (CI), 9-22]. The influence of therapy for the first cancer on subsequent leukemia risk was determined by a case-control study conducted on 25 cases and 90 matched controls. Treatment with alkylating agents was associated with a significantly elevated risk of leukemia (RR = 4.8; 95% CI, 1.2-18.9). A strong dose-response relationship was also observed between leukemia risk and total dose of alkylating agents, estimated by an alkylator score. The RR of leukemia reached 23 in the highest dose category. Radiation therapy, however, did not increase risk. Although doxorubicin was also identified as a possible risk factor, the excess risk of leukemia following treatment for childhood cancer appears almost entirely due to alkylating agents.

Alkylating Agents↗
PubMed1987

An averaging method for the interpretation of the Farnsworth-Munsell 100-Hue Test--I. Congenital colour vision defects.

A method is described for identifying polarity in Farnsworth-Munsell 100-Hue test data. The method is facilitated by the use of a micro-computer and involves the plotting of "averaged" scores for each cap of the test. Results are presented for 30 protanopes, 30 deuteranopes, 1 tritanope and 2 typical rod monochromats. Analysis of the results shows that the proposed technique is compatible with standard methods of interpreting 100-Hue plots and is suitable to use when error scores are high and when polarity is difficult to interpret.

Adolescent↗
PubMed1987

An averaging method for the interpretation of the Farnsworth-Munsell 100-Hue Test--II. Colour vision defects acquired in diabetic retinopathy.

The Farnsworth-Munsell 100-Hue test is frequently used to assess acquired colour vision defects. In diabetic retinopathy the acquired defect is a mild or severe type III (Tritan) defect which may be coupled with poor overall hue discrimination. In consequence, error scores are often high and the 100-Hue polar diagram is difficult to interpret. In this study the averaging method of analysis proposed by Dain and Birch is used to examine 120 100-Hue plots obtained by patients with proliferative diabetic retinopathy. These plots have either moderate (150-300) or high error scores (greater than 300). The method of analysis is found to be effective in determining whether a Tritan defect is present or not.

Adult↗
PubMed1986

Prolonged bleeding time, reduced platelet aggregation, altered PAF-acether sensitivity and increased platelet mass are a trait of asthma and hay fever.

In a case control study 31 asymptomatic patients with asthma and/or hay fever and 31 normal controls had their bleeding time measured using the Simplate II device and venostasis. Mean bleeding time in the atopic group (527 s) was significantly prolonged compared to the controls (393 s) (p less than 0.0005). Platelet aggregation to collagen and ADP (but not to PAF-acether) was significantly depressed in the atopics. Mean circulating platelet mass was significantly greater in atopics than in the controls (p = 0.006). Stepwise multiple regression analysis showed that within the control group bleeding time was best predicted by platelet mass (p = 0.007). No such relationship was found in the atopics. However stepwise multiple regression analysis showed that bleeding time in the atopics (but not in the controls) was best predicted by PAF-acether induced platelet aggregability (p less than 0.05). In neither group was bleeding time related to collagen induced platelet thromboxane B2 production. It is hypothesised that in respiratory atopy the depressed aggregatory function of platelets is not compensated for sufficiently by an increase in platelet mass, leading to prolongation of the bleeding time. This haemostatic imbalance, whose cause remains to be established, appears to constitute a trait of atopy.

Adenosine Diphosphate↗
PubMed1985

Cell kinetic studies in the epidermis of mouse. III. The percent labelled mitosis (PLM) technique.

Full PLM curves have been obtained for four sites in the mouse. The first peaks have been analysed by computer and the duration of the G2 + M and S phases determined together with their standard deviations. The full curves showed a general similarity for all four sites with no clear second peak. The data are compared with the published data for mouse and human epidermis using the in vivo PLM technique. The timing and shape of the first peak can vary considerably even for one site in mice. Hence, both G2 + M and S can vary in their durations. Cells labelled at one time of day exhibit different kinetic properties to those labelled at another time of day. The duration of G2 + M is shortest in dorsum labelled at 03.00 hours (3 X 2 hr) and longest in tail (up to 7 X 5 hr). The S-phase is shortest in dorsum (6 X 3-7 X 2 hr) and longest in tail or ear (13 X 3-14 X 1 hr). There is also a very large standard deviation in tail and foot. There is little general variability when the psoriatic human data are considered, which is surprising. The general variability amongst the data from experimental mice might also be expected amongst humans which might make comparisons between the cell kinetics of normal and diseased skin difficult.

Animals↗