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Biomedical subjects

J Allen

Publications and source records attributed to J Allen.

At least 217 records · Page 12Linked to original sources
PubMed1995

Prenatal diagnosis of galactosemia.

The experience from three different European centres with the prenatal diagnosis of galactose-1-phosphate-uridyltransferase (GALT) deficiency is presented and the question whether or not there is a need for prenatal diagnosis of this disorder is discussed. Most prenatal diagnoses (n = 50) have been performed by assay of GALT activity in cultured amniotic fluid cells. The assay used is reliable and clearly distinguishes homozygous affected fetuses (n = 11; 0%-2.3% of mean control enzyme activity) from non-(homozygous)-affected fetuses. The GALT assay for cultured amniocytes was adapted to assay the enzyme directly in chorionic villi. The experience with chorionic villi comprises 23 cases with 5 affected fetuses (0%-4.2% of mean control enzyme activity). In 36 cases galactitol was determined in amniotic fluid supernatant by gas chromatography-mass spectrometry. This method also differentiated affected (n = 11; galactitol 5.9-10.6 mumol/l) and unaffected pregnancies (galactitol 0.23-1.6 mumol/l) clearly and has the advantage of providing a result within a day or two after amniocentesis. Prenatal diagnosis of galactosemia is undertaken rarely and sometimes for the wrong reasons, but it should perhaps be considered more seriously until better methods of treatment are established.

Amniocentesis↗
PubMed1995

Small dishwashers for hospital ward kitchens.

A comparison of the cleaning efficiency and thermal disinfection capabilities of 12 small dishwashers being used in hospital wards was carried out. Machines installed prior to the establishment of a local purchase policy failed to achieve the standards required for hygienic washing up. Machines conforming to the purchasing criteria gave a satisfactory performance.

Cooking and Eating Utensils↗
PubMed1995

Aneuploidies and micronuclei in the germ cells of male mice of advanced age.

The objective of this research was to determine whether the frequencies of chromosomally defective germ cells increased with age in male laboratory mice. Two types of chromosomal abnormalities were characterized: (1) testicular spermatid aneuploidy (TSA) as measured by a new method of multi-color fluorescence in situ hybridization (FISH) with DNA probes specific for mouse chromosomes X, Y and 8, and (2) spermatid micronucleus (SMN) analyses using anti-kinetochore antibodies. B6C3F1 mice (aged 22.5 to 30.5 months, heavier than controls but otherwise in good health) showed significant approximately 2.0 fold increases in the aneuploidy phenotypes X-X-8, Y-Y-8, 8-8-X and 8-8-Y with the greatest effects appearing in animals aged greater than 28 months. No age effect was observed, however, in X-Y-8 hyperhaploidy. Major age-related increases were seen in Y-Y-8 and X-X-8 hyperhaploidies suggesting that advanced paternal age is associated primarily with meiosis II rather than meiosis I disjunction errors. A approximately 5 fold increase was also found in the frequency of micronucleated spermatids in aged mice when compared with young controls. All micronuclei detected in the aged animals lacked kinetochore labeling, suggesting that they either did not contain intact chromosomes or the chromosomes lacked detectable kinetochores. The findings of the TSA and SMN assays are consistent with meiotic or premeiotic effects of advanced age on germ cell chromosomes, but there were differences in the age dependencies of aneuploidy and micronuclei. In summary, advanced paternal age may be a risk factor for chromosomal abnormalities (both aneuploidy and structural abnormalities) in male germ cells.

Aging↗
PubMed1995

Poor fertilization may be related to oocyte or zona pellucida recognition defects specific to certain hyperstimulation regimens and limited to some males but not others: a case report.

OBJECTIVE: To determine if the controlled ovarian hyperstimulation (COH) regimen may cause sperm to appear subfertile only to improve considerably by changing the COH protocol. DESIGN: Case report with retrospective review of previous fertilization rates according to COH protocol used. MAIN OUTCOME MEASURES: Fertilization and pregnancy rates (PRs) after IVF-ET. RESULTS: Known fertile donor sperm failed to fertilize any of 11 oocytes compared with 14 of 18 for processed retrograde ejaculate using the same oocyte pool. Retrospective analysis of other cycles for different female patients but same donor found 16.6% fertilization rate whenever luteal phase leuprolide acetate (LA)-hMG regimen was used compared with 70.6% with short-flare regimen. CONCLUSION: Some COH regimens may cause oocyte or zona pellucida changes that create recognition defects for some sperm but not others. Interestingly, the sperm with the binding defect with the luteal phase LA-hMG COH protocol exhibited good fertilization rates with oocytes prepared with the short-flare protocol and demonstrated high in vivo PRs after IUI.

Adult↗
PubMed1995

Body surface ECG potential maps in acute myocardial infarction.

An algorithm for the early detection of acute myocardial infarction (MI) using body surface electrocardiographic potential mapping has been developed. The mapping system consists of a 64-hydrogel electrode harness applied rapidly to the anterior chest, from which electrocardiographic signals are stored on a memory card and processed by computer. At each of the 64 points, QRS and ST-T isointegrals and 10 other features of the QRST segment are measured. Using these measurements, new variables are derived that express the shape of the three-dimensional geometric surface of the map. The isointegrals, features, and shape variables are used in a variety of techniques to discriminate between MI and control subjects. Maps were recorded from 69 patients at initial presentation of chest pain suggestive of acute MI and from 80 healthy control subjects. Using a multiple logistic regression technique, 14 variables were identified that correctly classified 79 of the 80 control subjects (specificity, 98.8%) and 65 of the 69 MI patients (sensitivity, 94.2%). The algorithm based on these 14 variables was applied prospectively to maps recorded on a further 48 control subjects and 59 patients with acute MI. Of the MI patients, 31 had inferior, 13 inferoposterior, 10 anterior, 2 posterior, 1 lateral, 1 inferior with right bundle branch block, and 1 anterior non Q wave MI. The algorithm correctly classified all 48 control subjects (specificity, 100%) and 57 of the 59 MI patients (sensitivity, 96.6%). Marked differences in the three-dimensional geometric map surfaces between the control subjects and MI patients were demonstrated. Variables derived from these surfaces form the basis of an algorithm with a high sensitivity and specificity for the automated detection of acute MI. The design of adaptive algorithms and their application to patients with chest pain and atypical electrocardiographic changes, particularly ST depression, may lead to the earlier detection of MI and greater numbers of patients receiving thrombolytic therapy.

Adolescent↗
PubMed1995

Prospective assessment of an artificial neural network for the detection of peripheral vascular disease from lower limb pulse waveforms.

The diagnostic performance of an artificial neural network pulse classification system for the detection of peripheral vascular disease was investigated prospectively. Lower limb photoelectric plethysmographic pulses, and Doppler ankle/brachial pressure index (ABPI) measurements (pre- and post-exercise) were obtained from 200 patients referred to a vascular investigation laboratory. A single toe pulse was processed and used as input data to a neural network which had been trained previously with a set of pulses from 100 legs. The neural network outputs represented the diagnostic arterial disease classifications defined by the ABPI. From the 200 patients entered prospectively, 266 legs were available for neural network assessment. A network sensitivity of 92% and specificity of 63% were achieved with a diagnostic accuracy of 80%. By using a higher confidence for the classification decision a small, but insignificant overall improvement was obtained. When a borderline classification was introduced 100% sensitivity and 100% negative predictive value were obtained, though 31% of legs were unclassifiable. Nevertheless, the very high sensitivity and negative predictive value could make this quick and simple technique the one of choice for the first stage in screening large numbers of subjects.

Adult↗
PubMed1995

The localization of the target antigens and antibodies in linear IgA disease is heterogeneous, and dependent on the methods used.

Fifty-nine patients with linear IgA disease, 24 with onset in childhood and 35 with adult onset, were studied. Sera from all patients were tested by indirect immunofluorescence, using as substrates intact normal skin and normal skin which had been split through the lamina lucida region of the basement membrane zone by suction and by prolonged incubation with molar NaCl. This enabled the site of the target antigen for the circulating IgA antibodies to be determined. The sites of deposition of the IgA antibodies in vivo were detected by raising a suction blister in eight patients, and splitting seven patients' biopsies by prolonged incubation with molar NaCl. Eighteen sera were positive with intact skin, and 34 with split skin. Twenty-nine sera were positive with suction blisters as substrate; 14 bound to the epidermal aspect of the split skin, seven in a combined pattern (binding to the epidermis and dermis) and six to the dermal aspect. Thirty-one sera bound to salt-split skin, 24 to the epidermal side and seven on the dermal side. There was discordance between the two methods of skin splitting in 15 sera. Seven sera gave a combined pattern with suction but with salt-split skin, five of these bound epidermally, one was dermal, and one negative. Five sera showed epidermal binding on salt-split skin and were negative on suction blisters, and the reverse was seen with one serum. Two sera gave variable results on suction blisters. Direct immunofluorescence studies showed dermal binding on all eight patients with suction blisters, and epidermal binding in four and dermal binding in three patients with salt splitting.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

Childhood bullous pemphigoid--report of a case with dermal fluorescence on salt-split skin.

Bullous pemphigoid (BP) is an acquired bullous disorder which predominantly affects the elderly. It is rare in children, and may be clinically indistinguishable from other immunobullous disorders. As routine histology may be non-specific, a definitive diagnosis of childhood BP usually depends on the results of direct and indirect immunofluorescence investigations. We report a 5-year-old girl who developed bullous pemphigoid, associated with atypical immunofluorescence findings. Indirect immunofluorescence on split-skin showed a pure dermal pattern of IgG binding. This is usually suggestive of epidermolysis bullosa acquisita, but Western immunoblotting was positive with epidermal extracts, confirming a diagnosis of BP. Dermal binding on split-skin occurs in about 5% of adult cases of BP, and has not been reported previously in childhood BP.

Blotting, Western↗
PubMed1995

Bullous systemic lupus erythematosus: revised criteria for diagnosis.

Blistering in systemic lupus erythematosus has been divided into three groups. A specific subgroup of 'bullous systemic lupus erythematosus' has been defined by Gammon et al. on the basis of a number of criteria. From our experience of seven patients with bullous systemic lupus erythematosus, and after reviewing the literature, we suggest that the current classification is too narrow. Our patients displayed clinical and immunohistological (based on direct and indirect immunofluorescence and Western immunoblotting) heterogeneity. Sera from two patients bound to epidermal epitopes in sodium chloride-split skin, but immunoblotting was negative. In neither of these patients could the target antigen be type VII collagen, the only antigen identified as pathogenic in this disease. Patients with epidermal binding should not be excluded from a diagnosis of bullous systemic lupus erythematosus. SLE is a disease in which there is a genetic predisposition to form antibodies to type VII collagen, along with other autoantibodies, many of which may be implicated in blistering. We suggest that the criteria for the diagnosis of BSLE should be revised. We define this disease as an acquired subepidermal blistering disease in a patient with SLE, in which immune reactants are present at the basement membrane zone on either direct or indirect immunofluorescence.

Adult↗
PubMed1995

Developing the involvement of nurses in purchasing.

This article addresses the fact that nurses appear to be under-represented in National Health Service (NHS) purchasing, a situation which has recently been examined by a working group from the NHS Executive (1994) entitled 'Building a stronger team: the nursing contribution to purchasing'. A number of potential reasons for this situation, which is so important for the future of the nursing profession, will be outlined. A different perspective will then be introduced in the form of a psychological instrument, the Myers Briggs Type Indicator (MBTI) which will be described and related to this specific topic. The final section concerns a piece of current research which has the MBTI as its focus and contains material which is particularly relevant to the management of this problem.

Decision Making, Organizational↗
PubMed1995

A phase II trial of paclitaxel in squamous cell carcinoma of the head and neck with correlative laboratory studies.

Head and neck cancer is a major cause of cancer-related deaths. In general, early stage head and neck cancers are effectively treated with either radiation or surgery. More advanced tumors often require combined-modality therapy with both radiation therapy and surgery. Recent investigations indicate that the addition of chemotherapy may be helpful. One of the newer chemotherapy agents that appears to have significant activity against head and neck cancer is paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ). Paclitaxel, originally derived from the western yew Taxus brevifolia, acts by increasing the stability of microtubules and preventing mitosis. Recent evidence indicates that the microtubule system is vital to the release of various cytokines and that modulation of cytokine release may play a major role in the drug's antitumor activity. We report a phase II trial of paclitaxel in patients with head and neck cancer, not only to evaluate its clinical effects, but also to study its effect on cytokine release. We assessed interleukin-1 beta (IL-1 beta) and tumor necrosis factor-alpha production by using a sensitive enzyme-linked immunosorbent assay to assess the serum of patients receiving paclitaxel and to detect cytokine release in vitro. The objective response rate was 36%, with 12% complete responses and 24% partial responses. No IL-1 beta or tumor necrosis factor-alpha was detected in patient serum at any time during the infusion of paclitaxel or after overnight incubation with patient monocytes. No proIL-1 beta was detected in in vitro cultures of paclitaxel-treated patient monocytes. When monocytes were stimulated with endotoxin, IL-1 beta production was greatest at 48 hours, suggesting that paclitaxel can prime cells to produce greater quantities of cytokines after a second stimulus.

Adult↗
PubMed1995

In vivo and in vitro interaction of the novel selective histamine H1 receptor antagonist mizolastine with H1 receptors in the rodent.

The interaction of mizolastine (CAS 108612-45-9, SL 85.0324) with histamine H1 receptors has been evaluated in the rodent. Mizolastine inhibited with high affinity (IC50 = 47 nmol/l) the binding of [3H]pyrilamine to histamine H1 receptors in guinea pig cerebellar membranes and sections. The order of potency of mizolastine and various H1 antagonists in this binding assay was the following: cyproheptadine > pyrilamine > mequitazine > mizolastine > astemizole > terfenadine > cetirizine > loratadine. Mizolastine also potently antagonized the contractile effects of histamine in the guinea pig ileum (pA2 = 8.5) and histamine-induced stimulation of phosphoinositide turnover in rat cortical slices (IC50 = 0.35 mumol/l). In contrast, this compound displayed very low affinity for serotonergic, noradrenergic and muscarinic cholinergic receptors as evidenced in both binding assays and functional tests. In guinea pig cerebellar membranes, [3H]mizolastine labelled in a saturable and reversible manner a single population of binding sites with Kd and Bmax values of 1.1 nmol/l and 635 fmol/mg protein, respectively. [3H]Mizolastine binding in guinea pig cerebellar membranes was inhibited by histamine (IC50 = 30 mumol/l) and by drugs that possess affinity for the H1 receptor such as pyrilamine (IC50 = 1 nmol/1), DL-chlorphenyramine (IC50 = 6.4 nmol/l) terfenadine (IC50 = 6 nmol/l) and loratadine (IC50 = 50 nmol/l). At concentrations lower than 10 mumol/l, the H2 receptor ligands dimaprit and cimetidine and the H3 receptor ligands burimamide and 4-methyl-histamine failed to displace [3H]mizolastine binding.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Pediatric organ donation: impact of medical examiner refusal.

OBJECTIVES: To examine the national Pediatric Intensive Care Unit (PICU) experience regarding Medical Examiner (ME) refusal of organ procurement from potential donors. To review our experience regarding PICU mortalities, organ donation, and impact of the ME on the organ donation process. DESIGN: National survey of PICU directors requesting demographics, type of ME system, perceptions of ME responsiveness to organ donation, and data regarding potential donors and their outcomes. Also, a retrospective chart review of all PICU deaths from 1990 to 1992 at a tertiary care center, noting the number of potential organ donors, ME cases, those harvested, rejected, and reason for rejection. PARTICIPANTS: PICU directors selected from a list of Pediatric Section members of the Society of Critical Care Medicine. The response rate was 59%. The chart review was performed in a 1000-bed hospital with a 12-bed PICU. RESULTS: PICU directors' perceptions of ME responsiveness to organ donation were not determined by size of PICU, area served, type of hospital, ME system, or means of contacting the ME. ME refusal accounted for 15% and 16% of total refusals in the survey and chart review, respectively. Family refusal accounted for 49% and 28% in these same groups. Survey respondents' hints and suggestions to decrease denial and increase organ donation focused on improved communication (61% and 33%), and education (16% and 55%). CONCLUSIONS: ME refusal does impact on pediatric organ donation, but not as significantly as family refusal. Increased organ procurement in ME-related cases will require improved communication between MEs, physicians, and the Organ Procurement Organizations (OPOs).

Attitude of Health Personnel↗
PubMed1995

Caring in nursing: rhetoric or reality?

Nursing requires both a scientific and humanistic basis for practice. Nursing is a human science; a market-place ideology and a technological environment limit caring.

Empathy↗
PubMed1995

Age-specific incidence of cancer in Kingston and St. Andrew, Jamaica, 1988-1992.

During the period 1988-1992, a total of 4,030 malignant neoplasms were recorded in Kingston and St. Andrew, Jamaica. These comprised 1,829 in males and 2,201 in females. Histological confirmation was obtained in 83.4%. The crude incidence rate for males was 128.5, and 136.2 for females. The age-standardized rates (ASR) were 179.9 for males and 166.1 for females. Age-specific rates by site, sex and age are tabulated. Attention is drawn to increased incidence for cancers of prostate, larynx, bronchus and non-Hodgkin's lymphoma in males. There was also an increase in female breast cancer (crude rate 36.0; ASR 47.1). Invasive cervix cancer has shown no significant change in incidence. Neoplasms of the body of the uterus have increased (crude rate 7.6; ASR 9.5). The rise in cancer of breast and body of uterus suggests that the influence of exogenous oestrogens should be considered.

Adolescent↗