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Biomedical subjects

J McDermott

Publications and source records attributed to J McDermott.

At least 19 recordsLinked to original sources

Use of magnetic resonance angiography for the preoperative evaluation of patients with infrainguinal arterial occlusive disease.

PURPOSE: This study was designed to determine whether magnetic resonance angiography (MRA) will allow preoperative management decisions without the need for contrast arteriography in patients with lower extremity ischemia caused by infrainguinal arterial occlusive disease. METHODS: Forty-five patients with lower extremity ischemia in 50 limbs were evaluated by both two-dimensional time-of-flight MRA and intraarterial digital subtraction angiography (DSA) between February 1992 and June 1995. Independent management plans were based on clinical presentation, pulse volume recordings, and separate reviews of the MRA and DSA. RESULTS: Of 50 limbs, 23 required arterial bypass, 19 percutaneous transluminal angioplasty, 5 patch angioplasty, and 3 amputation. MRA and DSA correlated exactly in 89.5% of infrainguinal arterial segments, whereas interpretations disagreed in 10.5% of arterial segments. Mismatches that had an influence on patient treatment decisions occurred in only 8 (2.3%) of 352 arterial segments. Independent MRA- and DSA-based revascularization plans agreed in 45 (90%) extremities. MRA predicted the level of arterial reconstruction in all 23 limbs that required arterial bypass. MRA identified focal stenoses amenable to percutaneous transluminal angioplasty in 18 (94.7%) of the 19 limbs that ultimately underwent percutaneous transluminal angioplasty. A strategy of preoperative planning by MRA with confirmatory intraoperative arteriography would represent a 31% cost savings per patient at our institution while eliminating the morbidity of preoperative DSA. CONCLUSIONS: When used in combination with the patient's physical examination and segmental limb pressures with plethysmography, MRA is sufficient for planning infrainguinal arterial bypass procedures and selecting patients for percutaneous transluminal angioplasty.

Aged

Structural analysis of human immunodeficiency virus type 1 Gag protein interactions, using cysteine-specific reagents.

We have examined structural interactions of Gag proteins in human immunodeficiency virus type 1 (HIV-1) particles by utilizing cysteine mutagenesis and cysteine-specific modifying reagents. In immature protease-minus but otherwise wild-type (wt) particles, precursor Pr55Gag proteins did not form intermolecular cystines naturally but could be cross-linked at cysteines, and cross-linking appeared to occur across nucleocapsid (NC) domains. Capsid (CA) proteins in wt mature viruses possess cysteines near their carboxy termini at gag codons 330 and 350, but these residues are not involved in natural covalent intermolecular bonds, nor can they be intermolecularly cross-linked by using the membrane-permeable cross-linker bis-maleimido hexane. The cysteine at gag codon 350 (C-350) is highly reactive to thiol-specific modifying reagents, while the one at codon 330 (C-330) appears considerably less reactive, even in the presence of ionic detergent. These results suggest that the HIV-1 CA C terminus forms an unusually stable conformation. Mutagenesis of C-350 to a serine residue in the mutant C350S (C-350 changed to serine) virtually eliminated particle assembly, attesting to the importance of this region. We also examined a C330S mutant, as well as mutants in which cysteines were created midway through the capsid domain or in the C-terminal section of the major homology region. All such mutants appeared wt on the basis of biochemical assays but showed greatly reduced infectivities, indicative of a postassembly, postprocessing replicative block. Interestingly, capsid proteins of mature major homology region mutant particles could be cysteine cross-linked, implying either that these mutations permit cross-linking of the native C-terminal CA cysteines or that major homology regions on neighbor capsid proteins are in close proximity in mature virions.

Animals

Perinatal mortality in rural Malawi.

Reported are the results of a study to assess the prevalence and risk factors for perinatal death among pregnant women in Malawi over the period 1987-90. There were 264 perinatal deaths among the 3866 women with singleton pregnancies (perinatal mortality rate, 68.3 per 1000 births). Among the risk factors for perinatal mortality were the following: reactive syphilis serology, nulliparity, a late fetal or neonatal death in the most recent previous birth, maternal height < 150 cm, home delivery, and low socioeconomic status. Although unexplained perinatal deaths will continue to occur, perinatal mortality can be reduced if its causes and risk factors in a community are given priority in antenatal and intrapartum care programmes. The following interventions could potentially reduce the perinatal mortality in the study population: screening and treating women with reactive syphilis serology; and management from early labour, by competent personnel in a health facility, of nulliparous women and multiparous women who are short or have a history of a perinatal death.

Body Height

The first step.

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Health Care Reform

The effect of a carbohydrate-rich beverage on mood, appetite, and cognitive function in women with premenstrual syndrome.

OBJECTIVE: To test the efficacy of a specially-formulated, carbohydrate-rich beverage (one known to increase the serum ratio of tryptophan to other large neutral amino acids) on the mood, cognitive, and appetitive disturbances of premenstrual syndrome (PMS). METHODS: Twenty-four women with confirmed PMS were enrolled in a double-blind, crossover study to test the efficacy of the specially-formulated beverage compared with two other isocaloric products on PMS symptoms. The study was conducted over three menstrual cycles preceded by a 1-month placebo run-in. Patients were tested at home or work using an interactive computer-telephone system. Standardized measurements of mood, cognitive performance, and food cravings were made before and 30, 90, and 180 minutes after consumption of active and placebo beverages during the late luteal phase of the menstrual cycle. RESULTS: The experimental carbohydrate intervention significantly decreased self-reported depression, anger, confusion, and carbohydrate craving 90-180 minutes after intake. Memory word recognition was also improved significantly compared with scores obtained during the placebo run-in month (P < .05). The isocaloric placebo interventions had no significant effect on any of these measures. CONCLUSION: The results suggest that the psychological and appetitive symptoms of PMS can be relieved after consuming a specially-formulated, carbohydrate-rich beverage known to increase serum tryptophan levels.

Adult

Efficacies of dexfenfluramine and fluoxetine in preventing weight gain after smoking cessation.

We tested whether 14 wk of dexfenfluramine (30 mg) or fluoxetine (40 mg) treatment would prevent weight gain after subjects quit smoking. Normal-weight women (n = 144) were randomly assigned to drug or placebo on a double-blind basis for 2 wk before quitting smoking and 12 wk thereafter. The fluoxetine group had more dropouts (28/49, 57.1%) than the dexfenfluramine group (17/47, 36.2%), with an intermediate number of dropouts from the placebo group (21/48, 43.8%). All groups gained weight during treatment, but their amount and pattern of weight gain differed. In the first month after quitting smoking, the placebo group gained more weight than either the dexfenfluramine or fluoxetine group (P < 0.05). By 2 mo postcessation, dexfenfluramine still suppressed weight gain in comparison with placebo (P < 0.05); weight gain with fluoxetine was not differentiable from either dexfenfluramine or placebo. By 3 mo postcessation, the dexfenfluramine group had gained 1.0 +/- 0.7 kg, significantly less than either the placebo (3.5 +/- 0.7 kg) or fluoxetine (2.7 +/- 0.5 kg) groups. Three months after drug discontinuation, formerly medicated, but not placebo patients, showed additional weight gain, eliminating differences between groups. Results indicate that weight gain, an adverse accompaniment of smoking cessation, can be minimized to some degree by serotoninergic drugs, although only for the duration of drug treatment.

Adult

The voices of reform. The final stretch. Interview by Renee Blankenau.

Following a complex research and development process last year that led to the drafting of a comprehensive health care reform proposal, President Bill Clinton presented the U.S. Congress and the nation with an outline for reform in September, and followed up with a detailed plan and with a reform bill in October. Now it's Congress' turn to respond. Hospitals & Health Networks' senior editor Renee Blankenau interviewed 11 members of Congress whose views represent a broad spectrum of congressional opinion. What version of federal reform will emerge this year? These legislators have the inside track.

Forecasting

DNA markers linked to Malus floribunda 821 scab resistance.

Breeding resistant apple plants is an alternative way to control fungal pathogens reducing the environmental impact due to the use of pesticides. The breeding of apple cultivars resistant to Venturia inaequalis could be much improved by marker-assisted selection. A molecular marker closely linked to the resistance locus called Vf could replace selection based on infection studies. To find such molecular markers, DNA of progenies from crossings of a resistant and a susceptible apple tree was subject to bulked segregant analysis. Two markers were found with a genetic distance of 10.6% and 19.7% recombination frequency to the Vf locus.

DNA Primers

Outcome of adults with acquired immunodeficiency syndrome in Auckland 1983-9.

AIMS: To assess the survival of Auckland residents diagnosed with AIDS between 1983 and 1989. METHODS: Retrospective case review RESULTS: Sixty nine Auckland residents were diagnosed with AIDS between 1983 and the end of 1989, and were cared for by the infectious disease unit, Auckland Hospital. The overall median survival was 289 days with 48% and 20% surviving at one and two years respectively. Survival was longer among those who were infected through homosexual contact, were younger, and not known to the infectious disease unit prior to the diagnosis of AIDS. Although survival was longer for those diagnosed in 1988 compared to earlier years, it was shorter again for those diagnosed in 1989. Pneumocystis carinii pneumonia, the AIDS defining condition in 63.8% of people, was found less frequently in 1989, and overall was associated with a longer survival than most of the other AIDS-defining diagnoses. A quarter of the people were not known to be infected with HIV prior to the AIDS-defining condition. CONCLUSION: In New Zealand, as in other countries, changes in treatment strategies of people with HIV infection may impinge on the survival of people with AIDS.

Acquired Immunodeficiency Syndrome

Hospital associated costs of treating patients with AIDS.

AIM: To determine the hospital associated costs of caring for patients with AIDS. METHOD: We reviewed the notes of all 40 patients with AIDS admitted to the Auckland Hospital infectious disease unit during 1988. We used the resource utilisation system (RUS) to determine costs. RESULTS: Costs were maximal in the month of diagnosis of AIDS (ca $3500/month), falling thereafter to ca $1000/month until they rose again in the last months of life. Total costs were dominated initially by inpatient costs but subsequently by the costs of medicines. CONCLUSION: The hospital costs associated with the care of AIDS patients are not spaced evenly throughout the illness. Extended life will not increase costs proportionately.

Acquired Immunodeficiency Syndrome

MEF2C, a MADS/MEF2-family transcription factor expressed in a laminar distribution in cerebral cortex.

We have cloned cDNA encoding a human transcription factor that belongs to the MEF2 (myocyte-specific enhancer-binding factor 2) subfamily of the MADS (MCM1-agamous-deficiens-serum response factor) gene family. This factor, which we have named MEF2C, binds specifically to the MEF2 element and activates transcription via this element. Specific isoforms of this factor are found exclusively in brain and are robustly expressed by neurons in cerebral cortex. In situ hybridization indicates that the factor is expressed preferentially in certain neuronal layers of cortex and that expression declines during postnatal development. The unusual pattern of expression in brain suggests that this transcription factor may be important in the development of cortical architecture.

Amino Acid Sequence

Dexfenfluramine, fluoxetine, and weight loss among female carbohydrate cravers.

The consumption of excess calories as carbohydrates (CHO)-rich, protein-poor snacks characterizes the overeating of obese CHO cravers, premenstrual women, patients with Seasonal Affective Disorder, and former smokers. This specific appetite for CHOs may involve brain serotonin, as the synthesis and release of this neurotransmitter can increase following consumption of CHO-rich foods. To examine whether weight loss produced by serotoninergic drugs involves a selective reduction in CHO intake, obese females who consumed at least 30% of their daily calories from CHO-rich snacks were treated with dexfenfluramine ([DF] 15 mg b.i.d.); fluoxetine ([FL] 20 mg t.i.d.); or placebo (PL) for 12 weeks. Weekly weight loss for 25 of 29 PL completers was 0.22 kg +/- 0.06 (mean +/- SEM); for 21 of 28 DF completers, 0.56 +/- 0.08 kg; and for 18 of 30 FL completers, 0.58 +/- 0.09 kg (PL < DF = FL; p = .039). Seven FL subjects, 2 PL subjects, and 1 DF subject withdrew from the study due to side effects; other withdrawals were due to intercurrent illness or personal problems. Prior to treatment, subjects consumed over 40% of their daily CHO intake from snacks. Both of the drugs selectively decreased CHO snack intake (p < 0.05); DF, but not FL, also decreased meal CHO intake (p < .025). These results suggest that weight loss following treatment with serotoninergic drugs may relate to a selective decrease in CHO appetite.

Adult

Conditional infectivity of a human immunodeficiency virus matrix domain deletion mutant.

We constructed a human immunodeficiency virus (HIV) matrix (MA) deletion mutant by deletion of about 80% of the HIV type 1 Gag MA domain but retaining myristylation and proteolytic processing signals. The effects of this deletion matrix (dl.MA) mutant on HIV particle assembly, processing, and infectivity were analyzed. Surprisingly, the dl.MA mutant still could assemble and process virus particles, had a wild-type (wt) retrovirus particle density, and possessed wt reverse transcriptase activity. RNase protection experiments showed that dl.MA mutant particles preferentially packaged viral genomic RNA. When both mutant and wt particles were pseudotyped with an amphotropic murine leukemia virus envelope protein, mutant infectivity was about 10% of wt level. In contrast, infectivity of the dl.MA mutant was 1,000-fold less than that of wild-type when mutant and wt particles were pseudotyped with the HIV envelope protein. Protein analyses of pseudotyped virions indicated that there were no major differences between mutant and wt viruses in the efficiency of amphotropic murine leukemia virus envelope protein incorporation. In contrast, there was a reduction in the amount of mutant particle-associated HIV envelope protein gp120. Our results suggest that an intact HIV matrix domain is not absolutely required for reverse transcription, nuclear localization, or integration but is necessary for appropriate HIV envelope protein function.

Amino Acid Sequence

Syphilis-associated perinatal and infant mortality in rural Malawi.

In Mangochi District, a rural area of Malawi, the prevalence of active syphilis was 3.6% among 3591 women who had singleton births and who were negative for human immunodeficiency virus (HIV). Compared with non-syphilitic women, those with active syphilis (positive Venereal Disease Research Laboratory/rapid plasmin reagin tests (titre > or = 1:8) and a reactive microhaemagglutination assay) were more likely to experience stillbirths as well as the early and late neonatal deaths and even postneonatal deaths of their children. Characteristics associated with active syphilis were not very useful in targeting women at high risk of having the condition, which makes universal screening in antenatal programmes the most efficacious way to prevent syphilis-associated morbidity and mortality. The potential for a programme to prevent congenital syphilis in the perinatal, neonatal, and post-neonatal periods is evident. In considering resource allocation to child survival programmes in areas where the prevalence of syphilis is high, officials need to include antenatal syphilis screening, using rapid tests and treatment at the first contact of the mother with the health care system.

Child Welfare

Setting up a no smoking support group.

Smoking is the single greatest cause of ill-health and disability in the UK; some one million people die from smoking relating disease each year. It is a clear target for the health visitor's health promoting activities, argues Jayne McDermott. Here she describes setting up a successful 'No smoking' support group.

Community Health Nursing

The aromatic amino acid decarboxylase inhibitor, NSD-1015, increases release of dopamine: response characteristics.

Addition of the aromatic amino acid decarboxylase inhibitor, NSD-1015 (10 microM), to Krebs'-Ringer phosphate (KRP) superfusion medium, significantly increased the release of dopamine in vitro from superfused corpus striatum tissue fragments of male rats. A dose-dependent increase in release of dopamine was obtained in response to increasing concentrations of NSD-1015, with 1.0 microM being the minimally effective dose. In addition to the striatum, NSD-1015 also increased the release of dopamine from superfused hypothalamic tissue fragments. This capacity of NSD-1015 to increase release of dopamine was calcium-independent, appeared to be somewhat specific and could apparently increase the release of dopamine in vivo, as indicated by increases in the release of the metabolite of dopamine, DOPAC, under conditions of push-pull perfusion. Although the putative role of NSD-1015 is as an aromatic amino acid decarboxylase inhibitor, the present results demonstrate that, either as a result of this function and/or in addition to this role, NSD-1015 is a potent activator of the release of dopamine.

3,4-Dihydroxyphenylacetic Acid