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Biomedical subjects

M Dunn

Publications and source records attributed to M Dunn.

At least 37 records · Page 2Linked to original sources
PubMed2000

Chronic ectopic pregnancy--two cases of acute rupture despite negative beta hCG.

We present the cases of two women with chronic ectopic pregnancies who presented with acute tubal rupture and hemoperitoneum despite negative beta-human chorionic gonadotropin (beta hCG) pregnancy tests. The appropriate screening use of beta hCG assays to ascertain pregnancy status, the mechanisms by which ectopic pregnancy may be seen with negative beta hCG tests, and the limitations of various assays are discussed. One patient, not initially believed to be pregnant, underwent computed tomography (CT) scan. Experience with use of CT scan in ectopic pregnancy diagnosis is limited; our case illustrates some of the possible CT scan findings. These cases illustrate the potential for ectopic pregnancy to rupture with low, if not undetectable beta hCG hormone levels, and consequently why it is not recommended to rely on quantitative beta hCG levels to guide the decision to proceed with ultrasound imaging.

Abdominal Pain↗
PubMed2000

Subjective health in spinal cord injury after outpatient healthcare follow-up.

OBJECTIVE: To compare self-reported health, independence, and depression in two samples of people with spinal cord injury (SCI), one which receives regular, comprehensive outpatient health care follow-up and one that does not. DESIGN: Exploratory study of self-reported secondary conditions in 235 individuals with SCI who received health care follow-up using post hoc quasi-experimental comparisons with a group of 136 people with SCI who had no health care follow-up. SETTING: Outpatients at a Veterans Affairs Health Care System SCI Center. MAIN OUTCOME MEASURES: The Check Your Health Instrument surveyed three self-report measures: overall health, independence, and depression. The Secondary Conditions Screening Instrument (SCSI) addressed 40 secondary conditions that may have been experienced in the prior year. RESULTS: Study participants who receive ongoing SCI health care reported higher subjective health, independence, and absence of depression scores compared to those that did not receive regular SCI health care follow-up. Results on the SCSI showed similar secondary conditions in the two groups, but higher frequency and severity in the no follow-up group. CONCLUSION: SCI outpatient health care follow-up is associated with higher subjective health, independence, and absence of depression.

Activities of Daily Living↗
PubMed2000

Subgroups of children with autism by cluster analysis: a longitudinal examination.

OBJECTIVES: A hierarchical cluster analysis was conducted using a sample of 138 school-age children with autism. The objective was to examine (1) the characteristics of resulting subgroups, (2) the relationship of these subgroups to subgroups of the same children determined at preschool age, and (3) preschool variables that best predicted school-age functioning. METHOD: Ninety-five cases were analyzed. RESULTS: Findings support the presence of 2 subgroups marked by different levels of social, language, and nonverbal ability, with the higher group showing essentially normal cognitive and behavioral scores. The relationship of high- and low-functioning subgroup membership to levels of functioning at preschool age was highly significant. CONCLUSIONS: School-age functioning was strongly predicted by preschool cognitive functioning but was not strongly predicted by preschool social abnormality or severity of autistic symptoms. The differential outcome of the 2 groups shows that high IQ is necessary but not sufficient for optimal outcome in the presence of severe language impairment.

Autistic Disorder↗
PubMed2000

Recurrent sacculation of the pregnant uterus. A case report.

BACKGROUND: Recurrent uterine sacculation is very rare and associated only with pregnancy. It commonly complicates delivery with a retained placenta. CASE: A 24-year-old woman, gravida 4, para 0, with three previous elective abortions, presented in preterm labor at 32 6/7 weeks' gestation. Her second and third abortions were complicated by incomplete evacuation of uterine contents, and uterine sacculation was diagnosed. Preterm delivery and a retained placenta complicated the present pregnancy. At laparotomy, recurrence of uterine sacculation was noted in the left fundal region of a bicornuate uterus. A hysterotomy was performed to remove the placenta from the sacculation. CONCLUSION: In a patient with multiple uterine procedures and retained placenta, uterine sacculation can develop.

Adult↗
PubMed1999

Compound heterozygosity for the Achondroplasia-hypochondroplasia FGFR3 mutations: prenatal diagnosis and postnatal outcome.

We report on a male newborn infant, a compound carrier of heterozygous mutations in the FGFR3 gene causing achondroplasia and hypochondroplasia. The mother has achondroplasia and carries the common G1138 (G380R) mutation in the FGFR3 gene; the father has hypochondroplasia due to the C1620A (N540K) mutation in the same gene. The fetus was found to carry both mutations diagnosed prenatally by amniocentesis at 17.6 weeks of gestation, following maternal serum screening which showed an increased risk for Down syndrome (1:337). Detailed fetal ultrasound studies showed a large head, short limbs, and a small chest at 22 weeks of gestation. The changes were more severe than those of either achondroplasia or hypochondroplasia. The patient was born by cesarean section at 38 weeks of gestation and had rhizomelic shortness of the upper and lower limbs with excess skin folds, large head, enlarged fontanelles, frontal bossing, lumbar gibbus, trident position of the fingers, and a narrow chest with a horizontal line of demarcation at the narrowest area of the chest. Skeletal radiographs showed shortness of the long bones and flare of metaphyses. He had respiratory difficulties and was treated with nasal prongs. Seizures developed on day 2 of life and recurred on day 9 and responded to treatment with phenobarbital. Brain computed tomographic scan showed possible grey matter heterotopia, partial agenesis of the corpus callosum, and cortical dysplasia. To our knowledge, there are only two previously published cases of compound heterozygous achondroplasia-hypochondroplasia patients. The diagnosis was confirmed by DNA mutation analysis of the FGFR3 gene in both cases.

Abnormalities, Multiple↗
PubMed1999

Characteristics of sequences around individual nucleotide substitutions in IgVH genes suggest different GC and AT mutators.

Somatic hypermutation affects Ig genes during T-dependent B cell responses and is characterized by a high frequency of single base substitutions. Hypermutation is not a completely random process; a study of mutations in different systems has revealed the presence of sequence motifs that target mutation. In a recent analysis of the sequences surrounding individual mutated bases in out-of-frame human IgVH genes, we found that the target motifs around mutated G's and C's are reverse complements of each other. This finding suggests that hypermutation acts on both strands of DNA, which contradicts evidence of a strand-dependent mechanism as suggested by an observed bias in A and T mutations and the involvement of transcriptional machinery. We have now extended our database of out-of-frame genes and determined the sequence motifs flanking mutated A and T nucleotides. In addition, we have analyzed the flanking sequences for different types of nucleotide substitutions separately. Our results confirm the relationship between the motifs for G and C mutations and show that the motifs surrounding mutated A's and T's are weaker and do not have the same relationship. Taken together with our observation of A/T strand bias in out-of-frame genes, this observation suggests that there is a semitargeted G/C mutator that is strand-independent and a separate A/T mutator that is strand-dependent and is less reliant on the local target sequence.

Adenine↗
PubMed1999

Clenbuterol increases stroke power and contractile speed of skeletal muscle for cardiac assist.

BACKGROUND: Skeletal muscle assist (SMA) may be limited by loss of power, slowing of contraction and relaxation, and atrophy of the transformed latissimus dorsi muscle (LD). Clenbuterol (clen), a beta2-adrenergic receptor agonist, was used to improve the performance of trained skeletal muscle in sheep. METHODS AND RESULTS: The following 4 groups were used: A (n=6), untrained controls; B (n=6), left LD progressively transformed toward a slow-twitch and fatigue-resistant phenotype by electrical stimulation over 12 weeks (2.5 to 5 V, 240- microsec pulse duration, 35 Hz, 3 to 6 pulses per burst, and up to 40 bursts per minute); C (n=6), clen-treated (0.5 mg/kg SC) for 12 weeks; and D (n=6), clen+trained. In a terminal experiment, the mobilized LD was wrapped around a rubber aorta of a mock circulation and stimulated to contract 40 times per minute. Group A had an initial mean pressure augmentation (DeltaP) of 24.6 mm Hg and stroke power of 2.28 W/kg, but both fell to <20% of their original values by 15 minutes because of fatigue (P<0.005). Group B was fatigue-resistant, with a DeltaP and stroke power at 60 minutes of 13 mm Hg (70% of initial) and 0.34 W/kg (39% of initial), respectively. The performance of group C was similar to that of controls. In group D, however, the muscles were stronger at all time points than in B, with a DeltaP of 23 mm Hg and stroke power of 2.66 W/kg at 60 minutes (P<0.01). The speeds of contraction (+dP/dt:DeltaP) and relaxation (-dP/dt:DeltaP) were significantly greater in group D than B. Protein analyses showed group D to have only a trend toward greater abundance of the fast isoforms of myosin heavy chain and sarcoplasmic reticulum Ca2+-ATPase (P>0.1). CONCLUSIOINS: ++Clen improves the performance of trained skeletal muscle in a model of aortomyoplasty by unknown mechanisms. These findings may have important implications in SMA.

Adrenergic beta-Agonists↗
PubMed1999

Adolescent females with a substance use disorder: affiliations with adult male sexual partners.

OBJECTIVE: To test the hypothesis that low socioeconomic status (SES), a disturbed parent-daughter relationship, early sexual development, and antisocial behavior are risk factors in adolescent females affiliating with adult male sexual partners. To determine whether the relation between these risk factors and affiliating with adult male sexual partners is stronger in females with greater, rather than fewer, substance use disorders (SUD). METHOD: Subjects were 180 adolescent females with SUD and 87 normal controls (14-18 years of age). RESULTS: The SUD group had a lower SES and more negative parent-daughter interactions, and exhibited greater antisocial tendencies. Also, the SUD group showed a more frequent affiliation with adult male sexual partners. Chronological age, age of menarche (sexual development), antisocial behavior, and quality of the parent-daughter relationship were significantly associated with affiliation with adult male sexual partners. Moreover, the number of SUD diagnoses enhanced the relation between the quality of the parent-daughter relationship and antisocial behavior with affiliation with adult male sexual partners. CONCLUSIONS: From a prevention perspective, interventions directed at enhancing child rearing practices, communication skills, and involvement in children's needs and activities might result in improved parent-child attachments that may attentuate young women's propensities to become involved in antisocial behavior and affiliate with adult sexual partners. Also, the risk imposed by an early sexual maturation may be offset by enhancing the female adolescent's social skills to select non-deviant and supportive male partners.

Adolescent↗
PubMed1999

Threonine kinetics in preterm infants fed their mothers' milk or formula with various ratios of whey to casein.

BACKGROUND: Plasma threonine concentrations are elevated in infants fed formula containing a whey-to-casein protein ratio of 60:40 compared with concentrations in infants fed formula containing a ratio of 20:80 or human milk (60:40). OBJECTIVE: We studied whether degradation of excess threonine was lower in formula-fed infants than in infants fed their mothers' milk. DESIGN: Threonine kinetics were examined in 17 preterm infants (gestational age: 31+/-2 wk: birth weight: 1720+/-330 g) by using an 18-h oral infusion of [1-13C]threonine at a postnatal age of 21+/-11 d and weight of 1971+/-270 g. Five infants received breast milk. Formula-fed infants (n = 12) were randomly assigned to receive 1 of 3 formulas (5.3 g protein/MJ) that differed only in the whey-to-casein ratio (20:80, 40:60, and 60:40). RESULTS: Threonine intake increased significantly in formula-fed infants with increasing whey content of the formula (48.5, 56.4, and 63.2 micromol.kg(-1).h(-1), respectively; pooled SD: 2.2; P = 0.0001), as did plasma threonine concentrations (228, 344, and 419 micromol/L, respectively; pooled SD: 75; P = 0.03). Despite a generous threonine intake by infants fed breast milk (58.0+/-16.0 micromol.kg(-1).h(-1), plasma threonine concentrations remained low (208+/-41 micromol/L). Fecal threonine excretion and net threonine tissue gain, estimated by nitrogen balance, did not differ significantly among groups. Threonine oxidation did not differ significantly among formula-fed infants but was significantly lower in formula-fed infants fed than in infants fed breast milk (17.1% compared with 24.3% of threonine intake, respectively). CONCLUSION: Formula-fed infants have a lower capacity to oxidize threonine than do infants fed breast milk.

Administration, Oral↗
PubMed1998

An intensive weight loss programme in established type 2 diabetes and controls: effects on weight and atherosclerosis risk factors at 1 year.

The efficacy, safety, and effect on cardiovascular risk factors of two intensive weight loss programmes in overweight Type 2 diabetic subjects were studied. The patients were recruited from hospital diabetic clinics and control obese subjects from the community. Obese (BMI >30) patients with Type 2 diabetes mellitus and controls were offered intensive conventional diabetic advice or a very low calorie diet. Weekly 2 h sessions were conducted in two day-room areas of adjacent medical wards of Torbay Hospital. Non-diabetic and diabetic very low calorie diet groups reduced BMI by 6 and 5 kg m(-2), respectively, at 1 year. Waist-hip ratios (-0.06 and -0.05) were also reduced (p = 0.04 and p = 0.01), while HDL/total cholesterol ratios increased (+0.04 and +0.06, p = <0.01). Transient changes in blood pressure and antioxidant vitamin status occurred in the intensive conventional diet group. Fourteen of diabetic very low calorie diet subjects discontinued insulin and oral hypoglycaemic agents for the whole year, and psychological well-being transiently improved. Substantial weight loss and improvement in cardiovascular risk factors could be maintained for 1 year in Type 2 diabetic patients by the use of a very low calorie diet.

Adult↗
PubMed1998

Hypoxic cell death in human NT2-N neurons: involvement of NMDA and non-NMDA glutamate receptors.

Human NTera2 teratocarcinoma cells were differentiated into postmitotic NT2-N neurons and exposed to hypoxia for 6 h. The cultures were evaluated microscopically, and percent lactate dehydrogenase (LDH) release after 24 and 48 h was used as an assay for cell death. After 48 h LDH release was 24.3 +/- 5.6% versus 13.8 +/- 3.7% in controls (p < 0.001). Cell death was greatly diminished by MK-801 pretreatment (15.4 +/- 5.1%, p < 0.001). If glutamine was omitted from the medium, glutamate levels after 6 h of hypoxia were reduced from 101 +/- 63 to 2.3 +/- 0.3 microM, and cell death at 48 h was also markedly reduced (15.4 +/- 4.5%, p < 0.001). The alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (18.7 +/- 5.1%, p < 0.001) and mild hypothermia (33.5-34 degrees C) during hypoxia (19.5 +/- 2.7%, p < 0.05) were moderately protective. Basic fibroblast growth factor (24.1 +/- 3.2%), the nitric oxide synthase inhibitor N(G)-nitro-L-arginine methyl ester (22.8 +/- 8.1%), the antioxidant N-tert-butyl-o-phenyinitrone (18.9 +/- 5.9%), and the 21-aminosteroid U74389G (24.0 +/- 3.4%) did not protect the cells. N-Acetyl-L-cysteine even tended to increase cell death (30.1 +/- 2.5%, p = 0.06). Treatment with MK-801 at the end of hypoxia did not reduce cell death (23.3 +/- 2.3%). In separate experiments, a 15-min exposure to 1 mM glutamate without hypoxia did not result in significant cell death (14.7 +/- 2.4 vs. 12.2 +/- 2.1%, p = 0.07). We conclude that, although somewhat resistant to glutamate toxicity when normoxic, NT2-N neurons die via an ionotropic glutamate receptor-mediated mechanism when exposed to hypoxia in the presence of glutamate. As far as we know, this is the first reported analysis of the mechanism of hypoxic cell death in cultured human neuronlike cells.

Cell Death↗
PubMed1998

Susceptibilities of neonatal respiratory isolates of Ureaplasma urealyticum to antimicrobial agents.

Twenty-one neonatal respiratory isolates of Ureaplasma urealyticum were serotyped, and their susceptibilities to ciprofloxacin, gentamicin, chloramphenicol, erythromycin, azithromycin, and doxycycline were tested. Most patient strains were Ureaplasma urealyticum bv. parvum. Chloramphenicol, doxycycline, and azithromycin had the lowest MICs. This data may be useful when designing prophylactic or therapeutic trials of antibiotics for chronic lung disease of the newborn.

Anti-Bacterial Agents↗
PubMed1998

Detection of Ureaplasma urealyticum in endotracheal tube aspirates from neonates by PCR.

A PCR-based test was optimized for the detection of Ureaplasma urealyticum from neonatal respiratory specimens, with primers directed against the multiple-banded antigen gene (L. J. Teng, X. Zheng, J. I. Glass, H. Watson, J. Tsai, and G. H. Cassell, J. Clin. Microbiol. 32:1464-1469, 1994). Endotracheal tube aspirates (225) from 103 low-birth-weight neonates (<1,250 g) were taken, when possible, at days 0, 4, and 14 after birth and examined by culture and by PCR. Of 77 specimens positive by either method, 73 were detected by PCR and 60 were detected by culture. Overall, 36% of the neonates were positive for U. urealyticum by either method. Of 16 patients with PCR-positive-culture-negative results, 13 had positive cultures at another sampling point, and one additional patient had a twin with positive cultures. Of 11 patients with day 0 specimens positive by PCR alone, 9 subsequently became culture positive, demonstrating the utility of this test in early detection. Multiple serovars were present in over 50% of positive specimens, with serovars 3 and 14 in combination being most prevalent. The amplicon size generated from the specimen by PCR correctly predicted the biovars isolated in over 85% of positive specimens. Thus, this PCR test was valuable in allowing early detection of U. urealyticum in neonatal respiratory specimens, as well as in providing biovar information.

Humans↗