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Biomedical subjects

M L Reed

Publications and source records attributed to M L Reed.

At least 19 recordsLinked to original sources
PubMed2001

Edited transcripts compete with unedited mRNAs for trans-acting editing factors in higher plant chloroplasts.

Chloroplast RNA transcripts of vascular plants undergo C to U editing at approximately 30 sites, but there is no consensus sequence that identifies a C to be edited. Both sequences closely surrounding an edited C and unidentified site-specific trans-acting factors have been shown to be important for editing. The ability of an already edited transgenic sequence to bind and thus titrate a trans-acting editing factor was evaluated for two editing sites, ndhF and rpoB site 2. The U-containing rpoB transcripts did not affect editing of the endogenous rpoB transcripts, likely because the comparable C-containing transcripts containing 27 nucleotides surrounding the edited C were only 20% edited, indicating a low affinity of a trans-factor for this length of edited sequence. Surprisingly, U-containing ndhF transgene transcripts reduced endogenous ndhF transcript editing to the same degree as a C-containing transgene transcript. This indicates that the C target of editing is not a critical recognition feature for the site-specific trans-acting factor.

Binding Sites↗
PubMed2001

A single alteration 20 nt 5' to an editing target inhibits chloroplast RNA editing in vivo.

Transcripts of typical dicot plant plastid genes undergo C-->U RNA editing at approximately 30 locations, but there is no consensus sequence surrounding the C targets of editing. The cis-acting elements required for editing of the C located at tobacco rpoB editing site II were investigated by introducing translatable chimeric minigenes containing sequence -20 to +6 surrounding the C target of editing. When the -20 to +6 sequence specified by the homologous region present in the black pine chloroplast genome was incorporated, virtually no editing of the transcripts occurred in transgenic tobacco plastids. Nucleotides that differ between the black pine and tobacco sequence were tested for their role in C-->U editing by designing chimeric genes containing one or more of these divergent nucleotides. Surprisingly, the divergent nucleotide that had the strongest negative effect on editing of the minigene transcript was located -20 nt 5' to the C target of editing. Expression of transgene transcripts carrying the 27 nt sequence did not affect the editing extent of the endogenous rpoB transcripts, even though the chimeric transcripts were much more abundant than those of the endogenous gene. In plants carrying a 93 nt rpoB editing site sequence, transgene transcripts accumulated to a level three times greater than transgene transcripts in the plants carrying the 27 nt rpoB editing sites and resulted in editing of the endogenous transcripts from 100 to 50%. Both a lower affinity of the 27 nt site for a trans-acting factor and lower abundance of the transcript could explain why expression of minigene transcripts containing the 27 nt sequence did not affect endogenous editing.

Base Sequence↗
PubMed2001

High-level expression of a synthetic red-shifted GFP coding region incorporated into transgenic chloroplasts.

We describe here a synthetic red-shifted variant of GFP that can be introduced into tobacco plastid genomes and is highly expressed in regenerated plants that appear normal and fertile. The variant contains the S65G and S72A mutations which shift the absorption maximum from the 395 nm of wild-type GFP closer to 488 nm, a wavelength emitted by a laser commonly used in confocal microscopy. In addition to enhanced fluorescence, the removal of significant absorption below 450 nm will potentially facilitate double-labelling experiments. The variant GFP encoded by the synthetic gene can be expressed at a high level, forming approximately 5% of total leaf protein.

Amino Acid Sequence↗
PubMed2001

Single-follicular-unit hair transplantation to correct cleft lip moustache alopecia.

OBJECTIVE: To present the case of an 18-year-old boy with a cleft lip scar and an obligatory need for facial hair who underwent single-follicular-unit graft hair transplantation that resulted in significant moustache hair restoration in a single procedure. SETTING: The surgery was performed in an outpatient private practice setting using oral sedation and local anesthesia. RESULTS: Advances in instrumentation technology and an increased understanding of the anatomical clustering of hair follicles into so-called "follicular units" containing one to six hairs per unit has resulted in a rapid expansion of hair restoration surgery into new areas including female-pattern alopecia, scarring alopecias, and cosmetic surgery scars. These new techniques can be employed to create natural-looking hair lines in front of artificial hair replacement systems; to improve unnatural looking, old "large-plug" hair transplants; and to correct discontinuity of eyebrows and hairlines in patients with congenital facial clefts. Increased awareness is needed to incorporate follicular-unit graft hair transplant surgery into the family of corrective surgery subspecialties.

Adolescent↗
PubMed2000

Stent-based gene therapy.

Delivery of gene therapy to inhibit intimal hyperplasia has been proposed to prevent postangioplasty restenosis. We sought to apply gene therapy by using a stent-based technique. There are several hurdles that must be overcome before gene-stent therapy can be applied successfully in clinical trials. These include increasing the efficiency of gene delivery through atherosclerotic plaque; increasing intramural retention times; preventing the inflammatory reaction that stents coated with biodegradable polymers can elicit; overcoming the risk of systemic gene delivery; and accessing the adventitia via percutaneous approach. We evaluated a gene-stent delivery mechanism based on microporous metal microneedles developed with nanotechnology in an attempt to overcome some of these problems. A novel approach to the transfection of genes by microfabricated technology was evaluated in smooth muscle cells in culture. We demonstrated that microneedles can deliver gene therapy to smooth muscle cells in culture and can produce controlled penetration of the IEL and intima. We conclude that taller microneedles need to be developed to reach the media in diseased human arteries and that this technology has the potential to be incorporated in a stent to deliver gene therapy in atherosclerotic plaque.

Angioplasty, Balloon, Coronary↗
PubMed2000

Patients' perceptions of asthma control and impact on attitudes and self-management.

The objective of this work was to describe the incidence of chronic breathing problems, particularly asthma-related breathing problems, in a cross-section of the United States population and to assess the perceived impact of these problems on daily living. An initial screening survey was used in a nationwide panel of 30,000 households; an in-depth follow-up questionnaire was sent to a random sample of respondents who reported a breathing problem. A sample (n = 2,685) of respondents who reported persistent cough, shortness of breath, or wheezing within the previous 2 years were sent a newly developed questionnaire. A subsample (n = 723) of respondents reported a primary diagnosis of asthma and of these, 59.4% were female and 90.2% were white. Their mean age was 37.4 years. Respondents (n = 723) characterized their level of perceived asthma control as completely controlled, well controlled, somewhat controlled, or poorly/not controlled. At least 31% of those with a perception of some control and 59% of those with a perception of poor/no control reported their breathing problems had increased in the last year. Those who perceived their asthma-related breathing problems as poorly controlled reported significantly greater symptom frequency, activity restriction, fears and concerns about their breathing difficulties, less helpful coping strategies, and less confidence in their doctor's ability to care for them. Responses to many of the questions indicated that the worst levels of disease control were associated with poorer quality of life and a more negative perception of the disease and its effects on daily living. A significant portion of the U.S. population appears to suffer from chronic breathing problems; this requires confirmation and further exploration to reduce the potential mortality and morbidity due to asthma in the United States.

Activities of Daily Living↗
PubMed1998

Micromechanical devices for intravascular drug delivery.

Microfabrication technology, more commonly applied to the manufacture of integrated circuits, can be used to build devices useful for mechanical delivery of drugs and genes. Microprobes fabricated using silicon micromachining have been used to deliver DNA into cells as an alternative to bombardment and microinjection. This idea can be extended to intravascular stents with integrated microprobes capable of piercing compressed plaque and delivering anti-restenosis therapies into coronary arteries. Preliminary experiments using filleted rabbit arteries have demonstrated transection of the internal elastic lamina. New nonplanar microfabrication technologies are necessary for creating practical devices with cylindrical symmetry; a promising possibility is to use microfabricated structures of anodic metal oxides.

Animals↗
PubMed1997

A heterologous maize rpoB editing site is recognized by transgenic tobacco chloroplasts.

Single nucleotides in plant chloroplast transcripts are edited from the genomically encoded C to U, often resulting in changes of the encoded protein sequence. Site-specific trans-acting factors are postulated to direct the selection of edited residues. In order to further define cis sequences required for RNA editing, we investigated whether two editing sites present in maize rpoB mRNA would be recognized by the editing machinery of transformed tobacco chloroplasts. A 93-nucleotide (nt) segment surrounding site I is sufficient to direct editing of the maize sequence in tobacco chloroplasts. However, an 86-nt segment surrounding maize site IV (which is genomically encoded as a T in tobacco) does not confer editing of this site, suggesting that trans-acting factors necessary for recognition of site IV are not present in tobacco. The maize sequences surrounding site I were found to compete with the endogenous rpoB for a depletable trans factor and to reduce editing of endogenous site I. The presence of exogenous maize site I was also found to decrease editing of endogenous tobacco site II, indicating that there is a shared aspect of editing for some closely spaced editing sites.

Base Sequence↗
PubMed1994

Maternal imprinting of human SNRPN, a gene deleted in Prader-Willi syndrome.

Prader-Willi syndrome (PWS), a human neuroendocrine disorder, is associated with deficiencies of paternal chromosome 15q12. Small nuclear ribonucleoprotein polypeptide N (SNRPN) is the first expressed gene identified in the PWS critically deleted region. Following our demonstration that the murine homologue of SNRPN is imprinted, we have characterized a sequence polymorphism within expressed portions of human SNRPN and show that human SNRPN is monoallelically expressed in fetal brain and heart and in adult brain. Analysis of maternal DNA and SNRPN cDNA confirmed that the maternal allele of SNRPN is not expressed in fetal brain and heart. Maternal imprinting of SNRPN supports the hypothesis that paternal absence of SNRPN is responsible for the PWS phenotype.

Alleles↗
PubMed1994

Transgenic cattle resulting from biopsied embryos: expression of c-ski in a transgenic calf.

Producing transgenic cattle by microinjection of DNA into pronuclei has been inefficient and costly, in large part because of the cost of maintaining numerous nontransgenic pregnancies to term. We designed a system for early identification of transgenic embryos in which biopsies of embryos were assayed by polymerase chain reaction for presence of the transgene before embryo transfer. A total of 2555 embryos were microinjected with one of two DNA constructs. Of the 533 embryos biopsied, 112 were judged to be potentially transgenic and were transferred nonsurgically to recipients, resulting in production of 29 putative transgenic fetuses. One fetus and one calf (7% of offspring) were subsequently shown to be definitively transgenic. The calf was transgenic for a chicken c-ski cDNA, and several months after birth developed dramatic muscular hypertrophy followed by muscle degeneration. This phenotype was associated with expression of high levels of mRNA from the transgene.

Animals↗
PubMed1993

Effects of epidermal growth factor, insulin-like growth factor-I, and dialyzed porcine follicular fluid on porcine oocyte maturation in vitro.

Undefined follicular factors that may influence nuclear maturation and/or cytoplasmic maturation are required during in vitro maturation of pig oocytes. Epidermal growth factor (EGF), insulin-like growth factor-I (IGF-I), and dialysed porcine follicular fluid (dpFF) were evaluated for their effects on porcine oocyte nuclear maturation in vitro. In Experiment I, eight different maturation media were made in a split-plot factorial design with dpFF (0% vs. 10% v/v dialyzed pFF) as the whole plot component, and EGF (0.0 vs. 50 ng/ml) and/or IGF-I (0.0 vs. 100 ng/ml) as the factorial subplot component. Experiment II was a complete factorial design with dpFF and EGF. Pig follicular granulosa-cumulus-oocyte complexes (GCOC) were obtained from slaughterhouse ovaries, washed, and cultured at 38.5 degrees C in a humidified incubator with 5% CO2 in air for 42 h. Following culture, GCOC were mechanically stripped of granulosa-cumulus cells and evaluated for nuclear maturation by light microscopy. In Experiment I, the percentage of Metaphase II oocytes for control, IGF-I, EGF, and IGF-I+EGF treatments without pFF were 50.7%, 52.6%, 80.9%, and 84.3% (control and IGF-I groups significantly less, P < .001). The same treatments in the presence of pFF were similar and high (84.2, 84.9, 82.1, and 86.8%, respectively). Experiment II gave similar results. These results demonstrate that EGF, in the absence of pFF, promotes a similar level of oocyte nuclear maturation as does pFF alone or pFF with EGF and/or IGF-I. IGF-I does not appear to influence nuclear maturation of GCOC.

Animals↗
PubMed1992

Prevalence of migraine headache in the United States. Relation to age, income, race, and other sociodemographic factors.

OBJECTIVE: To describe the magnitude and distribution of the public health problem posed by migraine in the United States by examining migraine prevalence, attack frequency, and attack-related disability by gender, age, race, household income, geographic region, and urban vs rural residence. DESIGN: In 1989, a self-administered questionnaire was sent to a sample of 15,000 households. A designated member of each household initially responded to the questionnaire. Each household member with severe headache was asked to respond to detailed questions about symptoms, frequency, and severity of headaches. SETTING: A sample of households selected from a panel to be representative of the US population in terms of age, gender, household size, and geographic area. PARTICIPANTS: After a single mailing, 20,468 subjects (63.4% response rate) between 12 and 80 years of age responded to the survey. Respondents and non-respondents did not differ by gender, household income, region of the country, or urban vs rural status. Whites and the elderly were more likely to respond. Migraine headache cases were identified on the basis of reported symptoms using established diagnostic criteria. RESULTS: 17.6% of females and 5.7% of males were found to have one or more migraine headaches per year. The prevalence of migraine varied considerably by age and was highest in both men and women between the ages of 35 to 45 years. Migraine prevalence was strongly associated with household income; prevalence in the lowest income group (less than $10,000) was more than 60% higher than in the two highest income groups (greater than or equal to $30,000). The proportion of migraine sufferers who experienced moderate to severe disability was not related to gender, age, income, urban vs rural residence, or region of the country. In contrast, the frequency of headaches was lower in higher-income groups. Attack frequency was inversely related to disability. CONCLUSIONS: A projection to the US population suggests that 8.7 million females and 2.6 million males suffer from migraine headache with moderate to severe disability. Of these, 3.4 million females and 1.1 million males experience one or more attacks per month. Females between ages 30 to 49 years from lower-income households are at especially high risk of having migraines and are more likely than other groups to use emergency care services for their acute condition.

Adolescent↗
PubMed1992

Undiagnosed migraine headaches. A comparison of symptom-based and reported physician diagnosis.

BACKGROUND: Although migraine headaches are a common cause of temporary disability, many people with migraine have not been diagnosed. In a sample of the US population, we sought to determine the proportion of migraineurs diagnosed by a physician and to identify the headache characteristics and sociodemographic profiles associated with undiagnosed migraine. METHODS: A mail questionnaire survey was sent to 15,000 US households, selected from a panel to be representative of the US population. Of a total study base population of 23,611, excluding 3043 subjects less than 12 years of age and respondents with unreported gender, we analyzed data for 20,468 subjects aged 12 to 80 years. Migraine diagnoses were assigned on the basis of reported symptoms by means of operational diagnostic criteria. Physician diagnosis of migraine was ascertained on the basis of self-report. RESULTS: Forty-one percent of female and 29% of male migraineurs reported having been diagnosed by a physician. Diagnosis was more likely in females, in people with high income levels, and in individuals who reported migraine associated with aura, vomiting, or disability. Of the undiagnosed subjects, 80% experienced at least some headache-related disability. CONCLUSIONS: Results of this survey indicate that the majority of people with migraine in the United States do not report having been diagnosed by a physician. Given the high proportion of undiagnosed subjects with headache-related disability, efforts to improve the diagnosis and treatment of migraine are recommended.

Adolescent↗
PubMed1992

Maternal imprinting of the mouse Snrpn gene and conserved linkage homology with the human Prader-Willi syndrome region.

Prader-Willi syndrome (PWS) is associated with paternal gene deficiencies in human chromosome 15q11-13, suggesting that PWS is caused by a deficiency in one or more maternally imprinted genes. We have now mapped a gene, Snrpn, encoding a brain-enriched small nuclear ribonucleoprotein (snRNP)-associated polypeptide SmN, to mouse chromosome 7 in a region of homology with human chromosome 15q11-13 and demonstrated that Snrpn is a maternally imprinted gene in mouse. These studies, in combination with the accompanying human mapping studies showing that SNRPN maps in the Prader-Willi critical region, identify SNRPN as a candidate gene involved in PWS and suggest that PWS may be caused, in part, by defects in mRNA processing.

Amino Acid Sequence↗
PubMed1992

Medication use and disability among migraineurs: a national probability sample survey.

OBJECTIVE: To measure the use of prescription medication in treating migraine headache and the associations between medication use and sociodemographic factors, and headache characteristics. DESIGN: National sample survey using a mailed questionnaire to determine symptoms accompanying or preceding severe headaches; frequency, duration, and disability from severe attacks: use of medications to control pain; and medical-care use for severe headaches. SETTING: A stratified sample of United States households. PATIENTS: A sample of 20,468 respondents, aged 12 to 80 years, who responded to a survey on "severe" headaches during the prior year. MEASUREMENTS AND MAIN RESULTS: Overall, 20.2% of respondents reported severe headaches. Migraine was found in 17.6% of females and 5.7% of males. Of the migraineurs, 40.1% of female and 28.3% of male migraineurs reported using prescription drugs to control pain. Blacks were less likely than whites to report prescription use. Insignificant differences were seen in rates of prescription use among various income levels and regions of the country. Use of prescription medication varied considerably by symptoms and characteristics of migraine attacks. Vomiting and sensory aura were most frequently associated with medication use, as were severity and duration of attacks. Use of urgent-care services for severe headache attacks was associated with frequent use of prescription medications. Patients who reported a physician diagnosis of migraine were more likely to use prescription medication than other migraineurs. CONCLUSIONS: Most migraineurs in the United States are not being treated with prescription medications. Many active migraine patients would benefit from appropriate treatment if care was sought and diagnosis made.

Adolescent↗
PubMed1991

An evaluation of hamster, rat, and mouse sperm-cell motility in media formulated with water of different qualities.

The in vitro motility of caudal epididymal spermatozoa from four hamsters, four rats, and four mice was compared in modified Tyrode's medium (TLP-PVA) prepared with water of three qualities: (1) Sigma tissue culture water, 18 m omega, high quality (HQ); (2) deionized distilled water, 4.5 m omega prior to distillation, intermediate quality (IQ); and (3) tap water, low quality (LQ). The objective was to evaluate the in vitro bioassay potential of spermatozoa from these species, in terms of relative sensitivities to toxins in different qualities of water. An average sperm motility index (SMI) was calculated per treatment at 2, 4, and 6 hr, where SMI = fpm2 x % motility. Hamster SMI could be used to discriminate between HQ and IQ media at 4 and 6 hr (P less than 0.001), while rat SMI could be used to discriminate between HQ and IQ media at 6 hr (P less than 0.05). Mouse SMI did not differ between HQ and IQ media. The ability to discriminate between extremes in quality. HQ or IQ vs LQ, was equal between species (P less than 0.001). These results suggest that hamster spermatozoa provide the more sensitive in vitro bioassay model, while rat and mouse spermatozoa may be used for assay of extremes in water quality.

Animals↗
PubMed1990

Increases in Phosphorus Requirements for CO(2)-Enriched Pine Species.

Pinus radiata D. Don (half-sib families 20010 and 20062) and Pinus caribaea var hondurensis (an open-pollinated family) were grown for 49 weeks at seven levels of phosphorus and at CO(2) concentrations of either 340 or 660 microliters per liter, to establish if the phosphorus requirements differed between the CO(2) concentrations and if mycorrhizal associations were affected. When soil phosphorus availability was low, phosphorus uptake was increased by elevated CO(2). This may have been related to changes in mycorrhizal competition. When the phosphorus concentration in the youngest fully expanded needles was above 600 milligrams per kilogram the shoot weight of all pine families was greater at high CO(2) due to increases in rates of photosynthesis. More dry weight was partitioned to the stems of P. radiata family 20010 and P. caribaea. At foliar phosphorus concentrations above 1000 milligrams per kilogram (P. radiata) and 700 milligrams per kilogram (P. caribaea), growth did not increase at 340 microliters of CO(2) per liter. Soluble sugar levels in the same needles mirrored the growth response, but the starch concentration declined with increasing phosphorus. At 660 microliters of CO(2) per liter, shoot weight and soluble sugar concentrations were still increasing up to a foliar P concentration of 1800 milligrams per kilogram for P. radiata and 1600 milligrams per kilogram for P. caribaea. The starch concentrations did not decline. These results indicate that higher foliar phosphorus concentrations are required to realize the maximum growth potential of pines at elevated CO(2).

Journal Article↗