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Biomedical subjects

J Abbott

Publications and source records attributed to J Abbott.

At least 19 recordsLinked to original sources
PubMed1999

The stem-loop binding protein (SLBP1) is present in coiled bodies of the Xenopus germinal vesicle.

The stem-loop binding protein (SLBP1) binds the 3' stem-loop of histone pre-mRNA and is required for efficient processing of histone transcripts in the nucleus. We examined the localization of SLBP1 in the germinal vesicle of Xenopus laevis oocytes. In spread preparations of germinal vesicle contents, an anti-SLBP1 antibody stained coiled bodies and specific chromosomal loci, including terminal granules, axial granules, and some loops. After injection of myc-tagged SLBP1 transcripts into the oocyte cytoplasm, newly translated myc-SLBP1 protein was detectable in coiled bodies within 4 h and in terminal and axial granules by 8 h. To identify the region(s) of SLBP1 necessary for subnuclear localization, we subcloned various parts of the SLBP1 cDNA and injected transcripts of these into the cytoplasm of oocytes. We determined that 113 amino acids at the carboxy terminus of SLBP1 are sufficient for coiled body localization and that disruption of a previously defined RNA-binding domain did not alter this localization. Coiled bodies also contain the U7 small nuclear ribonucleoprotein particle (snRNP), which participates in cleavage of the 3' end of histone pre-mRNA. The colocalization of SLBP1 and the U7 snRNP in the coiled body suggests coordinated control of their functions, perhaps through a larger histone-processing particle. Some coiled bodies are attached to the lampbrush chromosomes at the histone gene loci, consistent with the view that coiled bodies in the oocyte recruit histone-processing factors to the sites of histone pre-mRNA transcription. The non-histone chromosomal sites at which SLBP1 is found include the genes coding for 5 S rRNA, U1 snRNA, and U2 snRNA, suggesting a wider role for SLBP1 in the biosynthesis of small non-spliced RNAs.

Amino Acid Sequence↗
PubMed1998

Pulsed electromagnetic fields simultaneously induce osteogenesis and upregulate transcription of bone morphogenetic proteins 2 and 4 in rat osteoblasts in vitro.

Pulsed electromagnetic fields (PEMF) are successfully employed in the treatment of a variety of orthopaedic conditions, particularly delayed and nonunion fractures. In this study, we examined PEMF effects on in vitro osteogenesis by bone nodule formation and on mRNA expression of bone morphogenetic proteins 2 and 4 by reverse-transcriptase polymerase chain reaction (RT-PCR) in cultured rat calvarial osteoblasts. PEMF exposure induced a significant increase in both the number (39% over unexposed controls) and size (70% larger compared to unexposed controls) of bone-like nodules formed. PEMF also induced an increase in the levels of BMP-2 and BMP-4 mRNA in comparison to controls. This effect was directly related to the duration of PEMF exposure. This study shows that clinically applied PEMF have a reproducible osteogenic effect in vitro and simultaneously induce BMP-2 and -4 mRNA transcription. This supports the concept that the two effects are related.

Animals↗
PubMed1998

Trauma deaths in a rural area.

This study was undertaken in order to clarify the causes of death amongst rural trauma victims in Union County, Arkansas. Over a five-year time interval, seventy-two percent (n = 60) of the trauma deaths occurred at the geographical site of injury before the arrival of any emergency medical services. Thus, prolonged time to discovery of trauma victims accounts for the most significant factor leading to trauma deaths in Union County. Education regarding injury prevention must continue to be emphasized to the public.

Adolescent↗
PubMed1997

Pulsed electromagnetic fields preserve proteoglycan composition of extracellular matrix in embryonic chick sternal cartilage.

The influence of pulsed electromagnetic fields (PEMF) on proteoglycan composition in cartilage extracellular matrix has been investigated. Day 16 embryonic chick sternal cartilage was explanted to culture and exposed for 3 h per day for 2 days to a repetitive single-pulse PEMF with frequency of 15 Hz and peak magnetic field of 1.25 G. PEMF treatment did not affect cell proliferation, as indicated by [3H]thymidine incorporation, but significantly stimulated the retention of glycosaminoglycans in the explants and reduced the release of glycosaminoglycans into the media. Determination of incorporation of [35S]sulfate and [3H]N-acetylglucosamine into proteoglycans in vitro and breakdown of in ovo labelled [35S]sulfated proteoglycans in vitro showed that PEMF treatment significantly suppressed the synthesis of proteoglycans and the degradation of both newly synthesized and pre-existing proteoglycans. Sepharose CL-2B chromatography demonstrated that PEMF did not affect either the size distribution of newly synthesized and pre-existing [35S]sulfated proteoglycans or their ability to aggregate with hyaluronate. Sepharose CL-6B chromatography followed by cellulose acetate electrophoresis revealed that the chain length and degree of sulfation of [35S]sulfated glycosaminoglycans were identical in control and PEMF-treated cultures. It is concluded that PEMF treatment preserved extracellular matrix integrity of cultured cartilage explants by down-regulating proteoglycan synthesis and degradation in a co-ordinated manner without affecting their gross structural nature.

Animals↗
PubMed1997

Injuries and illnesses of domestic violence.

Domestic violence (DV) is a common cofactor or cause of illness and injury in the emergency department. Research is hampered by varied definitions of DV and lack of epidemiologically sound surveys. Injuries related to DV are those common in assaultive injury. Trauma reported to have occurred in falls and accidents may actually be the result of DV. Medical complaints and psychiatric problems may also result from or be associated with DV. The record of DV detection in the ED remains poor.

Colorado↗
PubMed1997

Effect of tonicity of nebulised colistin on chest tightness and pulmonary function in adults with cystic fibrosis.

BACKGROUND: Inhalation of hypertonic nebulised colistin causes chest tightness and is a reason for discontinuing the treatment. This study examines the relationship of chest tightness and change in lung function in response to the inhalation of a range of tonicities of nebulised colistin and their influence on patients' preference. METHODS: Twenty seven adult patients with cystic fibrosis and a mean forced expiratory volume in one second (FEV1) of 54% predicted (range 24-98) were studied. They inhaled a nebulised solution of hypertonic, isotonic, and hypotonic colistin over three consecutive days in random order in a double blind fashion. Measurements of chest tightness, using a visual analogue scale (VAS), and FEV1 were recorded before and 0, 15, 30, 60, and 90 minutes following inhalation. The solution preferred by each patient was determined at the end of the three days. RESULTS: All tonicities caused a significant fall in FEV1 % predicted and an increase in chest tightness, with no differences between the solutions. However, the mean (SE) time to the maximum fall in FEV1 % predicted was significantly different between the solutions (hypertonic 7.8 (2.1) min, isotonic 19.2 (5.5) min, and hypotonic 34.2 (5.9) min) with a mean difference (95% CI) between hypotonic and hypertonic solutions of 28.04 (14.6 to 41.5) min, between isotonic and hypertonic solutions of 12.0 (-0.1 to 24.1) min, and between hypotonic and isotonic solutions of 15.6 (1.8 to 29.4) min. Positive correlations existed for the maximum fall in FEV1 % predicted between the hypertonic and isotonic solutions (r = 0.62, p < 0.001) and between the hypotonic and isotonic solutions (r = 0.64, p < 0.001). There was no correlation between the objective and subjective measurements for any solution. The patients' preference varied. CONCLUSIONS: All tonicities of colistin caused equal symptoms of chest tightness and reduction in pulmonary function. It is recommended that the patient is challenged with nebulised colistin before prescription of the drug and that the challenge is preceded by an inhaled bronchodilator. Most of the patients preferred the isotonic or hypotonic solutions. The isotonic solution reflects a fall in FEV1 representative of all the solutions. The fall in FEV1 to the hypotonic solution occurred over a longer period and may be better tolerated by some patients.

Administration, Inhalation↗
PubMed1996

Receptor recognition and specificity of interleukin-8 is determined by residues that cluster near a surface-accessible hydrophobic pocket.

To determine the regions of interleukin-8 (IL-8) that allow high affinity and interleukin-8 receptor type 1 (IL8R1)-specific binding of chemokines, we produced chimeric proteins containing structural domains from IL-8, which binds to both IL8R1 and interleukin-8 receptor type 2 (IL8R2) with high affinity, and from GRO gamma, which does not bind to IL8R1 and binds to IL8R2 with reduced affinity. Receptor binding activity was tested by competition of 125I-IL-8 binding to recombinant IL8R1 and IL8R2 cell lines. Substitution into IL-8 of the GRO gamma sequences corresponding to either the amino-terminal loop (amino acids 1-18) or the first beta-sheet (amino acids 18-32) reduced binding to both IL8R1 and IL8R2. The third beta-sheet of IL-8 (amino acids 46-53) was required for binding to IL8R1 but not IL8R2. Exchanges of the second beta-sheet (amino acids 32-46) or the carboxyl-terminal alpha-helix (amino acids 53-72) had no significant effect. When IL-8 sequences were substituted into GRO gamma, a single domain containing the second beta-sheet of IL-8 (amino acids 18-32) was sufficient to confer high affinity binding for both IL8R1 and IL8R2. The amino-terminal loop (amino acids 1-18) and the third beta-sheet (amino acids 46-53) of IL-8 had little effect when substituted individually but showed increased binding to both receptors when substituted in combination. Individual amino acid substitutions were made at positions where IL-8 and GRO gamma sequences differ within the regions of residues 11-21 and 46-53. IL-8 mutations L49A or L49F selectively inhibited binding to IL8R1. Mutations Y13L and F21N enhanced binding to IL8R1 with little effect on IL8R2. A combined mutation Y13L/S14Q selectively decreased binding to IL8R2. Residues Tyr13, Ser14, Phe21, and Lys49 are clustered in and around a surface-accessible hydrophobic pocket on IL-8 that is physically distant from the previously identified ELR binding sequence. A homology model of GRO gamma, constructed from the known structure of IL-8 by refinement calculations, indicated that access to the hydrophobic pocket was effectively abolished in GRO gamma. These studies suggest that the surface hydrophobic pocket and/or adjacent residues participate in IL-8 receptor recognition for both IL8R1 and IL8R2 and that the hydrophobic pocket itself may be essential for IL8R1 binding. Thus this region contains a second site for IL-8 receptor recognition that, in combination with the Glu4-Leu5-Arg6 region, can modulate receptor binding affinity and IL8R1 specificity.

Amino Acid Sequence↗
PubMed1996

Pulsed electromagnetic fields influence hyaline cartilage extracellular matrix composition without affecting molecular structure.

Pulsed electromagnetic fields (PEMF) influence the extracellular matrix metabolism of a diverse range of skeletal tissues. This study focuses upon the effect of PEMF on the composition and molecular structure of cartilage proteoglycans. Sixteen-day-old embryonic chick sterna were explanted to culture and exposed to a PEMF for 3 h/day for 48 h. PEMF treatment did not affect the DNA content of explants but stimulated elevation of glycosaminoglycan content in the explant and conserved the tissue's histological integrity. The glycosaminoglycans in sterna exposed to PEMF were indistinguishable from those in controls in their composition of chondroitin sulfate resulting from chondroitinase ABC digestion. Specific examination with [35S]-sulfate labels showed that PEMF treatment significantly suppressed both the degradation of pre-existing glycosaminoglycans biosynthetically labeled in ovo and the synthesis of new [35S]-sulfated glycosaminoglycans. The average size and aggregating ability of pre-existing and newly synthesized [35S]-sulfated proteoglycans extracted with 4 M guanidinium chloride from PEMF-treated cartilage explants were identical to controls. The chain length and degree of sulfation of [35S]-sulfated glycosaminoglycans also were identical in control and PEMF-treated cultures. PEMF treatment also reduced the amount of both unlabeled glycosaminoglycans and labeled pre-existing and newly synthesized [35S]-sulfated glycosaminoglycans recovered from the nutrient media. [35S]-Sulfated proteoglycans released to the media of both control and PEMF-treated cultures were mostly degradation products although their glycosaminoglycan chain size was unchanged. These results demonstrate that exposure of embryonic chick cartilage explants to PEMF for 3 h/day maintains a balanced proteoglycan composition by down-regulating its turnover without affecting either molecular structure or function.

Animals↗
PubMed1996

Accuracy of estimated fetal weight below 1,000 g.

The Warsof formula is 1 of 3 currently recommended by the Australian Society for Ultrasound in Medicine for the routine estimation of fetal weight. However, this formula was derived using mostly large fetuses, and its accuracy in extremely low birth-weight fetuses is not known. Using this formula, we studied 184 infants delivering within 14 days of an estimated fetal weight (EFW) < 1,000 g. The mean percent error in EFW was 11.7% underestimation, with 80% of infants underestimated and 61% of estimates within 15% error. The percent error was consistent at 9.6% throughout the first 9 days, but increased to 32% after 10 days post scan (p < 0.0001). There was a significant association between the accuracy of EFW and maternal height, but not with placental position, liquor volume or multiple pregnancy. EFW underestimated birth-weight on average by 9.6% during the first week, and this error appeared to be mainly due to the formula. The error in EFW became unacceptable after 9 days and repeating the estimate before 10 days is recommended. A different formula may be more suitable for extremely low birth-weight fetuses.

Birth Weight↗
PubMed1996

Health perceptions and treatment adherence in adults with cystic fibrosis.

BACKGROUND: Clinical and demographic variables are poor predictors of treatment adherence. This study therefore examined the relationships between the patients' perception of their cystic fibrosis and their reported adherence to physiotherapy, exercise, pancreatic enzyme and vitamin therapies. METHODS: Sixty adults with cystic fibrosis completed the Health Perception Scale, Health Locus of Control Scale, and the Manchester Adult Cystic Fibrosis Compliance Questionnaire. RESULTS: Reported adherence to physiotherapy, exercise, pancreatic enzyme and vitamin therapies was not influenced by patients' perceptions of their past, current and future disease severity, or their perceived susceptibility to recurrent infections. The greater their level of worry regarding their disease, the more likely they were to adhere to their physiotherapy (p < 0.002), pancreatic enzyme (p < 0.001) and vitamin (p < 0.001) regimens. No difference between the exercise adherent and non-adherent groups emerged regarding their level of worry. Compared with patients who believed that they were in control of their health, those who believed that their cystic fibrosis was controlled by others (family and health professionals) reported greater levels of adherence to their physiotherapy (p < 0.001), pancreatic enzyme (p < 0.001) and vitamin (p < 0.001) therapies. In contrast, patients who adhered to their exercise regimen believed that they were in control of their disease to a greater extent than those who did not (p < 0.003). CONCLUSIONS: Worrying about cystic fibrosis and the perception of having little personal control over the disease facilitated treatment adherence. It is clear that patients perceive exercise therapy differently from other forms of treatment.

Adolescent↗
PubMed1996

New formula for estimating fetal weight below 1000 g: comparison with existing formulas.

Most estimated fetal weight formulas have been derived and tested with larger fetuses, yet accuracy in predicting birth weight is more critical at the limit of viability. Complete data from 142 pregnancies in which delivery took place within 7 days of an ultrasonographic examination were used to create an appropriate formula for fetuses less than 1000 g and compare it with 10 currently available formulas. Our formula (In [BW] = 0.66 x 1n [HC] + 1.04 x 1n [AC] + 0.985 x 1n [FL]) was significantly more accurate than all other formulas and also performed better on a prospective cohort of 27 fetuses with estimated fetal weight less than 1000 g. Of the existing formulas, the Hadlock formula (using head circumference, abdominal circumference, femur length) was the most accurate, being significantly more accurate than all but the Woo formula with all but the Woo formula.

Birth Weight↗
PubMed1995

Domestic violence against women. Incidence and prevalence in an emergency department population.

OBJECTIVE: To determine the incidence, 1-year prevalence, and cumulative prevalence of domestic violence (DV) among female emergency department (ED) patients. DESIGN: Descriptive written survey. SETTING: Two teaching EDs, two hospital walk-in clinics, and one private hospital ED in Denver, Colo. PARTICIPANTS: Of 833 women presenting during 30 randomly selected 4-hour time blocks, 648 (78%) agreed to participate. Most respondents were young (median age, 34 years) and unemployed (62%); half (49%) had annual household incomes less than $10,000. MAIN OUTCOME MEASURES: Domestic violence was defined as an assault, threat, or intimidation by a male partner. Acute DV (incidence) and past DV exposure (1-year prevalence and cumulative prevalence) were determined. RESULTS: The incidence of acute DV among the 418 women with a current male partner was 11.7% (95% confidence interval [CI], 8.7% to 15.2%). Only 11 (23%) of these 47 women subjected to acute DV presented for care because of trauma, and only six (13%) either told staff about DV or were asked about DV by ED professionals. Among 230 women without current partners, 13 (5.6%) reported an episode of DV within the previous 30 days. For the entire sample, the cumulative lifetime prevalence of DV exposure was 54.2% (95% CI, 50.2% to 58.1%). Women exposed to acute or prior DV were more likely than unexposed women to have made suicide attempts (26% vs 8%; P < .001) and to report excessive ethanol use (24% vs 13%; P = .001). CONCLUSIONS: The incidence of acute DV is not as common among women visiting an ED as previously reported, although the cumulative prevalence of DV is strikingly high. Women who have experienced DV are seldom identified by ED professionals.

Adult↗
PubMed1995

Obstetric outcome after failed termination of pregnancy--a report of two cases.

Unsuccessful therapeutic abortion resulting in continued viability of the fetus is rare. No case of a live birth after unsuccessful vacuum curettage has been published. We report two cases with persistent pregnancies after failed termination, with outcomes complicated by premature rupture of membranes and preterm delivery.

Abortion, Therapeutic↗
PubMed1995

Clinical and microscopic diagnosis of vaginal yeast infection: a prospective analysis.

STUDY OBJECTIVES: To evaluate the accuracy of clinical findings and direct microscopy in the diagnosis of yeast vaginitis. DESIGN: Prospective. SETTING: Urban teaching hospital emergency department and walk-in clinic. PARTICIPANTS: Seventy-one consecutive nonmenstruating women with a presenting complaint of vaginal discharge, itching, or pain. INTERVENTIONS: Trained emergency physicians and nurse practitioners, blinded to culture results, collected clinical information, examined vaginal secretions, and obtained yeast cultures. Treatment was based on clinical impression and not altered by the study. Associations between clinical and laboratory parameters and yeast culture results were evaluated. RESULTS: Twenty-three patients (32.4%) had positive yeast cultures. Accepted risk factors were seen in patients with and without culture-positive yeast vaginitis. Clinical criteria for yeast vaginitis--including pruritus, caseous discharge, perineal edema or erythema, and patient self-diagnosis--were more common in women with yeast vaginitis but were seen with other causes of vaginitis. Watery discharge and amine odor (negative "whiff" test) were good predictors of an alternative diagnosis, but, again, accuracy was poor. Gram stain showing yeast was the most accurate laboratory method of diagnosis. Saline microscopy, potassium hydroxide, and methylene blue were all equal and only moderately accurate, with a significant proportion of false-negative and false-positive results. CONCLUSION: Standard criteria for diagnosis of monilial vaginitis are relatively unreliable. Gram stain, absence of watery discharge, and patient self-diagnosis of "another yeast infection" are the best independent predictors of a positive culture.

Adolescent↗
PubMed1995

Psychological and cardiovascular predictors of anaesthesia induction, operative and post-operative complications in minor gynaecological surgery.

This study aimed to clarify the pre-operative-personality-post-operative-recovery association by considering anaesthetic variables. Additionally, the work investigated the relationships between psychological and cardiovascular functioning and anaesthetic induction difficulties and operative problems. Two minor gynaecological procedures were evaluated (dilatation and curettage, laparoscopy) which differ greatly in anaesthetic and operative techniques. Psychological factors predicted cardiovascular responding immediately prior to the induction of anaesthesia, and combinations of cardiovascular and psychological variables were associated with anaesthetic induction, operative and post-operative problems. Health locus of control and worry concerning the various stages of the operation emerged as the most consistent psychological predictors of peri-operative outcome in both procedures.

Adolescent↗