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Biomedical subjects

D Miller

Publications and source records attributed to D Miller.

At least 163 records · Page 9Linked to original sources
PubMed1998

Close synchrony of ovulation in superstimulated heifers that have a downregulated anterior pituitary gland and are induced to ovulate with exogenous LH.

The synchrony of ovulation was examined in superstimulated heifers that had a downregulated pituitary gland and which were induced to ovulate by injection of exogenous LH. The pituitary was downregulated and desensitized to GnRH by treatment with the GnRH agonist deslorelin. Nulliparous heifers (3.5 yr old) at random stages of the estrous cycle were assigned to 1 of 3 groups, and on Day -7 received the following treatments: Group 1 (control, n = 8), 1 norgestomet ear implant; Group 2 (GnRH agonist, n = 8); Group 3 (GnRH agonist-LH protocol, n = 8), 2 deslorelin ear implants. Ovarian follicle growth in all heifers was superstimulated with twice-daily intramuscular injections of FSH (Folltropin-V): Day O, 40 mg (80 mg total dose); Day 1, 30 mg; Day 2; 20 mg; Day 3, 10 mg. On Day 2, all heifers were given a luteolytic dose of PGF (7 A.M.), Norgestomet implants were removed from heifers in Group 1 (6 P.M.). Heifers in Group 3 were given an injection of 25 mg, i.m. porcine LH (Lutropin) on Day 4 (4 P.M.). Ovarian follicle status was monitored at 8-h intervals from Day 3 (8 A.M.) to Day 6 (4 P.M.) using an Aloka Echo Camera and 7.5 MHz transducer. Heifers in Groups 2 and 3 exhibited estrus earlier (P < 0.05) than heifers in Group 1. Heifers in Group 2 did not have a preovulatory LH surge and they did not ovulate. Individual control heifers in Group 1 ovulated between 12 A.M. on Day 5 and 8 A.M. on Day 6. Heifers with deslorelin implants and injected with LH in Group 3 ovulated between 4 P.M. on Day 5 and 8 A.M. on Day 6. It was confirmed that superstimulated heifers with GnRH agonist implants can be induced to ovulate with LH. It was also demonstrated that ovulation is closely synchronized after injection of LH. Thus, a single, fixed-time insemination schedule could be used in a GnRH agonist-LH superovulation protocol, with significant practical and economic advantages for superovulation and embryo transfer programs.

Animals↗
PubMed1998

Microbial keratitis in children.

OBJECTIVE: Microbial keratitis is a major cause of corneal blindness worldwide. This problem is particularly relevant to children, because most of their visual life is ahead of them, and they are uniquely at risk for irreversible ocular deficits, such as those resulting from amblyopia. The objective of this study was to determine the etiologic agents and predisposing factors in childhood infectious keratitis and to examine the outcome of treatment in terms of structure and visual acuity. DESIGN: The study design was a retrospective cases series. PARTICIPANTS: The authors studied 113 eyes in 107 children 16 years of age and younger who were treated for (nonviral) microbial keratitis at the LV Prasad Eye Institute in Hyderabad, India, during the 4.5-year period between February 1, 1991, and June 30, 1995. INTERVENTION: The patients who met the following criteria were included in the study: (1) corneal stromal infiltrate was present on slit-lamp examination; and (2) a corneal scraping was taken at the time of examination for suspected microbial keratitis. MAIN OUTCOME MEASURES: Etiologic micro-organisms, predisposing factors, treatment method, structural treatment outcome, and visual acuity treatment outcome of the infectious keratitis episode were measured. RESULTS: The principal predisposing factors identified in this study were trauma (21.2%), ocular disease (17.7%), systemic disease (15.9%), and prior penetrating keratoplasty in the same eye (8.8%). Vitamin A deficiency was an important factor within the category of severe systemic disease, and contact lens wear was not involved in any of the cases. A total of 85 organisms were isolated in cultures of corneal scrapings from 64 (56.6%) of the 113 cases. Staphylococcus species (43.7%), Streptococcus pneumoniae (18.8%), and fungi (17.2%) were the most common isolates. Eighteen eyes (15.9%) required surgery, and 28 (36.4%) of the 77 patients on whom visual acuity was assessed at last follow-up achieved an unaided visual acuity of 20/60 or better at last follow-up. CONCLUSION: This work represents the largest recent study on childhood (nonviral) microbial keratitis, its management, and treatment outcomes. In this study, amblyopia is highlighted as a potentially significant sequela of childhood microbial keratitis. Identification of the appropriate predisposing factors, etiologic microbial organisms, and treatment outcome from this study may aid in early recognition and treatment of microbial keratitis in children.

Adolescent↗
PubMed1998

Nontuberculous mycobacterial keratitis in south Florida.

OBJECTIVE: This study aimed to review the clinical features, therapeutic response, and histopathology of cases of nontuberculous mycobacterial keratitis at the Bascom Palmer Eye Institute. DESIGN AND PARTICIPANTS: Retrospective review of medical records, clinical photographs, histopathology, and microbiology of 24 cases of nontuberculous acid-fast keratitis over the past 15 years. RESULTS: Causal organisms included Mycobacterium chelonae (16), M. fortuitum (3), M. avium-intracellulare (2), M. nonchromogenicum (1), M. triviale (1), and M. asiaticum (1). Clinically, the keratitis had a superficial location except in those patients with a history of surgery. Amikacin was the most commonly used antibiotic (63%). Three patients were treated with Clarithromycin. In one patient, it was stopped because of toxicity; the other two had resolution of their infiltrates. Fifty-five percent did not respond to topical antimicrobial therapy. The organisms as a group were sensitive to amikacin and Clarithromycin and resistant to the fluoroquinolones. Sixty-four percent of the group that failed to respond to medical treatment were treated with steroids after the diagnosis was known, in comparison to 44% of the group treated successfully with medications. The histopathology of the patients treated with steroids showed minimal inflammation despite a large number of organisms, in contrast to the dense infiltrates seen in the specimens from patients not treated with topical steroids. CONCLUSION: Nontuberculous mycobacterial keratitis is a chronic insidious infection that is often unresponsive to medical therapy. The authors recommend that steroids be withheld. Based on the authors' experience of three patients, topical Clarithromycin may hold promise as a therapeutic agent. Lamellar keratectomy or penetrating keratoplasty should be considered in those patients who do not respond to medical therapy or those who have recurrent exacerbations on attempted weaning of topical antibiotic therapy.

Adult↗
PubMed1998

Cytogenetic effects of energetic ions with shielding.

In order to understand the effects of shielding on the induction of biological damages by charged particles, we conducted experiments with accelerated protons (250 MeV) and iron particles (1 GeV/u). Human lymphocytes in vitro were exposed to particle beams through polyethylene with various thickness, and chromosomal aberrations were determined using FISH technique. Dose response curves for chromosome aberrations were obtained and compared for various particle types. Experimental results indicated that for a given absorbed dose at the cell, the effectiveness of protons and iron particles in the induction of chromosomal aberrations was not significantly altered by polyethylene with thickness up to 30-cm and 15-cm respectively. Comparing with gamma rays, charged particles were very effective in producing complex chromosomal damages, which may be an important mechanism in alterating functions in non dividing tissues, such as nervous systems.

Chromosome Aberrations↗
PubMed1998

Evaluation of recombinant factor VIII (Kogenate) stability for continuous infusion using a minipump infusion device.

Continuous infusion of recombinant factor VIII (rFVIII) is desirable in clinical settings in order to maintain haemostatic levels in a cost-effective manner. This study was designed to determine rFVIII stability over time using a minipump set-up, which has been employed by clinicians for continuous infusion of rFVIII. Vials from three lots of Kogenate (Bayer Corporation) were reconstituted in sterile water for injection, pooled and transferred to minipump infusion sets composed of either polyvinylchloride (Medex # IPR86/tube volume 0.5 mL) or polyethylene (McGraw S5904-52, tube and adapter volume 2.1 mL), and held in temperature-controlled rooms at 5 degrees C, 25 degrees C and 30 degrees C. Additional bags of rFVII were prepared with heparin (4 U mL-1), and maintained at 30 degrees C. rFVIII was infused at a rate of 1.0 mL h-1. Samples were analysed for rFVIII activity over a 7-day period at 0, 1, 15, 24, 78 and 168 h. Prior to the start of the timed study, rFVIII activity was measured in the lot pools and in the polyvinylchloride or polyethylene bags, and in the first flush volumes through the tubing. There was no difference in rFVIII activity measured in the pools compared to the bags. rFVIII levels in the initial 3-mL infusion through the tubing showed a slight decrease in activity compared to the initial level which amounted to an insignificant loss of activity for the polyvinylchloride tubing but a significant loss in the polyethylene tubing (approximately 10 IU absolute loss in polyvinylchloride vs. 100 IU loss in polyethylene). After an initial flush of 1.0 mL for polyvinylchloride and 5.0 mL for polyethylene, activity returned to baseline and subsequently remained stable for all time points and temperatures from 5-30 degrees C over the 7-day period. We conclude that the standard polyvinylchloride in polyethylene minipump bags and tubing provide excellent delivery and stability of rFVIII for continuous infusion with or without heparin, and can be used in hospital and ambulatory settings.

Drug Evaluation↗
PubMed1998

Comparison of oral and intraperitoneal iron supplementation in anaemic rats: a re-evaluation of the mucosal block theory of iron absorption.

To evaluate the extent to which daily oral Fe supplements may block Fe absorption from a subsequent dose, we compared effects of oral and intraperitoneal (i.p.) Fe supplementation on Fe status in anaemic rats (haemoglobin (Hb) 90 g/l). A ligated duodenal loop technique was used to assess the effects of the Fe supplements administered either orally or i.p. at different frequencies on Fe absorption from a subsequent test dose. Anaemic Sprague-Dawley rats were assigned to seven groups of eight rats each and received either oral or i.p. Fe supplements for 3 d as follows: (1) 4 mg oral supplement daily (three doses in 3 d); (2) 4 mg oral supplement once (one dose on day 1, low-Fe dose on days 2 and 3); (3) 12 mg oral supplement once (one dose on day 1, low-Fe dose on days 2 and 3); (4) 3.2 mg i.p. supplement daily (three doses in 3 d); (5) 3.2 mg i.p. supplement once (one dose on day 1); (6) 9.6 mg i.p. supplement once (one dose on day 1); (7) low-Fe diet (control). The effectiveness of the supplements in treating Fe deficiency on each of the two test-factors, i.e. route of administration and frequency of dose, was assessed by determining Hb-Fe gain and liver-Fe stores after the 3 d test period. Oral supplementation was as effective as i.p. in improving the Fe status of the anaemic animals. However, a 15 min absorption of a radio-Fe test dose from a ligated loop in i.p.-supplemented groups was significantly higher (11.68 (SD 1.70)%, 17.49 (SD 4.59)%, 16.71 (SD 3.39)%) than in orally supplemented groups (3.24 (SD 1.35)%, 2.45 (SD 1.05)%, 1.80 (SD 0.35)%) despite equal body Fe stores. No significant difference in intestinal Fe absorption efficiency was detected within the oral groups but those supplemented only once were more effective than or as effective as the group receiving daily supplements for 3 d in improving Fe status as indicated by Hb-regeneration efficiency. We conclude that there is a mucosal block with the administration of oral Fe supplements but the extent of this blocking effect during oral Fe supplementation is not as dramatic as currently thought in the context of the poor efficacy of daily Fe supplementation programmes.

Administration, Oral↗
PubMed1998

Social support, social conflict, and adjustment among adolescents with cancer.

OBJECTIVE: Evaluate support and conflict in close relationships of adolescents in active medical treatment for cancer. Family and friend perceptions of supportive and conflictual behaviors were examined in relation to psychological distress, taking into account the impact of functional impairment induced by the illness. METHODS: Using self-report questionnaires, 50 adolescents between the ages of 12 and 20 years rated the frequency of supportive and conflictual interactions with parents, siblings and best friends. RESULTS: Results indicated that perceived maternal conflict was associated with psychological distress. Conflict with fathers, siblings, and best friends was not associated with distress. Supportive aspects of close relationships did not predict psychological distress. The amount of physical impairment accounted for the most variance in distress, contributing between 35% and 38% of the variance. CONCLUSION: Results suggest that mother-adolescent conflict would be an appropriate target for psychosocial interventions.

Adaptation, Psychological↗
PubMed1998

Prophylactic atenolol reduces postoperative myocardial ischemia. McSPI Research Group.

BACKGROUND: Perioperative myocardial ischemia occurs in 20-40% of patients at risk for cardiac complications and is associated with a ninefold increase in risk for perioperative cardiac death, myocardial infarction, or unstable angina, and a twofold long-term risk. Perioperative atenolol administration reduces the risk of death for as long as 2 yr after surgery. This randomized, placebo-controlled, double-blinded trial tested the hypothesis that perioperative atenolol administration reduces the incidence and severity of perioperative myocardial ischemia, potentially explaining the observed reduction in the risk for death. METHODS: Two-hundred patients with, or at risk for, coronary artery disease were randomized to two study groups (atenolol and placebo). Monitoring included a preoperative history and physical examination and daily assessment of any adverse events. Twelve-lead electrocardiography (ECG), three-lead Holter ECG, and creatinine phosphokinase with myocardial banding (CPK with MB) data were collected 24 h before until 7 days after surgery. Atenolol (0, 5, or 10 mg) or placebo was administered intravenously before induction of anesthesia and every 12 h after operation until the patient could take oral medications. Atenolol (0, 50, or 100 mg) was administered orally once a day as specified by blood pressure and heart rate. RESULTS: During the postoperative period, the incidence of myocardial ischemia was significantly reduced in the atenolol group: days 0-2 (atenolol 17 of 99 patients; placebo, 34 of 101 patients; P = 0.008) and days 0-7 (atenolol, 24 of 99 patients; placebo, 39 of 101 patients; P = 0.029). Patients with episodes of myocardial ischemia were more likely to die in the next 2 yr (P = 0.025). CONCLUSIONS: Perioperative administration of atenolol for 1 week to patients at high risk for coronary artery disease significantly reduces the incidence of postoperative myocardial ischemia. Reductions in perioperative myocardial ischemia are associated with reductions in the risk for death at 2 yr.

Adrenergic beta-Antagonists↗
PubMed1998

Using PDSA (Plan-Do-Study-Act) to establish academic-community partnerships: the Cleveland experience.

The Schools of Medicine and Nursing at Case Western Reserve University and the Program in Health Administration at Cleveland State University have created an interdisciplinary course in continuous improvement that emphasizes learning through experience, accommodates a large number of students, and has created new partnerships with Cleveland area health care organizations. An approach that respects these partners as customers and refines the relationships with serial tests of change (e.g., PDSA) has contributed significantly to this program's success.

Community-Institutional Relations↗
PubMed1998

Building-associated pulmonary disease from exposure to Stachybotrys chartarum and Aspergillus versicolor.

The authors present an outbreak of disease associated with exposure to Stachybotrys chartarum and Aspergillus species. A courthouse and two associated office buildings had generated discomfort among employees for two years since initial occupancy. Multiple interventions had been unsuccessful An initial evaluation of 14 individuals identified three with potential asthma and three with symptoms consistent with interstitial lung disease. A clinical screening protocol to identify individuals who should be removed from work identified three likely and seven possible cases of building-related asthma. Detailed environmental and engineering assessments of the building identified major problems in mechanical system design, building construction, and operational strategies leading to excess moisture and elevated relative humidities. Moisture-damaged interior surfaces in both buildings were contaminated with S. chartarum, A. versicolor, and Penicillium species. Aspergillus species, especially A. versicolor, at concentrations of 10(1) to 10(4)/m3 dominated the indoor air under normal operating conditions. Bulk samples also revealed large quantities of Stachybotrys. A questionnaire survey of the three case and two control buildings documented between three- and 15-fold increases in symptoms. A nested case-control study suggested emphysematous-like disease in individuals meeting questionnaire definitions for cases. Replication of analysis strategies used in similar previous investigations suggested an association between worsening symptoms and decreased diffusing capacity of the lung. Performance on neuropsychological measures was similar for both cases and controls, although workers with symptoms reported increased levels of current but not past psychiatric symptomatology. Chemical analyses demonstrated the presence of satratoxins G and H. Cytotoxic laboratory analyses demonstrated the presence of agents with biological effectiveness in bulk materials. No association was seen between IgE or IgG antibodies and the presence of disease. This outbreak represents a likely human response to inhaled fungal toxins in indoor environments. Moisture indoors represents a public health issue currently inadequately addressed by building, health, or housing codes.

Adult↗
PubMed1998

Molecular epidemiology of Staphylococcus aureus and Enterococcus faecalis in endophthalmitis.

Genomic DNA fingerprint analysis was performed on 39 Staphylococcus aureus and 28 Enterococcus faecalis endophthalmitis isolates collected from multiple clinical centers. Among 21 S. aureus genomic DNA fingerprint patterns identified, five clonotypes were recovered from multiple unrelated patients and accounted for 58.9% (23 of 39) of the isolates analyzed. Compared with strains having unique genomic DNA fingerprint patterns, the S. aureus clonotypes occurring more than once were more likely to result in visual acuities of 20/200 or worse (P = 0.036 [chi2 test]). In contrast to the S. aureus isolates, the E. faecalis endophthalmitis isolates were a clonally diverse population, enriched for the expression of a known toxin, cytolysin, which is plasmid encoded.

Bacterial Typing Techniques↗
PubMed1998

Insertional editing of mitochondrial tRNAs of Physarum polycephalum and Didymium nigripes.

tRNAs encoded on the mitochondrial DNA of Physarum polycephalum and Didymium nigripes require insertional editing for their maturation. Editing consists of the specific insertion of a single cytidine or uridine relative to the mitochondrial DNA sequence encoding the tRNA. Editing sites are at 14 different locations in nine tRNAs. Cytidine insertion sites can be located in any of the four stems of the tRNA cloverleaf and usually create a G. C base pair. Uridine insertions have been identified in the T loop of tRNALys from Didymium and tRNAGlu from Physarum. In both tRNAs, the insertion creates the GUUC sequence, which is converted to GTPsiC (Psi = pseudouridine) in most tRNAs. This type of tRNA editing is different from other, previously described types of tRNA editing and resembles the mRNA and rRNA editing in Physarum and Didymium. Analogous tRNAs in Physarum and Didymium have editing sites at different locations, indicating that editing sites have been lost, gained, or both since the divergence of Physarum and Didymium. Although cDNAs derived from single tRNAs are generally fully edited, cDNAs derived from unprocessed polycistronic tRNA precursors often lack some of the editing site insertions. This enrichment of partially edited sequences in unprocessed tRNAs may indicate that editing is required for tRNA processing or at least that RNA editing occurs as an early event in tRNA synthesis.

Animals↗
PubMed1998

Respiratory insufficiency due to high anterior cervical cord infarction.

OBJECTS AND METHODS: Respiratory dysfunction may occur as a result of lesions in the upper cervical spinal cord disturbing the descending pathways subserving automatic and volitional ventilatory control. Four patients are described who presented with acute respiratory insufficiency caused by infarction of the anterior portion of the upper cervical cord due to presumed anterior spinal artery occlusion. RESULTS: Two patients presented after respiratory arrests; they were ventilated and there was no automatic or volitional respiratory effort. Both had signs of an extensive anterior spinal cord lesion at the C2 level and this was confirmed by MRI. One patient presented with a C4 infarction and required ventilation for three months. Ventilatory recovery was characterised by the development of an automatic respiratory pattern. The fourth patient required ventilation for two months after infarction at the C3 level. On attempted weaning he had prolonged periods of hypoventilation and apnoea during inattention and sleep indicating impairment of automatic respiratory control. CONCLUSION: Infarction of the spinal cord at high cervical levels may be due to fibrocartilaginous embolism and involvement of the descending respiratory pathways may occur. Extensive lesions at C1/2 cause complete interruption of descending respiratory control leading to apnoea. Partial lesions at C3/4 cause selective interruption of automatic or voluntary pathways and give rise to characteristic respiratory patterns. The prognosis depends on the level and extent of the lesion.

Adult↗
PubMed1998

Psychological factors associated with recurrent vaginal candidiasis: a preliminary study.

OBJECTIVE: To identify psychological factors associated with chronic recurrent vaginal candidiasis. DESIGN: A cross sectional exploratory study of women with chronic, recurrent vaginal candidiasis. PATIENTS: 28 women found culture positive and treated for vaginal candidiasis by a clinic physician at least twice within the past 6 months. All women reported that they had experienced vaginal thrush six or more times within 1 year. A comparison group comprised 16 women with no history of recurrent vaginal candidiasis, of similar age range, and recruited from a women's family planning service. METHODS: Both groups were compared on demographic criteria, sexual health histories, mental health, and psychological health characteristics. A purpose designed structured interview was administered alongside a battery of standardised psychometric instruments measuring mood, satisfaction with life, self esteem, and perceived stress. RESULTS: The two groups showed considerable similarities, with no significant differences in demographic characteristics and most sexual health issues. However, women with recurrent vaginal candidiasis were significantly more likely to suffer clinical depression, to be less satisfied with life, to have poorer self esteem, and to perceive their lives as more stressful. Additionally, women with recurrent vaginal candidiasis reported that their candidiasis seriously interfered with their sexual and emotional relationships. CONCLUSIONS: Overall, this study identified many areas of psychological morbidity associated with chronic vaginal candidiasis, and indicates that development of appropriate psychological treatment initiatives in this area is long overdue.

Adult↗