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Biomedical subjects

J M Miller

Publications and source records attributed to J M Miller.

At least 127 records · Page 7Linked to original sources
PubMed1999

KHRI-3 monoclonal antibody-induced damage to the inner ear: antibody staining of nascent scars.

Intracochlear infusion of the KHRI-3 monoclonal antibody results in in vivo binding to guinea pig inner ear supporting cells, loss of hair cells and hearing loss. To further characterize the basis for KHRI-3-induced hearing loss, antibody was produced in a bioreactor in serum-free medium, affinity purified, and compared to conventionally prepared antibody by infusion into the scala tympani using mini-osmotic pumps. In vivo antibody binding was observed in 10 of 11 guinea pigs. A previously unreported pattern of KHRI-3 antibody binding to cells involved in scar formation was noted in five guinea pigs. All but one of the KHRI-3-infused animals demonstrated a hearing loss of > 10 dB in the treated ear. In five of 11 animals the threshold shift was 30 dB or more, and all had hair cell losses. In one guinea pig infused with 2 mg/ml of antibody, the organ of Corti was absent in the basal turn of the infused ear. This ear had a 45-50 dB threshold shift but, curiously, no detectable antibody binding in the residual organ of Corti. Organ of Corti tissue was fragile in antibody-infused ears. Breaks within the outer hair cell region occurred in 5/11 infused ears. The contralateral ears were normal except for one noise-exposed animal that demonstrated hair cell loss in the uninfused ear. Three animals were exposed to 6 kHz noise (108 dB) for 30 min on day 7. Antibody access to the organ of Corti may be increased in animals exposed to noise, since the strongest in vivo binding was observed in noise-exposed animals. Loss of integrity of the organ of Corti seems to be the primary mechanism of inner ear damage by KHRI-3 antibody. The binding of KHRI-3 antibody in new scars suggests a role of the antigen in scar formation. Antibodies with binding properties similar to KHRI-3 have been detected in 51% of patients diagnosed with autoimmune sensorineural hearing loss; thus, it seems likely that such autoantibodies also may have pathologic effects resulting in hearing loss in humans.

Animals↗
PubMed1999

Visual acuity screening versus noncycloplegic autorefraction screening for astigmatism in Native American preschool children.

INTRODUCTION: Visual acuity screening (VAS) is less reliable in preschoolers than in school-aged children as a means of detecting significant refractive error. We wished to compare the effectiveness of VAS with the effectiveness of an objective method, noncycloplegic autorefraction screening (NCARS), in detecting the presence of significant astigmatism warranting spectacle correction. METHODS: We examined 245 Native American Head Start registrants aged 3 to 5 years. We attempted to obtain uncorrected visual acuity using Lea Symbols logMAR Chart (Precision Vision Inc, Villa Park, Ill), noncycloplegic autorefraction using the Nikon Retinomax K-plus (Nikon Corp, Melville, NY), and cycloplegic refraction (CR) on each eye. The VAS failure criterion was either a 2-line acuity difference between eyes or acuity worse than 20/40 in either eye. The NCARS and CR failure criterion was the spectacle correction threshold exceeding the 50th percentile on the basis of a survey of AAPOS members. RESULTS: We completed VAS in 96% of children and NCARS and CR in 100% of children. There was high prevalence (31%) of significant astigmatic refractive error in this sample. Ten subjects who did not permit bilateral visual acuity measurements were scored as having a positive test result. The sensitivity and specificity of VAS were 90% and 44%, respectively. NCARS had sensitivity and specificity of 91% and 86%, respectively. NCARS becomes cost-effective after 1044 children are screened, assuming that the cost of the autorefractor is 300 times the cost of the referral examination. CONCLUSION: VAS offers high sensitivity but suffers from poor specificity. NCARS greatly reduces the number of unnecessary referrals. In this population, NCARS becomes cost-effective after approximately 1000 children are screened.

Arizona↗
PubMed1999

Is knowledge about signs and symptoms of preterm labor related to low birth weight?

The intent of this study was to explore the relationship of patient knowledge about the signs and symptoms of preterm labor and low birth weight. To this end, 538 women were interviewed in the postpartum period. Five aspects of preterm labor knowledge (abdominal tightness, vaginal discharge, cramping, diarrhea, and bleeding) were sought, along with standard demographic information. Data were analyzed as dichotomous variables and compared using odds ratios. Logistic regression was chosen to calculate adjusted odds ratios, including only those factors found to be associated with low birth weight. Patient knowledge of each varied from 46 to 87% for the five items. Only one third knew all five areas. Knowledge of the importance of abdominal tightness, vaginal discharge, and cramping were associated with a reduction in low birth weight, as was knowledge of all five aspects. However, regression analysis failed to support a significant association with any of the five areas alone or when considered as a group. The low sensitivity of the relationship between patient knowledge and low birth weight and the lack of correlation after regression suggest that programs focusing on enhanced patient education may have limited benefits.

Abdomen↗
PubMed1999

On the lack of correlation between self-report and urine loss measured with standing provocation test in older stress-incontinent women.

This study examined the association between the measured amount of urine lost during a standardized series of coughs in clinic (paper towel test) and questionnaire estimates of stress-related urine loss in 51 older women with mild to moderate urinary incontinence. It also examined the relationship between these questionnaire estimates and a 6-day urinary diary self-report of incontinence frequency and voiding episodes. Pearson's correlation coefficient and percent agreement were used to analyze the relationship between the variables. No significant correlations were found between the paper towel test results and questionnaire items reporting volume of urine loss. The relationship between urinary diary results and questionnaire items regarding the number of incontinence occurrences was weak but significant (r = 0.33, p = 0.045), with agreement in 53% of cases. Agreement was achieved in 68% of cases for number of voids per day recorded by urinary diary and reported by questionnaire (r = 0.65, p = 0.000). This study has quantified a weak correlation between objective and subjective measures of urine loss. These weak correlations could arise from either methodologic limitations in quantifying incontinence or the degree to which differences arise because different phenomena are being measured.

Aged↗
PubMed1999

Radiofrequency catheter ablation for postinfarct ventricular tachycardia.

Catheter mapping and radiofrequency ablation of postinfarct sustained ventricular tachycardia (VT) remain one of the greatest challenges for the electrophysiologist. Although there were no major breakthroughs during the past year, several refinements and clarifications of existing mapping criteria were published. In addition, initial reports appeared describing new mapping systems and ablation technologies that may significantly impact the way ablation studies are performed as well as the way in which they affect success rates. Uncertainties remain as to how effective catheter ablation will be as a longterm cure for this type of VT. For the foreseeable future, catheter ablation in postinfarct VT will remain adjunctive rather than primary therapy.

Catheter Ablation↗
PubMed1999

Ethical dilemmas in critical care: nurse case managers' perspective.

Nurse case managers often face ethical dilemmas as they advocate for their critically ill and critically injured patients. They experience the tension that exists between advocating for the critically ill, the patient's right to self-determination, and the payer source constraints. When there are no good alternatives for the patient or the list of options include none that are desirable, the nurse case manager may experience an ethical dilemma. Working with the critically ill and injured inherently presents a spectrum of biopsychosocial complexities, which present potential ethical dilemmas for the nurse case manager. The three case studies presented posed particular challenges to the nurse case managers and deal with the ethical principles of beneficence, autonomy, veracity, and justice.

Adult↗
PubMed1999

Corneal and refractive astigmatism in a sample of 3- to 5-year-old children with a high prevalence of astigmatism.

PURPOSE: To examine the relation between corneal and refractive astigmatism in a sample of pre-school-age Native American children with a high prevalence of astigmatism. METHODS: Subjects were 250 Tohono O'Odham children, 3 to 5 years of age. Each child had corneal astigmatism measured with the Marco Nidek KM-500 portable autokeratometer without pupil dilation, and with the Nikon Retinomax K-Plus portable autorefractor/autokeratometer without and with pupil dilation. Refractive astigmatism was measured using the Retinomax K-Plus, with cycloplegia, confirmed by retinoscopy. RESULTS: Corneal astigmatism exceeded refractive astigmatism, with a median vector dioptric difference of 0.88 D for the KM-500, 0.76 D for the Retinomax K-Plus without dilation, and 0.75 for the Retinomax K-Plus with dilation. The relation between corneal and refractive astigmatism was adequately described by the modification by Grosvenor et al. of Javal's rule, but not by laval's rule. CONCLUSIONS: The results are in agreement with data reported previously for older Native American and non-Native American populations. The modified laval's rule adequately describes the relation between corneal and refractive astigmatism in a population; however, this rule does not provide accurate prediction of refractive astigmatism in individual children or adults.

Arizona↗
PubMed1999

Software error resulting in malfunction of an implantable cardioverter defibrillator.

Loss of ventricular output resulting from an unexpected software error in a dual chamber implantable cardioverter defibrillator (ICD) is reported. A 70-year-old man with a dual chamber ICD implanted for a history of cardiac arrest and infra-Hisian block presented with acute onset of dizziness. He was found to have loss of ventricular output due to an internal software problem. The problem was corrected by software reprogramming via the programmer. This malfunction exemplifies the potential ability to correct current-generation ICD software problems noninvasively, thus avoiding the need for replacement.

Aged↗
PubMed1999

Molecular subtyping of Clostridium perfringens by pulsed-field gel electrophoresis to facilitate food-borne-disease outbreak investigations.

Clostridium perfringens is a common cause of food-borne illness. The illness is characterized by profuse diarrhea and acute abdominal pain. Since the illness is usually self-limiting, many cases are undiagnosed and/or not reported. Investigations are often pursued after an outbreak involving large numbers of people in institutions, at restaurants, or at catered meals. Serotyping has been used in the past to assist epidemiologic investigations of C. perfringens outbreaks. However, serotyping reagents are not widely available, and many isolates are often untypeable with existing reagents. We developed a pulsed-field gel electrophoresis (PFGE) method for molecular subtyping of C. perfringens isolates to aid in epidemiologic investigations of food-borne outbreaks. Six restriction endonucleases (SmaI, ApaI, FspI, MluI, KspI, and XbaI) were evaluated with a select panel of C. perfringens strains. SmaI was chosen for further studies because it produced 11 to 13 well-distributed bands of 40 to approximately 1,100 kb which provided good discrimination between isolates. Seventeen distinct patterns were obtained with 62 isolates from seven outbreak investigations or control strains. In general, multiple isolates from a single individual had indistinguishable PFGE patterns. Epidemiologically unrelated isolates (outbreak or control strains) had unique patterns; isolates from different individuals within an outbreak had similar, if not identical, patterns. PFGE identifies clonal relationships of isolates which will assist epidemiologic investigations of food-borne-disease outbreaks caused by C. perfringens.

Centers for Disease Control and Prevention, U.S.↗
PubMed1999

Isolation of Providencia heimbachae from human feces.

Providencia heimbachae was first described in 1986. It has been isolated from penguin feces and an aborted bovine fetus. To date, there has been no reported isolation of this organism from human specimens. We now report the isolation of P. heimbachae from the stool of a 23-year-old woman with idiopathic diarrhea. The identity of the human strain was determined biochemically and by DNA relatedness to the type strain of P. heimbachae.

Adult↗
PubMed1999

Polymerase chain reaction identification of Mycobacterium avium in formalin-fixed, paraffin-embedded animal tissues.

A PCR procedure previously developed for identification of Mycobacterium bovis in formalin-fixed tissues was used to identify mycobacteria of the M. avium complex. Tissues were examined from 100 culture-positive cases of M. avium complex infection, including 86 in which the subspecies was not identified and 14 that had been identified as M. avium subsp. paratuberculosis. Each sample was tested with 5 primer sets, 16S ribosomal RNA (rRNA), IS900, IS901, IS1245, and a heat shock protein (hspX), that detect 1 or both M. avium subspecies. The success rate of PCR detection varied with the primers used and the animal species tested. Among the 86 cases with no M. avium subspecies designation, primers for the 16S rRNA gene were clearly the most efficient because they produced amplicons from all samples that reacted with any other primer set. The overall detection rate in this group of samples was 71%: highest in avian tissues (89%) followed by swine (72%) and ruminants (57%) None of the avian or swine tissues reacted with primers for IS900 or hspX, which identify M. a. paratuberculosis. In contrast, 7 of the 12 ruminant samples that were 16S rRNA positive reacted with 1 or both of these primers. All of the 14 cases shown by culture to be M. a. paratuberculosis infections were positive with IS900 primers, whereas only 11 were positive for 16S rRNA. These results indicate that 16S rRNA primers are the most useful for PCR identification of M. avium in formalin-fixed tissues of nonruminant species. However, IS900 primers should also be used when ruminant tissues are examined because these primers provide the greatest sensitivity for detection of M. a. paratuberculosis infections.

Animals↗
PubMed1999

Detection of Mycobacterium avium subspecies avium in formalin-fixed, paraffin-embedded tissues of captive exotic birds using polymerase chain reaction.

A presumptive diagnosis of avian tuberculosis can be made when characteristic histologic lesions and acid-fast bacilli are observed in avian tissue samples. However, a definitive diagnosis requires isolation and identification of the causative organism, a process that can take several weeks to complete. The purpose of the study was to determine whether formalin-fixed, paraffin-embedded archival avian tissues could be tested by polymerase chain reaction (PCR) to reliably and rapidly diagnose avian tuberculosis. Tissues were examined from both presumptive and definitive cases of avian tuberculosis from captive exotic birds obtained over a 14-yr period (1983-1997). The cases chosen consisted of birds that had characteristic histologic lesions with acid-fast bacilli. The primers used for PCR amplified a 180-base-pair fragment of 16S ribosomal RNA, a sequence specific for both Mycobacterium avium subsp. avium and M. avium subsp. paratuberculosis. If a sequence was detected in a sample, it was presumed that M. a. avium was the organism being detected. This M. avium fragment sequence was detected in 26 of the 97 samples (27%). Some of the negative PCR results may be explained by any of several factors that adversely affect nucleic acid integrity, particularly prolonged fixation in formalin. Of the 17 samples that were culture positive for M. avium and were known to have been fixed in formalin for < or = 4 wk, 11 tested positive by PCR (65%). The findings of this study show that PCR can be a rapid indicator of the presence of M. a. avium in formalin-fixed, paraffin-embedded tissues. However, the relatively low detection rate the test demonstrated in this sample set may limit its practical use as a diagnostic tool.

Air Sacs↗
PubMed1999

Evaluation of low birthweight in African Americans.

This study evaluates risk factors associated with low birthweight in an African-American population. Records of 225 women delivering liveborn, nonanomalous singletons weighing < 2500 g were reviewed. The next parturient, matched for race only, of a similar infant weighing > or = 2500 g constituted the control. This case-control study was conducted among women delivering at University Hospital in New Orleans during 1996-1997. Mothers of infants weighing < 2500 g were more likely to not have finished high school (49% versus 38%), to have received no prenatal care (26% versus 7%), or to have five or fewer visits if care was obtained (52% versus 33%). The mother was more likely to weigh < 60 kg (49% versus 32%), to smoke (24% versus 11%), or to have used cocaine (18% versus 5%) or alcohol (11% versus 5%). Parturients of low birthweight newborns were more likely to have had a prior low birthweight infant (44% versus 19%) and themselves to have had a birthweight < 2500 g (30% versus 13%). Regression analysis confirmed the importance of three parameters as associated with low birthweight: no prenatal care (odds ratio [OR] = 6.0 [1.1-31.4]), alcohol use (OR = 5.2 [1.1-24.8], and low maternal birthweight (OR = 3.9 [1.9-7.9]. These results indicate that evaluations of low birthweight in African Americans should consider maternal birthweight and that efforts to improve pregnancy outcome should be structured in terms of generations.

Black or African American↗
PubMed1999

Relationship of phencyclidine and pregnancy outcome.

OBJECTIVE: To analyze the relationship of phencyclidine (PCP) and pregnancy outcome, as judged by low birth weight (< 2,500 g). STUDY DESIGN: A retrospective, case-control study of PCP use was conducted among pregnant women who delivered at a large hospital in New Orleans. PCP use was ascertained by urine screening at the time of obstetric admission. Three control patients were selected for each case, matched for age, parity and month of delivery. The study intended to address the prevalence of low birth weight. RESULTS: Between January 1990 and June 1996, 13,653 patients delivered. Of these, 23 were identified as PCP users. PCP users had smaller infants (2,698 vs. 3,011 g, P < .05); that may have been accounted for by a reduction in gestational age (37.3 vs. 38.3 weeks, P = NS). The users were more likely to give histories of using tobacco, alcohol or marijuana but not cocaine. Syphilis and diabetes mellitus were found more often in the study group. Multisubstance use was also common in the study group. The prevalence of low birth weight was not statistically different for the study and control groups. CONCLUSION: PCP use was not associated with an increase in low birth weight. When identified, patients using PCP require comprehensive evaluation.

Adult↗
PubMed1998

Influence of intense sound exposure on glutathione synthesis in the cochlea.

Previous studies have shown that depletion of endogenous glutathione (GSH) potentiates noise-induced hearing loss (NIHL), whereas replenishment of GSH attenuates NIHL (Yamasoba et al., Brain Res. 784 (1998) 82-90). Since these findings indicate an important role of GSH in protection from NIHL, we assessed the influence of intense sound exposure (broadband noise, 105 dB SPL, 5 h) on GSH and cysteine levels in the guinea pig cochlea using high performance liquid chromatography. GSH levels were significantly increased in the lateral wall 2 and 4 h post-exposure and returned to normal 6 h post-exposure. GSH levels in the sensory epithelium and modiolus did not show significant changes following noise. Cysteine levels were unchanged in any of the cochlear segments. For the cochlea as a whole, intense sound exposure did not significantly change GSH or cysteine levels throughout the 6-h measurement period post-exposure. These results indicate that GSH synthesis is markedly upregulated selectively in the lateral wall by noise exposure, presumably in response to the robust consumption of GSH, as it is utilized in scavenging reactive oxygen species.

Animals↗
PubMed1998

Cholesterol depletion delocalizes phosphatidylinositol bisphosphate and inhibits hormone-stimulated phosphatidylinositol turnover.

Caveolae and detergent-insoluble, glycosphingolipid-enriched domains (DIGs) are cholesterol-enriched membrane domains that have been implicated in signal transduction because a variety of signaling proteins as well as phosphatidylinositol bisphosphate (PtdInsP2) are compartmentalized in these domains. We report here that depletion of cellular cholesterol leads to the inhibition of epidermal growth factor- and bradykinin-stimulated PtdIns turnover in A431 cells. This is associated with the loss of compartmentalization of epidermal growth factor receptors, Gq, and PtdInsP2 in the low density membrane domains. Replacement of cellular cholesterol leads to the reorganization of signaling molecules in the low density domains and the reestablishment of hormone-stimulated PtdIns hydrolysis. Oxysterol derivatives show a variable ability to functionally replace the cholesterol in this system. These data are consistent with the hypothesis that localization of signaling proteins and lipids to cholesterol-enriched domains is required for the proper function of hormone-stimulated PtdIns turnover.

Bradykinin↗