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Biomedical subjects

J P Taylor

Publications and source records attributed to J P Taylor.

At least 19 recordsLinked to original sources
PubMed2001

Evidence of activity-dependent withdrawal of corticospinal projections during human development.

OBJECTIVE: To characterize the development of ipsilateral corticospinal projections from birth and compare to 1) development of contralateral projections in the same subjects and 2) ipsilateral corticospinal projections in subjects with unilateral lesions of the corticospinal system acquired perinatally or in adulthood. METHOD: Transcranial magnetic stimulation excited the motor cortex, and responses were recorded bilaterally in pectoralis major, biceps brachii, and the first dorsal interosseus muscles. Subjects studied included 9 neonates recruited at birth, studied longitudinally for 2 years; 85 healthy subjects aged from birth to adulthood; 10 subjects with hemiplegic cerebral palsy; and 8 with hemiplegia after stroke. RESULTS: In neonates, ipsilateral responses had significantly shorter onsets than contralateral responses but similar thresholds and amplitudes. Thresholds within both pathways increased in the first 3 months. Differential development was present from 3 months so that by 18 months ipsilateral responses were significantly smaller and had significantly higher thresholds and longer onset latencies than contralateral responses. A similar pattern of smaller and later ipsilateral responses was observed after transcranial magnetic stimulation of the intact cortex in subjects with stroke. In contrast, subjects with hemiplegic cerebral palsy had ipsilateral responses with onsets, thresholds and amplitudes similar to those of contralateral responses. Significant branching of contralateral corticospinal axons from the intact motor cortex was excluded by cross-correlation analysis. CONCLUSIONS: These data, together with previously published anatomic and radiologic studies, are consistent with activity-dependent corticospinal axonal withdrawal during development and maintenance of increased corticomotoneuronal projections from the intact hemisphere after unilateral perinatal lesions.

Adolescent↗
PubMed2001

Clinical, laboratory, and epidemiologic features of murine typhus in 97 Texas children.

OBJECTIVE: To document the clinical, laboratory, and epidemiologic characteristics of pediatric patients with murine typhus. DESIGN: Pediatric patients were diagnosed using serologic testing, and clinical, laboratory, and epidemiologic data were retrospectively reviewed. SETTING: Of 97 patients, 77 (79%) were identified and treated as inpatients and 20 (21%) were treated as outpatients; most resided in south Texas. PATIENTS: Between 1979 and 1996, medical records and patient-physician interviews were available for 97 patients aged 16 years and younger with murine typhus. MAIN OUTCOME MEASURES: The frequency of clinical symptoms and signs, abnormal laboratory findings, epidemiologic findings, and measures of disease severity were determined. RESULTS: The clinical triad of fever, headache, and rash occurred in only 43 (49%) of 87 pediatric patients throughout the illness. Musculoskeletal symptoms were experienced by 43% of patients, whereas gastrointestinal tract symptoms (nausea, vomiting, anorexia, and diarrhea) occurred in 77%. Systemic involvement was evident by the frequent occurrence of abnormal laboratory findings referable to multiple organ systems, including the liver, kidney, blood, and central nervous system. CONCLUSIONS: Pediatric infection by Rickettsia typhi usually causes mild to moderate systemic illness. In children, the median duration of illness was 12 days (range, 5-29 days), but severe complications were rare. Length of illness was significantly related to the initial diagnosis, whereas the interval to defervescence was related to therapy with a tetracycline or chloramphenicol. Early recognition and treatment is important to prevent prolonged morbidity.

Adolescent↗
PubMed2001

Transcription of intermediate filament genes is enhanced in focal cortical dysplasia.

Focal cortical dysplasia (FCD) is characterized by disorganized cerebral cortical cytoarchitecture. Increased expression of several intermediate filament (IF) proteins such as neurofilament, vimentin, alpha-internexin, and nestin observed in dysplastic "balloon" neurons (DN) may contribute to disrupted cortical lamination. We hypothesized that increased IF protein expression results from enhanced IF gene transcription within dysplastic neurons. We used a novel strategy to evaluate IF mRNA expression in three FCD specimens from medically intractable epilepsy patients. Poly(A) mRNA was amplified (aRNA) from single microdissected DN, morphologically normal neurons at the margin of the FCD resection, morphologically normal neurons in non-FCD cortex from epilepsy patients, and normal control neurons. Radiolabeled aRNA from single neurons was used to probe cDNA arrays containing the low (NFL), medium (NFM) and high (NFH) molecular weight neurofilament isoform, alpha-internexin, desmin, vimentin, peripherin (PRPH), nestin, and glial fibrillary acidic protein (GFAP) cDNAs. Hybridization intensity of aRNA-cDNA hybrids was used to quantify relative IF abundance. Increased expression of nestin, alpha-internexin, PRPH, vimentin, NFL, NFM, and NFH mRNAs was found in DN when compared with the three control neuronal subtypes. Desmin and GFAP mRNAs were not detected in any cell types. Expression of PRPH mRNA and protein in select DN was confirmed by reverse transcription-polymerase chain reaction and immunohistochemistry. We conclude that aberrant expression of IF proteins in FCD likely results from enhanced transcription of IF genes in dysplastic neurons and propose that future analysis of transcriptional elements that regulate IF expression be evaluated in FCD.

Adolescent↗
PubMed2001

Secretory bulk flow of soluble proteins is efficient and COPII dependent.

COPII-coated vesicles, first identified in yeast and later characterized in mammalian cells, mediate protein export from the endoplasmic reticulum (ER) to the Golgi apparatus within the secretory pathway. In these organisms, the mechanism of vesicle formation is well understood, but the process of soluble cargo sorting has yet to be resolved. In plants, functional complements of the COPII-dependent protein traffic machinery were identified almost a decade ago, but the selectivity of the ER export process has been subject to considerable debate. To study the selectivity of COPII-dependent protein traffic in plants, we have developed an in vivo assay in which COPII vesicle transport is disrupted at two distinct steps in the pathway. First, overexpression of the Sar1p-specific guanosine nucleotide exchange factor Sec12p was shown to result in the titration of the GTPase Sar1p, which is essential for COPII-coated vesicle formation. A second method to disrupt COPII transport at a later step in the pathway was based on coexpression of a dominant negative mutant of Sar1p (H74L), which is thought to interfere with the uncoating and subsequent membrane fusion of the vesicles because of the lack of GTPase activity. A quantitative assay to measure ER export under these conditions was achieved using the natural secretory protein barley alpha-amylase and a modified version carrying an ER retention motif. Most importantly, the manipulation of COPII transport in vivo using either of the two approaches allowed us to demonstrate that export of the ER resident protein calreticulin or the bulk flow marker phosphinothricin acetyl transferase is COPII dependent and occurs at a much higher rate than estimated previously. We also show that the instability of these proteins in post-ER compartments prevents the detection of the true rate of bulk flow using a standard secretion assay. The differences between the data on COPII transport obtained from these in vivo experiments and in vitro experiments conducted previously using yeast components are discussed.

COP-Coated Vesicles↗
PubMed2000

CREB-binding protein sequestration by expanded polyglutamine.

Spinal and bulbar muscular atrophy (SBMA) is one of eight inherited neurodegenerative diseases known to be caused by CAG repeat expansion. The expansion results in an expanded polyglutamine tract, which likely confers a novel, toxic function to the affected protein. Cell culture and transgenic mouse studies have implicated the nucleus as a site for pathogenesis, suggesting that a critical nuclear factor or process is disrupted by the polyglutamine expansion. In this report we present evidence that CREB-binding protein (CBP), a transcriptional co-activator that orchestrates nuclear response to a variety of cell signaling cascades, is incorporated into nuclear inclusions formed by polyglutamine-containing proteins in cultured cells, transgenic mice and tissue from patients with SBMA. We also show CBP incorporation into nuclear inclusions formed in a cell culture model of another polyglutamine disease, spinocerebellar ataxia type 3. We present evidence that soluble levels of CBP are reduced in cells expressing expanded polyglutamine despite increased levels of CBP mRNA. Finally, we demonstrate that over-expression of CBP rescues cells from polyglutamine-mediated toxicity in neuronal cell culture. These data support a CBP-sequestration model of polyglutamine expansion disease.

Animals↗
PubMed2000

ATP-dependent regulation of nuclear Ca(2+) levels in plant cells.

Localised alterations in cytoplasmic Ca(2+) levels are an integral part of the response of eukaryotic cells to a plethora of external stimuli. Due to the large size of nuclear pores, it has generally been assumed that intranuclear Ca(2+) levels reflect the prevailing cytoplasmic Ca(2+) levels. Using nuclei prepared from carrot (Daucus carota L.) cells, we now show that Ca(2+) can be transported across nuclear membranes in an ATP-dependent manner and that over 95% of Ca(2+) is accumulated into a pool releasable by the Ca(2+) ionophore A.23187. ATP-dependent nuclear Ca(2+) uptake did not occur in the presence of ADP or ADPgammaS and was abolished by orthovanadate. Confocal microscopy of nuclei loaded with dextran-linked Indo-1 showed that the initial ATP-induced rise in [Ca(2+)] occurs in the nuclear periphery. The occurrence of ATP-dependent Ca(2+) uptake in plant nuclei suggests that alterations of intranuclear Ca(2+) levels may occur independently of cytoplasmic [Ca(2+)] changes.

Adenosine Triphosphate↗
PubMed2000

Prevalence and risk factors of drug-resistant tuberculosis along the Mexico-Texas border.

OBJECTIVES: This study determined factors associated with drug resistance among 3496 patients with tuberculosis who resided in Texas counties along the Mexican border. METHODS: Univariate and logistic regression analyses were performed to identify risk factors associated with drug resistance. RESULTS: Among patients with a history of previous tuberculosis, being 19 years or younger was the only factor associated with multiple drug resistance. Female sex, being 20 to 39 years of age, and foreign birth were risk factors for resistance among patients with no history of previous tuberculosis. CONCLUSIONS: Factors contributing to drug resistance among Hispanic tuberculosis patients along the Texas-Mexico border may differ from those among other populations in the United States.

Adult↗
PubMed1999

Epidemiology of drug-resistant tuberculosis in Texas.

During 1987-1996, over 22,000 tuberculosis cases were reported in Texas, at an average annual incidence rate of 12.5 cases per 100,000 population. Counties with the highest rates were located along the Mexico-Texas border and in northwestern Texas. Nine percent of cases were resistant to at least one of the five first-line antituberculosis drugs used for treatment. Almost 5 percent (4.6%) were resistant to isoniazid, either alone or in combination with other antibiotics; 2.3% were resistant to rifampin; and only 1.3% were resistant to both isoniazid and rifampin. Being a recurrent case, being foreign-born, being 20-39 years of age, and residing in a Mexico-Texas border county were independent risk factors for isoniazid resistance and rifampin resistance. Tuberculosis patients with human immunodeficiency virus (HIV) infection were more likely to have rifampin resistance and less likely to have isoniazid resistance than patients without HIV infection. Factors associated with multi-drug-resistant tuberculosis included a history of previous tuberculosis (relative risk (RR) = 4.91, 95% confidence interval (CI) 3.5-6.8), non-US birth (RR = 2.69, 95% CI 2.1-3.5), age younger than 20 years (RR = 1.97, 95% CI 1.1-3.5), age 20-39 years (RR = 1.82, 95% CI 1.3-2.6), and residence in a Mexico-Texas border county (RR = 2.33, 95% CI 1.8-3.1).

AIDS-Related Opportunistic Infections↗
PubMed1999

A continuing focus of Hansen's disease in Texas.

To describe epidemiologic and clinical characteristics of Hansen's disease cases in Texas, information was abstracted from records of 810 patients reported from 1973 through 1997. Annually, from 18 to 54 patients were reported. Average annual incidence rates ranged from 1.9 to 2.4 cases per million population. A majority of the patients were male (63%) and white (77%). More than half (53%) of the patients were born in the United States; a majority (83%) of the patients born in the United States were born in Texas. Most (76%) patients were diagnosed with multi-bacillary leprosy. Foreign-born patients were more likely to be younger at onset and have multi-bacillary disease compared with patients born in the United States. Within Texas, an endemic focus of Hansen's disease exists along the Gulf of Mexico coast.

Black or African American↗
PubMed1998

Efficacy of meningococcal vaccine and barriers to vaccination.

CONTEXT: Use of the quadrivalent meningococcal vaccine for control of outbreaks has increased in recent years, but the efficacy of meningococcal vaccine during mass vaccination campaigns in US civilian populations has not been assessed. OBJECTIVES: To evaluate the efficacy of the quadrivalent meningococcal vaccine against serogroup C meningococcal disease in a community outbreak setting and to evaluate potentially modifiable barriers to vaccination in an area with persistent meningococcal disease following immunization. DESIGN: Matched case-control study of vaccine efficacy using cases of serogroup C meningococcal disease in persons eligible for vaccination during mass vaccination campaigns. Control patients were matched by neighborhood and age. The control group was used to identify possible barriers to vaccination. SETTING: Gregg County, Texas, population 106076, from 1993 to 1995. PARTICIPANTS: A total of 17 case patients with serogroup C meningococcal disease eligible for vaccine and 84 control patients. MAIN OUTCOME MEASURES: Vaccine efficacy and risk factors associated with nonvaccination. RESULTS: Vaccine efficacy among 2- to 29-year-olds was 85% (95% confidence interval, 27%-97%) and did not change in bivariate analyses with other risk factors that were significant in univariate analysis. Among control patients, older age was strongly associated with nonvaccination; vaccination rates for 2- to 4-year-olds, 5- to 18-year-olds, and 19- to 29-year-olds were 67%, 48%, and 20%, respectively (chi2 for linear trend, P=.01). CONCLUSIONS: The meningococcal polysaccharide vaccine was effective against serogroup C meningococcal disease in this community outbreak. Although specific barriers to vaccination were not identified, older age was a risk factor for nonvaccination in the target population of 2- to 29-year-olds. In future outbreaks, emphasis should be placed on achieving high vaccination coverage, with special efforts to vaccinate young adults.

Adolescent↗
PubMed1998

Assessing adherence to a rotary diversified diet, a treatment for 'environmental illness'.

OBJECTIVES: To develop and test a method to assess adherence to a rotary diversified diet (RDD), a treatment for environmental illness, which is a putative disorder characterized by multiple sensitivities to foods, chemicals, or inhalants. The RDD requires the elimination of prohibited foods and rotation of remaining nonprohibited foods and their "food families" within a 4- to 7-day cycle. The regimen has yet to be validated to the satisfaction of the scientific community. DESIGN: Details of the 2 components of the RDD prescription, elimination and rotation, were documented, and a food record method of assessing adherence was developed. Adherence to the RDD was then assessed in a cohort of women who were enrolled in a larger prospective study. Test-retest reliability of the adherence assessment method was determined by calculating ratings twice on the same set of patient food records, with 1 week between trials. SUBJECTS/SETTING: All patients were contacted through a private environmental medicine clinic in Toronto, Canada. Eight patients provided the food records needed for development of the method; adherence was then assessed in 22 women aged 25 to 67 years. STATISTICAL ANALYSES: Means, standard deviations, and 95% confidence intervals for adherence ratings were calculated. The reliability of the adherence assessment method was determined by calculating Pearson correlation coefficients for adherence ratings from each trial. A paired t test was also used to determine if the mean differences in ratings between trials were significant. RESULTS: Patients experienced difficulties following both components of the RDD: 37% to 44% of foods consumed were either prohibited or allowed, but were consumed on the incorrect day. The adherence assessment method was found to have high levels of reliability. APPLICATIONS: The adherence assessment method can be used in future evaluations of the RDD, although further testing of the method is recommended. Increased involvement of dietitians with patients diagnosed with environmental illness is recommended.

Adult↗
PubMed1998

Improved reproducibility of magnetic stimulation-evoked motor potentials in the human masseter by a new method for locating stimulation sites on the scalp.

In magnetic-stimulation studies where motor-evoked potentials (MEP) are measured on different occasions, accurate relocation of the stimulation site on the scalp is essential. Here a novel method of locating neural stimulation sites was tested and the reproducibility of MEPs in the human masseter assessed. The heads of the participants were immobilized in a plastic mask that incorporated a grid overlying the left cerebral hemisphere. A figure-of-eight coil was oriented with a micromanipulator. Electrodes were placed over the right masseter using a standardized method. Two discrete sites on the grid were stimulated alternately at threshold + 10% whilst participants clenched their teeth. Recordings were repeated after the mask and electrodes had been removed and replaced. Within individual participants, the latency and amplitude of the MEP were reproducible between trials and when the mask and electrodes were replaced. The new method appears to be accurate and practical when recording longitudinal MEP data in the masseter.

Adult↗
PubMed1998

Crayfish: a newly recognized vehicle for vibrio infections.

We conducted a 1-year case-control study of sporadic vibrio infections to identify risk factors related to consumption of seafood products in two coastal areas of Louisiana and Texas. Twenty-six persons with sporadic vibrio infections and 77 matched controls were enrolled. Multivariate analysis revealed that crayfish (P < 0.025) and raw oysters (P < 0.009) were independently associated with illness. Species-specific analysis revealed an association between consumption of cooked crayfish and Vibrio parahemolyticus infection (OR 9.24, P < 0.05). No crayfish consumption was reported by persons with V. vulnificus infection. Although crayfish had been suspected as a vehicle for foodborne disease, this is the first time to our knowledge that consumption of cooked crayfish has been demonstrated to be associated with vibrio infection.

Animals↗
PubMed1998

A large outbreak of botulism: the hazardous baked potato.

In April 1994, the largest outbreak of botulism in the United States since 1978 occurred in El Paso, Texas. Thirty persons were affected; 4 required mechanical ventilation. All ate food from a Greek restaurant. The attack rate among persons who ate a potato-based dip was 86% (19/22) compared with 6% (11/176) among persons who did not eat the dip (relative risk [RR] = 13.8; 95% confidence interval [CI], 7.6-25.1). The attack rate among persons who ate an eggplant-based dip was 67% (6/9) compared with 13% (241189) among persons who did not (RR = 5.2; 95% CI, 2.9-9.5). Botulism toxin type A was detected from patients and in both dips. Toxin formation resulted from holding aluminum foil-wrapped baked potatoes at room temperature, apparently for several days, before they were used in the dips. Consumers should be informed of the potential hazards caused by holding foil-wrapped potatoes at ambient temperatures after cooking.

Animals↗
PubMed1998

Prospective investigation of cryptic outbreaks of Salmonella agona salmonellosis.

The number of Salmonella agona isolates reported annually in Texas from 1992 through 1994 ranged from 14 to 21. An increase in incidence of S. agona infections was noted in the fall of 1995. Pulsed-field gel electrophoresis (PFGE) analysis identified prospectively two possible cryptic outbreaks caused by an indistinguishable strain which was isolated from 18 of 59 patients who were culture positive from March through December 1995. These 18 patients had onset of illness from 20 May through 3 October 1995. Eight individuals resided in the Austin area, eight resided in San Antonio, and two resided in Houston; none had attended a common social gathering or owned common pets. Six patients in San Antonio and one patient from Houston recalled eating food items from the same Mexican food restaurant in San Antonio. S. agona organisms with the same PFGE profile were isolated from machacado, an air-dried, raw beef product prepared at the restaurant. The machacado had been shredded in a kitchen blender which was the probable source for cross-contamination of other food items. Five patients in Austin reported eating at a popular Mexican food restaurant in Austin. Improperly prepared machacado also may have been served at the Austin restaurant; however, sufficient quantities of machacado were not available for analysis. PFGE was essential in determining whether the cases constituted outbreaks and was invaluable in guiding the epidemiological investigation.

Demography↗
PubMed1998

Risk factors for rifampin mono-resistant tuberculosis.

Use of rifampin is required for short-course treatment regimens for tuberculosis. Tuberculosis caused by isolates of M. tuberculosis with resistance to rifampin and susceptibility to isoniazid is unusual, but it has been recognized through surveillance. Patients with tuberculosis (cases) with rifampin mono-resistance were compared with HIV-matched controls with tuberculosis caused by a drug-susceptible isolate. A total of 77 cases of rifampin mono-resistant tuberculosis were identified in this multicenter study. Three were determined to be laboratory contaminants, and 10 cases had an epidemiologic link to a case with rifampin mono-resistant tuberculosis, suggesting primary acquisition of rifampin-resistant isolates. Of the remaining 64 cases and 126 controls, there was no difference between cases and controls with regard to age, sex, race, foreign birth, homelessness, or history of incarceration. Cases were more likely to have a history of prior tuberculosis than were controls. Of the 38 cases and 74 controls with HIV infection, there was no difference between cases and controls with regard to age, sex, race, foreign birth, homelessness, history of incarceration, or prior tuberculosis. Cases were more likely to have histories of diarrhea, rifabutin use, or antifungal therapy. Laboratory analysis of available isolates showed that there was no evidence of spread of a single clone of M. tuberculosis. Further studies are needed to identify the causes of the development of rifampin resistance in HIV-infected persons with tuberculosis and to develop strategies to prevent its emergence.

AIDS-Related Opportunistic Infections↗
PubMed1997

Comparison of serum antibiotic levels in acne patients receiving the standard or a modified release formulation of minocycline hydrochloride.

Serum levels of minocycline hydrochloride were determined by bioassay in a total of 223 acne patients (123 male, 100 female) receiving either the recommended dose (100mg/day) or a high dose (200mg/day) of the standard preparation (101 patients) of a modified release formulation (132 patients). Sera were collected within 6 h of the morning dose 7-10 days after the start of treatment. Mean minocycline serum levels were consistently higher in females than in males, irrespective of dose or formulation. The differences only reached statistical significance (P < 0.05, Student's t-test) in the case of the standard preparation at a dose of 50 mg, b.d. Serum levels were increased significantly in both sexes at the higher dosage of each formulation (P < 0.01) but there was no significant difference between formulations at either dosage. Variation in serum concentrations was not accounted for by variation in body mass. Serum levels above the modal minimum inhibitory concentration (MIC) of minocycline for fully sensitive strains of Propionibacterium acnes I (0.125 micrograms/mL) were recorded in all patients. In contrast, serum levels equal to or greater than the modal MIC of minocycline for resistant propionibacteria (2 micrograms/mL) were recorded in only 17.9% of patients on the low dose standard preparation compared with 55.6% on the high dose standard preparation (P < 0.001, chi 2). Even in females on the high-dose modified release formulation, 32.2% had serum levels below the modal MIC of minocycline for resistant strains. We conclude that, in terms of achievable serum levels over a short time period, there is no advantage of the modified release formulation over the standard preparation of minocycline. Whichever formulation is used, dose manipulation may be necessary to achieve maximum therapeutic benefit, especially in those individuals who are colonized by propionibacteria with reduced sensitivity to minocycline.

Acne Vulgaris↗