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J J Meyer

Publications and source records attributed to J J Meyer.

At least 19 recordsLinked to original sources
PubMed2001

Transformation of naturally-occurring 1,9-trans-9,5-cis sweroside to all trans sweroside during acetylation of sweroside aglycone.

From the rootstock of Scabiosa columbria L. loganin and sweroside were isolated. Sweroside showed moderate antibacterial activity. Pure sweroside was converted to the sweroside aglycone 1-acetoxy derivative (DABCO/Ac2O) after hydrolysis of the glucose unit. X-ray crystallography of the monoacetate showed unambiguously that it had been transformed to a new seco-iridoid having the novel trans diaxial configuration for the protons on C-1, C-9 and C-5. The mechanism for the rearrangement is discussed.

Acetylation↗
PubMed2001

Combining phase and energy detection with mathematical morphology in dual time-frequency representation leads to improved SSP noise robustness.

In this paper a fusion algorithm for the detection of specular echoes blurred by coloured Gaussian noise is proposed. The phase and energy criteria, characteristic of these echoes, are handled separately. First, the detection capabilities of split spectrum (phase) and short time Fourier transform spectrogram (energy) are compared theoretically and experimentally. Second, the new algorithm based on mathematical morphology operators using both time-frequency representations is proposed. In the last part our method is shown to be more robust than absolute minimisation split spectrum processing.

Algorithms↗
PubMed2001

In vitro antiplasmodial activity and cytotoxicity of ethnobotanically selected South African plants.

The resistance of Plasmodium spp. to currently used drugs has become a serious problem and efforts are being directed in obtaining new drugs with different structural features. One option favoured is the search for new plant derived antimalarial drugs. Bark and leaves of 20 extracts from 14 South African plant species were tested for in vitro antiplasmodial activity by means of the flow cytometric test. The most active extract of each species giving more than 70% inhibition at 50 microg/ml was selected for determination of IC(50) values. Two extracts had IC(50) values below 2 microg/ml, another seven had IC(50) values between 2 and 5 microg/ml while one had an IC(50) of 10.1 microg/ml. Chloroquine had an IC(50) of 0.043 microg/ml. Cytotoxicities of the five most active extracts at 50 microg/ml were determined with the monkey kidney cell toxicity test and the ID(50) values ranged between 35 and 100 microg/ml.

Animals↗
PubMed2000

An acylated phloroglucinol with antimicrobial properties from Helichrysum caespititium.

A new acylated form of a phloroglucinol with significant antimicrobial properties was isolated by bioactivity guided fractionation from Helichrysum caespititium (Asteraceae). The structure elucidation, and conformation of the new phloroglucinol, 2-methyl-4-[2',4',6'-trihydroxy-3'-(2-methylpropanoyl) phenyl]but-2-enyl acetate, was established by high field NMR spectroscopic and MS data. The compound inhibited growth of Bacillus cereus, B. pumilus, B. subtilis and Micrococcus kristinae at the very low concentration of 0.5 microg/ml and Staphylococcus aureus at 5.0 microg/ml. Six fungi tested were similarly inhibited at low MICs, Aspergillus flavus and A. niger (1.0 microg/ml), Cladosporium chladosporioides (5 microg/ml), C. cucumerinum and C. sphaerospermum (0.5 microg/ml) and Phylophthora capsici at 1.0 microg/ml.

Anti-Infective Agents↗
PubMed2000

Antibacterial activity of linoleic and oleic acids isolated from Helichrysum pedunculatum: a plant used during circumcision rites.

The antibacterial activity-guided fractionation of the dichloromethane extract of leaves of Helichrysum pedunculatum resulted in the isolation of linoleic and oleic acids. Linoleic acid inhibited the growth of all the Gram-positive bacterial species tested with the minimum inhibitory concentration (MIC) varying between 0.01 and 1.0 mg/ml. Oleic acid was active against three of the five Gram-positive bacteria at a MIC of 1.0 mg/ml. Both compounds were inactive against the Gram-negative species tested. A synergistic effect between the two fatty acids was observed against Staphylococcus aureus and Micrococcus kristinae.

Anti-Bacterial Agents↗
PubMed2000

Antibacterial activity of water and acetone extracts of the roots of Euclea natalensis.

Water and acetone extracts of the roots of Euclea natalensis A.DC. were investigated for their in vitro antibacterial properties. The Gram-positive bacteria tested appeared to be more susceptible to the extracts than the Gram-negative bacteria. The water and acetone extracts inhibited the growth of Bacillus cereus, Bacillus pumilus, Bacillus subtilis, Micrococcus kristinae and Staphylococcus aureus at concentrations ranging between 0.1 and 6.0 mg/ml. The water extract did not exert any inhibitory action on Gram-negative bacteria while the acetone extract showed inhibitory activity at a concentration of 5.0 mg/ml against all the Gram-negative bacteria investigated. The antibacterial activity of acetone extract was also investigated by a direct bioassay on TLC plates against S. aureus.

Acetone↗
PubMed2000

Effects of guidelines implementation in a surgical intensive care unit to control nighttime light and noise levels.

OBJECTIVE: Because of around-the-clock activities, environmental noise and light are among the many causes of sleep disturbance in an intensive care unit (ICU). The implementation of guidelines may potentially change behavior rules and improve sleep quality. DESIGN: A prospective interventional study, observing the effects of simple nighttime guidelines on light and noise levels in an ICU. SETTING: A modern surgical ICU, subdivided into six identical three-bed rooms. PATIENTS: Critically ill adult patients. INTERVENTION: Between two observation periods, five guidelines were implemented to decrease both light and noise during the night shift in the patient's room. MEASUREMENT: Light levels and noise levels were obtained using a luxmeter and a sound level meter [A-weighted decibels (dB) scale] and were monitored continuously from 11 pm to 5 am both before (period P1) and after (period P2) the implementation of guidelines. MAIN RESULTS: Similar patient's gravity and nursing workload scores were observed between P1 and P2. A low mean (<5 Lux) and maximal light level were measured during both P1 and P2. The implementation of guidelines lowered mean light disturbance intensity with a greater variability of light during P2. All noise levels were high and corresponded more to a quiet office for noise level equivalents and to a busy restaurant for peak noise levels during both P1 and P2. Guidelines decreased the noise level equivalent (P1, 51.3 dB; P2, 48.3 dB), peak noise level (P1, 74.9 dB; P2, 70.8 dB), and the number of acoustic identified alarms (P1, 22.1 dB; P2, 15.8 dB) during P2. CONCLUSION: The night light levels were low during both periods, and lowering the light levels induced a greater variation of light, which may impair sleep quality. All measured noise levels were high during both periods, which could contribute to sleep disturbance, and the implementation of guidelines significantly lowers some important noise levels. The background noise level was unchanged.

Adult↗
PubMed2000

1999 American Urological Association Gallup Survey: changes in physician practice patterns, treatment of incontinence and bladder cancer, and impact of managed care.

PURPOSE: The Health Policy Survey and Research Committee of the American Urological Association and the Gallup Organization have performed a yearly survey of American urologists since 1992 to assess practice patterns. The results of the 1999 survey are presented. MATERIALS AND METHODS: A random sample of 503 urologists was interviewed in February and March 1999. Major content areas were physician practice patterns, the impact of managed care, and the treatment of pediatric patients, prostate cancer and benign prostatic hyperplasia, female incontinence and bladder cancer. RESULTS: The average urologist is 46.8 years old, certified by the American Board of Urology, sees 78 patients and performs 3.1 major surgical procedures weekly, refers moderate and complex pediatric procedures to specialists, and receives 40.6% of practice income from managed care. CONCLUSIONS: In an era when large group practices seem to be the norm remarkably 32% of urologists remain in solo practice. There has been a shift in where urologists spend their time, that is more in the office and less in the operating room. Minor and major open surgical procedures increased from 12.4 weekly to 16.4 and 2.9 to 3.1 in 1995 and 1999, respectively. Most urologists are comfortable treating straightforward pediatric problems such as cryptorchidism but refer more complex problems to pediatric urologists. Managed care represents an ever increasing proportion of urologist practice income, while office expenses continue to increase.

Adult↗
PubMed1999

Characteristics of three homologous 202 genes (Ifi202a, Ifi202b, and Ifi202c) from the murine interferon-activatable gene 200 cluster.

The Ifi202 gene is part of the interferon-activatable murine gene 200 cluster on chromosome 1. Ifi202 encodes the p202 protein whose overexpression is growth inhibitory and which can bind and inhibit the activity of numerous transcription factors including c-Jun, c-Fos, NF-kappaB, E2F-1, E2F-4, MyoD, and myogenin. We report here the exon-intron structure of Ifi202 and the discovery of Ifi202b and Ifi202c, close homologs of Ifi202 (whose designation we now change to Ifi202a). Ifi202a, b, and c were colocalized to chromosome 1 bands H4-H5 by fluorescence in situ hybridization. Ifi202b encodes p202b, which is interferon-inducible and differs from p202a in only 7 of 445 amino acids. 202b mRNA is constitutively expressed in tissues in which 202a mRNA is expressed. Ifi202c is apparently an unexpressed pseudogene. In murine embryonic fibroblasts (MEFs) from 129 mice, the level of 202b mRNA is approximately half that of 202a mRNA. We knocked out the Ifi202a gene from 129 mice. The expression of 202b mRNA, but not 202a mRNA, persisted in the knockout mice and their MEFs at the same level as in wildtype mice. However, in MEFs from the knockout mice, the constitutive and interferon-induced levels of p202b were approximately as high as the constitutive and the interferon-induced levels of p202a plus p202b, respectively, in MEFs from wildtype mice. These findings suggest dosage compensation at the posttranscriptional level. This might account for the apparent lack of phenotype of the knockout mice.

Animals↗
PubMed1999

1998 American Urological Association Gallup Survey: changes in physician practice patterns, treatment of ureteral stones and impact of managed care.

PURPOSE: The American Urological Association first commissioned the Gallup Organization to conduct a study to assess urologist practice patterns in 1992. We present the results of the seventh consecutive Gallup Survey performed for the Association. MATERIALS AND METHODS: A random sample of 537 American urologists who completed urological residency and practiced at least 20 hours weekly in 1997 were interviewed by telephone in March 1998. Major topic areas included general demographics, practice patterns, treatment of ureteral stones and experience with managed care. RESULTS: Demographic trends indicated a significant decrease in average urologist age from 49.4 years in 1992 to 46.8 in 1998. Of the urologists 99% reported that they treat ureteral stones. Managed care had an increasingly larger role in most practices, particularly in the western United States, where 73% of urologists reported that they contract with a Medicare health maintenance organization. CONCLUSIONS: The average age of practicing urologists significantly decreased, which may be due to an increasing number of urologists retiring at an earlier age, although this finding is not clear. Nearly all urologists treated ureteral stones with considerable consistency. Finally, managed care appeared to have a major impact on most urologists throughout the United States.

Adult↗
PubMed1999

Two approaches to multiple specular echo detection using split spectrum processing: moving bandwidth minimization and mathematical morphology.

A split spectrum processing technique using a novel moving bandwidth minimization (MBM) method was developed to detect multiple specular targets having different spectral characteristics. Mathematical morphology (MM) algorithms were also implemented in order to compare the results. An experimental approach to optimal parameter determination is described. These non-linear filtering methods are applied to medical in vivo imaging to illustrate specular detection and signal to noise ratio (SNR) enhancement.

Algorithms↗
PubMed1999

In vitro inhibition of drug-resistant and drug-sensitive strains of Mycobacterium tuberculosis by ethnobotanically selected South African plants.

Twenty South African medicinal plants used to treat pulmonary diseases were screened for activity against drug-resistant and drug-sensitive strains of Mycobacterium tuberculosis. A preliminary screening of acetone and water plant extracts against a drug-sensitive strain of Mycobacterium tuberculosis, H37Rv, was done by the agar plate method. Fourteen of the 20 acetone extracts showed inhibitory activity at a concentration of 0.5 mg/ml against this strain. Acetone as well as water extracts of Cryptocarya latifolia, Euclea natalensis, Helichrysum melanacme, Nidorella anomala and Thymus vulgaris inhibited the growth of M. tuberculosis. Given the activity of 14 acetone extracts at 0.5 mg/ml against the drug-sensitive strain by the agar plate method, a further study was done employing a rapid radiometric method to confirm the inhibitory activity. These active acetone extracts were screened against the H37Rv strain as well as a strain resistant to the drugs isoniazid and rifampin. The minimal inhibitory concentration of Croton pseudopulchellus, Ekebergia capensis, Euclea natalensis, Nidorella anomala and Polygala myrtifolia was 0.1 mg/ml against the H37Rv strain by the radiometric method. Extracts of Chenopodium ambrosioides, Ekebergia capensis, Euclea natalensis, Helichrysum melanacme, Nidorella anomala and Polygala myrtifolia were active against the resistant strain at 0.1 mg/ml. Eight plants showed activity against both strains at a concentration of 1.0 mg/ml.

Acetone↗
PubMed1999

Incidence and clinical significance of echogenic vasculature in the basal ganglia of newborns.

Cranial sonography has become the main modality of the investigation and diagnosis of a wide variety of neonatal intracranial abnormalities. Occasionally, cranial sonograms reveal basal ganglia and thalami bright echoes. It is believed that these lesions are indicative of vasculitis due to intrauterine infections, in particular with cytomegalovirus (CMV). We hypothesized that the incidence of proven neonatal intrauterine TORCH infection is low and that screening of all asymptomatic infants with bright lenticulostriate echodensities would not be cost-effective. We reviewed brain sonograms of 3700 infants, performed over a period of 3 1/2 years. Echogenic basal ganglia vasculature were observed in 75 patients (2%). Chart review performed for clinical presentation and TORCH studies showed that only one infant had confirmed intrauterine congenital infection, which was by CMV. This infant had no signs or symptoms of CMV. In addition, there were 4 patients with chromosomal anomalies among the 75 patients (5%), of these one had trisomy 13 and another-trisomy 21. Our results indicate that echogenic basal ganglia blood vessels are not an exceptional finding on cranial sonograms, and are seldom associated with intrauterine infection. We conclude that it is not cost-effective to screen infants with echogenic basal ganglia blood vessels for intrauterine infection, unless clinical suspicion exists.

Basal Ganglia↗
PubMed1998

1997 American Urological Association Gallup survey: Changes in diagnosis and management of prostate cancer and benign prostatic hyperplasia, and other practice trends from 1994 to 1997.

PURPOSE: The American Urological Association first commissioned the Gallup Organization to conduct a study to assess urologist practice patterns in 1992. We present the results of the 1997 survey, the sixth consecutive Gallup survey performed for the Association. MATERIALS AND METHODS: A random sample of 502 American urologists who had completed urological residency and practiced at least 20 hours weekly in 1996 was interviewed by telephone in February and March 1997. RESULTS: Emerging trends showed significant changes since 1994 in how urologists diagnosed and treated prostate cancer. The survey revealed a significant change in the tests routinely ordered to stage newly diagnosed prostate cancer and for diagnostic evaluation of patients with benign prostatic hyperplasia. CONCLUSIONS: Urologists are becoming more cost conscious and effective in ordering pretreatment testing. Urologists are becoming more oriented toward medical treatment for the management of benign prostatic hyperplasia, and less laser surgery is being performed.

Adult↗
PubMed1998

Subspecialization, recruitment and retirement trends of American urologists.

PURPOSE: Trends of urology workforce, subspecialization, recruitment practices, retirement planning, practice characteristics and managed care impacts in the United States were assessed. MATERIALS AND METHODS: In February 1996 the executive interviewing branch of The Gallup Organization selected randomly and interviewed by telephone 507 practicing urologists in the United States who had provided urological patient care for more than 20 hours per week, practiced in 1995 and completed a urological residency program. RESULTS: Several important issues emerged. Urologists think we may be training too many urologists, subspecialty board certification would be a divisive issue to urology as a whole and 90% of urologists have an active retirement plan, although 23% are not funding the plan fully. CONCLUSIONS: The American Urological Association Gallup Poll, as refined by the Health Policy Survey and Research Committee, continues to be a unique and valuable tool in assessing practice patterns, gathering demographic data and measuring opinions of the American urologist. This information will help us chart our way to the twenty-first century.

Adult↗
PubMed1998

Neuroimaging of children with partial seizures.

The predictive value of abnormal neurological findings on neuroimaging (NI) of children with partial seizures (PS) was studied. The sample comprised 143 children and adolescents with PS from 1979 to 1996. Fifty patients had the following abnormal NI findings: diffuse atrophy and porencephalic cyst (5.6% each), hemiatrophy, tumors, neurocutaneous syndrome brain lesions, and dysgenesis (4.2% each), and arachnoid cyst and hydrocephalus (2.1% each). There were significantly more NI abnormalities among those with simple PS than among the other groups of complex PS or PS with secondary generalization. All cases of porencephalic cyst (n = 8), and hemiatrophy (n = 6) were in the hemiparetic group, all cases of tumor (n = 6) were in the normal group, while most cases of diffuse atrophy were in the mentally retarded group. Patients with abnormal NIs had a significantly earlier age of seizure onset than the others. The chance of finding a treatable abnormality in neuroimaging was 5% for tumors and 2% for arachnoid cysts in the group of patients with PS and normal neurological findings. Neither an abnormality detected in a neurological examination nor the type of seizure are predictive parameters for suggesting the presence of a resectable brain tumor. All patients with newly diagnosed PS should undergo an MRI.

Adolescent↗