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Biomedical subjects

K Weiss

Publications and source records attributed to K Weiss.

At least 19 recordsLinked to original sources
PubMed2000

Delivery room management of the apparently vigorous meconium-stained neonate: results of the multicenter, international collaborative trial.

OBJECTIVE: Disagreement exists concerning the appropriate delivery room management of the airway of vigorous meconium-stained infants. Some suggest a universal approach to intubation and suctioning of the airway in all such neonates, whereas others advocate a selective approach. We performed this investigation: 1) to assess whether intubation and suctioning of apparently vigorous, meconium-stained neonates would reduce the incidence of meconium aspiration syndrome (MAS); and 2) to determine the frequency of complications from delivery room intubation and suctioning of such infants. METHODS: Inclusion criteria included: 1) gestational age >/=37 weeks; 2) birth through meconium-stained amniotic fluid of any consistency; and 3) apparent vigor immediately after birth. Subjects were randomized to be intubated and suctioned (INT) or to expectant management (EXP). Primary outcome measures included: 1) the incidence of respiratory distress, including MAS, and 2) the incidence of complications from intubation. RESULTS: A total of 2094 neonates were enrolled from 12 participating centers (1051 INT and 1043 EXP). Meconium-stained amniotic fluid consistency was similar in both groups. Of the 149 (7.1%) infants that subsequently demonstrated respiratory distress, 62 (3.0%) had MAS and 87 (4.2%) had findings attributed to other disorders. There were no significant differences between groups in the occurrence of MAS (INT = 3.2%; EXP = 2.7%) or in the development of other respiratory disorders (INT = 3.8%; EXP = 4.5%). Of 1098 successfully intubated infants, 42 (3.8%) had a total of 51 complications of the procedure. In all cases, the complications were mild and transient in nature. CONCLUSIONS: Compared with expectant management, intubation and suctioning of the apparently vigorous meconium-stained infant does not result in a decreased incidence of MAS or other respiratory disorders. Complications of intubation are infrequent and short-lived.

Adult↗
PubMed1999

Group A Streptococcus carriage among close contacts of patients with invasive infections.

During the past few years, the incidence of invasive group A Streptococcus (GAS) infection has been increasing. However, there are presently no clear recommendations regarding antibiotic prophylaxis for close contacts of index patients. The aims of this study were 1) to determine the prevalence of carriage of the same GAS strain as the patient's among contacts of patients with invasive infections and 2) to assess the importance of exposure duration. From March 1995 to March 1996, the authors prospectively included in the study all patients with invasive GAS infection, as defined by the Working Group on Severe Streptococcal Infections, who came to Hôpital Maisonneuve-Rosemont in Montreal, Quebec, Canada. An epidemiologic investigation was systematically carried out for each index case. Contacts were divided into two groups: those who had spent 24 hours or more with the index patient during the week preceding the beginning of his or her illness and those who had spent 12-24 hours with the index patient during that week. Strains of GAS were examined by serotyping (proteins M and T and the presence or absence of the serum opacity factor) and by characterization of streptococcal pyrogenic exotoxins (exotoxins A, B, and C). One hundred and two contacts of 17 index cases with invasive GAS infection were systematically screened. Contacts were considered positive if they carried the same strain of the bacterium and the same streptococcal pyrogenic exotoxin as the index case. Among the contacts who had spent at least 24 hours per week with their respective index cases, 13 out of 48 (27%) were found to be harboring the same serotype of GAS as the index patient (95% confidence interval 14.5-39.5). By comparison, only one of the 54 contacts in the 12- to 24-hour group (1.8%) was found to be carrying the same strain of the bacterium (95% confidence interval 0-5.3). This difference between the two groups was statistically significant (p<0.001). The median age of the positive carriers (10 years) was significantly lower than the median age of the noncarriers (39 years) (p< or =0.0005). This study showed that close contacts who had spent 12-24 hours with the index patient were rarely colonized with GAS. If antibiotic prophylaxis against GAS is recommended, it should probably target contacts who spent at least 24 hours with an infected patient during the week preceding illness onset.

Adolescent↗
PubMed1999

Adenoviral transfer of the viral IL-10 gene periarticularly to mouse paws suppresses development of collagen-induced arthritis in both injected and uninjected paws.

Gene therapy is a promising new approach in the treatment of rheumatoid arthritis. Gene delivery to diseased joints offers the prospect of achieving high, local concentrations of a therapeutic gene product in a sustained manner, while minimizing exposure of nontarget organs. We report that a single administration of a modified adenovirus encoding the Epstein-Barr-derived homologue of IL-10 can suppress the development of disease for extended periods of time when injected locally within the periarticular tissue surrounding the ankle joints of mice with collagen type II-induced arthritis. Furthermore, we show that injection of an adenoviral vector carrying the IL-10 gene into a single paw can suppress development of arthritis in other, noninjected paws of the same individual. The systemic protection resulting from local gene therapy occurred in the absence of detectable levels of viral IL-10 in the serum. Circulating Ab levels to heterologous collagen were unaffected; however, treatment with viral IL-10 significantly suppressed the development of Abs to autologous mouse type II collagen. Thus, the treatment of a single joint by local delivery of the vIL-10 gene may protect multiple joints of the same individual while avoiding deleterious side effects often associated with systemic therapy.

Adenoviridae↗
PubMed1999

[Investigations on the fermentation quality of silage from low-nitrate green forage].

In 3-year-experiments green forage from Dactylis glomerata and Festuca species, produced by differentiated cutting frequencies, was ensiled under laboratory conditions. The forage was almost without nitrate. Because of the higher content of water-soluble carbohydrates the fermentability coefficients of Festuca species were above of Dactylis glomerata. The fermentability coefficients of both plant species were inferior in the second and third cut, even if the first cut was delayed until July. Despite of similar fermentability coefficients of the two plant species silages contained different amounts of lactic and butyric acid. The portion of lactic acid amounted to 52 to 57% and 60 to 73% of total acids, the proportion of butyric acid 30 to 35% and 18 to 25% for Dactylis glomerata and Festuca species, respectively. According to the high fermentability coefficients silages free of butyric acid would be expected, however, by both species butyric acid always was formed, in some cases at high concentrations. In the contrary the amounts of ammonia, acetic acid and alcohol as well as the pH-value were almost extremely low. It can be concluded that the quality of silages produced of green forages with low nitrate cannot be assessed adequately by the current evaluation key.

Acetic Acid↗
PubMed1999

Varicella-zoster screening and management programs in healthcare facilities in Canada.

A 24-question survey on varicella-zoster screening programs and control measures for varicella-zoster infections was sent to 170 Canadian healthcare facilities. The results indicated that 60% of Canadian healthcare facilities have well-established preemployment varicella-zoster screening programs for healthcare workers. Overall, 30% of healthcare facilities impose work restrictions for susceptible healthcare workers, 49% use negative-pressure rooms for varicella-zoster management, and 28% have a policy to discharge susceptible exposed patients. Large variations exist among Canadian healthcare facilities in their varicella-zoster infection control policies.

Canada↗
PubMed1999

High-resolution structural analysis of chromatin at specific loci: Saccharomyces cerevisiae silent mating-type locus HMRa.

Genetic and biochemical evidence implicates chromatin structure in the silencing of the two quiescent mating-type loci near the telomeres of chromosome III in yeast. With high-resolution micrococcal nuclease mapping, we show that the HMRa locus has 12 precisely positioned nucleosomes spanning the distance between the E and I silencer elements. The nucleosomes are arranged in pairs with very short linkers; the pairs are separated from one another by longer linkers of approximately 20 bp. Both the basic amino-terminal region of histone H4 and the silent information regulator protein Sir3p are necessary for the organized repressive chromatin structure of the silent locus. Compared to HMRa, only small differences in the availability of the TATA box are present for the promoter in the cassette at the active MATa locus. Features of the chromatin structure of this silent locus compared to the previously studied HMLalpha locus suggest differences in the mechanisms of silencing and may relate to donor selection during mating-type interconversion.

Chromatin↗
PubMed1998

Development of a TEM to study in situ structural and chemical changes at an atomic level during gas-solid interactions at elevated temperatures.

A Philips (Eindhoven, The Netherlands) 430 (300 keV) high resolution transmission electron microscope has been modified for in situ study of gas-solid interactions at elevated temperatures. This microscope can be best described as a synthesis, processing, and characterization laboratory for nano-size materials. A differentially pumped environmental cell (E-cell), capable of handling up to 20 torr of gas pressure, is fitted in the objective lens pole-piece gap. Single-tilt or double-tilt heating holders can be used to heat the samples up to 1,300 degrees C and 850 degrees C, respectively. The system can handle any non-corrosive gases such as H2, O2, N2, NH3, CO, water vapor. Electron diffraction patterns are used to elucidate the reaction path and to identify stable and/or metastable phases formed. Time, temperature, and pressure resolved electron diffraction patterns can also be used to estimate the thermodynamical conditions for the onset of a reaction and the stability range of different phases observed during the process can also be determined. The high resolution imaging capabilities enable elucidation of the basic structural mechanisms involved at near atomic level. The TV rate camera/video recording system is used to measure the reaction rates (kinetics of the reaction). A post projector energy filter (Gatan Imaging Filter, GIF) is attached at the bottom of the microscope in order to filter the inelastic scattering from the gases/thick samples as well as to obtain energy filtered images (chemical maps). The GIF can also be used as a parallel electron energy loss spectrometer (PEELS) to obtain changes in the sample composition during the reactions. The changes in the near-edge structures of PEELS spectrum is used to monitor changes in bonding and/or chemical environment elements during reaction. The chemical maps obtained can also be used to identify preferred regions of gas reactions, e.g., grain boundaries or surfaces, etc. Various modifications of the microscope are described in detail, with suitable examples showing the performance.

Cerium↗
PubMed1998

Mcm1 regulates donor preference controlled by the recombination enhancer in Saccharomyces mating-type switching.

Switching of Saccharomyces mating type by replacement of sequences at the MAT locus involves a choice between two donors, HML and HMR. MATalpha cells inhibit recombination along the entire left arm of chromosome III, including HML, whereas MATa cells activate this same region. MATa-dependent activation of HML depends on a small, cis-acting DNA sequence designated the recombination enhancer (RE), located 17 kb centromere-proximal to HML. A comparison of RE sequences interchangeable between Saccharomyces cerevisiae and Saccharomyces carlsbergensis defines a minimum RE of 244 bp. RE activity is repressed in MATalpha cells by binding of the Matalpha2-Mcm1 corepressor to a site within the RE. Mutation of the two Matalpha2 binding sites removes most, but not all, of this repression, and RE chromatin structure in MATalpha cells becomes indistinguishable from that seen in MATa. Surprisingly, a 2-bp mutation in the Mcm1 binding site completely abolishes RE activity in MATa cells; moreover, RE chromatin structure in the MATa mutant becomes very similar to that seen in MATalpha cells with a normal RE, displaying highly ordered nucleosomes despite the absence of Matalpha2. Further, a mutation that alters the ability of Mcm1 to act with Matalpha2 in repressing a-specific genes also alters donor preference in either mating type. Thus, Mcm1 is critically responsible for the activation as well as the Matalpha2-Mcm1-mediated repression of RE activity.

Base Sequence↗
PubMed1998

Part I. A look at population-based medical care.

Recent trends toward managed health care have generated interest in developing strategies to manage the health care of a population as a whole. Population-based medicine places the individual patient within the context of the larger community, which is composed of both sick and well individuals; when viewed in these terms, only a small proportion of the people who consult a primary care physician are at risk for substantial morbidity. However, the physician serves as the central figure for delivering population-based health care to the entire community. Many strategies for population-based care contain the following 4 basic elements: 1. Identifying the health and disease states that are likely to be responsive to population-based care, 2. Applying principles of epidemiology to define the population-of-interest, 3. Assembling a multidisciplinary team, and 4. Building information systems to support ongoing surveillance of population-based care. To date, most of the published examples of population-based management have been conducted in managed care environments, but population-based management may also be used by a single physician practice or a small group practice. Programs aimed at health promotion or disease prevention are among the easiest to implement. By examining the results of an entire population with a given condition, physicians and their teams may begin to identify ways to improve the overall delivery of care, either by establishing new procedures or improving old ones.

Community Health Planning↗
PubMed1998

Primary renal mucormycosis.

Primary renal mucormycosis is a rare infection capable of acute illness with sepsis. Few cases have been reported. We report a case of an acute primary renal mucormycosis and review the published reports. The incidence of primary renal mucormycosis has risen in recent years. The most frequently reported underlying predisposing disorders are human immunodeficiency virus infection, intravenous drug abuse, and diabetes mellitus. Primary renal mucormycosis should be suspected in patients with an immunocompromising illness or particular risk factors, when persistent flank pain and fever with sterile urine not responding to appropriate antibiotics are associated with enlarged heterogeneous kidneys.

Acute Disease↗
PubMed1998

Trends in antibiotic resistance of staphylococci over an eight-year period: differences in the emergence of resistance between coagulase positive and coagulase-negative staphylococci.

The antimicrobial susceptibilities of 1058 Staphylococcus aureus and 2,163 coagulase-negative staphylococci (CNS) isolates obtained from clinical specimen between 1988 and 1995, were determined against 13 anti-staphylococcal antibiotics. During the study period the resistance of Staphylococcus aureus to ciprofloxacin, ceftazidime, and norfloxacin increased significantly by 7%, 4%, and 6%, respectively (p < or = 0.001). By comparison, the antibiotic resistance of CNS to ceftazidime, oxacillin, norfloxacin, ciprofloxacin, fusidic acid, and cefoxitin increased by 20%, 17%, 15%, 14%, 12% and 10%, respectively (p < or = 0.001). Invasive and noninvasive S. aureus had similar antibiotic resistance, whereas CNS invasive isolates were more resistant than noninvasive isolates to every antibiotics, except vancomycin and fusidic acid. These differences were significant (p < 0.001) for oxacillin, cefoxitin, and clindamycin. Our observations confirm that staphylococci and particularly CNS isolates show an important rate of increased resistance to the standard antimicrobials used for therapy, and that the rate of emergence of resistance differ considerably between coagulase-positive and coagulase-negative staphylococci.

Anti-Bacterial Agents↗
PubMed1998

Comparative activity of trovafloxacin and Bay 12-8039 against 452 clinical isolates of Streptococcus pneumoniae.

The principal aim of this study was to evaluate the in-vitro activity of new quinolones against clinical strains of Streptococcus pneumoniae. Four hundred and fifty-two single clinical isolates (of which 362 were susceptible to penicillin, 54 intermediate and 36 highly resistant) were tested against penicillin, cefuroxime, ciprofloxacin, levofloxacin, trovafloxacin and Bay 12-8039. Of the tested S. pneumoniae strains, 97.1 % had MICs of trovafloxacin of < or = 0.25 mg/L, and 96.7% had MICs of Bay 12-8039 of < or = 0.25 mg/L (difference not statistically significant); 81.9% of strains had MICs of cefuroxime of < or = 0.25 mg/L (P < or = 0.001 against both quinolones). Only 4% and 0.7% of the strains had MICs of levofloxacin and ciprofloxacin respectively of < or = 0.25 mg/L. Compared with older quinolones, trovafloxacin and Bay 12-8039 have good in-vitro activity against S. pneumoniae.

Anti-Infective Agents↗
PubMed1998

Diagnostic validity of pulmonary artery catheterization for residents at an intensive care unit.

OBJECTIVE: To assess the amount of additional information provided by measurements derived from pulmonary artery catheter (PAC) use beyond that derived from clinical evaluation by intensive care residents. METHODS: One hundred forty-nine consecutive patients undergoing right-heart catheterization were prospectively included in the study. Before inserting a PAC, physicians had to predict pulmonary arterial pressure (PAP), pulmonary capillary wedge pressure (PCWP), systemic vascular resistance index (SVRI), cardiac index (CI), mixed venous oxygen saturation (SvO2), oxygen delivery (DO2), oxygen consumption (VO2), and pulmonary shunt fraction (Qs/Qt) by selecting a given option on a questionnaire. Ranges of options were chosen to create clear clinical differences among them. RESULTS: The correct value was predicted in a median of 50% of cases (range, 45-63%). PAP was predicted correctly in 55%, PCWP in 46%, SVRI in 63%, CI in 62%, SvO2 in 45%, DO2 in 45%, VO2 in 51%, and Qs/Qt in 51%. A significant difference was found between estimated and measured values for all parameters (p < 0.01). No significant differences were detected between more and less experienced physicians. There was no significant difference between estimated and measured values with respect to the different courses of intensive care unit admissions or the different indications for PAC insertion. CONCLUSION: In a selected group of critically ill patients, the PAC adds valuable and clinically relevant information to clinical assessment in about 50% of cases. Its use should not be withheld in patients with unclear hemodynamic and metabolic profiles.

Catheterization, Swan-Ganz↗
PubMed1998

Patient-provider communication during the emergency department care of children with asthma. The National Cooperative Inner-City Asthma Study, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD.

OBJECTIVES: Poor children's reliance on emergency facilities is one factor implicated in the rise of morbidity attributed to asthma. Although studies have examined doctor-patient communication during routine pediatric visits, little data are available about communication during emergency care. This study sought to describe communication during emergency treatment of childhood asthma to learn if a "patient-centered" provider style was associated with increased parent satisfaction and increased parent and child participation. METHODS: This cross-sectional, observational study examined 104 children aged 4 to 9 years and their guardian(s) attending emergency departments in seven cities. Quantitative analysis of provider-family dialogue was performed. Questionnaires measured satisfaction with care, provider informativeness, and partnership. RESULTS: Providers' talk to children was largely supportive and directive; parents received most counseling and information. Children spoke little to providers (mean: 20 statements per visit versus 156 by parents). Providers made few statements about psychosocial aspects of asthma care (mean: three per visit). Providers' patient-centered style with parents was associated with more talk from parents and higher ratings for informativeness and partnership. Patient-centered style with children was associated with five times the amount of talk from children and with higher parent ratings for "good care," but not for informativeness or partnership. CONCLUSIONS: Communication during emergency asthma care was overwhelmingly biomedical. Children took little part in discussions. A patient-centered style correlated with increased parent and child participation, but required directing conversation toward both parents and children.

Asthma↗
PubMed1998

Perspectives on genetic aspects of dental patterning.

Nearly a century of speculation and experimentation has gone into trying to understand the mechanisms that establish the pattern of the differentiated heterodont dentition. Regionally differing qualitative (combinatorial) expression of regulatory genes appears to be involved in this process. Work by our laboratory and others shows that the six members of the mammalian Dlx family of homeobox genes are expressed (a) at multiple times during dental development, (b) differently at different stages, (c) in a way that is related to their genomic organization as gene-pairs linked to three of the four Hox clusters of positional patterning genes. The expression appears to be involved in jaw regionalization, tooth initiation, and tooth development. However, this expression correlates with no single aspect of dental patterning or tooth development, involves redundant and complementary function, and developmental differences between the maxillary and mandibular dentition suggest that other elements remain to be identified. For example, the possibility that quantitative aspects of gene expression specify developmental fields in the dentition has not yet been investigated. Although the maxilla and mandible develop differently, indirect evidence suggests that, especially in the future midline (incisor) regions, both jaws may be patterned by a consistent process that occurs before neural crest migration takes place, and we hypothesize that signaling factors like Sonic hedgehog and Pax transcription factors may be involved.

Animals↗