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Biomedical subjects

L Petersen

Publications and source records attributed to L Petersen.

At least 19 recordsLinked to original sources
PubMed1999

[Pacemaker failure in elective DC cardioversion of atrial tachycardia].

A 74-year-old woman with a VVI-rate-responsive pacemaker (Pacesetter 2033K; unipolar pacing electrode) was admitted for cardioversion of atrial tachycardia. Antiarrhythmic medication included flecainide 100 mg x 2. Electrical defibrillation was followed by transient, but severe nodal bradycardia and pacemaker malfunction characterized by loss of ventricular capture and sensing. The incident probably represents an example of pacemaker failure due to an acute increase in the stimulation threshold, most likely caused by current-induced tissue damage at the electrode-endomyocardial interface. Flecainide might have contributed to the increase in stimulation threshold. The clinician should be prepared for the possible consequences of pacemaker failure after external defibrillation.

Aged↗
PubMed1999

Quality of life of African-American and white long term breast carcinoma survivors.

BACKGROUND: Increasingly, the quality of life (QOL) of women diagnosed with breast carcinoma is being studied. However, there is little information regarding long term survivors among ethnic minority women. The purpose of this study was to describe the QOL of long term breast carcinoma survivors (BCS) and to examine the role of ethnicity in influencing their well-being. METHODS: The authors conducted a mailed survey to examine QOL, health perceptions, and life stress among long term BCS. Subjects diagnosed between 1989 and 1990 were identified among respondents to a prior study who were originally recruited from the California Tumor Registry. This survey instrument included standard measures of QOL (e.g., the RAND SF-36 Health Perceptions Scale, the Cancer Rehabilitation and Evaluation Survey-Short Form [CARES-SF], and the Ladder of Life) and new items. RESULTS: Two hundred and seventy-eight women participated; 117 were African-American, and 161 were white. The initial univariate evaluation of the CARES-SF and the RAND SF-36 Health Perceptions Scale suggested potential ethnicity-related differences in QOL. To control for various medical and demographic characteristics and to examine the potential relation between ethnicity and QOL, multiple regression analyses were conducted. The final model accounted for 45% (R-square = 0.450) of the variance in QOL with general health perception, life stress, income, partnership status, and comorbid conditions included in the model. CONCLUSIONS: The results of this study suggest that, overall, BCS report favorable health-related QOL. Differences in QOL outcomes are attributable to socioeconomic and life-burden factors and not to ethnicity.

Adult↗
PubMed1999

Community-wide outbreak of enteroviral illness caused by echovirus 30: a cross-sectional survey and a case-control study.

BACKGROUND: In June, 1997, 21 children from a single community in Germany were hospitalized with aseptic meningitis. An epidemiologic investigation was conducted to determine the extent of the outbreak and risk factors for illness. METHOD: The extent of the outbreak was assessed with a cross-sectional survey of every 10th child listed in the town register among the 2240 town children < 16 years old. A case-control study determined risk factors for illness. Sixty-two cases were identified through the cross-sectional survey from hospitalized persons and from persons seen by local physicians. Controls were 114 asymptomatic persons identified from the cross-sectional survey. RESULTS: The overall attack rate was 16%, with the highest attack rates (24%) among the 6- to 8-year olds. Onsets occurred during a 37-day period. Among the 2240 town children <16 years of age, an estimated 353 met the case definition for enteroviral illness, 168 visited a doctor and 21 were hospitalized. Data from the case-control study indicated that contact with an ill household member [odds ratio (OR) = 6.3; 95% confidence interval (CI) 2.6 to 15.5], day-care attendance (OR = 2.6; 95% CI 1.1 to 6.2) and playground use, either two to three times per week (OR = 3.7; 95% CI 1.3 to 10.2) or daily (OR = 4.3; 95% CI 1.6 to 11.3), were risk factors for illness. CONCLUSION: Echovirus 30 caused substantial morbidity during this community outbreak caused by person-to-person spread. Household contacts, day-care centers and playgrounds were prominent risk factors for transmission.

Adolescent↗
PubMed1998

Toward a better understanding of health-related quality of life: a comparison of the Medical Outcomes Study HIV Health Survey (MOS-HIV) and the HIV Overview of Problems-Evaluation System (HOPES).

Although enthusiasm for measuring health-related quality of life (HRQL) in clinical trials exists, information is limited on the meaning of scores. We examined the relation between scores from the 34-item Medical Outcomes Study HIV Health Survey (MOS-HIV) and the more detailed HIV Overview of Problems-Evaluation System (HOPES) using the responses of 318 HIV-infected outpatients being treated in Los Angeles and Baltimore. With the HOPES problem statements as independent variables, statistically significant predictors of the variation in MOS-HIV scores for the Physical Function, Mental Health, and Energy/Fatigue scales were identified using stepwise regression. Approximately 60% to 70% of the variation in each of the scores was explained by five to seven different HOPES problem statements, with a single item explaining 47% to 59% of the variation. We created illustrative profiles for each of the three MOS-HIV scales using the HOPES items identified in the regressions. Independent of the scale, persons scoring in the top MOS-HIV quartile tended to report few if any problems, whereas a decline in score to the next quartile was characterized by functional difficulties (e.g., "HIV interferes with work"). The onset of specific problems might trigger further evaluation and potential intervention from health care providers to help maintain patient functioning.

Acquired Immunodeficiency Syndrome↗
PubMed1998

An outbreak of sheep-associated Q fever in a rural community in Germany.

In spring 1996, an outbreak of Q fever occurred among residents of a rural town (population: 300) in Germany. A retrospective cohort study was conducted to ascertain the extent of the outbreak and to assess potential risk factors for illness. In July 1996, all residents > or =15 years received a self-administered questionnaire and were offered Coxiella burnetii antibody testing. Residents were considered to have probable Q fever if they had a positive result for IgM C. burnetii antibodies by ELISA or possible Q fever if they had fever > or =39 degrees C lasting >2 days and > or =3 symptoms (chills, sweats, severe headache, cough, aching muscles/joints, back pain, fatigue, or feeling ill) after 1 January 1996. Two hundred (84%) of the 239 residents aged > or =15 years either completed the questionnaire or submitted blood for antibody testing. Forty-five (23%) of these 200 met the probable or possible case definitions. Onsets of illness occurred in January-June 1996. Cases were geographically distributed throughout the town. Persons reporting contact with sheep (32% vs 18%, RR: 1.8, 95% CI: 1.1-2.9) and walking near a large sheep farm located next the town (34% vs 8%, RR: 4.5, 95% CI: 1.7-12.2) were more likely to have met the case definition than those without these exposures. Fifteen of 20 samples from the large sheep flock were positive for C. burnetii antibodies. The sheep had lambed outdoors in December 1995-January 1996 while the weather was extremely dry. The timing of the outbreak after lambing, the uniform distribution of cases throughout the town and the absence of risk factors among most case-persons suggest airborne transmission of C. burnetii from the large sheep farm.

Adolescent↗
PubMed1998

Modality interactions of speech and signing in simultaneous communication.

This study addresses speech and signing interaction during simultaneous communication (SC). Productions of sentence stimuli by ASL-English bilinguals (CODAs) and signed English (SE) users who know no ASL (SIMCOMs) were compared in two conditions (speech-alone or signing-alone, speech and signing combined). Speech took longer combined than alone, whereas SE took longer alone than combined. The increased duration of speech-combined resulted from increased syllable duration, number of gaps, and gap duration. Rate of signing had a significant effect on speech duration. The decreased duration of signed sentences combined resulted from decreased sign duration, decreased gap duration, and increased sign omissions. Knowledge of ASL was reflected in qualitative differences between the two groups. Sign omissions were analyzed by grammatical category; these are discussed in terms of context-supported permissible deletions and the compensatory use of ASL nonmanual marking devices.

Adult↗
PubMed1998

Normalization of serum thyrotrophin by means of radioiodine treatment in subclinical hyperthyroidism: effect on bone loss in postmenopausal women.

BACKGROUND: Patients with subclinical hyperthyroidism (reduced serum TSH and normal free T4 and T3 concentrations) have slightly increased bone turnover and might have reduced bone mass, especially among postmenopausal women (due to concomitantly reduced oestrogen production), as also seen during suppressive L-T4 treatment. OBJECTIVE: We have evaluated whether normalization of serum TSH using radioiodine treatment (RAI) in postmenopausal women with a nodular goitre and subclinical hyperthyroidism, protects against bone loss? DESIGN: Prospective, non-randomized study, outpatients 2 years follow-up. PATIENTS: Postmenopausal women with a nodular goitre, biochemically subclinical hyperthyroidism (TSH < 0.2 mU/I, and signs of a growing goitre or compression symptoms. Sixteen were treated with RAI (median dose 555 MBq) (+RAI), whereas 12 were followed without treatment (-RAI). MEASUREMENTS: Serum TSH (third generation technology), free T4 and T3 indices, and bone mass (BMD) as measured by Dual Photon Absorptiometry (4 in each group) (only spine) or Dual X-ray Absorptiometry (DEXA) (both spine and hip), were measured yearly for up to 2 years. RESULTS: The two groups did not differ regarding age, thyroid hormone parameters, and absolute levels of BMD at spine and hip. RAI resulted in normalization of TSH in all 16 women, and FT4I as well as FT3I decreased to 78% after one year (P < 0.01). These parameters did not change in the untreated group, thus serum TSH remained reduced. BMD at the spine tended to increase (n.s.) after RAI to (median) 101.9% after one year, and 101.5% after 2 years. In contrast the -RAI group experienced a continued fall in BMD to 97.3% after one year, and 95.5% after 2 years, both reduced as compared to the +RAI group (P < 0.02). BMD of the hip also increased after RAI, to 102.3% after one year, and 101.7% after 2 years. In contrast BMD in the -RAI group decreased to 94.8% after one year, and 98.0% after 2 years, both lower than in the +RAI group (P < 0.01). CONCLUSIONS: Subclinical hyperthyroidism due to a nodular goitre in postmenopausal women resulted in a continued loss of bone mass of about 2% per year. Radioiodine treatment resulting in normalization of serum TSH prevented this continued bone loss for at least 2 years. Our study supports earlier intervention in such patients.

Aged↗
PubMed1998

Subbandage pressure measurements comparing a long-stretch with a short-stretch compression bandage.

Forty-three patients with venous leg ulcers were randomized into treatment with either a long- or a short-stretch compression bandage. Subbandage pressure was regularly measured during rest and walking for a period of up to 1 year. The long-stretch bandage was kept on as long as possible, often up to 1 week. It maintained a significantly higher subbandage pressure in the upright position and during passive dependency as well as during walking than the short-stretch bandage after both 2 and 24 h. The difference between maximum and minimum subbandage pressures during walking did not differ between the two groups. Thus, in contrast to general opinion, the short-stretch bandage did not produce a higher peak working pressure than the long-stretch bandage. The pressure decreased in the supine position in both groups.

Bandages↗
PubMed1997

Solution structure and backbone dynamics of the human alpha3-chain type VI collagen C-terminal Kunitz domain,.

The solution structure and backbone dynamics of the 58-residue C-terminal Kunitz domain fragment [alpha3(VI)] of human alpha3-chain type VI collagen has been studied by two-dimensional 1H-1H and 1H-15N nuclear magnetic resonance spectroscopy at 303 K. The solution structure is represented by an ensemble of 20 structures calculated with X-PLOR using 612 distance and 47 dihedral angle restraints. The distance restraints were obtained by a complete relaxation matrix analysis using MARDIGRAS. The root mean squared (rms) deviation is 0.91 A for the backbone atoms of the residues Thr2(8)-Gly12(18), Arg15(21)-Tyr35(41), and Gly40(46)-Pro57(63). The central beta-sheet [residues Ile18(24)-Tyr35(41)] and the C-terminal alpha-helix [residues Gln48(54)-Cys55(61)] are better defined with a backbone rms deviation of 0.46 A. The solution structure of alpha3(VI) is virtually identical to the crystal structure of alpha3(VI) and to the solution structure of bovine pancreatic trypsin inhibitor (BPTI). The 15N spin-lattice and spin-spin relaxation rates and the 1H-15N heteronuclear nuclear Overhauser enhancement (NOE) were analyzed using both the "model-free" formalism [Lipari, G., & Szabo, A. (1982) J. Am. Chem. Soc. 104, 4546-4559 and 4559-4570] and the reduced spectral density mapping procedure [Farrow, N. A., Szabo, A., Torchia, D. A., & Kay, L. E. (1995) J. Biomol.NMR 6, 153-162]. The results obtained from the "model-free" analysis include an overall correlation time tauc of 3. 00 ns and backbone order parameters S2 in the range from 0.28 to 0. 93. The necessity of including an exchange term in the analysis of the relaxation data from 14 residues indicated that these residues are involved in motions on the micro- to millisecond time scale. The majority of the 14 residues are located in the vicinity of the Cys14(20)-Cys38(44) disulfide bond, suggesting the presence of a disulfide bond isomerization similar to the one observed in BPTI [Otting, G., Liepinsh, E., & Wüthrich, K. (1993) Biochemistry 32, 3571-3582]. It is suggested that this disulfide bond isomerization is the main reason for the surprisingly small effect on trypsin inhibition observed when Thr13(19) of alpha3(VI) is substituted with Pro.

Amino Acid Sequence↗
PubMed1997

Giant Friedel Oscillations on the Beryllium(0001) Surface

Large-amplitude electron density oscillations were observed on a Be(0001) surface by means of variable-temperature scanning tunneling microscopy. Fourier transforms of the images showed a ring of radius 2kF, where kF is the Fermi wave vector of the Be(0001) surface state. This wavelength was expected from Friedel oscillations caused by electronic screening of surface defects, but the amplitude of the waves for energies near the Fermi energy was anomalously large and inconsistent with the Friedel concept of screening. The enhanced amplitude of the waves must be a many-body effect, either in the electron gas (possibly an incipient charge density wave) or in the response of the lattice (electron-phonon coupling).

Journal Article↗
PubMed1997

A comparison of EF-18 agar and modified brilliant green agar with lutensit for isolation of Salmonella from poultry samples.

Two selective plating media were compared to determine their performance in a three-step protocol for isolation of Salmonella from faecal, litter, and fluff samples. The enrichment protocol consisted of: 1) Preenrichment in buffered peptone water (BPW), 2) Selective enrichment in Rappaport-Vassiliadis broth, and 3) Plating onto EF-18 agar and BGA/L simultaneously. From a total of 1101 samples, Salmonella was isolated from 158, 157 of which were faecal samples. Thirty-one of these isolates were recovered on one medium only, 18 could not be found on BGA/L and 13 could not be found on EF-18 agar. The relative specificity and sensitivity of each plating agar was determined by enumeration of false-positive and false-negative reactions. EF-18 agar compared favourably with BGA/L, displaying a sensitivity of 0.92 as opposed to 0.89 for BGA/L, calculated for the "fecal samples" group only. The calculated specificities for each group of samples were likewise considerably higher for EF-18 agar (0.75-0.91) than for BGA/L (0.35-0.55). Though EF-18 agar is slightly more expensive than BGA/L, the routine use of the former may result in a considerable reduction in overall laboratory costs due to its superior selectivity. On the other hand the combination of the 2 media clearly would reduce the number of false negative results, with little extra cost.

Agar↗
PubMed1996

Breast cancer survivors: psychosocial concerns and quality of life.

PURPOSE: To describe the psychosocial concerns and quality of life of breast cancer survivors evaluated 2 and 3 years after primary treatment. METHODS: A sample of 139 breast cancer survivors who had been interviewed during the first year after primary treatment participated in a mailed survey at 2 years (N = 69) and 3 years (N = 70) after initial surgery. A random sample of these survivors were also interviewed in person. The mailed questionnaire included standardized instruments to assess quality of life (QL), rehabilitation needs, and psychological distress. Additional survey questions were developed to examine post-surgical recovery, employment and insurance problems, social support, and existential concerns. The in-person interviews expanded on these questions and systematically compared these patients' rehabilitation needs to those which existed at the time of an interview 1 year after surgery. RESULTS: The 2 and 3 year participants in this follow-up study did not differ from each other on their prior assessments with standardized QL instruments during the first year after surgery, nor did they differ from the full study sample of 227 women. The scores on the Profile of Mood States and the Functional Living Index-Cancer were the same for the 2 and 3 year survivor groups and did not differ from the previous assessments at 1 year after initial treatment. The scores on the Cancer Rehabilitation Evaluation System showed a significant decline in Global Quality of Life, Sexual Functioning and Marital Functioning between the 1 year and 3 year evaluations. For the 2 year sample only Sexual Functioning showed a deterioration between the 1 and 2 year evaluations. Using the RAND 36-Item Health Survey 1.0, the breast cancer survivors were compared with patients from the Medical Outcomes Study. The breast cancer survivors demonstrated higher levels of functioning in many dimensions (role functioning, social functioning, pain, and general health) than the patients with chronic medical conditions. In spite of relatively good physical and emotional functioning on this generic measure of health status and quality of life, these breast cancer survivors reported a number of important and severe rehabilitation problems that persisted beyond one year after primary treatment. Especially frequent were problems associated with physical and recreational activities, body image, sexual interest, sexual function, and problems with dating for those who were single. CONCLUSIONS: Breast cancer survivors appear to attain maximum recovery from the physical and psychological trauma of cancer treatment by one year after surgery. A number of aspects of QL and rehabilitation problems worsen after that time. Nevertheless, breast cancer survivors rate their QL more favorably than outpatients with other common medical conditions, and they identify many positive aspects from the cancer experience.

Adaptation, Psychological↗
PubMed1996

Genetic analysis of metabolic crosstalk and its impact on thiamine synthesis in Salmonella typhimurium.

The first five steps in de novo purine biosynthesis are involved in the formation of the 4-amino-5-hydroxymethyl-2-methyl pyrimidine (HMP) moiety of thiamine. We show here that the first enzyme in de novo purine biosynthesis, PurF, is required for thiamine synthesis during aerobic growth on some but not other carbon sources. We show that PurF-independent thiamine synthesis depends on the recently described alternative pyrimidine biosynthetic (APB) pathway. Null mutations in zwf (encoding glucose-6-dehydrogenase), gnd (encoding gluconate-6-P dehydrogenase), purE (encoding aminoimidazole ribonucleotide carboxylase), and purR (encoding a regulator of gene expression) were found to affect the function of the APB pathway. A model is presented to account for the involvement of these gene products in thiamine biosynthesis via the APB pathway. Results presented herein demonstrate that function of the APB pathway can be prevented either by blocking intermediate formation or by diverting intermediate(s) from the pathway. Strong genetic evidence supports the conclusion that aminoimidazole ribotide (AIR) is an intermediate in the APB pathway.

Carboxy-Lyases↗
PubMed1996

Mutations in apbC (mrp) prevent function of the alternative pyrimidine biosynthetic pathway in Salmonella typhimurium.

The alternative pyrimidine biosynthetic (APB) pathway can synthesize the 4-amino-5-hydroxymethyl-2-methyl pyrimidine (HMP) moiety of thiamine in Salmonella typhimurium independently of de novo purine biosynthesis. When mutants defective in function of the APB pathway were isolated, the predominant class (40%) were defective in a single locus we have designated apbC. Mutations in apbC block function of the APB pathway since they prevent growth of a purF mutant in the absence of thiamine. Lesions in apbC also cause a thiamine auxotrophy in strains proficient in purine biosynthesis when fructose is provided as the sole carbon and energy source. Results presented here are consistent with ApbC being involved in the conversion of aminoimidazole ribonucleotide to HMP, and we suggest that ApbC performs a redundant step in thiamine synthesis. Sequence analysis demonstrated that apbC mutations were alleles of mrp, a locus previously reported in Escherichia coli as a metG-related protein. We propose that this locus in S. typhimurium be designated apbC to reflect its involvement in thiamine synthesis.

Alleles↗
PubMed1995

The 1.6 A structure of Kunitz-type domain from the alpha 3 chain of human type VI collagen.

The C-terminal Kunitz-type domain from the alpha 3 chain of human type VI collagen (C5), a single 58 amino acid residue chain with three disulfide bridges, was cloned, expressed and crystallized in a monoclonic form, space group P2(1), with a = 25.7 A, b = 38.2 A, c = 28.8 A and beta = 109 degrees. The structure was resolved by molecular replacement, using Alzheimer's protein precursor inhibitor and bovine pancreatic trypsin inhibitor three-dimensional structures as search models. The molecule with one sulfate ion and 43 associated water molecules was refined by XPLOR to an R-factor of 18.9% at 1.6 A. The molecule was not degraded by trypsin and did not inhibit trypsin or tested serine proteases. As opposed to the other Kunitz family members, C5 demonstrates left-handed chirality of the Cys14-Cys38 disulfide bond. Inversion of the Thr13 carbonyl and bulky side-chains at the interface with trypsin in a model of the C5-trypsin complex may explain the lack of inhibition of trypsin.

Amino Acid Sequence↗
PubMed1995

Human immunodeficiency virus seroprevalence in community-based primary care practices, 1990-1992. A report from the Ambulatory Sentinel Practice Network.

OBJECTIVE: To estimate the seroprevalence of human immunodeficiency virus type 1 (HIV-1) infection in primary care practices. METHODS: Fifty-four practices in the United States participated in an anonymous, unlinked HIV seroprevalence study between January 1990 and December 1992. Residual blood samples drawn for routine clinical tests from patients 15 to 49 years of age were centrally tested for the HIV-1 antibody for 1 month of each quarter. Information about patient demographics, clinician-recognized risk factors, the known HIV status of the patient, and whether the blood was drawn for HIV testing was recorded with each specimen. RESULTS: Of 21,998 specimens collected, 99 (0.45%) were seropositive. Of these 99 seropositive persons, 31.3% (a seroprevalence of 0.15%) were not suspected by their clinicians of being infected with HIV. Seroprevalences in men (0.96%) exceeded those in women (0.22%), and rates in rural practices (0.18%) were lower than in urban practices (0.71%). Among patients with unsuspected HIV infection, however, the gender differences, especially in rural areas, were less pronounced. Risk factors for HIV infection were infrequently noted. There was an increase in the overall seroprevalence during the 1990 to 1992 study period (0.36% to 0.53%); however, this trend was not statistically significant. CONCLUSIONS: Within a 3-year period, clinicians in at least two of five primary care practices can expect to encounter patients infected with HIV, regardless of practice location. Also, nearly one third of the patients with HIV infection will not be suspected of having this condition by their clinician.

Adolescent↗
PubMed1994

[Causes of relapse during attempted smoking cessation using nicotine or placebo plasters].

The causes of relapses to smoking when attempting smoking cessation are not fully understood, but several factors are of importance. Addiction to nicotine is one of the most prominent factors. In order to determine predictors of outcome in smoking cessation, we performed univariate and multivariate analysis of a large smoking cessation trial comprising 289 subjects. Weight gain and withdrawal symptoms were analyzed separately as predictors. To determine the relative magnitude of self-perceived reasons for relapse we created a questionnaire, which was answered by 132 relapsers. Previous attempts to stop smoking and a low Horn-Russell scale were significantly associated with abstinence in the nicotine-treated group. A trend towards higher abstinence rates was found in males and in subjects with low smoking saliva cotinine levels. A logistic regression analysis showed higher success rates in subjects with the largest weight gain during the first week but there was a tendency towards higher relapse rates in subjects with the greatest weight gain later. Only 20% reported weight gain to be a major problem. Minor smoking was highly correlated to later relapse. The weight gain after smoking cessation should not be prevented in the first weeks after cessation. Complete abstinence should be emphasized in smoking cessation.

Administration, Cutaneous↗