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Biomedical subjects

T Bauer

Publications and source records attributed to T Bauer.

At least 55 records · Page 3Linked to original sources
PubMed2001

Welfare reform and the perinatal health and health care use of Latino women in California, New York City, and Texas.

OBJECTIVES: This study analyzed changes in the financing of prenatal care and delivery, the use of prenatal care, and birth outcomes among foreign-born vs US-born Latino women following enactment of the Personal Responsibility and Work Opportunity Reconciliation Act (PRWORA) in August 1996. METHODS: We used a pre-post design with a comparison group. The sample consisted of resident Latinas in California, New York City, and Texas who delivered a live infant in 1995 or 1998. RESULTS: The proportion of births to Latinas that initiated prenatal care in the first 4 months of pregnancy increased for all foreign-born Latinas in California, New York City, and Texas between 1995 and 1998 (P <.05). Except for non-Dominicans in New York City, there was no increase in the proportion of low- or very-low-birthweight births among foreign-born vs US-born Latinas in the 3 localities between 1995 and 1996. CONCLUSIONS: There is little evidence from vital statistics in California, New York City, and Texas that PRWORA had any substantive impact on the perinatal health and health care utilization of foreign-born relative to US-born Latinas.

California↗
PubMed2001

Preclinical evaluation of motexafin lutetium-mediated intraperitoneal photodynamic therapy in a canine model.

Intraperitoneal photodynamic therapy (IP PDT) is an experimental cancer treatment in clinical development for the treatment of peritoneal carcinomatosis and sarcomatosis. A canine study of motexafin lutetium (Lu-Tex)-mediated IP PDT was performed to evaluate normal tissue toxicities of this treatment in the presence and absence of a bowel resection and to assess the feasibility of measuring Lu-Tex fluorescence in abdominal tissues. Thirteen dogs were treated with Lu-Tex (0.2-2 mg/kg) i.v. 3 h before laparotomy and 730-nm light delivery (fluences, 0.5-2.0 J/cm2; average fluence rate <150 mW/cm2). Laparoscopy was performed 7-10 days after the procedure to assess acute toxicities. In situ fluorescence spectra were obtained from various abdominal tissues before and after light delivery using a fiber array probe with fixed-source detector distances. Lu-Tex-mediated IP PDT was well tolerated at the doses of drug and light studied. Bowel toxicity was not observed in animals treated with a bowel resection before PDT. Mild transient liver function test abnormalities without associated clinical sequelae were observed. No gross PDT-related abnormalities were observed at laparoscopy or necropsy; however, thickening in the glomerular capillary wall and the mesangium were noted microscopically in the kidneys of seven dogs. No renal function abnormalities were found. Analysis of the fluorescence spectra from intra-abdominal tissues suggests that measurements of Lu-Tex in situ are feasible and may provide a way of assessing photosensitizer concentration in vivo without the need for a biopsy. These results support the continued development of Lu-Tex as a candidate photosensitizer for IP PDT.

Abdomen↗
PubMed2001

[Diagnosis and differential diagnosis of bronchial asthma].

Asthma and COPD (chronic obstructive pulmonary disease) are the most important obstructive pulmonary diseases. Patient's history and physical evaluation give major hints of the underlying disease. Further diagnostic measures comprise lung function analysis including spirometry, plethysmography and--in severe cases--blood gas analysis. Bronchial hyperreactivity may be quantified with an unspecific inhalative provocation test. In many cases allergic diseases are accompanied by asthma. Thus, allergy tests--particularly skin prick tests--have to be carried out. To further define an underlying allergy, in some cases even specific inhalative provocation tests have to be performed. X-ray of the thorax and other imaging techniques, detailed blood analysis, further diagnosis of the upper respiratory tract and the cardiac system may have to be carried out a) to quantify the effects of a severe form of asthma or COPD on other organs, and b) for differential diagnostic examinations.

Asthma↗
PubMed2000

The influence of hormone replacement therapy (HRT) on serum leptin concentration in postmenopausal women.

OBJECTIVE: This study aimed to evaluate the influence of hormone replacement therapy (HRT), the estradiol concentration and body mass index (BMI, kg/m(2)) on the serum leptin concentration in postmenopausal women. SUBJECTS AND METHODS: 352 healthy postmenopausal women (mean age, 60.9 +/- 8.5 years) participated in this comparative study. 71 (30%) women (mean age 55.9 +/- 8.3 years) had taken HRT, while 281 (70%) women (mean age, 59.1 +/- 10.6 years) had not. Baseline characteristics -age, weight, height, BMI (greater than or = 25 or <25), follicle stimulating hormone, estradiol, and leptin values-were compared in the two groups. In a second analysis to evaluate the influence of HRT, estradiol concentrations, and BMI on leptin concentrations, these data were analysed in women allocated to one of four groups: (a) postmenopausal women not on HRT with a BMI <25 (n = 130); (b) postmenopausal women not on HRT with a BMI greater than or = 25 (n = 151); (c) postmenopausal women on HRT with a BMI<25 (n = 48); and (d) postmenopausal women on HRT with a BMI greater than or = 25 (n = 23). Leptin concentrations were subsequently analysed in relation to BMI and age and BMI and estradiol concentrations to determine any independent effect of these variables. RESULTS: The women taking HRT had a significantly lower mean age, weight, BMI and follicle stimulating hormone concentration than those who were not taking HRT. Furthermore, they had a higher mean height and serum estradiol value, but a significantly lower serum leptin concentration. After controlling for BMI, neither the use of HRT nor the estradiol concentration was found to be related to the leptin value (group (a) versus (c) and group (b) versus (d)), but there were significant differences in leptin concentrations between HRT users with BMI greater than or = 25 and BMI <25 and between women not taking HRT with BMI greater than or = 25 and BMI <25 (groups (a) versus (b) and (c) versus (d)). Furthermore, women with a BMI greater than or = 25 had significantly higher leptin concentrations than women with a BMI<25, irrespective of the HRT use. CONCLUSIONS: Leptin concentrations are significantly higher in obese postmenopausal women than in their non-obese counterparts. Serum leptin concentrations are not influenced by HRT use or estradiol concentrations. Further studies are needed to elucidate the role of HRT and estrogen on serum leptin concentrations.

Age Distribution↗
PubMed2000

Median nerve injury caused by missed foreign body. Case report.

A 56-year-old woman sustained a delayed median nerve division after a penetrating injury of the right wrist by a piece of wood had gone unnoticed. There was no neurological damage at the time of the injury. The foreign body spread the median nerve apart, which subsequently reduced the sensitivity in the index finger. Removal of the wood resulted in complete recovery.

Diagnostic Errors↗
PubMed2000

Gastrocnemius myotendinous flap for patellar or quadriceps tendon repair, or both.

The authors' experience with simultaneous reconstruction of the quadriceps femoris or patellar tendon or both and soft tissue defect using a musculotendinous unit of the gastrocnemius muscle is presented. Five patients with a partial or complete defect of the quadriceps or patellar tendon or both and additional large soft tissue defects underwent reconstruction applying this technique as a one-stage surgical procedure in different variations. In cases with a partial defect of the tendon or loss of tendon thickness, the thick aponeurosis from the deeper aspect of the gastrocnemius was dissected and transferred as a pedicled tendon flap to reconstruct the tendon defect. In cases with a complete defect of the tendon, the superficial layer of the Achilles tendon together with the deep aponeurotic layer of the gastrocnemius muscle served to reconstruct the tendon. In both procedures the gastrocnemius muscle belly provided soft tissue coverage and was covered with a split thickness skin graft. One patient had a marginal deep necrosis develop that had to be covered with the other gastrocnemius muscle in a second operation. One patient with chronic polyarthritis and infection of his knee prosthesis declined additional reconstruction surgery and had the leg amputated. The average followup was 3.5 years. All patients achieved good results in active extension of the knee with an extension deficit of only 5 degrees to 15 degrees. The range of flexion was at least 90 degrees. The surgical technique described in this report provides functional tendon reconstruction and adequate soft tissue repair simultaneously.

Adolescent↗
PubMed2000

High genetic variability of the group-specific a-determinant of hepatitis B virus surface antigen (HBsAg) and the corresponding fragment of the viral polymerase in chronic virus carriers lacking detectable HBsAg in serum.

Chronic carriers of hepatitis B virus (HBV) usually show hepatitis B surface antigen (HBsAg) in their sera, which is considered the best marker for acute and chronic HBV infection. In some individuals, however, this antigen cannot be detected by routine serological assays despite the presence of virus in liver and peripheral blood. One reason for this lack of HBsAg might be mutations in the part of the molecule recognized by specific antibodies. To test this hypothesis, the HBV S gene sequences were determined of isolates from 33 virus carriers who were negative for HBsAg but showed antibodies against the virus core (anti-HBc) as the only serological marker of hepatitis B. Isolates from 36 HBsAg-positive patients served as controls. In both groups, a considerable number of novel mutations were found. In isolates from individuals with anti-HBc reactivity only, the variability of the major hydrophilic loop of HBsAg, the main target for neutralizing and diagnostic antibodies, was raised significantly when compared with the residual protein (22. 6 vs 9.4 mutations per 1000 amino acids; P<0.001) and with the corresponding region in the controls (22.6 vs 7.5 exchanges per 1000 residues; P<0.001). A similar hypervariable spot was identified in the reverse transcriptase domain of the viral polymerase, encoded by the same nucleotide sequence in an overlapping reading frame. These findings suggest that at least some of the chronic low-level carriers of HBV, where surface antigen is not detected, could be infected by diagnostic escape mutants and/or by variants with impaired replication.

Amino Acid Substitution↗
PubMed2000

Antimicrobial treatment failures in patients with community-acquired pneumonia: causes and prognostic implications.

The aim of the study was to determine the causes and prognostic implications of antimicrobial treatment failures in patients with nonresponding and progressive life-threatening, community-acquired pneumonia. Forty-nine patients hospitalized with a presumptive diagnosis of community-acquired pneumonia during a 16-mo period, failure to respond to antimicrobial treatment, and documented repeated microbial investigation >/= 72 h after initiation of in-hospital antimicrobial treatment were recorded. A definite etiology of treatment failure could be established in 32 of 49 (65%) patients, and nine additional patients (18%) had a probable etiology. Treatment failures were mainly infectious in origin and included primary, persistent, and nosocomial infections (n = 10 [19%], 13 [24%], and 11 [20%] of causes, respectively). Definite but not probable persistent infections were mostly due to microbial resistance to the administered initial empiric antimicrobial treatment. Nosocomial infections were particularly frequent in patients with progressive pneumonia. Definite persistent infections and nosocomial infections had the highest associated mortality rates (75 and 88%, respectively). Nosocomial pneumonia was the only cause of treatment failure independently associated with death in multivariate analysis (RR, 16.7; 95% CI, 1.4 to 194.9; p = 0.03). We conclude that the detection of microbial resistance and the diagnosis of nosocomial pneumonia are the two major challenges in hospitalized patients with community-acquired pneumonia who do not respond to initial antimicrobial treatment. In order to establish these potentially life-threatening etiologies, a regular microbial reinvestigation seems mandatory for all patients presenting with antimicrobial treatment failures.

Community-Acquired Infections↗
PubMed2000

The effect of long-term, non-suppressive levothyroxine treatment on quantitative ultrasonometry of bone in women.

OBJECTIVE: To evaluate the impact of long-term, non-suppressive levothyroxine (L-T(4)) treatment on quantitative ultrasonometry in women. DESIGN: This was a case-control study. SUBJECTS AND METHODS: Altogether 667 women (mean age+/-s.d., 49.5+/-13.1 years) were studied. Of these, 156 (23%) had non-toxic goitre or hypothyroidism and had been taking L-T(4) (75-100 microg/day) for at least 5 years (mean+/-s.d., 12.5+/-7.5 years); the remaining 511 (77%) women were not receiving L-T(4). All women had completed a questionnaire on risk factors for thyroid dysfunction and osteoporosis, and those with diseases or treatments known to effect bone metabolism - other than thyroxine or hormone replacement therapy (HRT) - were excluded. Women underwent quantitative ultrasonometry (QUS) at the heel. Speed of sound (SOS), broadband ultrasound attenuation (BUA) and the stiffness index (SI) were compared, first, in all women taking L-T(4) and controls and, secondly, in women taking L-T(4) and controls pair-matched for age, weight, body mass index (BMI), menopausal status and HRT use. RESULTS: Even after matching for age, weight, BMI, menopausal and HRT status, women taking L-T(4) had significantly lower values for SOS and SI (P<0.05), but not for BUA. However, absolute T- and Z-scores for SI were not low in either the study or control groups. Lower values were associated, but not significantly so, with years since the menopause and duration of L-T(4) treatment. CONCLUSIONS: Long-term, non-suppressive L-T(4) treatment in women with goitre or hypothyroidism was associated with a slight reduction in QUS values, which was more pronounced in postmenopausal women. This group could be at higher risk for osteoporotic fracture.

Adult↗
PubMed2000

The influence of menopause and body mass index on serum leptin concentrations.

OBJECTIVE: The aim of this study was to evaluate the influence of menopausal status, serum estradiol and body mass index (BMI) on serum leptin concentration in a large sample of pre- and postmenopausal women. DESIGN: 434 healthy women (mean age +/-s.d., 52.2 +/- 10.3 years) were recruited at the University of Marburg on the occasion of a routine gynecological visit. Two hundred and eighteen (50.2%) women were premenopausal (mean age, 36.5 +/- 10.4 years) and not on oral contraceptives or hormone replacement therapy (HRT) and 216 (49.8%) women were postmenopausal (mean age 61.8 +/- 8.9 years) not on HRT. To evaluate the influence of menopausal status, estradiol level and BMI on serum leptin concentrations, women were allocated to one of the four groups: (a) premenopausal women BMI <25 kg/m(2) (n=137), (b) premenopausal women BMI >25 kg/m(2) (n=81), (c) postmenopausal women BMI <25 kg/m(2) (n=94) and (d) postmenopausal women BMI >25 kg/m(2) (n=122). RESULTS: Irrespective of the menopausal status, women with a BMI >25 kg/m(2) had significantly higher leptin concentrations in all age groups compared with women with a BMI <25 kg/m(2) (P<0.001). The multiple linear regression analyses showed that BMI was the only statistically significant independent predictor for leptin. In comparison to postmenopausal women, premenopausal women showed a significantly lower mean age, weight, BMI and FSH concentration (P<0. 001), a higher mean height and serum estradiol (P<0.01 and P<0.001 respectively) but significantly lower serum leptin concentration (P<0.01). The multiple linear regression model showed no significant influence of menopausal status or serum estradiol on serum leptin concentration, even after controlling for BMI. CONCLUSIONS: Serum leptin concentrations are significantly higher in pre- and postmenopausal obese women, compared with normal weight controls. Serum leptin concentrations are not influenced by menopausal status or serum estradiol level.

Adult↗
PubMed1999

A novel deletion mutant of hepatitis B virus surface antigen.

HBsAg is the most important serological marker for acute or chronic hepatitis B. Nevertheless, there are reports of HBsAg-negative virus carriers, either with anti-HBc as the only marker for hepatitis B virus (HBV) infection or even positive for anti-HBs and anti-HBc. We report isolates from a patient, in which a deletion in the HBs-gene was associated with persisting viremia in the presence of anti-HBs. The 62-year-old female, infected most likely by her husband, had detectable markers of chronic active hepatitis B, such as HBsAg, HBeAg, and anti-HBc-IgM, for 2 years. The patient then seroconverted to anti-HBs, although HBeAg and anti-HBc-IgM remained detectable. At this time, semiquantitative polymerase chain reaction showed about 10(4) viral genomes per milliliter of serum. Direct sequencing of the amplified products revealed a major population of DNA molecules with a deletion of nucleotide 31 of the HBs-gene, which up to now has not been described. This deletion led to a frame-shift and introduced a stop-codon after 21 amino acids of the sHBsAg. We suspect that this deletion, and the resulting HBsAg lacking the major epitopes recognized by specific antibodies, could favor ongoing viral replication, despite the presence of anti-HBs. However, because the reading frame of the polymerase was also severely damaged by this deletion, it is assumed that a minor population of intact genomes was present to help in the formation of virus particles.

Amino Acid Sequence↗
PubMed1999

Comparative validation of prognostic rules for community-acquired pneumonia in an elderly population.

The aim of the study was to validate the prediction rule of M.J. Fine and coworkers for clinical outcome variables and three prognostic rules for the individual outcome of community-acquired pneumonia in an elderly population (rule 1: respiratory frequency > or =30 breaths x min(-1), diastolic blood pressure < or =60 mmHg, blood urea nitrogen >7 mM; rule 2: respiratory frequency > or =30 breaths x min(-1), diastolic blood pressure < or =60 mmHg, mental confusion; and rule 3: systolic blood pressure < or =80 mmHg, cardiac frequency > or =90 beats x min(-1), lactate dehydrogenase activity > or =260 IU x L(-1); death was predicted in the presence of at least two of three parameters). Overall 168 consecutive episodes of community-acquired pneumonia in patients aged > or =65 yrs and hospitalized in a primary care hospital were studied prospectively. Fine's rule was tested for its ability to predict length of hospital stay, requirement for intensive care unit (ICU) admission and death. For the three prognostic rules of individual outcome, performance regarding predicting death was determined. Mortality was 17/168 (10%). Fine's rule accurately predicted length of stay, the requirement for ICU admission and the risk of death from pneumonia as compared to the original derivation and validation cohorts. All three rules achieved moderate-to-high specificity (73%, 88% and 80%, respectively) and high negative predictive values (95%, 94% and 93%, respectively) but had a low sensitivity (65%, 47% and 47%, respectively). Rule 2 most closely reflected the risk of death from pneumonia when Fine's classification was used as reference. Fine's rule proved to give valid estimations regarding clinical outcome variables of community-acquired pneumonia in the elderly. The prognostic rules may be useful in determining individual patients at lower risk of death caused by pneumonia.

Aged↗
PubMed1999

Control of K+ channel gating by protein phosphorylation: structural switches of the inactivation gate.

Fast N-type inactivation of voltage-dependent potassium (Kv) channels controls membrane excitability and signal propagation in central neurons and occurs by a 'ball-and-chain'-type mechanism. In this mechanism an N-terminal protein domain (inactivation gate) occludes the pore from the cytoplasmic side. In Kv3.4 channels, inactivation is not fixed but is dynamically regulated by protein phosphorylation. Phosphorylation of several identified serine residues on the inactivation gate leads to reduction or removal of fast inactivation. Here, we investigate the structure-function basis of this phospho-regulation with nuclear magnetic resonance (NMR) spectroscopy and patch-clamp recordings using synthetic inactivation domains (ID). The dephosphorylated ID exhibited compact structure and displayed high-affinity binding to its receptor. Phosphorylation of serine residues in the N- or C-terminal half of the ID resulted in a loss of overall structural stability. However, depending on the residue(s) phosphorylated, distinct structural elements remained stable. These structural changes correlate with the distinct changes in binding and unbinding kinetics underlying the reduced inactivation potency of phosphorylated IDs.

Animals↗