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Biomedical subjects

D Pieper

Publications and source records attributed to D Pieper.

16 recordsLinked to original sources
PubMed2005

Bacterial community dynamics during in-situ bioremediation of petroleum waste sludge in landfarming sites.

In-situ bioremediation of petroleum waste sludge in landfarming sites of Motor Oil Hellas (petroleum refinery) was studied by monitoring the changes of the petroleum composition of the waste sludge, as well as the changes in the structure of the microbial community, for a time period of 14 months. The analyses indicated an enhanced degradation of the petroleum hydrocarbons in the landfarming areas. A depletion of n-alkanes of approximately 75-100% was obtained. Marked changes of the microbial communities of the landfarms occurred concomitantly with the degradation of the petroleum hydrocarbons. The results obtained from terminal restriction fragment length polymorphism (T-RFLP) analysis of polymerase chain reaction (PCR) amplified 16S rRNA genes demonstrated that bacteria originating from the refinery waste sludge and newly selected bacteria dominated the soil bacterial community during the period of the highest degradation activity. However, the diversity of the microbial community was decreased with increased degradation of the petroleum hydrocarbons contained in the landfarms. T-RFLP fingerprints of bacteria of the genera Enterobacter and Ochrobactrum were detected in the landfarmed soil over the entire treatment period of 14 months. In contrast, the genus Alcaligenes appeared in significant numbers only within the 10 month old landfarmed soil. Genes encoding catechol 2,3-dioxygenase (subfamily I.2.A) were detected only in DNA of the untreated refinery waste sludge. However, none of the genes known to encode the enzymes alkane hydroxylase AlkB, catechol 2,3-dioxygenase (subfamily I.2.A) and naphthalene dioxygenase nahAc could be detected in DNA of the landfarmed soils.

Biodegradation, Environmental↗
PubMed2001

The effects of triiodothyronine augmentation on antithrombin III levels in sepsis.

Sepsis and multisystem organ failure are often associated with disseminated intravascular coagulation and consumption of coagulation inhibitors such as antithrombin III (ATIII). The "sick euthyroid syndrome" is also seen in association with significant illnesses and consists of decreased levels of circulating triiodothyronine (T3). We evaluated whether T3 supplementation would affect ATIII levels in septic rats. Thirty Sprague-Dawley rats were divided into three groups: sham laparotomy (S) plus saline, cecal ligation and puncture (CLP) plus saline, and CLP plus T3 (3 ng/hour) via an osmotic minipump. Twenty-four hours after laparotomy blood was drawn, and T3 and ATIII levels were then compared with baseline values. T3 supplementation partially negated the sepsis-induced decrease in circulating T3 levels. The levels are expressed as percentage change from the levels before surgery (S, -12.9 +/- 3.1; CLP, -60.0 +/- 5.3; CLP + T3, -34.9 +/- 4.3; mean +/- standard error; P < 0.05). T3 supplementation also statistically changed the percentage difference in ATIII levels toward the control (S, 9.6 +/- 2.8; CLP, -37.9 +/- 5.4; CLP + T3, -16.0 +/- 4.5; mean +/- standard error; P < 0.01). T3 supplementation reduced the sepsis-induced decrease in ATIII levels. Whether this was accomplished by decreased consumption or increased production of ATIII via the direct anabolic effect of T3 on acute-phase protein synthesis in the liver is unknown and warrants further investigation.

Analysis of Variance↗
PubMed2001

Intraoperative and early postoperative gastric intramucosal pH predicts morbidity and mortality after major abdominal surgery.

The present study was undertaken to investigate the correlation between the intraoperative and postoperative gastric intramucosal pH (pHi) with important perioperative variables and to explore any potential relationship of the measured pHi with the patients' postoperative course. A prospective study was carried out in a group of 48 patients who underwent major abdominal operations over an 8-month period at St. John Hospital and Medical Center. An automated air tonometer was used for gastric pHi monitoring. Twenty-eight elective and 20 emergency abdominal operations were performed in 23 men and 25 women. Twenty-six patients (54%) required postoperative hospitalization in the Intensive Care Unit (ICU). Seventeen patients (35%) developed early postoperative complications. The non-ICU and ICU mortality rates were 4.5 and 19.2 per cent respectively. The mean intraoperative pHi (pHiOR) and postoperative pHi (pHiPO) ranged between 7.03 and 7.58 (7.38+/-0.12) and 6.89 and 7.56 (7.35+/-0.12) respectively (mean +/- standard deviation). There was a significant decrease of the gastric pHi at the first hour intraoperatively compared with the pHi after induction to anesthesia (7.44 vs 7.38+/-0.14, P < 0.001). Patients who underwent emergent abdominal procedures were characterized by lower pHiOR and pHiPO values (7.43+/-0.08 vs 7.30+/-0.13 and 7.39+/-0.84 vs 7.30+/-0.15, P < 0.001 and P < 0.05). Similarly patients who required surgical ICU admission had significantly lower pHiOR and pHiPO measurements (7.3+/-0.12 and 7.28+/-0.12) compared with the rest (7.46+/-0.06 and 7.43+/-0.06; P < 0.001). Overall, lower pHiOR and pHiPO values were associated with the occurrence of postoperative complications (P < 0.001), the postoperative mortality (P < 0.001), the requirement for postoperative mechanical ventilator (P < 0.001) and its duration (P < 0.001), longer ICU stay (P < 0.001), and prolonged hospitalization (P < 0.05). Evidence of intraoperative and early postoperative gastric mucosal ischemia (pHiOR and pHiPO < or = 7.32) was observed in 12 (25%) and 15 (31%) patients respectively. The incidence of postoperative complications and the mortality rate were higher in this group of patients (P < 0.001). At a cutoff point of 7.32 gastric pHiOR gave a sensitivity of 69 per cent and specificity of 97 per cent for predicting postoperative complications as well as a sensitivity and specificity of 67 per cent and 81 per cent for predicting death. Intraoperative and early postoperative gastric pHi is a reliable predictor of patient outcome after major abdominal operations. Splanchnic ischemia may play an important role in determining early complications and survival; therapy guided by the gastric pHi might improve outcome.

Adult↗
PubMed2000

Effect of biocompatibility of hemodialysis membranes on serum albumin levels.

Hypoalbuminemia in end-stage renal disease is a marker of high morbidity and mortality. In some patients, the cause of low serum albumin levels is easily identified and therefore treatable, but in many patients, the cause is not clear. We studied the effect of changing the dialysis membrane from a bioincompatible to a biocompatible membrane on serum albumin level. Stable hemodialysis patients dialyzed with cuprammonium membranes who had serum albumin levels less than 3.5 g/dL were switched to the more biocompatible membrane, polysulfone. Serum albumin levels increased from 3.22 +/- 0.037 to 3.35 +/- 0.038 g/dL (mean +/- SE; P < 0.002). The increase was seen in patients both with and without diabetes. Thus, dialyzer membrane may affect serum albumin levels and should be considered in the differential diagnosis of hypoalbuminemia in patients undergoing hemodialysis with bioincompatible membranes. Membrane choice may have an important effect on the outcome of morbidity and mortality of hemodialysis patients.

Adult↗
PubMed2000

A consortium-based research education program for residents.

With growing pressures to consolidate and reorganize health care delivery systems, graduate medical education (GME) consortia can draw faculty from affiliated members to assemble educational programs. The authors report on consortium-based research education seminars of a quality that many residency programs would be unable to develop and support on their own. Drawing a diverse faculty from consortium members and area universities, the OHEP Center for Medical Education's annual Research Workshop Series focuses on the design of research projects; data analysis and hypothesis testing; and written and oral presentation of scientific research. Each spring, OHEP sponsors a research forum in which the best research projects from consortium members are presented by the resident-researchers, who compete for recognition and prize money. Further, of the 128 presentations made thus far at the annual OHEP Research Forum, 25% were subsequently published. The consortium's research education program has been well received by residents, is cost-effective, and is an integral component of the research curricula of many area residency programs. Including research training in GME provides residents an opportunity to become more competitive for fellowship, faculty, and leadership positions.

Curriculum↗
PubMed2000

Chromosomal integration of tcb chlorocatechol degradation pathway genes as a means of expanding the growth substrate range of bacteria to include haloaromatics.

The tcbR-tcbCDEF gene cluster, coding for the chlorocatechol ortho-cleavage pathway in Pseudomonas sp. strain P51, has been cloned into a Tn5-based minitransposon. The minitransposon carrying the tcb gene cluster and a kanamycin resistance gene was transferred to Pseudomonas putida KT2442, and chromosomal integration was monitored by selection either for growth on 3-chlorobenzoate or for kanamycin resistance. Transconjugants able to utilize 3-chlorobenzoate as a sole carbon source were obtained, although at a >100-fold lower frequency than kanamycin-resistant transconjugants. The vast majority of kanamycin-resistant transconjugants were not capable of growth on 3-chlorobenzoate. Southern blot analysis revealed that many transconjugants selected directly on 3-chlorobenzoate contained multiple chromosomal copies of the tcb gene cluster, whereas those selected for kanamycin resistance possessed a single copy. Subsequent selection of kanamycin resistance-selected single-copy transconjugants for growth on 3-chlorobenzoate yielded colonies capable of utilizing this carbon source, but no amplification of the tcb gene cluster was apparent. Introduction of two copies of the tcb gene cluster without prior 3-chlorobenzoate selection resulted in transconjugants able to grow on this carbon source. Expression of the tcb chlorocatechol catabolic operon in P. putida thus represents a useful model system for analysis of the relationship among gene dosage, enzyme expression level, and growth on chloroaromatic substrates.

Blotting, Southern↗
PubMed1999

3-nitroadipate, a metabolic intermediate for mineralization of 2, 4-dinitrophenol by a new strain of a Rhodococcus species.

The bacterial strain RB1 has been isolated by enrichment cultivation with 2,4-dinitrophenol as the sole nitrogen, carbon, and energy source and characterized, on the basis of 16S rRNA gene sequence comparison, as a Rhodococcus species closely related to Rhodococcus opacus. Rhodococcus sp. strain RB1 degrades 2,4-dinitrophenol, releasing the two nitro groups from the compound as nitrite. The release of nitro groups from 2,4-dinitrophenol occurs in two steps. First, the 2-nitro group is removed as nitrite, with the production of an aliphatic nitro compound identified by 1H nuclear magnetic resonance and mass spectrometry as 3-nitroadipate. Then, this metabolic derivative is further metabolized, releasing its nitro group as nitrite. Full nitrite assimilation upon reduction to ammonia requires that an additional carbon source be supplied to the medium.

2,4-Dinitrophenol↗
PubMed1998

A new intermediate in the mineralization of 3,4-dichloroaniline by the white rot fungus Phanerochaete chrysosporium.

Phanerochaete chrysosporium ATCC 34541 has been reported to be unable to mineralize 3,4-dichloroaniline (DCA). However, high mineralization is now shown to occur when a fermentation temperature of 37 degrees and gassing with oxygen are used. Mineralization did not correlate with lignin peroxidase activity. The latter was high under C limitation and low under N limitation, whereas the reverse was true for mineralization. The kinetics of DCA metabolism was studied in low-N and low-C and C- and N-rich culture media by metabolite analysis and 14CO2 determination. In all cases, DCA disappeared within 2 days, and a novel highly polar conjugate termed DCAX accumulated in the growth medium. This metabolite was a dead-end product under C and N enrichment. In oxygenated low-C medium and in much higher yield in oxygenated low-N medium, DCAX was converted to DCA-succinimide and then mineralized. DCAX was purified by high-performance liquid chromatography and identified as N-(3,4-dichlorophenyl)-alpha-ketoglutaryl-delta-amide by high-performance liquid chromatography and mass spectroscopy, gas chromatography and mass spectroscopy, and nuclear magnetic resonance spectroscopy. The formation of conjugate intermediates is proposed to facilitate mineralization because the sensitive amino group of DCA needs protection so that ring cleavage rather than oligomerization can occur.

Aniline Compounds↗
PubMed1996

The confirmation of a biochemical marker for women's hormonal migraine: the depo-estradiol challenge test.

PRECIS: Will estrogen withdrawal cause migraines in post-menopausal women? OBJECTIVE: To record the changes in serum estradiol and total estrogen levels after an intramuscular estradiol injection in menopausal subjects and then record any subsequent migraine occurrence. DESIGN: Open selection process, comparative trial. PATIENTS: Twenty-eight postmenopausal women volunteers were given 5 mg depo-estradiol cyprionate as an intramuscular injection. Sixteen (migraine group) had a history of severe, cyclic, menstrually related migraine attacks before becoming menopausal. Twelve (control group) had no history of migraine or headache. All volunteers were on continuous estrogen replacement therapy at the beginning of the study. Progestins were not used in the study. MAIN OUTCOME MEASURES: Serum estradiol and total estrogen levels were measured prior to the depo-estradiol injection and on subsequent days 4, 7, 14, 21, and 28. RESULTS: Total estrogen and estradiol levels varied greatly at every measured interval. Menopausal complaints of vasomotor symptoms were relieved for at least the first 2 weeks of the study. No member of the control group reported a migraine during the month. However, a severe migraine was reported by all 16 women with a history of migraine. The average day of the migraine occurrence was 18.5 +/- 2.8. The serum level of estradiol on the day of the worst migraine was 46.4 +/- 5.6 pg/mL. The significance of these findings was at the 95% confidence level. CONCLUSIONS: This study confirms two factors about menopausal hormonal migraine: (1) it can be precipitated by a drop in serum estrogen levels, and (2) a period of estrogen priming is a necessary prerequisite. This study also identifies that there are two biologically different populations of postmenopausal women: (1) those who developed migraine after a single depo-estradiol injection, and (2) those who did not. By understanding that in addition to the biological predisposition to migraine there exists the biochemical cofactor of falling estrogen levels, we may better understand this phenomenon and develop means to prevent its occurrence.

Adult↗
PubMed1993

Molecular characterization of a cloned idiotypic cascade containing a network antigenic determinant specific for the human carcinoembryonic antigen.

The monoclonal anti-idiotypic antibody (maId) 6G6.C4, directed against the carcinoembryonic antigen (CEA)-specific T84.66 immunoglobulin, was recently shown to act as a surrogate antigen for CEA in experimental animals. In this report, we have extended our studies. 1) The kinetics of complex formation in this CEA-specific idiotypic cascade were investigated using Biosensor technology. 2) Bacterial expression studies show that the mimicked epitope can be delimited to the A3 domain of CEA. 3) We cloned and characterized the genes coding for maId 6G6.C4. 4) Comparison of this epitope-bearing domain with the hypervariable region sequences of 6G6.C4 yields substantial amino acid similarity. Sequence homology between maId 6G6.C4 and anti-CEA antibodies binding to the T84.66 epitope led us to investigate the interaction of maId 6G6.C4 and CEA. Surprisingly, 6G6.C4 specifically binds to CEA but not CEA-related antigens in Western blots. 6G6.C4 and T84.66 recognize different epitopes on CEA. Our results suggest that the T84.66 epitope functionally mimicked by maId 6G6.C4 may be involved in the homophilic binding between CEA molecules, and that heterophilic interactions in the CEA-family are mediated by different binding sites. A model for the intermolecular adhesion of CEA is presented.

Amino Acid Sequence↗
PubMed1993

Contraction rates of meshed, nonexpanded split-thickness skin grafts versus split-thickness sheet grafts.

Contraction rates of wounds covered by meshed, nonexpanded split-thickness skin grafts were compared with split-thickness sheet-grafted wounds in a porcine model. No significant difference was found in wound contraction. When compared with previous studies, this study shows that differences in contraction previously observed were not a result of meshing and suggests that expansion may be the cause of the difference previously observed.

Animals↗
PubMed1991

Ultrasound surveillance of the cervix in twin gestations: management of cervical incompetency.

Fifty-one consecutive twin pregnancies studied prospectively were compared with 153 consecutive control twin gestations that were concurrently delivered, but chosen retrospectively. Study patients were managed by a protocol that used weekly ultrasound surveillance combined with clinical assessment. Control subjects were not managed by protocol or ultrasound surveillance. Seven of 51 study patients (13.7%) were diagnosed as having cervical incompetency before 30 weeks' gestation (range 18-28 weeks, mean 24). In comparison, 14 of 153 controls (9.2%) delivered before 30 weeks' gestation (range 18-29 weeks, mean 25). The mean cervical length, dilatation, and membrane herniation (funneling) at diagnosis were 1.9, 2.2, and 3.6 cm, respectively, for patients with cervical incompetency. There was a significant difference in perinatal mortality. All study twins survived, whereas nine control subjects delivered at a mean gestational age of 22.7 weeks, with a loss of 17 infants. Life table analysis demonstrated that a significantly greater proportion of controls delivered very low birth weight, premature twins. The use of ultrasound and clinical criteria to select patients for cerclage placement helped prevent birth of the youngest and smallest twins and significantly decreased perinatal mortality in the study group. Routine cerclage placement is not recommended for twin gestations, but multifetal gestations may benefit from ultrasound surveillance for cervical incompetency.

Birth Weight↗
PubMed1990

Toxicity of cleaning agents for removal of grease from wounds.

Industrial injuries are often open wounds contaminated with grease. Commercial compounds used for removing grease from intact skin are composed of petroleum distillates. These products are occasionally used to remove grease from open wounds. Using an animal model, this study examines the use of commercial compounds in open wounds in comparison with mild detergent and water. A clear correlation is established between their use and adverse tissue reaction. The use of soap and water as opposed to petroleum-based compounds is recommended for removal of grease from a wound.

Animals↗
PubMed1989

Complications of reduction mammaplasty: comparison of nipple-areolar graft and pedicle.

A retrospective study of breast reductions in 268 patients by two plastic surgeons was performed. Particular attention was paid to those patients treated by inferior pedicle techniques; these patients were compared with those treated by free nipple grafts. According to our findings, patients with skin loss were heavier and had longer suprasternal notch-to-nipple distances. Patients who had free nipple grafts were older and heavier and had larger specimen weights and longer suprasternal notch-to-nipple distances. Fifty-four of the original 268 patients were included in a substudy of larger breasts, defined as those with a specimen weight of over 700 g. Nineteen patients underwent free nipple grafts, and 35 underwent inferior pedicle techniques. None of the 19 patients having free nipple grafts developed complications, whereas 6 of the 35 undergoing inferior pedicle techniques sustained significant complications. We conclude that free nipple grafts should be considered over inferior pedicles in heavier patients with breast ptosis.

Adult↗
PubMedDate not supplied

Does exercise affect female hamster gonadotropins by reducing estradiol negative feedback?

Exercise stimulates reproductive function in hamsters exposed to short-day photoperiod (SDP) in contrast to its inhibitory effects in women and rats. SDP inhibits hamster reproduction in part by increasing the sensitivity of the hypothalamo-pituitary-gonadal axis (HPGA) to the negative feedback of gonadal steroids. To determine whether EX facilitates reproduction in female hamsters by affecting this mechanism, we examined the influence of estradiol (E2) on basal LH and FSH concentrations in exercising and sedentary hamsters maintained on long-day photoperiod (LD 14:10, LDP) or SDP (LD 8:16). In the LDP, serum LH and FSH were unaffected or reduced by exercise in ovariectomized (OVX) nonhormone-replaced hamsters, and LH was increased after tonic E2 replacement compared to sedentary controls. In the SDP, serum LH and FSH were significantly higher in OVX exercising than in sedentary hamsters, whether the exercisers were injected with a high dose of E2 or not. Thus, the effects of exercise on basal gonadotropin secretion in female hamsters appear to depend on the level of estradiol negative feedback (ENF). When this feedback is low (LDP OVX condition), exercise is either ineffective or inhibitory. When the ENF is increased by exposure to SDP and/or by treatment with E2, exercise has a stimulatory effect on basal gonadotropin secretion. Exercise may stimulate hamster gonadotropin secretion by reducing the ENF either by lowering the sensitivity of the HPGA to steroid negative feedback or by other means.

Animals↗