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P Mucha

Publications and source records attributed to P Mucha.

At least 19 recordsLinked to original sources
PubMed2001

Anticodon domain methylated nucleosides of yeast tRNA(Phe) are significant recognition determinants in the binding of a phage display selected peptide.

The contributions of the natural modified nucleosides to RNA identity in protein/RNA interactions are not understood. We had demonstrated that 15 amino acid long peptides could be selected from a random phage display library using the criterion of binding to a modified, rather than unmodified, anticodon domain of yeast tRNA(Phe) (ASL(Phe)). Affinity and specificity of the selected peptides for the modified ASL(Phe) have been characterized by fluorescence spectroscopy of the peptides' tryptophans. One of the peptides selected, peptide t(F)2, exhibited the highest specificity and most significant affinity for ASL(Phe) modified with 2'-O-methylated cytidine-32 and guanosine-34 (Cm(32) and Gm(34)) and 5-methylated cytidine-40 (m(5)C(40)) (K(d) = 1.3 +/- 0.4 microM) and a doubly modified ASL(Phe)-Gm(34),m(5)C(40) and native yeast tRNA(Phe) (K(d) congruent with 2.3 and 3.8 microM, respectively) in comparison to that for the unmodified ASL(Phe) (K(d) = 70.1 +/- 12.3 microM). Affinity was reduced when a modification altered the ASL loop structure, and binding was negated by modifications that disfavored hairpin formation. Peptide t(F)2's higher affinity for the ASL(Phe)-Cm(32),Gm(34),m(5)C(40) hairpin and fluorescence resonance energy transfer from its tryptophan to the hypermodified wybutosine-37 in the native tRNA(Phe) placed the peptide across the anticodon loop and onto the 3'-side of the stem. Inhibition of purified yeast phenylalanyl-tRNA synthetase (FRS) catalyzed aminoacylation of cognate yeast tRNA(Phe) corroborated the peptide's binding to the anticodon domain. The phage-selected peptide t(F)2 has three of the four amino acids crucial to G(34) recognition by the beta-structure of the anticodon-binding domain of Thermus thermophilus FRS and exhibited circular dichroism spectral properties characteristic of beta-structure. Thus, modifications as simple as methylations contribute identity elements that a selected peptide specifically recognizes in binding synthetic and native tRNA and in inhibiting tRNA aminoacylation.

Anticodon↗
PubMed2000

Specific induction of Z-DNA conformation by a nuclear localization signal peptide of lupin glutaminyl tRNA synthetase.

Recently we have sequenced cDNA of plant glutaminyl-tRNA synthetase (GlnRS) from Lupinus luteus. At the N terminal part the protein contains a lysine rich polypeptide (KPKKKKEK), which is identical to a nuclear localization signal (NLS). In this paper we showed that two synthetic peptides (20 and 8 amino acids long), which were derived from lupin GlnRS containing the NLS sequence interact with DNA, but one of them (8aa long) changing its conformation from the B to the Z form. This observation clearly suggests that the presence of the NLS polypeptide in a leader sequence of GlnRS is required not only for protein transport into nucleus but also for regulation of a gene expression. This is the first report suggesting a role of the NLS signal peptide in structural changes of DNA.

Amino Acid Motifs↗
PubMed1999

Experimental models of protein-RNA interaction: isolation and analyses of tRNA(Phe) and U1 snRNA-binding peptides from bacteriophage display libraries.

Peptides that bind either U1 small nuclear RNA (U1 snRNA) or the anticodon stem and loop of yeast tRNA(Phe) (tRNA(ACPhe)) were selected from a random-sequence, 15-amino acid bacteriophage display library. An experimental system, including an affinity selection method, was designed to identify primary RNA-binding peptide sequences without bias to known amino acid sequences and without incorporating nonspecific binding of the anionic RNA backbone. Nitrocellulose binding assays were used to evaluate the binding of RNA by peptide-displaying bacteriophage. Amino acid sequences of RNA-binding bacteriophage were determined from the foreign insert DNA sequences, and peptides corresponding to the RNA-binding bacteriophage inserts were chemically synthesized. Peptide affinities for the RNAs (Kd approximately 0.1-5.0 microM) were analyzed successfully using fluorescence and circular dichroism spectroscopies. These methodologies demonstrate the feasibility of rapidly identifying, isolating, and initiating the analyses of small peptides that bind to RNAs in an effort to define better the chemistry, structure, and function of protein-RNA complexes.

Amino Acid Sequence↗
PubMed1997

Galanin, galantide and galanin (1-14)-[alpha-aminobutyric acid8]-scyliorhinin-I: structure dependent effects on the rat isolated gastric fundus.

The study was undertaken using selected pharmacodynamic parameters to describe the effects of porcine galanin(1-29)-NH2; porcine galanin fragments; galantide; porcine galanin(1-14)-[alpha-aminobutyric acid8]scyliorhinin-I and the analogues of the latter peptides on rat isolated gastric fundus muscle. All tested peptides, apart from galanin(16-29)-NH2 evoked reproducible concentration-dependent contractions with significantly decreased activities in comparison to the potency of the native galanin(1-29)-NH2 molecule. The order of the contractile ability in the group of galanin(1-29)-NH2 short fragments was as follows: [lysine14]galanin(1-15)-NH2 > galanin(1-15)-OH > galanin(1-15)-NH2 > [glycine5] galanin(1-15)-NH2 > galanin(2-15)-NH2 > [glycine5,lysine14]galanin(1-15)-NH2. Aside from [lysine14]galanin(1-15)-NH2 which had a lower efficacy, none of the peptides showed significant changes in this respect in comparison to the intact galanin(1-29)-NH2 molecule. The concentration-response curves of the tested peptides were to the right and their slopes besides from: galanin(1-15)-OH; galanin(2-15)-NH2; [glycine5]galanin(1-15)-NH2 remained not significantly different from galanin(1-29)-NH2. Hill's coefficient for galanin(1-29)-NH2 is 1.03 indicating an interaction of one galanin(1-29)-NH2 molecule with one receptor, fulfilling criteria of classical receptor theory. For galanin fragments Hill's coefficients are < 1 implying that the rules of classical theory may not apply. Galantide and analogues exhibited a subsequent decrease in potency: [cycloleucine4] galantide > galantide > [homoserine6]galantide > [phenylalnine(4fluor)17] galantide. Galanin(1-14)-[alpha-aminobutyric acid8]-scyliorhinin-I and its analogues contracted the gastric fundus with a decline in strength: galanin(1-13)-[norleucine10]-scyliorhinin-I(3-10) > galanin(1-13)-[phenylalanine(4fluor)7]-scyliorhinin-I > galanin(1-14)-[alpha-aminobutyric acid8]-scyliorhinin-I > galanin(1-13)-[alpha-aminobutyric acid8, norleucine10]-scyliorhinin-I(3-10). They all displayed a greater efficacy than galanin(1-29)-NH2, and the concentration-response curves were slightly to the right, almost parallel to that of galanin(1-29)-NH2. Slopes of the curves were not significantly different from galanin(1-29)-NH2. Hill's coefficient for the galantide, [cycloleucine4]galantide; [homoserine6]galantide; [phenylalanine(4fluor)17]galantide and galanin(1-13)-[phenylalanine(4fluor)7]-scyliorhinin-I are < 1. Hill's coefficients for galanin(1-13)-[norleucine10]-scyliorhinin-I(3-10); galanin(1-14)-[alpha-aminobutyric acid8]-scyliorhinin-I; galanin(1-14)-[alpha-aminobutyric acid8, norleucine10]-scyliorhinin-I(3-10) are > 1. A Hill's coefficient markedly different from 1 might indicate that an activation of more than one type of receptors, negative or positive receptor cooperativity or multiple-step agonist-receptor reaction.

Analysis of Variance↗
PubMed1997

The clinical usefulness of routine stacked multiplanar reconstruction in helical abdominal computed tomography.

RATIONALE AND OBJECTIVES: The authors evaluate the usefulness of stacked multiplanar reconstructions in routine, thick-section abdominal computed tomography. MATERIALS AND METHODS: Twenty-five routine, thick-section contrast abdominal CTs performed with equivalent technique were reformatted by multiplanar reconstructions in sagittal and coronal planes sequentially from side-to-side and front-to-back. The image sets were submitted, first axial images only followed by axial plus multiplanar reconstructions (MPRs), to 5 separate physician readers including 2 radiologists and 3 nonradiologists. These readers graded the visualization of a variety of normal and up to 5 pathologic lesions per patient on a scale of 1 to 5 (5 = best). RESULTS: The addition of sagittal and coronal multiplanar reconstructions significantly improved the visualization of all normal anatomic structures (mean axial only, 3.8; mean axial plus MPR, 4.1; P < 0.0001). In addition, most pathologic lesions were statistically better visualized with the addition of multiplanar reconstructions (mean axial images only, 3.9; mean axial plus MPR, 4.1; P < 0.0001). All five readers found improved visualization in nearly every category with the addition of the multiplanar reconstructions. However, in only 7% of cases, did a reviewer find new diagnostic information with the addition of MPR images. CONCLUSIONS: Stacked multiplanar reconstructions of routine, thick-section abdominal CT has clinical value in both the display of normal anatomic and pathologic lesions. Further studies, however, are required to confirm these findings before it is commonly used.

Humans↗
PubMed1997

Lysine14galanin(1-15)-NH2: a partial agonist at galanin receptors in rat isolated gastric fundus.

The study was undertaken to characterize the effects of the porcine galanin [pGal(1-29)-NH2] analogue [Lys14]pGal(1-15)-NH2 on rat gastric fundus. [Lys14]pGal(1-15)-NH2 is a less potent contractile agent than pGal(1-29)-NH2 (EC50 74.1 vs. 43.7 nmol/l, respectively) and shows a significantly lower maximal response than pGal(1-29)-NH2. Concentration-contraction curves were constructed for pGal(1-29)-NH2 alone (control) and pGal(1-29)-NH2 in the presence of 10, 100, and 1,000 nmol/l of [Lys14]pGal(1-15)-NH2. [Lys14]pGal(1-15)-NH2 shifted the concentration-contraction curves of pGal(1-29)-NH2 significantly to the right, whereas their linear portions remained parallel to that for the pGal(1-29)-NH2 control. [Lys14]pGal(1-15)-NH2 markedly increased the EC50 of the respective pGal(1-29)-NH2 concentration-contraction curves. It did not substantially change the maximal response of the muscles to pGal(1-29)-NH2 and the form of the respective concentration-contraction curves. Schild's plot gave a straight line with a slope of 0.84. The pA2 value for [Lys14]pGal(1-15)-NH2 was 8.23. [Lys14]pGal(1-15)-NH2 seems to be a partial Gal receptor agonist. Since the lack of specific Gal receptor antagonists in the gastrointestinal tract makes a precise characterization of its role as a motility modulator difficult, the position 14 in the pGal(1-29)-NH2 molecule looks as an attractive target in the search of a pure Gal receptor antagonist in the smooth muscles of the gut.

Amino Acid Sequence↗
PubMed1997

Interaction of HIV Tat model peptides with tRNA and 5S rRNA.

New data are presented on the interaction of model synthetic peptides containing an arginine-rich region of human immunodeficiency virus (HIV-Tat), with native RNA molecules: tRNA(Phe) of Saccharomyces cerevisiae and 5S rRNA from Lupinus luteus. Both RNA species form complexes with the Tat1 (GRKKRRQRRRA) and Tat2 (GRKKRRQRRRAPQDSQTHQASLSKQPA) peptides, as shown by electrophoretic gel shift and RNase footprint assays, and CD measurements. The nucleotide sequence UGGG located in the dihydrouridine loop of tRNAPhe as well as in the loop D of 5S rRNA is specifically protected against RNases. Our data indicate direct interactions of guanine of RNA moieties with arginine residues. These interactions seem similar to those observed in DNA-protein complexes, but different from those previously observed in the TAR RNA-Tat complexes.

Amino Acid Sequence↗
PubMed1996

Contractile action of galanin analogues on rat isolated gastric fundus strips is modified by tachyphylaxis to substance P.

This study was undertaken to characterize the interaction of porcine galanin (Gal) and some of its analogues with their receptors on rat gastric fundus muscle strips. Gal, galantide (M15) and Gal(1-14)-[Abu8]SCY-I evoked concentration-dependent contractions of gastric smooth muscle strips. Reproducible effects were observed in concentrations of 1-300, 3-1000 and 100-3000 nM, respectively. Specific EC50 for the contractile effect equalled 13.70 and 187 nM. Hill's coefficient for Gal is 1.03 indicating an interaction of one Gal molecule with one receptor, fulfilling the criteria of classical receptor theory. For M15 and Gal(1-14)-[Abu8]SCY-I Hill's coefficients are different from 1, namely 0.73 and 1.56, pointing out that the principle of interaction of one drug molecule with one receptor may not apply. The contraction induced by 300 nM of Gal was not significantly modified by tachyphylaxis to substance P (SP). On the contrary the introduction of tachyphylaxis to SP decreased the contractile effects of M15 and Gal(1-14)-[Abu8]SCY-I by about 57.7 +/- 3% and 39.6 +/- 5%, respectively. The findings suggest that contractile actions of M15 and Gal(1-14)-[Abu8]SCY-I are probably not only due to their agonist activities at Gal receptors but may result from a subsequent stimulation of receptors for SP or release of endogenous SP.

Amino Acid Sequence↗
PubMed1996

Nonoperative management of the ruptured spleen: a revalidation of criteria.

BACKGROUND: Our goal was to revalidate this institution's original criteria for safe nonoperative management of splenic injury. METHODS: This was a prospective series between October 1991 and December 1995 entering all patients with splenic injury to a modified algorithm. Patients were taken to the operating room if hemodynamically unstable (systolic blood pressure less than 90 mm Hg; pulse greater than 110 beats per minute) after 2 liters of fluid resuscitation, positive abdominal examination findings, American Association for the Surgery of Trauma Organ Injury Scale Grade IV or V injuries by computed tomographic scan (unless younger than 15 years old), or associated severe head injuries (unless younger than 15 years old), or age greater than 55. The remainder of the patients were closely observed. RESULTS: One hundred seventy-three patients were entered-six were excluded by death before operating room salvage, and one was excluded because of operation for a ruptured thoracic aorta. Therefore 166 patients were reviewed. Seventy splenectomies and 18 splenorrhaphies were performed, and 78 patients were treated nonoperatively (58% splenic salvage). Two failures occurred in the nonoperative group: a 16-year-old with a grade IV hilar injury was operated on on the eighth day after injury because of a continually falling hematocrit, and a 25-year-old with unresolved tachycardia was operated on at 6 hours (97% success rate). The patients in the operative group had a greater severity of injury as determined by mean Injury Severity Score of 32, 18 deaths, a mean transfusion requirement of 14 units of blood compared with mean injury severity score of 21, two deaths from brain injury, and no transfusions given in 58 of the 78 nonoperative cases. CONCLUSIONS: Prospectively applied, these guidelines allow the safe nonoperative management of patients with blunt splenic injury.

Adolescent↗
PubMed1992

Prevention of infection in critically ill patients by selective decontamination of the digestive tract.

OBJECTIVE: To determine whether selective decontamination of the digestive tract using oral and nonabsorbable antimicrobial agents and parenteral cefotaxime prevents infection in critically ill patients. DESIGN: Randomized, controlled trial without blinding. SETTING: Surgical trauma and medical intensive care units in a tertiary referral hospital. PATIENTS: One hundred fifty patients admitted to surgical trauma and medical intensive care units during a 3-year interval, whose condition suggested a prolonged stay (greater than 3 days). INTERVENTION: Patients were randomly allocated to an experimental group (n = 75) that received cefotaxime, 1 g intravenously every 8 hours for the first 3 days only, and oral, nonabsorbable antibiotics (gentamicin, polymyxin, and nystatin by oral paste and oral liquid) for the entire stay in the intensive care unit. Control patients (n = 75) received usual care. MEASUREMENTS: The number of infections, total hospital days, and deaths, as well as the number of days in intensive care unit, were recorded. RESULTS: Control patients experienced more infections (36 compared with 12, P = 0.04), including bacteremias (14 compared with 4, P = 0.05) and pulmonary infections (14 compared with 4, P = 0.03). Although total hospital days, days in intensive care, and the overall death rate all were lower in the treatment group, these differences were not statistically significant. Clinically important complications of selective decontamination of the digestive tract were not encountered. CONCLUSIONS: Selective decontamination of the digestive tract decreases subsequent infection rates, especially by gram-negative bacilli, in selected patients during long-term stays in the intensive care unit.

Administration, Oral↗
PubMed1992

Blunt colonic injury--a multicenter review.

During the past decade there has been a shift in the management of injuries of the colon to primary repair without a protective diverting colostomy. Unfortunately, reports concerning this practice contain relatively few patients with blunt trauma and it is unclear whether the principles established for penetrating injury should be applied in the setting of blunt colon injury. A retrospective review of 54,361 major blunt trauma patients admitted to nine regional trauma centers from January 1, 1986, through December 31, 1990, was conducted. Statistical analysis of the data collected regarding 286 (0.5%) of these patients who suffered colonic injury revealed: (1) injury to the colon is found in more than 10% of patients undergoing laparotomy following blunt trauma; (2) available diagnostic modalities are unreliable in detecting isolated colonic pathology; (3) primary repair of full-thickness injuries or resection and anastomosis may be safely performed without diversion; (4) gross fecal contamination is the strongest contraindication to primary repair. Further, delay of surgery, shock, and the timing of antibiotic administration were not associated with significantly increased morbidity.

Abbreviated Injury Scale↗
PubMed1992

Primum non nocere.

Explore the source record for details and available documents.

Catheterization, Peripheral↗
PubMed1992

Ruptured abdominal aortic aneurysms: repair should not be denied.

The records of 231 patients (189 men, 42 women) treated during the last decade for ruptured infrarenal abdominal aortic aneurysm were reviewed to evaluate complications and mortality rates and to determine if preoperative factors would preclude attempt at surgical repair. Mean age was 73.7 years (range, 50 to 95 years). Fifty-seven patients (24.7%) were greater than or equal to 80 years of age. Sixty-eight patients (29.4%) had known abdominal aortic aneurysm before rupture. Preoperative systolic blood pressure was less than or equal to 90 mm Hg in 155 patients (67.1%). Fifty-six patients (24.2%) had cardiac arrest before operation. The overall mortality rate from admission until the end of the hospital stay was 49.4% (114 of 231). Seventeen patients (7.4%) died in the emergency department, 40 (17.3%) in the operating room, 27 (11.7%) during the first 48 postoperative hours, and 30 (13.0%) died later but during the same hospitalization. The 30-day operative mortality rate was 41.6%. Mean age of those who died was higher (75.3 years) than of those who survived (72.2 years) (p less than 0.02). Of patients greater than or equal to 80 years, 43.9% survived. Survival was lower among women (35.7%) than men (54.0%; p less than 0.04). A high APACHE II score, a low initial hematocrit, preoperative hypotension, and chronic obstructive pulmonary disease were associated multivariately with increased mortality rates (p less than 0.02). However, 59 of the 155 patients (38.1%) with preoperative hypotension survived. Deaths were high (80.4%) among patients with cardiac arrest (45 of 56); still, 28.2% of patients (11 of 39) survived repair after cardiac arrest.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Hepatic enzyme response and hyperpyrexia after severe liver injury.

A multi-center experience with 210 severe liver injuries was reviewed to define postoperative changes in hepatic enzyme levels and body temperature profile. The 129 patients who survived initial operation comprised the data base. Serum glutamic oxaloacetic transaminase (SGOT) and lactate dehydrogenase (LDH) peaked within 24 hours (750 +/- 92 IU/L, 870 +/- 120 IU/L) and decreased rapidly during the first 4 days. Serum bilirubin was maximal at 7 days, while alkaline phosphatase rose slowly throughout 14 days. Hepatic enzyme elevations were more dramatic after blunt trauma, reflecting greater hepatocellular disruption. Maximum daily temperatures exceeding 38.0 degrees C and 39.0 degrees C were recorded for the first 3 postoperative days in 82 (64%) patients and 14 (11%) patients, respectively. No infectious source was evident in 13 (93%) of 14 patients with severe hyperpyrexia, implicating release of inflammatory mediators associated with major hepatic trauma. Convalescence from severe hepatic injury is marked by release of SGOT and LDH, as well as fever, which may be anticipated during the first 4 days postinjury.

Adult↗
PubMed1991

Acute necrotizing pancreatitis: management by planned, staged pancreatic necrosectomy/debridement and delayed primary wound closure over drains.

We reviewed our recent experience with management of 23 consecutive patients with acute necrotizing pancreatitis. All patients had documented necrotizing pancreatitis with parenchymal or peripancreatic necrosis. Our method of treatment has evolved from our previous approach of controlled open lesser sac drainage (marsupialization) to staged necrosectomy/debridement with delayed primary closure over drains. With this latter approach, hospital mortality was 4 of 23 patients (17 per cent), but significant morbidity still occurred in 12 of 23 patients (52 per cent). However, recurrent intra-abdominal abscess before discharge occurred in only one patient. We believe that this operative approach toward the severely ill patient with acute necrotizing pancreatitis who requires operative intervention will minimize the occurrence of intra-abdominal sepsis.

Acute Disease↗
PubMed1991

Rhabdomyolysis and renal failure following a wolf attack: case report.

Trauma-induced rhabdomyolysis and myoglobinuric renal failure are well recognized. The mechanism of trauma in reported cases has been burns, crush injuries, or compression syndromes. We report a case of myoglobinuric renal failure in a 5-year-old boy who suffered primarily lacerations and penetrating wounds from a wolf attack. We are unaware of any other reports of nonvenomous bites or penetrating trauma causing rhabdomyolysis and myoglobinuric renal failure. Early suspicion, diagnosis, and treatment of this condition result in an excellent prognosis. Pathogenesis, treatment, and a review of the literature are presented.

Acute Kidney Injury↗