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Biomedical subjects

L Kohl

Publications and source records attributed to L Kohl.

14 recordsLinked to original sources
PubMed2002

Allergic contact dermatitis from cosmetics. Retrospective analysis of 819 patch-tested patients.

BACKGROUND: Cosmetics have been used since the oldest known civilisations, and nowadays almost everybody resorts to beauty products. OBJECTIVE: Considering the increasing incidence of contact dermatitis, the aim of the study is to determine the impact of allergy to cosmetics. METHODS: From January 1998 to December 1999, 819 patients were subjected to epicutaneous tests for suspicion of allergic contact dermatitis (ACD). The results were analysed retrospectively in the total population and in that of children under 16: the interest has been focused on cosmetics. RESULTS: 297 patients (36.3%) with ACD to 1 or more cosmetic ingredients have been detected. 34 (48.6%) out of 70 children patch tested showed an ACD: cosmetics represented the first cause. CONCLUSION: For two decades, the incidence of ACD has been rising; two main reasons can be put forward: a rising product consumption and a more exhaustive allergen research in patch testing.

Adolescent↗
PubMed2001

A trypanosome structure involved in transmitting cytoplasmic information during cell division.

African trypanosomes are protozoan parasites that cause sleeping sickness in humans through a tsetse fly vector. The procyclic form of Trypanosoma brucei has a single, attached flagellum that describes a helical path along the cell from posterior to anterior. During division, a specific flagellum-flagellum connection is elaborated between the new and old flagellum. This connector was present only during cell duplication and was found to be involved in the replication of the helical cell pattern and polarity. This finding implicates the concept of cytotaxis in cell morphogenesis in trypanosomes.

Animals↗
PubMed2000

Flagellum ontogeny in trypanosomes studied via an inherited and regulated RNA interference system.

The African trypanosome, Trypanosoma brucei possesses a large and unique intraflagellar structure called the paraflagellar rod (PFR). The PFR is composed of 2 major proteins, PFRA and PFRC. We have generated an inducible mutant trypanosome cell line (snl-2) that expresses linked inverted copies of a PFRA gene, capable of forming a PFRA double-stranded (ds) RNA. When expression of this dsRNA was induced, new PFRA RNA and PFRA protein quickly disappeared and PFR construction was affected, resulting in cell paralysis. This inducible RNA interference (RNAi) effect was fast-acting, heritable and reversible. It allowed us to demonstrate that PFR proteins are able to enter both mature and growing flagella but appear to concentrate differentially in new flagella because of the construction process. The PFR is constructed by a polar assembly process at the distal end of the flagellum resulting in a stable cytoskeletal structure with low turn-over. The inducible RNAi approach will have widespread applicability in studies of gene function and cellular processes in parasites.

Animals↗
PubMed1995

Nonoperative salvage of computed tomography-diagnosed splenic injuries: utilization of angiography for triage and embolization for hemostasis.

OBJECTIVES: The aims of this study were to determine if angiographic findings can be used to predict successful nonoperative therapy of splenic injury and to determine if coil embolization of the proximal splenic artery provides effective hemostasis. METHODS: Splenic injuries detected by diagnostic imaging between 1981 and 1993 at a level I trauma center were prospectively collected and retrospectively reviewed after management by protocol that used diagnostic peritoneal lavage, computed tomography (CT), angiography, transcatheter embolization, and laparotomy. Computed tomography was performed initially or after positive diagnostic peritoneal lavage. Angiography was performed urgently in stabilized patients with CT-diagnosed splenic injuries. Patients without angiographic extravasation were treated by bed rest alone; those with angiographic extravasation underwent coil embolization of the proximal splenic artery followed by bed rest. RESULTS: Patients (172) with blunt splenic injury are the subject of this study. Twenty-two patients were initially managed operatively because of associated injuries or disease (11 patients) or because the surgeon was unwilling to attempt nonoperative therapy (11 patients) and underwent splenectomy (17 patients) or splenorrhaphy (5 patients). One hundred fifty of 172 consecutive patients (87%) with CT-diagnosed splenic injury were stable enough to be considered for nonoperative management. Eighty-seven of the 90 patients managed by bed rest alone, and 56 of 60 patients treated by splenic artery occlusion and bed rest had a successful outcome. Overall splenic salvage was 88%. It was 97% among those managed nonoperatively, including 61 grade III and grade IV splenic injuries. Sixty percent of patients received no blood transfusions. Three of 150 patients treated nonoperatively underwent delayed splenectomy for infarction (one patient) or splenic infection (two patients). CONCLUSIONS: (1) Hemodynamically stable patients with splenic injuries of all grades and no other indications for laparotomy can often be managed nonoperatively, especially when the injury is further characterized by arteriography. (2) The absence of contrast extravasation on splenic arteriography seems to be a reliable predictor of successful nonoperative management. We suggest its use to triage CT-diagnosed splenic injuries to bed rest or intervention. (3) Coil embolization of the proximal splenic artery is an effective method of hemostasis in stabilized patients with splenic injury. It expands the number of patients who can be managed nonoperatively.

Adolescent↗
PubMed1994

Triose-phosphate isomerase of Leishmania mexicana mexicana. Cloning and characterization of the gene, overexpression in Escherichia coli and analysis of the protein.

The gene of triose-phosphate isomerase in Leishmania mexicana has been cloned and characterized. The gene encodes a polypeptide of 251 amino acids, with a calculated molecular mass of 27,561 Da and a net charge of +2. Only one gene could be detected, although the enzyme is present in two different compartments of the cell, in microbody-like organelles called glycosomes and in the cytosol. The primary structure of the enzyme has many features in common with that of triose-phosphate isomerase in the related organism Trypanosoma brucei. Their sequences are 68% identical. The residues constituting the subunit interface are highly conserved between the enzyme of L. mexicana and T. brucei, but are mostly different from those in the enzyme of other organisms. One major substitution was detected in the interface region of the L. mexicana protein: a glutamate was found at position 66, instead of glutamine in all other available 20 sequences. The glutamine is thought to be important for the stability of the dimeric enzyme. L. mexicana triose-phosphate isomerase has been overexpressed in Escherichia coli. Growth conditions were established to obtain high levels of soluble and active protein. The enzyme has been purified to near homogeneity. It appears a stable dimeric protein with a specific activity of 5500 units/mg protein, a subunit mass of 28 kDa and an isoelectric point of 9.0. The enzyme has also been partially purified from glycosomes of cultured L. mexicana promastigotes. Some kinetic properties of the recombinant protein have been compared with those of the promastigote enzyme and with the values previously reported for the T. brucei enzyme. The kinetics of the different enzyme preparations were very similar. For the recombinant enzyme the following values were measured: with glyceraldehyde 3-phosphate as substrate Km = 0.30 +/- 0.05 mM and kcat = 2.5 x 10(5) min-1; with dihydroxyacetone phosphate as substrate Km = 1.3 +/- 0.3 mM and kcat = 2.8 x 10(4) min-1.

Amino Acid Sequence↗
PubMed1994

Exercise-induced rhabdomyolysis.

STUDY OBJECTIVE: To describe the syndrome of exercise-induced rhabdomyolysis and to investigate the relation between exercise-induced rhabdomyolysis and the development of acute renal failure. DESIGN: Retrospective chart analysis on all patients with a discharge diagnosis of rhabdomyolysis from January 1988 to January 1993. SETTING: An urban tertiary care center with 225,000 annual emergency department visits. TYPE OF PARTICIPANTS: Thirty-five patients met the inclusion criteria for exercise-induced rhabdomyolysis: a history of strenuous exercise, creatine phosphokinase level more than 500, and urine dipstick positive for blood without hematuria. We excluded patients with a history of trauma, myocardial infarction, stroke, or documented sepsis. Charts also were examined for the presence of nephrotoxic cofactors (ie, hypovolemia and/or acidosis). RESULTS: All 35 patients were men without significant past medical history and were an average age of 24.4 years. The average admission creatine phosphokinase was 40,471 U/L. No patient presented with or developed nephrotoxic cofactors during hospitalization. None of our study patients experienced acute renal failure. CONCLUSION: Previous literature has described a 17% to 40% incidence of acute renal failure in rhabdomyolysis. None of our patients developed acute renal failure, signifying a much lower incidence of acute renal failure in exercise-induced rhabdomyolysis without nephrotoxic cofactors than in other forms of rhabdomyolysis.

Acute Kidney Injury↗
PubMed1992

Molecular analysis of the cytosolic and glycosomal glyceraldehyde-3-phosphate dehydrogenase in Leishmania mexicana.

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) activity was detected in two cell compartments of Leishmania mexicana promastigotes. These activities could be attributed to two different isoenzymes, one residing in glycosomes, the other in the cytosol. We have cloned and sequenced the genes for both isoenzymes. The glycosomal enzyme is encoded by two tandemly linked genes of identical sequence and contains features frequently found in glycosomal enzymes: the presence of peptide insertions, a small carboxy-terminal extension with a potential glycosomal targeting signal (-SKM) and an excess of positively charged residues (net charge +7). Only one open reading frame was detected for the cytosolic enzyme. The amino acid sequences of the two proteins are only 55% identical. We discuss some evolutionary aspects of the observed organization of the GAPDH genes in the Trypanosomatidae and the role of the two isoenzymes in the metabolism of these organisms. The possibility to develop GAPDH-specific inhibitors that will be effective against the enzyme of various parasitic members of this family is explored.

Amino Acid Sequence↗
PubMed1992

Digitalis toxicity caused by toad venom.

A case of toad venom-induced digitalis toxicity is presented. A pause of 13.5 s was noted in the patient taking a Chinese medication which contained toad venom. This is the first case report of clinical digitalis toxicity related to toad venom in Western society.

Aged↗
PubMed1991

The cytosolic and glycosomal isoenzymes of glyceraldehyde-3-phosphate dehydrogenase in Trypanosoma brucei have a distant evolutionary relationship.

Trypanosoma brucei contains two isoenzymes for glyceraldehyde-3-phosphate dehydrogenase: one enzyme resides in a microbody-like organelle, the glycosome; the other is found in the cytosol. Previously we have reported the characterization of the gene for the glycosomal enzyme [Michels, P. A. M., Poliszczak, A., Osinga, K. A., Misset, O., Van Beeumen, J., Wierenga, R. K., Borst, P. & Opperdoes, F. R. (1986) EMBO J. 5, 1049-1056]. Here we describe the cloning and analysis of the gene that codes for the cytosolic isoenzyme. The gene encodes a polypeptide of 330 amino acids, with a calculated molecular mass of 35440 Da. The two isoenzymes are only 55% identical. The cytosolic glyceraldehyde-3-phosphate dehydrogenase differs from the glycosomal enzyme in the following respects: (a) its subunit molecular mass is 3.4 kDa smaller due to the absence of insertions and a small C-terminal extension which are unique to the glycosomal protein; (b) the cytosolic enzyme has a lower pI (7.9, as compared to 9.3 for the glycosomal isoenzyme), which is due to a reduction in the excess of positively charged amino acids (the calculated net charges of the polypeptides are +2 and +11, respectively). We have compared the amino acid sequences of the two T. brucei glyceraldehyde-3-phosphate dehydrogenases, with 24 available sequences of the corresponding enzyme of other organisms from various phylogenetic groups. On the basis of this comparison an evolutionary tree was constructed. This analysis strongly supports the theory that T. brucei diverged early in evolution from the main eukaryotic branch of the phylogenetic tree. Further, two separate branches for the lineages leading to Trypanosoma are inferred from the amino acid sequences, suggesting that the genes for the two glyceraldehyde-3-phosphate dehydrogenases of the trypanosome are distantly related and must have been acquired independently by the trypanosomal ancestor. The branching determined with the glycosomal enzyme precedes that found with the cytosolic enzyme. The available data do not allow us to decide which of the two genes originally belonged to the trypanosome lineage and which entered the cell later by horizontal gene transfer.

Amino Acid Sequence↗
PubMedDate not supplied

Cloning and characterization of the NAD-linked glycerol-3-phosphate dehydrogenases of Trypanosoma brucei brucei and Leishmania mexicana mexicana and expression of the trypanosome enzyme in Escherichia coli.

A polyclonal antiserum raised against the purified glycosomal glycerol-3-phosphate dehydrogenase of Trypanosoma brucei brucei has been used to identify the corresponding cDNA clone in a T.b. brucei expression library. This cDNA was subsequently used to obtain genomic clones containing glycerol-3-phosphate dehydrogenase genes. Two tandemly arranged genes were detected in these clones. Characterization of one of the genes showed that it codes for a polypeptide of 353 amino acids, with a molecular mass of 37,651 Da and a calculated net charge of +8. Using the T.b. brucei gene as a probe, a corresponding glycerol-3-phosphate dehydrogenase gene was also identified in a genomic library of Leishmania mexicana mexicana. The L.m. mexicana gene codes for a polypeptide of 365 amino acids, with a molecular mass of 39,140 Da and a calculated net charge of +8. The amino-acid sequences of both polypeptides are 63% identical and carry a type-1 peroxisomal targeting signal (PTS1) SKM and -SKL at their respective C-termini. Moreover, the L.m. mexicana polypeptide also carries a short N-terminal extension reminiscent of a mitochondrial transit sequence. Subcellular localisation analysis showed that in L.m. mexicana the glycerol-3-phosphate dehydrogenase activity co-fractionated both with mitochondria and with glycosomes. This is not the case in T. brucei, where the enzyme is predominantly glycosomal. The two trypanosomatid sequences resemble their prokaryotic homologues (32-36%) more than their eukaryotic counterparts (25-31%) and carry typical prokaryotic signatures. The possible reason for this prokaryotic nature of a trypanosomatid glycerol-3-phosphate dehydrogenase is discussed.

Amino Acid Sequence↗
PubMedDate not supplied

Assembly of the paraflagellar rod and the flagellum attachment zone complex during the Trypanosoma brucei cell cycle.

Trypanosomes possess a single flagellum that is attached to their cell body via the flagellum attachment zone (FAZ). The FAZ is composed of two structures: a cytoplasmic filament complex and four microtubules situated next to it. There is a complex transmembrane crosslinking of this FAZ to the paraflagellar rod (PFR) and axoneme within the flagellum. We have partially purified the FAZ complex and have produced monoclonal antibodies both against the FAZ and the paraflagellar rod. The two antibodies against the FAZ (L3B2 and L6B3) recognise the cytoplasmic filament in immunofluorescence and in immunoelectron microscopy. On western blot, they detect a doublet of high molecular weight (M(r) 200,000). Two anti-PFR antibodies (L13D6 and L8C4) recognise the paraflagellar rod in immunofluorescence, but show a difference on Western blot: L13D6 recognises both major PFR proteins, whereas L8C4 is specific for only one of them. Using these new antibodies we have shown that although the growth of both cytoplasmic FAZ filament and external PFR are related, their growth initiates at different time points during the cell cycle and the two structures elongate at distinct rates.

Animals↗
PubMedDate not supplied

Percutaneous central venous access for resuscitation in trauma.

OBJECTIVE: To determine the safety of percutaneous central venous access when used for trauma resuscitation and whether the initial hemodynamic status of the patient or the site of placement affects the ease or success of line placement. METHOD: Consecutive major-trauma patients were managed using a resuscitation protocol guiding intravenous line use. Percutaneous peripheral venous access was initially attempted in all patients. If this approach was unsuccessful or proved to be inadequate for volume resuscitation, venous access was attempted using central venous catheter-introducer sets. The site of the central venous access was determined by protocol. For thoracic injury, access was via the ipsilateral subclavian vein (SCV), the ipsilateral internal jugular vein (IJV), or the femoral vein. For suspected mediastinal injury, access was via the contralateral SCV or IJV, or the femoral vein. For abdominal or flank injury, access was via the SCV or IJV only. Multiple central venous access sites were used at the discretion of the trauma team. RESULTS: Central venous access was successful at 144 of 147 sites (99%) used in 122 patients during the study period. There was only one major complication (rate = 0.7%; 95% CI 0.0-3.8%). Mean catheter placement time was 1.9 minutes, and cannulation occurred with a mean of 1.8 needle passes. Most patients (81/122) were hypotensive (blood pressure < or = 90 torr) at the time of line placement, including 44 who were in cardiac arrest and four awake patients who had no obtainable blood pressure. Neither the access site nor the presence of hypotension was associated with the mean time to obtain central venous access, the mean number of attempts, or the complication rate. CONCLUSION: Percutaneous central venous access is relatively safe and reliable for gaining intravenous access when resuscitating trauma patients, when used in a center where physicians are experienced in the technique. Consideration should be given to expanding the use of central venous access in trauma resuscitation.

Adult↗