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P Heine

Publications and source records attributed to P Heine.

At least 19 recordsLinked to original sources
PubMed2001

The C-terminal cysteine-rich region dictates specific catalytic properties in chimeras of the ectonucleotidases NTPDase1 and NTPDase2.

Ecto-nucleoside triphosphate diphosphohydrolases (E-NTPDases) comprise a novel family of ectonucleotidases that are important in the hydrolysis of extracellular nucleotides. The related NTPDase1 (ecto-apyrase) and NTPDase2 (ecto-ATPase) share a common membrane topography with a transmembrane domain at both the N- and C-terminus, an extensive extracellular loop with five 'apyrase conserved regions' (ACR1 to ACR5), and a cysteine-rich C-terminal region. Whereas NTPDase1 expressed in CHO cells hydrolyzes ATP and ADP equivalently, NTPDase2 has a high preference for the hydrolysis of ATP over ADP. In addition recombinant NTPDase1 hydrolyzes ATP to AMP with the formation of only minor amounts of free ADP. In contrast, ADP appears as the major free product when ATP is hydrolyzed by NTPDase2. In order to determine molecular domains responsible for these differences in catalytic properties, chimeric cDNAs were constructed in which N-terminal sequences of increasing length of NTPDase1 were substituted by the corresponding sequences of NTPDase2 and vice versa. The turnover points were contained within ACR1 to ACR5. Chimeric cDNAs were expressed in CHO cells and surface expression was verified by immunocytochemistry. ATP and ADP hydrolysis rates and ADP and AMP product formation were determined using HPLC. Amino-acid residues between ACR3 and ACR5 and in particular the cysteine-rich region between ACR4 and ACR5 conferred a phenotype to the chimeric enzymes that corresponded to the respective wild-type enzyme. Protein structure rather than the conserved ACRs may be of major relevance for determining differences in the catalytic properties between the related wild-type enzymes.

Adenosine Diphosphate↗
PubMed2001

Multiple ecto-nucleotidases in PC12 cells: identification and cellular distribution after heterologous expression.

The physiological action of extracellular ATP and other nucleotides in the nervous system is controlled by surface-located enzymes (ecto-nucleotidases) of which several families with partially overlapping substrate specificities exist. In order to identify ecto-nucleotidases potentially associated with neural cells, we chose PC12 cells for analysis. PC12 cells revealed surface-located ATPase and ADPase activity with apparent K(m)-values of 283 microM and 243 microM, respectively. Using PCR we identified the mRNA of all members of the ecto-nucleoside triphosphate diphosphohydrolase family investigated (NTPDase1 to NTPDase3, NTPDase5/6), of ecto-nucleotide pyrophosphatase/phosphodiesterase3 (NPP3), tissue-non-specific alkaline phosphatase and ecto-5'-nucleotidase. The surface-located catalytic activity differed greatly between the various enzyme species. Our data suggest that hydrolysis of ATP and ADP is mainly due to members of the ecto-nucleoside triphosphate diphosphohydrolase family. Activity of ecto-5'-nucleotidase and alkaline phosphatase was very low and activity of NPP3 was absent. For a detailed analysis of the cellular distribution of ecto-nucleotidases single and double transfections of PC12 cells were performed, followed by fluorescence analysis. Ecto-nucleotidases were distributed over the entire cell surface and accumulated intracellularly in varicosities and neurite tips. PC12 cell ecto-nucleotidases are likely to play an important role in terminating autocrine functions of released nucleotides and in producing extracellular nucleosides supporting the survival and neuritic differentiation of PC12 cells.

Adenosine Diphosphate↗
PubMed1999

Functional characterization of rat ecto-ATPase and ecto-ATP diphosphohydrolase after heterologous expression in CHO cells.

The recently cloned ecto-ATPase and ecto-apyrase (ecto-ATP diphosphohydrolase) are plasma-membrane-bound enzymes responsible for the extracellular degradation of nucleoside 5'-triphosphates and nucleoside 5'-diphosphates. We expressed the rat-derived enzymes in CHO cells to compare their molecular and functional properties. Sequence-specific polyclonal antibodies differentiate between the two proteins and reveal identical molecular masses of 70-80 kDa. Both enzymes are stimulated by either Ca2+ or Mg2+ and reveal a broad substrate specificity towards purine and pyrimidine nucleotides. Whereas ecto-apyrase hydrolyzes nucleoside 5'-diphosphates at a rate approximately 20-30% lower than nucleoside-5'-triphosphates, ecto-ATPase hydrolyzes nucleoside-5'-diphosphates only to a marginal extent. The sensitivity of the two enzymes to the inhibitors of P2 receptors suramin, PPADS and reactive blue differs. Hydrolysis of ATP by ecto-ATPase leads to the accumulation in the medium of extracellular ADP as an intermediate product, whereas ecto-apyrase dephosphorylates ATP directly to AMP. Our results suggest that previous data describing extracellular hydrolysis of ATP by a variety of intact cellular systems with unidentified ecto-nucleotidases may be explained by the coexpression of ecto-ATPase and ecto-apyrase.

Adenosine Triphosphatases↗
PubMed1997

An ecto-ATPase and an ecto-ATP diphosphohydrolase are expressed in rat brain.

Extracellular nucleotides acting as signaling molecules are inactivated by hydrolysis catalyzed by ecto-nucleotidases. ATP is sequentially degraded via ADP and AMP to adenosine. Enzymes that can be involved in the extracellular hydrolysis chain are ecto-ATP diphosphohydrolase (ecto-apyrase), ecto-ATPase, ecto-ADPase and 5'-nucleotidase. Mammalian ecto-ATP diphosphohydrolase is a member of a family of apyrases sharing four "apyrase conserved regions" that presumably participate in the formation of the catalytic site. We report the presence of ecto-ATP diphosphohydrolase in rat brain and the primary structure of a new mammalian member of the apyrase family. Expression in CHO cells shows that it represents an ecto-ATPase. As revealed by Northern analysis of rat tissues, the ecto-ATPase is co-expressed with ecto-ATP diphosphohydrolase in heart, kidney, spleen, thymus, lung, skeletal muscle and brain. Signals for both ecto-nucleotidases are very weak in liver. mRNAs for both proteins are present in PC12 cells, suggesting that the two nucleotidases may be co-expressed in the same neural cell. Using computer-aided sequence analysis, primary structure and membrane topography are compared with those of other members of the apyrase family.

Adenosine Triphosphatases↗
PubMed1993

Trichomonas vaginalis: a reemerging pathogen.

Infestation with T. vaginalis is a common and potentially morbid infection. In addition to reproductive tract discharge and irritation, infection with this protozoa is increasingly recognized to be associated with reproductive tract complications, including postabortal infection, postcesarean infection, preterm birth, and PROM. Clinical diagnosis is often difficult and newer approaches using specific antigen and nucleic acid technologies will probably replace "wet prep" microscopic techniques. Effective treatments continue to depend on oral metronidazole treatment. Cure of resistant strains, which remain rare, depends on administration of higher, more prolonged doses of metronidazole. Improved understanding of the natural history, pathobiology, diagnosis, and treatment of this common protozoa is urgently needed. Practitioners should consider routinely screening and treating women for trichomoniasis before any reproductive tract surgery (chorionic villi sampling, hysterectomy, cesarean section, dilatation and curettage, therapeutic abortion, and so on), after changing sexual partners, and during pregnancy. Both symptomatic and asymptomatic patients and their sexual contacts should be treated.

Diagnosis, Differential↗
PubMed1993

[The action of atracurium and vecuronium in chronically hemodialyzed patients].

UNLABELLED: Reports on the duration of action of atracurium (Atr) and vecuronium (Vec) in patients with renal failure are contradictory. It is either stated that the duration is equal for both relaxants or that Atr acts for a longer duration. Because of these conflicting results, we measured the times for latency (tL), onset (tA), duration of action (tW), and recovery (tE) for both agents. METHODS: Fourty patients with end-stage renal failure on chronic haemodialysis were randomly assigned to receive either Atr (0.4 mg.kg-1 BW) or Vec (0.08 mg.kg-1 BW). After induction with thiopentone and 0.1 mg fentanyl, anaesthesia was maintained with nitrous oxide and 1 vol.% ethrane and expiratory CO2 partial pressure was kept between 4.6 and 4.9 kPa. If the twitch height of T1 regained 25% of the pre-relaxation value, 20% of the initial relaxant bolus was injected. Relaxation was monitored with a relaxograph after calibration of the device. After testing for a normal distribution, statistical analysis was done by Student's t-test. A value of P < or = 0.05 was chosen for statistical significance. RESULTS: There were no significant differences regarding tL (Atr: 1.0 +/- 0.5 min; Vec: 1.1 +/- 0.5 min) and tA (Atr: 5.5 +/- 2.1 min; Vec 4.1 +/- 2.4 min); tW (Atr: 21.3 +/- 13.1 min; Vec 31.7 +/- 15.6 min) and tE (Atr: 19.0 +/- 9.0 min; Vec 30.1 +/- 19.0) were significantly different. DISCUSSION: Our results are not in accordance with those authors who found in comparison with Atr an equal or shorter duration of action for Vec in patients with renal failure. If the duration of action is equal in subjects with no renal insufficiency, our measurements are in accordance with kinetic evaluations showing the same clearance and half-life for Atr in patients with and without renal insufficiency, but 40% diminished clearance and 60% prolonged half-life for Vec in renal insufficiency.

Adult↗
PubMed1989

Sex practice correlates of human immunodeficiency virus transmission and acquired immunodeficiency syndrome incidence in heterosexual partners and offspring of U.S. hemophilic men.

We assessed the risk of human immunodeficiency virus (HIV) transmission from heterosexual seropositive hemophilic men to their female sex partners through an HIV serosurvey and questionnaire study conducted during 1984-1987. Five percent of 21 female partners of asymptomatic men and 11% of 35 partners of HIV-symptomatic (acquired immunodeficiency syndrome [AIDS], AIDS-related complex [ARC], peripheral generalized lymphadenopathy [PGL]) hemophilic men had been infected when first tested. One of 19 seronegative women tested about 1 year later reportedly seroconverted. Only 18% of a sample of the serosurvey women responding to sex practices questions said their partners used condoms "nearly always." Over 60% engaged in oral/genital sex in addition to vaginal intercourse. Only 12% of still-seronegative women followed the preventive strategy of consistent avoidance of oral/genital sex, together with consistent condom use by the male partner. Further evidence for heterosexual transmission comes from the CDC national AIDS surveillance reports showing 25 women who acquired HIV infection through heterosexual contact with U.S. hemophilic men (September 6, 1988). Seven (28%) were diagnosed and reported in the first 6 months of 1988. Their ages range from 20 years to more than 70 years. The dates of infection for the women are unknown but must have been at least 5 years before AIDS diagnosis for at least one. Only approximately 30% of their male partners had already manifested any HIV-associated illness. Through May 18, 1988, six cases of AIDS have occurred in children whose infection was acquired through exposure of the mother to a hemophilic partner. Four were diagnosed in latter 1987. The median age at diagnosis was 4.5 months. Four had died. None of their mothers is as yet diagnosed.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Focal myelin thickenings in a peripheral neuropathy associated with IgM monoclonal gammopathy.

Nerve biopsy in peripheral neuropathies associated with an IgM monoclonal gammopathy may occasionally display focal myelin thickenings. In a patient with such an IgM neuropathy, in whom an anti-myelin-associated glycoprotein (MAG) antibody activity was present in the serum, single-fiber preparations revealed 34% of internodes bearing myelin swellings. The morphometric, morphological and ultrastructural findings were reminiscent but not identical to those of the hereditary tomaculous neuropathy with liability to pressure palsies. Atypical features for tomacula included lack of spiralization of the redundant loops of myelin around the axons and their predominant external situation with regard to the myelin sheath. The frequent colocalization of myelin thickenings and the widening of myelin lamellae typical of IgM neuropathies, are highly suggestive of some pathogenetic link between the two abnormalities. The redundant loops of myelin in IgM neuropathies possibly result from a defect in the axon-myelin adhesion secondary to the binding of IgM on an epitope of MAG directly involved in cell-cell adhesion.

Aged↗
PubMed1989

[A new metal tube for laser surgery of the laryngotracheal region].

Various measures have been taken to minimize laser-specific hazards during laryngotracheal microsurgery with CO2-laser equipment. Endorsing Norton's view that only a metal tube ensures complete safety during laser surgery, we tested the "Laser-Flex", a new endotracheal tube (ETT) of high-grade stainless steel. This reconstructed, flexible, gas-tight ETT was designed to avoid perforation and even ignition of the tube with consecutive inhalation of combustion products known to be very strong lung irritants. The dull surface of the spiral ETT prevents damage to the surrounding mucosa by diverging the laser beam. The flexibility and greater stability compared with PVC- or silicone armored tubes makes intubation possible without a guide even under difficult conditions. A small PVC-tube with two high-volume-low-pressure cuffs is attached to the distal end of the metal ETT. The cuffs are filled via different inlets clearly distinguished by color as well as by the inscriptions "proximal" and "distal". Both inlet lines float inside the metal tube, thus being protected from accidental laser beams. The cuffs are filled with saline solution. In case of inflammation and destruction of the proximal cuff, the discharged solution will extinguish the flame and also protect the distal cuff, ensuring normal ventilation. Thus none of the laser operations had to be interrupted during our test period if accidentally perforation of the proximal cuff occurred. The high price of the "Laser-Flex" should not be a reason to abstain from using this tube. In view of the higher margin of patient safety, this tube might be used even from an economic point of view. In our tests we reused each tube five to eight times, thus lowering the costs with each reuse. Checks following sterilization after each use did not show any dysfunction of the cuffs or valves.

Humans↗
PubMed1988

[Anesthesia and laser surgery of the laryngo-nasal-ear region].

The applications of lasers in surgery is nowadays a widely used and well appreciated technique. Besides convincing advantages (precision in surgical manipulations, excellent hemostasis, minimal postoperative swelling, rapid healing) laser-unique hazards require particular safety considerations to avoid accidental injuries to patients and medical personnel. For damage of the eyes is the greatest risk in laser surgery goggles designed to the respective wavelength of the specific laser must be worn by everyone in the operation theatre. The patient's eyes are best protected by covering them with water moistened gauze pads. To avoid reflection of the laser beam only instruments with dull surfaces should be used. The proper function of the laser itself has been tested by a well trained surgeon before operation. Especially in microlaryngeal surgery carried out under general anaesthesia, severe complications, e.g. pneumothorax, penetration of large vessels or destruction of the surrounding tissues, may be the result of beam reflection or unskilled use. However, the most serious hazard for the patient-and even that one with the highest incidence (0.4 to 1.5%)-arises from the close neighbourhood of endotracheal tube and laser beam while operating in the larynx or the upper airways. In tests it has been demonstrated that the beams of different lasers penetrate tubes of various materials (silicone, semi- or transparent pvc) to a different extent, often igniting the material. High oxygen and nitrous oxide contents support tube ignition. The inhalation of smoke and toxic pyrolysis products either of tube-material or, possibly, of volatile anaesthetics are followed by serious damage of trachea and lung tissue.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia↗
PubMed1987

Hemophiliac patient's knowledge and educational needs concerning acquired immunodeficiency syndrome.

The Patient Knowledge Assessment Study (PKAS) was conducted among 107 male hemophilic patients, aged 15 to 67 years, at 19 hemophilia treatment centers (HTC). Participants were given a 30-item questionnaire concerning the cause of acquired immunodeficiency syndrome (AIDS), the groups at risk, and modes of transmission. The questionnaire included questions on the participant's status in regard to antibody to human T-lymphotropic retrovirus, type III/lymphadenopathy-associated virus (HTLV-III/LAV), and the meaning of this test result. HTC health-care providers were asked to complete a separate questionnaire containing 17 questions about information given patients concerning their HTLV-III/LAV antibody status and its meaning. Overall, patients had a good base of knowledge about AIDS; however, there were gaps in this knowledge. Twenty-nine percent of patients did not know that spouses of AIDS patients were at risk for AIDS; 47% did not know that sexual partners of persons with hemophilia were at risk; and 32% did not know that hemophilic children were at risk. Further, only 69% understood that antibody-positive individuals had had contact with the AIDS virus. Identifying these and other areas of misunderstanding will provide the information needed to design educational strategies and psychosocial support programs appropriate for the hemophilic population, and which may serve as a model for other populations.

Acquired Immunodeficiency Syndrome↗
PubMed1984

[Presence of high concentrations of aluminum in neurons of a patient dying from a rapidly developing dementia].

Ultrastructural observation of brain cells of a patient dead from senile dementia associated with myoclonies, has shown a number of intracytoplasmic dense structures. High concentration of Aluminium has been detected in these structures by electron probe X ray analysis. The clinical symptomatology, the evolution and the cell pathology observed in this patients are very similar to the classical features observed in dialysis encephalopathy the origin of which is an aluminium intoxication. In this patient, the possible origin of the intoxication is the absorption in the last 10 years of aluminium gels.

Aged↗