Biomedical subjects
M John
Publications and source records attributed to M John.
The role of nodulation genes in bacterium-plant communication.
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Free radicals in children with rheumatic diseases in serum and synovial fluid.
Free radicals, demonstrable by thiobarbituric acid, are also significant in the pathogenic concept of juvenile chronic arthritis. 41 patients without therapy demonstrate significantly increased values in serum, compared with the same patients after a treatment of 4 weeks. There are relations between ESR and the concentration of thiobarbituric acid reactive substances in serum, but without statistic significance. In the synovial fluid the radicals are increasingly demonstrable, but there is no relation to the number of cells or granulocytes.
Purification of a Ca2+/calmodulin-dependent nitric oxide synthase from porcine cerebellum. Cofactor-role of tetrahydrobiopterin.
L-Arginine-derived nitric oxide acts as an inter- and intracellular signal molecule with cytosolic guanylyl cyclase as the effector system. Two NO synthase isoenzymes are postulated: a cytokine-inducible enzyme in macrophages and a constitutive, Ca2(+)-regulated enzyme in various other cells. An NO synthase was isolated from porcine cerebellum by ammonium sulfate precipitation and affinity chromatography on 2',5'-ADP-Sepharose. The enzyme was identified as an NO synthase with a specific NO-chemiluminescence method and with purified cytosolic guanylyl cyclase as an NO-sensitive detection system. The purified NO synthase was, besides Ca2+/calmodulin and NADPH, largely dependent on tetrahydrobiopterin as a cofactor.
Bronchiolitis in tropical south India.
In a prospective hospital-based study of 328 children under 5 years of age with acute lower respiratory infections, 114 (35%) were diagnosed to have acute bronchiolitis. Of them, 87 (76%) were less than 1 year and 107 (94%) were less than 2 years of age. Signs of severe lower respiratory infections, namely tachypnea (respiratory rate greater than 50/min) and subcostal retraction, were present in 95% and 93%, respectively. Of 88 children of whom roentgenographs were taken, 30 (34%) had evidence of pneumonia. No clinical signs discriminated between those with and without pneumonia. By culture or immunofluorescence antigen detection, viruses were found in 81 (71%) children with bronchiolitis; respiratory syncytial virus was the most common agent, found in 65 (57%). Parainfluenza viruses were the next most common, found in 12 (11%). Most cases of bronchiolitis occurred in outbreaks during the rainy months of August through November, coinciding with respiratory syncytial virus outbreaks. Although bacterial culture of blood was done in 56 children, no respiratory pathogen was isolated. In one child with bronchiolitis and consolidation, postmortem lung aspirate yielded Staphylococcus aureus. Thus, bronchiolitis is primarily a viral syndrome in this tropical region, just as it is in temperate regions. Eight (7%) children died (all were infants); 5 had roentgenographic pneumonia and the remaining had other abnormalities contributing to death; all had been treated with antibiotics. Since one third of lower respiratory infections are bronchiolitis, and among infants under 1 year of age bronchiolitis comprises 47% of all lower respiratory infection cases, criteria for antibiotic management must take into account the availability of roentgenographic investigation.
Urokinase and tissue type plasminogen activators in human keratinocyte culture.
Using immunocytochemical and biochemical techniques, we have demonstrated that cultured human epidermal keratinocytes contain both urokinase and tissue type plasminogen activators. In subconfluent colonies the distribution of the two enzymes differed. Tissue type plasminogen activator (tPA) was distributed evenly throughout the colony, while, as we have demonstrated previously, urokinase type plasminogen activator (uPA) was preferentially localized at the migrating edges of the colony. Using zymographic analyses, both tPA and uPA activities were detected in cell extracts. Depending on the procedure used to prepare cell extracts, tPA was detected either as free enzyme or in complex with PA inhibitor type 1. PA inhibitor type 1 was deposited onto the extracellular matrix of the keratinocyte cultures and formed a complex with cell-associated tPA when cells and matrix were extracted together. The most differentiated keratinocytes in the culture, which were spontaneously shed from the culture surface, also contained both tPA and uPA. However, these spontaneously shed cells had a higher ratio of tPA:uPA than did the less differentiated cells from the same culture. In conjunction with our previous studies, these results demonstrate the complex nature of the plasminogen activator system, including enzymes and inhibitors, that is present in human keratinocytes. In addition, our data suggest that the relative amounts of uPA and tPA in epidermal cells vary with differentiation state.
Preliminary results of concurrent radiotherapy and chemotherapy in advanced cervical carcinoma: a phase I-II prospective intergroup NCOG-RTOG Study.
Thirty-eight patients with advanced carcinoma of the cervix were prospectively treated with a concurrent combination of radiotherapy (RT) and chemotherapy (CT) using the drugs 5-fluorouracil (5FU), mitomycin C and cis-platinum as part of a Northern California Oncology Group (NCOG) and Radiation Therapy Oncology Group (RTOG) intergroup study. RT consisted of 36.00 Gy to the pelvis in 4 weeks followed by a 9.00-Gy parametrial boost. This was followed by two intracavitary applications for a total of 4000 mg hr of radium equivalent when possible. 5FU (1000 mg/m2/24 hr for 96 hr by iv infusion) and mitomycin C (10 mg/m2/iv bolus) were given during the second week of external RT. 5FU (dose as above) and cis-platinum (75 mg/m2/iv over 6 hr) were given during the first intracavitary application. Of 36 patients evaluable for toxicity, 11% had grade 3 nonhematological toxicity and 11% had reversible grade 4 hematological toxicity. There were no toxic deaths. A complete response rate of 62.5% was obtained overall (median survival not reached). This study suggests that this particular combination of RT and CT in advanced cervical carcinoma is effective and well tolerated.
Prophylactic irradiation of the para-aortic lymph node chain in stage IIB and bulky stage IB carcinoma of the cervix, initial treatment results of RTOG 7920.
From November 1979 to October 1986, 367 patients were entered onto RTOG 7920 and randomized to receive either pelvic irradiation alone or pelvic plus para-aortic radiation. Patients with Stage IIB cervical carcinoma who had not undergone curative surgery and patients with Stages IB and IIA cervical carcinoma who were determined by digital exam to have primary tumors measuring 4 cm or greater in lateral dimension were eligible for this study. Clinically apparent or surgically involved para-aortic nodes were reason for exclusion from the study. Pelvic irradiation consisted of 1.6-1.8 Gy per day for 5 days per week to a total of 40-50 Gy. Para-aortic irradiation delivered 44 to 45 Gy in 1.6-1.8 Gy per day, 5 days per week. Pelvic irradiation was to be completed in 4 1/2 to 6 1/2 weeks and para-aortic irradiation in 4 1/2 to 5 1/2 weeks. Intracavitary brachytherapy delivered a total of 4000-5000 mg hr of radium-equivalents or 30-40 Gy to point A. Patients were stratified prior to random treatment assignment by histology, para-aortic nodal status (negative vs. unevaluated), and FIGO stage. As of June 1, 1989, 30 cases were excluded, including five patients who were inevaluable. Two patients who refused the assigned treatment were also excluded. Therefore, a total of 330 cases were analyzable. At 5 years the estimates of survival, the primary endpoint, for the pelvic only and pelvic plus para-aortic irradiation arms are 55% and 65%, respectively (p = 0.043). Several secondary endpoints were also analyzed. Estimates for loco-regional control at 5 years are, for pelvic irradiation only, 66%, and for pelvic plus para-aortic irradiation, 75% (p = 0.21). Distant metastases are estimated in 32% of pelvic irradiation only patients and 25% of pelvic plus para-aortic irradiation patients at 5 years (p = 0.17). When the first disease failure patterns are examined, more patients fail distally when treated only with pelvic radiation than when using pelvic plus para-aortic fields (p = .04). In analysis of patients with grade 3 (severe), grade 4 (life-threatening), and grade 5 (fatal complications), 8% of the patients in both groups had grade 3 severe complications. In the pelvic plus para-aortic group, 11 patients had grade 4 and 2 had grade 5 complications, whereas 6 had grade 4 and none had grade 5 in the pelvic only treatment group.(ABSTRACT TRUNCATED AT 400 WORDS)
Oxidation products of caffeic acid as model substances for the antigonadotropic activity of plant extracts.
Phenolic plant constituents exert antigonadotropic activity following an oxidation. The resulting complex mixture of mostly instable products impedes the elucidation of the various oxidation steps as well as the mode of antigonadotropic action. Thus caffeic acid was chosen as a single model phenolic to facilitate the interpretation. The oxidation of caffeic acid with KMnO4 as well as with polyphenoloxidase leads to the instable caffeic acid o-quinone as the first oxidation product. Following the initial oxidation, a number of products was indicated via HPLC. Two of them were isolated and characterized as oligomers of caffeic acid, one of them with phenolic, acid and, quinoic structural components and a relative molecular mass similar to caffeic acid tetramer. It was shown that caffeic acid quinone cannot be the antigonadotropically active principle. Correspondingly, the isolated oxidation products exhibit pronounced antigonadotropic activity. It could be proved that oxidation products of caffeic acid bind to PMSG, forming PMSG-inhibitor-complexes. In such complexes the gonadotropic activity of PMSG is completely abolished.
Structures of compounds with antigonadotropic activity obtained by in vitro oxidation of caffeic acid.
Two new cyclolignan derivatives were isolated by HPLC from the mixture of substances obtained after oxidation of caffeic acid with KMnO4. Their structures were elucidated by spectroscopic methods as 2,3-dicarboxy-6,7-dihydroxy-1-(3', 4'-dihydroxy)-phenyl-1, 2-dihydronaphthalene (1) and 3-carboxy-6,7-dihydroxy-1-(3', 4'-dihydroxy)-phenylnaphthalene (2). Compounds 1 and 2 exhibit antigonadotropic activity as do the extracts of crude drugs of Lycopus europaeus and Lithospermum officinale after oxidation by plant enzymes.
Cerebrospinal fluid C-reactive protein measurement--a bedside test in the rapid diagnosis of bacterial meningitis.
C-reactive protein (C-RP) determinations were performed by the Latex agglutination method on the cerebrospinal fluid (CSF) samples of 212 patients with clinical features suggestive of meningitis. Patients were grouped as follows Group I: bacterial meningitis and partially treated bacterial meningitis (n = 22). Group II: viral encephalitis (n = 11). Group III: tuberculous meningitis (n = 18). Group IV: (i) febrile convulsions (n = 87); (ii) epileptic seizures (n = 70); (iii) intracranial haemorrhage (n = 4). C-RP was a better indicator of bacterial meningitis (sensitivity 91 per cent) than the Gram's stain (sensitivity 46 per cent). C-RP was positive in 91 per cent of patients in Group I, none in Groups II and III and 0.6 per cent in Group IV. C-RP determination in CSF proved to be a useful indicator of bacterial meningitis and served to distinguish it from viral encephalitis, tuberculous meningitis, febrile convulsions and other central nervous system disorders.
Comparison of immunofluorescence & culture for the diagnosis of respiratory syncytial virus infection.
In 809 infants and children with acute respiratory infection, HEp-2 cells were used for the isolation of respiratory syncytial virus (RSV) and an indirect immunofluorescence technique (IIF) was used for the detection of RSV antigen in the epithelial cells of nasopharyngeal secretions. While RSV was detected in culture in only 87 subjects, IIF was positive for viral antigen in 158 subjects. In children with bronchiolitis and in those with pneumonia 57 and 19 per cent respectively, had evidence of RSV infection by culture or IIF. The frequency of virus antigen detection by IIF was above 90 per cent irrespective of the duration of symptoms before specimen collection. The frequency of virus isolation in culture was 86 per cent in children with less than 2 days duration of symptoms and 42 to 69 per cent in those with duration of symptoms of 2 days or more. However, this difference was not statistically significant. In conclusion, the IIF test was not only rapid, but also more sensitive for the detection of RSV infection than culture.
Positive and negative control of nod gene expression in Rhizobium meliloti is required for optimal nodulation.
We show that expression of common nodulation genes in Rhizobium meliloti is under positive as well as negative control. A repressor protein was found to be involved in the negative control of nod gene expression. Whereas the activator NodD protein binds to the conserved cis-regulatory element (nod-box) required for coordinated regulation of nod genes, the repressor binds to the overlapping nodD1 and nodA promoters, at the RNA polymerase binding site. A model depicting the possible interaction of the plant-derived nod gene inducer (luteolin), the NodD and the repressor with the nod promoter elements is presented. Mutants lacking the repressor exhibited delayed nodulation phenotype, indicating that fine tuning of nod gene expression is required for optimal nodulation of the plant host.
[Speech and conviction as determinants of behavior and perception in interactions: an example of physician-patient relations].
We report on a simulation study with 72 student subjects as well as on an inquiry of 58 patients on the doctor-patient interaction. We were especially interested in inferences that patients draw from general practitioners' behaviors, i.e., their warmth, their kind of talk, and their embarrassment. The simulation study as well as the inquiry reveal patients' inferences that were highly consistent in 9 (out of 16) dependent variables. Patients' inferences on the state of the disease, on the doctor's competence, interest and warmth, on the doctor's kind of talk and sympathy, all consistently depended on the doctor's behaviors. The psychological as well as medical implications of these results are discussed.
[Relation of the family physician to his patient and evaluation of the patient: aspects of willingness to comply?].
This study was conducted to examine the influence of general practitioner's behavior (i.e. the patient-centered behavior) on patients' inferences as well as on patient's compliance. We demonstrated in a simulation study as well as in an inquiry of patients in general practice that doctor's competence, interest and sympathy are estimated higher, if the doctor's behavior is patient-centered. Significant single results are reported in respect to patients' knowledge, their inference on the state of the disease and on the convalescence. Patient-centered behavior did not have a direct influence on patients' compliance.
Evaluation of simple clinical signs for the diagnosis of acute lower respiratory tract infection.
The reliability of clinical signs that might be used by village health workers in distinguishing acute lower respiratory infection (LRI) from upper respiratory infections (URI) in children was evaluated. 142 infants and 108 preschool children with LRI and 151 infants and 281 preschool children with URI, attending hospital, were studied. Respiratory rates of over 50/min in infants and over 40/min in children 12-35 months of age, as well as a history of rapid breathing and the presence of chest retractions in both age groups, were found to be sensitive and specific indicators of LRI. Increased respiratory rates and history of rapid breathing were also sensitive in diagnosis of less severe LRI that did not necessitate admission to the wards, whereas chest retraction was not. All these clinical signs had a low sensitivity in diagnosing LRI in children aged 36 months and over.
[Efficacy of halofantrine in Plasmodium falciparum or Plasmodium vivax malaria in a resistance area (French Guiana)].
Halofantrine (WR 171.669) is a phenanthrene methanol derivative effective against the multidrug resistant strains of Plasmodium falciparum. One hundred and one patients, 48 men and 53 women, 53 adults and 48 children (less than or equal to 12 years old) aged from 1.5 to 57 years were treated. Fifty-one patients received a single 16 mg/kg dose and 50 patients received 24 mg/kg/day in 3 doses at 6-hour intervals. Parasite counts with examination of both thin and thick smears were performed twice daily for 5 to 6 days following treatment, or until smears were negative for parasites for 24 hours, and then weekly for 4 weeks. Thirteen patients reported clinical side effects. Six treated patients had no parasites. One patient had mixed parasitemia. Eighty three patients had P. falciparum malaria, with mean parasitemias between 26,850 +/- 36,679 and 35,412 +/- 50,527 per cubic millimeter. Halofantrine was very effective in the two doses tested from 87.5 to 100 p. 100. Eleven patients had in vivo resistant strains; ten in vitro tests were successful and nine were resistant to chloroquine. Thirteen patients with P. vivax and a mean parasitemia of 13,858 +/- 10,835 per cubic millimeter were cured but 3 had a relapse 3 to 4 weeks after treatment. At the 2 dosage levels tested halofantrine proved highly effective in the treatment of malaria caused by resistant and sensitive strains to P. falciparum.
Transmembrane orientation and receptor-like structure of the Rhizobium meliloti common nodulation protein NodC.
The 46.8-kd NodC protein of Rhizobium meliloti is a membrane protein, essential for nodule formation. Gene fusions of nodC to a portion of the lambda cI repressor gene were used to define the membrane-anchor domain which is necessary for membrane insertion of the NodC protein into the membrane. The transmembrane orientation of NodC was confirmed by surface-specific radiolabeling and proteolysis experiments. A highly hydrophobic transmembrane-anchor domain was found near the carboxyl terminus, separating a large extracellular domain which contains an unusual cysteine-rich cluster from a short putative intracellular domain. Cross-linking studies showed that the NodC protein exists in the membrane probably as a dimer. The domain structure of the NodC protein shows striking similiarities with cell surface receptors. In nodules of various legumes a truncated form of the NodC protein was detected. The processed NodC was associated with the bacteroids and the amount of this protein increased during nodule development.