Cloning and expression of cytochrome P450 enzymes catalyzing the conversion of tyrosine to p-hydroxyphenylacetaldoxime in the biosynthesis of cyanogenic glucosides in Triglochin maritima

Two cDNA clones encoding cytochrome P450 enzymes belonging to the CYP79 family have been isolated from Triglochin maritima. The two proteins show 94% sequence identity and have been designated CYP79E1 and CYP79E2. Heterologous expression of the native and the truncated forms of the two clones in Escherichia coli demonstrated that both encode multifunctional N-hydroxylases catalyzing the conversion of tyrosine to p-hydroxyphenylacetaldoxime in the biosynthesis of the two cyanogenic glucosides taxiphyllin and triglochinin in T. maritima. This renders CYP79E functionally identical to CYP79A1 from Sorghum bicolor, and unambiguously demonstrates that cyanogenic glucoside biosynthesis in T. maritima and S. bicolor is catalyzed by analogous enzyme systems with p-hydroxyphenylacetaldoxime as a free intermediate. This is in contrast to earlier reports stipulating p-hydroxyphenylacetonitrile as the only free intermediate in T. maritima. L-3,4-Dihydroxyphenyl[3-(14)C]Ala (DOPA) was not metabolized by CYP79E1, indicating that hydroxylation of the phenol ring at the meta position, as required for triglochinin formation, takes place at a later stage. In S. bicolor, CYP71E1 catalyzes the subsequent conversion of p-hydroxyphenylacetaldoxime to p-hydroxymandelonitrile. When CYP79E1 from T. maritima was reconstituted with CYP71E1 and NADPH-cytochrome P450 oxidoreductase from S. bicolor, efficient conversion of tyrosine to p-hydroxymandelonitrile was observed.

Recurrence of uterine intravenous leiomyomatosis with intracardiac extension. Diagnostic considerations and surgical removal

A 28-year-old woman (gravida 2, para 2) was admitted 20 months after a hysterectomy because of fibromyoma. The hysterectomy specimen had shown intravenous leiomyomatosis. The patient presented with unspecific abdominal symptoms, serologic signs of hepatic and renal failure and clinical right-sided heart failure. Progression despite treatment with a gonadotropin-releasing hormone analogue promoted transferral to the present centre. Abdominal ultrasonography, phlebography and transoesophageal echocardiography showed a left pelvic mass and a seemingly free-floating tumour extending from the left main iliac vein via the inferior caval vein to the right ventricle. During a combined cardiac and distal caval approach using extracorporeal circulation, a 45 cm massive leiomyoma was removed successfully. Seven weeks later the left pelvic tumour was removed radically together with left oophorectomy. At control 12 months later the patient was well and without any remaining symptoms.

The T-superfamily of conotoxins

We report the discovery and initial characterization of the T-superfamily of conotoxins. Eight different T-superfamily peptides from five Conus species were identified; they share a consensus signal sequence, and a conserved arrangement of cysteine residues (- -CC- -CC-). T-superfamily peptides were found expressed in venom ducts of all major feeding types of Conus; the results suggest that the T-superfamily will be a large and diverse group of peptides, widely distributed in the 500 different Conus species. These peptides are likely to be functionally diverse; although the peptides are small (11-17 amino acids), their sequences are strikingly divergent, with different peptides of the superfamily exhibiting varying extents of post-translational modification. Of the three peptides tested for in vivo biological activity, only one was active on mice but all three had effects on fish. The peptides that have been extensively characterized are as follows: p5a, GCCPKQMRCCTL*; tx5a, gammaCCgammaDGW(+)CCT( section sign)AAO; and au5a, FCCPFIRYCCW (where gamma = gamma-carboxyglutamate, W(+) = bromotryptophan, O = hydroxyproline, T( section sign) = glycosylated threonine, and * = COOH-terminal amidation). We also demonstrate that the precursor of tx5a contains a functional gamma-carboxylation recognition signal in the -1 to -20 propeptide region, consistent with the presence of gamma-carboxyglutamate residues in this peptide.

Biosynthesis of cyanogenic glucosides in Triglochin maritima and the involvement of cytochrome P450 enzymes

The biosynthesis of the two cyanogenic glucosides, taxiphyllin and triglochinin, in Triglochin maritima (seaside arrow grass) has been studied using undialyzed microsomal preparations from flowers and fruits. Tyrosine was converted to p-hydroxymandelonitrile with V(max) and K(m) values of 36 nmol mg(-1) g(-1) fresh weight and 0.14 mM, respectively. p-Hydroxyphenylacetaldoxime and p-hydroxyphenylacetonitrile accumulated as intermediates in the reaction mixtures. Using radiolabeled tyrosine as substrate, the radiolabel was easily trapped in p-hydroxyphenylacetaldoxime and p-hydroxyphenylacetonitrile when these were added as unlabeled compounds. p-Hydroxyphenylacetaldoxime was the only product obtained using microsomes prepared from green leaves or dialyzed microsomes prepared from flowers and fruits. These data contrast earlier reports (Hösel and Nahrstedt, Arch. Biochem. Biophys. 203, 753-757, 1980; and Cutler et al., J. Biol. Chem. 256, 4253-4258, 1981) where p-hydroxyphenylacetaldoxime was found not to accumulate. All steps in the conversion of tyrosine to p-hydroxymandelonitrile were found to be catalyzed by cytochrome P450 enzymes as documented by photoreversible carbon monoxide inhibition, inhibition by antibodies toward NADPH-cytochrome P450 oxidoreductase, and by cytochrome P450 inhibitors. We hypothesize that cyanogenic glucoside synthesis in T. maritima is catalyzed by multifunctional cytochrome P450 enzymes similar to CYP79A1 and CYP71E1 in Sorghum bicolor except that the homolog to CYP71E1 in T. maritima exhibits a less tight binding of p-hydroxyphenylacetonitrile, thus permitting the release of this intermediate and its conversion into triglochinin.

[Acute porphyria and multiple organ failure during treatment with lamotrigine]

A 38-year-old female suffered from an acute porphyric attack, multi-organ failure and disseminated intravascular coagulation (DIC) within two weeks of starting lamotrigine, a new antiepileptic drug. The porphyric attack was characterized by excess urinary excretion of aminolevulinic acid (ALA), porphobilinogen (PBG) and coproporphyrin III, a pattern similar to that seen in hereditary coproporphyria, however the diagnostic criteria for this specific porphyria were not fulfilled. We suggest that the observed clinical picture represents a rare adverse reaction to lamotrigine.

Generation of 90-mW continuous-wave tunable laser light at 280 nm by frequency doubling in a KDP crystal

Laser light at a wavelength of 560 nm from a commercial ring dye laser has been frequency doubled in an external enhancement cavity with a KDP crystal. The cavity employs a new design consisting of only three mirrors, permitting a shorter cavity length as well as compensation for astigmatism and coma. With an input power of ~950 mW of green light, ~90 mW of UV light has been produced. The wavelength of the UV light can be tuned corresponding to +/-3 nm by angle tuning of the crystal, and the optical frequency can be scanned electronically up to +/-10 GHz.

[Endocarditis--clinical picture of native valve infection]

In a population of 930,000 inhabitants all records of native valve infective endocarditis diagnosed in the decade 1980-89 were reviewed. One hundred and thirty-two cases were found, of whom 23 were not diagnosed until postmortem. Median prehospital duration of symptoms was 20 days (range 0-180) and median in-hospital diagnostic delay five days (range 0-54). Known cardiac disease was found in 42%, possible portal of entry in 33%, but in 36% no predisposing factors were found. During the clinical course 55% experienced cardiac failure and 17% embolic episodes. Surgery was required in 19 patients. Of 111 culture positive cases, streptococci were found in 61 and staphylococci in 45 cases. Overall mortality was 33% with a mortality of clinically diagnosed cases of 18%. Native valve endocarditis is thus associated with a significant mortality in part due to significant diagnostic delays and a large number of post-mortem diagnosed cases. Only by securing a high level of alertness towards endocarditis can we expect a reduced mortality.

Bronchogenic metastasis to the gingiva

We report a rare case of a bronchogenic adenocarcinoma metastatic to the lower gingiva as the first clinical sign of metastatic disease. The following safe approach is recommended: a tumor in the oral cavity should be regarded as malignant or as a metastasis until the hypothesis can be abandoned.

Native valve infective endocarditis in the general population: a 10-year survey of the clinical picture during the 1980s

In a population of 930,000 inhabitants all records of native valve infective endocarditis diagnosed in the decade 1980-89 were reviewed. Using strict case definitions 132 clinically well-defined or post-mortem diagnosed cases were found. Included were cases referred to the local department of cardiology, as well as cases treated in non-specialized departments. Of 132 cases found 23 were only diagnosed post mortem. The male/female ratio was 71/61. The median prehospital duration of symptoms was 20 days (range 0-180 days) and the median in-hospital diagnostic delay was 5 days (range 0-54 days). Known cardiac disease was found in 42% of cases, a possible portal of entry was found in 33%, but in 36% there were no predisposing factors. Remarkably, only two patients had known rheumatic heart disease and none had a known dental focus. During the clinical course 55% experienced cardiac failure and 17% embolic episodes. In 19 patients surgery was required. Of 111 culture-positive cases streptococci were found in 61 and staphylococci in 45 cases. Echocardiography was performed in 95 cases with echocardiographic signs of endocarditis in 65 patients. Overall mortality was 33% with a mortality in clinically diagnosed cases of 18%. Of 14 cases needing immediate surgical intervention, two died.

[Incapacitating angina pectoris treated with electric stimulation of the spinal cord]

Thirty patients who had severe incapacitating angina pectoris which had not reacted to the conventional therapeutic measures and which required massive daily opioid consumption were treated with electrical spinal cord stimulation (SCS) by means of a completely implantable stimulation system. The therapeutic effect was good in 87% of the patients who experienced considerably reduced frequency of attacks and markedly reduced opioid consumption (p less than 0.00005). Nine of the patients could reduce opioid consumption and 14 out of 27 could cease their otherwise daily opioid consumption. In four patients, the therapeutic effect was unsatisfactory. In the first 22 patients in whom a unipolar electrode was introduced, displacement of the electrode and subsequent reoperation was a frequent problem. This problem disappeared after change to multipolar electrodes as slight changes in placing of the electrode could easily be compensated for via the external programming equipment. This investigation reveals that SCS is a good therapeutic alternative for this selected patient category.

EDTA treatment of intermittent claudication--a double-blind, placebo-controlled study

A double-blind, randomized multicentre study was undertaken to evaluate the possible effect of chelation treatment with ethylenediamine-tetraacetic acid (EDTA) in patients with severe intermittent claudication. A total of 153 patients received 20 intravenous infusions of either 3 g Na2EDTA or placebo during a period of 5-9 weeks. Vitamin, mineral and trace element supplements were administered orally. The changes observed in the pain-free and maximal walking distances, measured on a treadmill, were similar in the two groups. During the 3-month (n = 149) and 6-month (n = 123) follow-up period, no long-term therapeutic effect of EDTA could be demonstrated. The ankle-brachial blood pressure index remained unchanged throughout the study period. This study failed to demonstrate any effect of EDTA chelation treatment in intermittent claudication.

Hereditary peromelia in Mohair goats

The occurrence of a new congenital defect of the appendicular skeleton in Mohair goats is described. The malformation is peromelia and occurs in a familiar pattern. The defect seems to have an autosomal recessive mode of inheritance with variation in the expressivity of the genotype. The pathological abnormalities were described in 8 cases, all characterized by agenesia of the phalanges and parts of the metacarpus or metatarsus affecting one or more limbs. In some cases additional skeletal defects were found. Furthermore, 5 cases were reported by the owners with a description of the limb affected and 1 case was examined clinically. Predisposition for pelvic limbs to be affected was observed. The defect, which does not seem to have been described in goats previously, is phenotypically similar to and possibly also genetically homologous to a defect described in sheep.

[Residual metastases from testicular cancer. CT as a diagnostic and strategic adjuvant]

Forty-nine young males with advanced testicular cancer treated between March 1982 and June 1989 comprised a 49/588 (8%) subgroup with distant metastases to the retroperitoneum, mediastinum and lungs, and required mandatory surgery on basis of the risk for reactivation of "slumbering" malignant components in tumor tissue temporarily inactivated by chemotherapy and/or radiotherapy. Preoperative CAT-scan was carried out with the intention of mapping regional pathology related to the size, number, burden of the tumor tissue, and the occasional and prognostic ominous invasion of the great vessels. Regarding radical surgery, the positive predictive value of CAT-scan was found to be 33/34 (97%). The negative predictive value was 5/15 (33%) and was interpreted as an expression of the radiologist's cautious assessment. 14/49 (29%) died before March 1990. Poor prognosis was related to invasion of major vessels and was found in 14 patients of whom eight died. It seems established that CAT-scan presents an extremely valuable preoperative investigation when it comes to planning of surgical strategy in a patient population with testicular cancer metastases with difficult access.

Heart rate response to breathing: dependency upon breathing pattern

Heart rate responses to stepwise and periodic changes in lung volume were studied in seven young healthy males. Stepwise inspiration and expiration both resulted in an increase in heart rate followed by a rapid decrease in heart rate. The fastest heart rate was reached in 1.6 +/- 0.5 s and in 3.6 +/- 1.4 s in response to inspiration and expiration, respectively (P less than 0.01). The slowest heart rate was reached in 4.8 +/- 1.0 s and in 7.6 +/- 1.9 s in response to inspiration and expiration, respectively (P less than 0.01). Following this biphasic change the heart rate returned to a steady level. The difference between the fastest and the slowest heart rates was significantly larger in response to inspiration (21.7 +/- 7.3 beats per minute) than in response to expiration (12.0 +/- 7.3 beats per minute; P less than 0.01). Periodic changes in lung volume were performed with frequencies from 3.0 to 12.0 respirations per minute (r.p.m.). The changes in heart rate showed a constant amplitude in the frequency range below 5.5 r.p.m. Maximal heart rate changes were found at frequencies of 5.5 to 7.0 r.p.m. Changes in heart rate decreased in a linear manner on a log-log scale in the frequency range above 7.0 r.p.m. The relation between frequency and changes in heart rate is explained by interference between the transient changes in heart rate induced both by inspiration and by expiration. It is concluded that if heart rate changes in response to periodic changes in lung volume are to be used as a measure of vagal function a number of factors have to be taken into consideration and to simplify the analysis of heart rate responses to breathing we recommend, instead, the use of the transient changes in heart rate induced by stepwise changes in lung volume.