Respiratory and cardiac function in congenital muscular dystrophies with alpha dystroglycan deficiency.

The aim of this retrospective study was to assess respiratory and cardiac function in a large cohort of patients with congenital muscular dystrophies (CMD) with reduced glycosylation of alphadystroglycan (α-DG). Thirteen of the 115 patients included in the study died between the age of 1 month and 20 years. The age at last follow up of the surviving 102 ranged between 1 year and 68 years (median: 9.3 years). Cardiac involvement was found in 7 of the 115 (6%), 5 with dilated cardiomyopathy, 1 cardiac conductions defects and 1 mitral regurgitation. Respiratory function was impaired in 14 (12%). Ten of the 14 required non invasive nocturnal respiratory support, while the other four required invasive ventilation. Cardiac or respiratory involvement was found in patients with mutations in FKRP, POMT1, POMT2. All of the patients in whom mutation in POMGnT1 were identified had normal cardiac and respiratory function.

Maternal exposure to the antiepileptic drug vigabatrin affects postnatal development in the rat.

The objective was to investigate, in the rat, the effects of maternal exposure to vigabatrin (VGB) on the postnatal motor-cognitive behaviour of the offspring. We used an experimental evaluator-blind, placebo-controlled study in the rat. Ten pregnant rats were divided into five groups and treated with different doses of VGB (250, 500, 750, 1000 mg/kg/day) or placebo from gestation day (GD) 6 to GD10. After delivery, 56 pups (40 pups prenatally exposed to VGB and 16 pups exposed to placebo) were evaluated for motor-cognitive behaviour throughout postpartum day 40. At the end of testing sessions the animals were sacrificed and brain tissues processed for biochemical analysis of GABA levels. Body weight of pups and young rats whose mothers were treated with a dose of 750 mg/kg/day were significantly lower both at birth and during the whole postnatal life with respect to the control groups. Young rats of this group exhibited impaired performance in both the open-field and water maze tasks. Brain GABA contents were dramatically increased in this group of rats. No other significant nutritional, biochemical or behavioural changes were observed after treatments with doses of VGB lower than 750 mg/kg/day. The exposure to a dose of 1000 mg/kg caused abortion. Maternal exposure to VGB at relatively high doses (750 mg/kg/day) is likely to cause some important changes of the nutritional status during the pre- and postnatal life. Thus, the biochemical and cognitive abnormalities observed in this study could be related to some disturbances of brain development induced by malnutrition and/or to a disturbance of neuronal programming of the gabaergic system.

Regulatory role of ALA-S and ALA-D in a haem-deficient mutant of Saccharomyces cerevisiae.

The biochemical characteristics of a haem-deficient mutant strain B231 of Saccharomyces cerevisiae isolated from D273-10B strain are described. B231 strain accumulates substantial amounts of 5-aminolevulinic acid (ALA) and uroporphyrin III (uro III). This pattern of porphyrins accumulation is due to both a defect in uroporphyrinogen decarboxylase (Uro-D) activity and an enhancement of porphobilinogenase (PBGase) activity. ALA accumulation would indicate that feed-back control by haem is not operating in this strain. ALA synthase (ALA-S), ALA-dehydrase (ALA-D) and PBGase activities; intracellular content of ALA (I-ALA) and porphyrins (I-porphyrins) were examined during the different phases of growth. Both accumulation of metabolites and enzyme activities reached their maximum values at 20 hrs. of growth, when glucose concentration in the medium fell to zero. Evidence for negative feed-back control on ALA-S and ALA-D by heme are provided by the observations of both enhanced I-ALA accumulation and increased ALA-D activity (2.5 times) in the mutant strain. Our results would indicate that both ALA-S and ALA-D can be considered regulatory enzymes in yeast.

Preliminary evaluation of 5 alpha-reductase type 2 in urine as a potential marker for prostate disease.

The objective of this study was to find a biomarker, easily detectable and measurable, that could be useful to the physician for the diagnosis and management of prostate cancer. An immunoaffinity-purified polyclonal antibody to the 5 alpha-reductase type 2 isozyme was prepared following standard procedures in New Zealand White rabbits. One hundred and seven urine samples were examined for the presence of this isozyme by Western blot, dot blot, and enzyme-linked immunosorbent assay assays. In a control group of 91 subjects (46 females and 45 males) with no history of prostate disease, only 1 female tested positive. In a test group of 16 males, 4 males with adenocarcinoma of the prostate under treatment with lupron/flutamide tested negative. Four males with untreated adenocarcinoma of the prostate tested positive. Two males with transitional cell carcinoma invading the prostatic ducts and two males with basal cell hyperplasia of the prostate with intraductal dysplasia tested positive. These results support the need for an extended study to explore the use of the Western blot or the simple dot blot and enzyme-linked immunosorbent assays for the detection of 5 alpha-reductase type 2 in urine as a potential marker for prostate disease.

Preliminary studies on the isolation and characterization of predominant prostatic proteins.

BACKGROUND: The increasing incidence of prostate cancer demands that we give our full attention not only to the etiology and prevention of this common type of cancer, but also to the diagnosis and prognostic course of this disease. In an effort to develop new prostatic tumor markers that could be useful to the physician at the current state of our knowledge in the diagnosis and prognosis of this disease, our laboratories have undertaken an effort to isolate and characterize the nature of the major proteins in the normal prostate and in prostatic neoplasia. METHODS: In this preliminary study, tissue was obtained from open prostatic surgery in patients with a pre- and postoperative diagnosis of benign prostatic hyperplasia. The initial fractionation and separation of the proteins was achieved through the use of ultrafiltration of homogenates followed by SDS-PAGE. Initial analysis of four prominent protein bands was accomplished by amino acid sequencing, and identified by a search in GeneBank data base. RESULTS: Two proteins previously identified in prostatic tissue were prostate specific antigen (M(r) 26,496) with 240 amino acid residues and beta-inhibin (M(r) 10,704) with 94-amino acid residues. A third protein was identified as human cysteine rich protein (hCRP). This protein functions as a DNA binding protein and has previously been postulated to contain four putative zinc fingers and to play a fundamental role in cellular function. Ubiquitin, the fourth major protein identified was a 76-amino acid polypeptide whose function is to target other proteins for destruction. CONCLUSIONS: hCRP and ubiquitin are reported as being found in high levels in prostatic tissue for the first time.

Immunochemical detection of 5 alpha-reductase in human serum.

This study represents a continuing effort to find a new biomarker for the diagnosis and management of prostatic cancer. Polyclonal antibodies were prepared to a peptide (CAKP) representing amino acids 28 to 43 of the 5 alpha-reductase type 2 isozyme. Using immunoaffinity-purified antibodies, the sera of 62 patients were examined by Western blot following polyacrylamide gel electrophoresis. A positive band was detected in the sera of several patients at 42 kDa compatible with the purified native glycosylated 5 alpha-reductase type 2. These bands were nullified on coincubation of the antibody with the CAKP peptide. Analysis by high-performance liquid chromatography and amino acid sequencing by N-terminal Edman degradation of the immunoaffinity-purified antigen to the antipeptide antibodies of a patient with adenocarcinoma of the prostate suggests that the 5 alpha-reductase type 2 isozyme may be linked to an immunoglobulin. An identical immunoaffinity-purified antigen to the CAKP peptide was isolated from a section of prostatic tissue from a different patient showing benign prostatic hypertrophy with severe dysplasia. It is suggested that an immunological response to the 5 alpha-reductase type 2 isozyme was elicited in both instances.

Inhibition of porphobilinogenase by porphyrins in Saccharomyces cerevisiae.

The biosynthesis of uroporphyrinogen III, the precursor of hemes, chlorophylls, corrins and related structures, is catalyzed by the porphobilinogenase system (PBGase), a complex of two enzymes, PBG-Deaminase (PBG-D) and Isomerase. Although the separate enzymes have been studied in some detail less work has been performed on the properties of the complex. In this study the kinetic behaviour of the enzyme PBGase in a normal yeast strain, D273-10B, and its derivative B231 has been investigated. Uroporphyrinogen formation was linear with time up to 2 hr at 37 degrees C. The enzyme complex shows classical Michaelis-Menten kinetics. From the double reciprocal plots kinetic parameters were estimated for PBGase and PBG-D. Porphyrins were found to be competitive inhibitors with respect to porphobilinogen (PBG) and these compounds appeared to act as inhibitors by forming dead-end complexes with the free enzyme. 5-Aminolevulinic acid (ALA) also inhibited PBGase and this inhibition was overcome by addition of levulinic acid (2 microM). These results indicate that ALA, is not an inhibitor but acts through its conversion into porphyrins which are the true inhibitors.

Unusual presentation of glomerulocystic kidney disease in an adult patient.

A 38-year-old Latin-American man developed uremic syndrome without any evidence of previous kidney diseases or any other health problems. Ultrasound and CT scan confirmed normal size of the kidneys without evidence of urinary tract obstruction or renal parenchymal cysts. Kidney biopsy showed cystic dilatation of Bowman's space (glomerulocystic kidney disease). The patient was started on hemodialysis. Severe renal dysfunction and uremic symptoms are a rare initial manifestation of glomerulocystic kidney disease. This pathology should be considered in the differential diagnosis of patients with normal size kidney and chronic renal failure.

Testicular androgens in prostate cancer patients treated with a luteinizing hormone releasing hormone agonist.

Luteinizing hormone releasing hormone agonists have been shown to reduce the levels of androgens in the peripheral circulation and to reduce prostate volume. The objective of this study was to quantify testicular function in patients with metastatic carcinoma of the prostate treated with a luteinizing hormone releasing hormone agonist, leuprolide, by analysis of spermatic vein blood for testosterone and androstenedione, and by determination of the maximum velocity of the 17 beta-hydroxysteroid oxidoreductase enzyme in testicular tissue in vitro. A chemical analysis of the spermatic vein blood of 19 patients with a median age of 78 years revealed the presence of significantly high levels of testosterone and androstenedione, 20.7 +/- 1.9 micrograms % and 6.7 +/- 0.7 micrograms %, respectively. These androgens could not be detected in patients treated with leuprolide before orchiectomy. Patients treated with leuprolide for several months followed by a period of no treatment before orchiectomy secreted testosterone and androstenedione levels comparable to the control group. The maximum velocity of the 17 beta-hydroxysteroid oxidoreductase enzyme in vitro in the testes of the leuprolide treated patients was significantly inhibited. Enzyme activity returned to normal levels when leuprolide treatment was followed by a recovery period of no treatment before orchiectomy.

In vitro studies on the inhibition of testosterone synthesis in the human testis by atamestane.

In view of the well established clinical results of the deprivation of androgens through orchiectomy in prostatic cancer and the structural similarities of 4-androsten-3,17-dione and atamestane (1-methyl-ADD), we studied the influence of 1-methyl-ADD on the conversion of 4-androsten-3,17-dione to testosterone by the 17 beta-hydroxysteroid reductase enzyme in human testicular tissue. Our studies, presented in this manuscript, demonstrate that 1-methyl-ADD is a competitive inhibitor of 4-androsten-3,17-dione in its reduction to testosterone by the 17 beta-hydroxysteroid reductase enzyme in the human testis.

A study of androgen biosynthesis by the human testis in vitro.

The biosynthetic pathways in human testicular tissue have been studied extensively in our laboratory without the use of radioisotopes. Experiments were conducted with normal testicular tissue from patients undergoing orchiectomy for prostatic cancer. These studies have shown that the preferred pathway of testosterone biosynthesis is influenced by the nature and concentration of cofactor added to the incubation medium. Four enzymes are involved in the transformation of pregnenolone to testosterone, that is, 3 beta-hydroxysteroid dehydrogenase, 17 alpha-hydroxylase, C17-C20 lyase and 17 beta-hydroxysteroid oxidoreductase. Our studies show that the 4-ene pathway predominates in the biosynthesis of testosterone from pregnenolone. Analysis of several samples of human testicular vein blood supports the contention that 4-androsten-3,17-dione is the immediate precursor of testosterone.

In vitro studies on the effect of cofactors on the 5 alpha-reductase and 3 alpha- and 3 beta-hydroxysteroid reductase activities in the hyperplastic human prostate.

Many studies have intimated that the accumulation and hence elevation of dihydrotestosterone (DHT) in the human prostate may be the primary factor in the development of benign prostatic hyperplasia (BPH). This accumulation has been explained in terms of an increase in the 5 alpha-reductase enzymatic activity which converts testosterone to DHT and a decrease in the relative activities of the 3 alpha-HSORred and 3 beta-HSORred enzymes. To investigate this hypothesis further, the activities of these two enzymes were studied in the presence and absence of NADPH in benign hyperplastic tissue and in normal peripheral (NPR) and benign hyperplastic periurethral (BPH) tissue taken from the same prostate. The results of these studies demonstrate a several fold increase in the activities of 3 alpha-HSORred and 3 beta-HSORred in the presence of NADPH in the hyperplastic human prostate. This increase in the activities of these two enzymes is found to the same degree in normal peripheral and benign hyperplastic periurethral tissue taken from the same prostate. There was no difference in percent increase in 3 alpha- and 3 beta-diol formation from DHT with NADPH in normal peripheral versus benign hyperplastic periurethral prostatic tissue. In subsequent experiments, Vmax/Km, as an index of the enzymatic capacity of the 3 alpha-HSORred and 3 beta-HSORred enzymes, was determined in both NPR and BPH tissue in media fortified with one mM NADPH. This quotient was found to be essentially the same in NPR and BPH tissue for both the 3 alpha-HSORred and the 3 beta-HSORred. Subsequently, the Vmax/Km value for the 5 alpha-reductase in BPH tissue was found to be equal to the combined Vmax/Km values of the 3 alpha-HSORred and 3 beta-HSORred. The reverse reaction or the conversion of 5 alpha-androstane-3 alpha,17 beta-diol and 5 alpha-androstane-3 beta,17 beta-diol is completely blocked in a medium containing one mM NADPH. These studies suggest that the concentration of DHT in prostatic tissue is dependent on the level of NADPH necessary for the 3 alpha-HSORred and 3 beta-HSORred enzymes to convert DHT to its respective diols.

Glutamate:4,5-dioxovaleric acid transaminase from Euglena gracilis. Kinetic studies.

The kinetic properties of the enzyme L-glutamate:4,5-dioxovaleric acid aminotransferase (Glu:DOVA transaminase) from Euglena gracilis have been studied. 5-Aminolevulinic acid formation was linear with time for at least 45 min at 37 degrees C and L-glutamate was the most effective amino-group donor. Lineweaver-Burk double-reciprocal plots suggested a ping-pong reaction mechanism, with Km values for L-glutamate and DOVA of 1.92 mM and 0.48 mM respectively. Competitive parabolic substrate inhibition by DOVA at concentrations greater than 3.5-4.5 mM was observed. Glyoxylate (4-10 mM) was found to be a competitive inhibitor with respect to DOVA, whereas at low concentrations (0-4 mM) noncompetitive plots were obtained. An analysis of the possible enzyme forms involved, was carried out. In more crude preparations most of the enzyme is found to be in the form of an enzyme-glutamate complex.

Saccharomyces cerevisiae porphobilinogenase: some physical and kinetic properties.

1. Properties of porphobilinogenase (PBGase), the enzyme complex converting porphobilinogen (PBG) into uroporphyrinogens, were studied in a wild strain, D273-10B and a mutant, B231, of Saccharomyces cerevisiae. 2. A well-defined maximum of enzyme activity was observed for the mutant strain after 20 hr of growth; whilst the activity in the wild strain did not vary significantly during growth. 3. Neither PBG consumption nor uroporphyrinogen formation were modified by the presence of air either in the wild or in the mutant strain. 4. In both the wild and mutant strains uroporphyrinogen formation increased linearly with both protein concentration and incubation time. 5. The addition of a mixture of sodium and magnesium salts to the assay system inhibited the enzyme activity of both strains by 50% without modifying the isomer composition. 6. The same optimum pH (7.4) and mol. wt (50,000 +/- 5000) was found for the enzyme from both strains. 7. The enzyme from both the wild and mutant strains shows Michaelis-Menten kinetics when isolated from cells at either the exponential or the stationary phases of growth. Accumulation of porphyrins and delta-aminolevulinic acid occurring during the exponential phase in the mutant strain, did not modify the kinetics.

[Saccharomyces cerevisiae: porphobilinogenase activity in a wild-type strain and its heme-deficient mutant]. / Saccharomyces cerevisiae: actividad de porfobilinogenasa en una cepa salvaje y su mutante hemo-deficiente.

Properties of Porphobilinogenase (PBGase), the enzyme complex converting porphobilinogen (PBG) into uroporphyrinogens, were comparatively studied in a wild strain D273-10B and its mutant B231 of Saccharomyces cerevisiae, Figure 1 shows the growth curves for both strains. The basic pattern of growth was observed but, although S. cerevisiae is a facultative aerobe and was grown on dextrose, a diauxic growth curve was not observed. The beginning of the exponential phase was slightly delayed for the mutant, so, its generation time (G = 3.20 h) was greater than that for the wild strain (G = 1.26 h). Optimum conditions for extracting the enzyme from both strains were found to be sonication at 10 mu for 3 min (Table 1). Table 2 shows the effect of centrifugation at 24,000 xg for 30 min on activity. For both strains the amount of porphyrins formed was the same either in the absence or presence of air. It was found (Figure 2) that urogen formation was linear with protein over a wide range of concentrations and with incubation time up to 2h in agreement with previous results for the enzyme of different sources. Figure 3 shows the effect of pH on PBGase activity. An optimum pH of 7.4 was found for both strains employing sodium phosphate buffer pH 8.0. The shape of the pH curve as well as optimum pH were the same in both Tris-HCl and phosphate buffer, however PBGase was 15% less active in the former. When plots of velocity against PBG concentration were analyzed for PBGase, it was found that measuring the rate of the reaction on the basis of total urogen formation, saturation curves for wild and mutant strains harvested at the exponential phase, followed classical Michaelis-Menten kinetics. Saturation was reached at PBG concentration of about 70-90 microM. Therefore, double reciprocal plots (Figure 4) were linear and from these plots apparent Km's values of 20 and 14 microM were obtained for the wild and mutant strain respectively. It is known that in some organisms, the activity of the enzyme of heme synthesis is significantly influenced by the days of growing; therefore the effect of time growing on PBGase activity was studied (Figure 5). A well defined maximum of enzyme activity was observed for the mutant strain after 20h of growing; while activity of wild strain did not significantly vary during growth.

Saccharomyces cerevisiae: actividad de porfobilinogenasa en una cepa salvaje y su mutante hemo-deficiente. / [Saccharomyces cerevisiae: porphobilinogenase activity in a wild-type strain and its heme-deficient mutant]

Properties of Porphobilinogenase (PBGase), the enzyme complex converting porphobilinogen (PBG) into uroporphyrinogens, were comparatively studied in a wild strain D273-10B and its mutant B231 of Saccharomyces cerevisiae, Figure 1 shows the growth curves for both strains. The basic pattern of growth was observed but, although S. cerevisiae is a facultative aerobe and was grown on dextrose, a diauxic growth curve was not observed. The beginning of the exponential phase was slightly delayed for the mutant, so, its generation time (G = 3.20 h) was greater than that for the wild strain (G = 1.26 h). Optimum conditions for extracting the enzyme from both strains were found to be sonication at 10 mu for 3 min (Table 1). Table 2 shows the effect of centrifugation at 24,000 xg for 30 min on activity. For both strains the amount of porphyrins formed was the same either in the absence or presence of air. It was found (Figure 2) that urogen formation was linear with protein over a wide range of concentrations and with incubation time up to 2h in agreement with previous results for the enzyme of different sources. Figure 3 shows the effect of pH on PBGase activity. An optimum pH of 7.4 was found for both strains employing sodium phosphate buffer pH 8.0. The shape of the pH curve as well as optimum pH were the same in both Tris-HCl and phosphate buffer, however PBGase was 15

less active in the former. When plots of velocity against PBG concentration were analyzed for PBGase, it was found that measuring the rate of the reaction on the basis of total urogen formation, saturation curves for wild and mutant strains harvested at the exponential phase, followed classical Michaelis-Menten kinetics. Saturation was reached at PBG concentration of about 70-90 microM. Therefore, double reciprocal plots (Figure 4) were linear and from these plots apparent Kms values of 20 and 14 microM were obtained for the wild and mutant strain respectively. It is known that in some organisms, the activity of the enzyme of heme synthesis is significantly influenced by the days of growing; therefore the effect of time growing on PBGase activity was studied (Figure 5). A well defined maximum of enzyme activity was observed for the mutant strain after 20h of growing; while activity of wild strain did not significantly vary during growth.