Eighteen diabetic children aged between 8.5 and 16.5 years (mean 12.5 years) who had been diabetic for 1 to 10 years (mean 4.1 years) were examined for their urinary glomerular basement membrane (GBM) antigen excretion by means of immunoelectrophoresis and for alterations of the retinal vessels by fluorescence angiography. None of these patients showed albuminuria or hypertension. As compared to 40 healthy controls aged between 5 and 17 years, altered GBM antigen mobility (alpha-1) was found in 9 out of these 18 diabetics, whereas the remaining 9 children had normal GBM antigen mobility (alpha-2). Pathological fluorescence angiography findings on the other hand were evident in 7 children with altered GBM mobility, but only in 4 diabetics with normal GBM antigen mobility. This trend reflects the similarity of biochemical and functional characteristics of basement membranes in the retinal and kidney vessels supporting the well established association of vascular changes in both organs in patients with diabetes mellitus. GBM antigen excretion into urine could be useful for detecting early microvascular alterations in the kidneys in juvenile diabetics where diagnosis of early glomerulosclerosis is important.

Adolescent↗

PubMedDate not supplied

Influence of glucose fluctuations on alkaline phosphatase activity.

It has been suggested previously that non-enzymatic glycosylation of certain enzymes results in decreased enzymatic activity. In order to examine the role of high blood glucose concentrations (BG) on serum alkaline phosphatase (AP) activity, we determined BG and serum AP in 32 healthy children during an oral glucose tolerance test (OGTT) and in 10 type I diabetic children at 30-min intervals for at least 150 min. A significant negative correlation was noted for BG and AP during the oral glucose load (r = -0.57, p less than 0.01). In diabetics, however, only children with marked BG fluctuations showed this inverse relationship between BG and AP. These observations could be explained by the formation of a Schiff base as the initial step of non-enzymatic glycosylation of AP. This assumption was further confirmed by in vitro experiments, in which AP was incubated with glucose resulting in decreased enzymatic activity. The dialyzable aldimine formed initially is subsequently stabilized as ketoamine after long-term incubation.

Adolescent↗

PubMedDate not supplied

Convenient preparation of no-carrier-added technetium-99m radiopharmaceuticals using solid-phase technology.

A solid-phase technetium chelation chemistry was developed as a means of preparing (99m)Tc radiopharmaceuticals at high effective specific activity (HSA). Three peptidic N(3)S (99m)Tc ligands [mercaptoacetyl-Gly-Gly-Gly (MAG3), picolinyl-Ser-Cys-Gly-Thr-Lys-Pro-Pro-Arg (RP063), and dimethyl-Gly-Ser-Cys-Gly-Thr-Lys-Pro-Pro-Arg (RP128)] were used. The free thiol of Cys in each was attached to a series of commercially available amine-functionalized supports in a two-step process. The amine groups on the solid supports were converted to maleimide groups followed by the attachment of the (99m)Tc chelators through a thiol ether linkage with Cys. The optimized loading of the supports ranged 6-122 micromol/g support as determined by amino acid analysis. Each of the peptide-loaded supports (50-100 mg) was placed in either glass syringe vessels or disposable chromatography columns. Labeling with [(99m)Tc]pertechnetate (200-800 MBq) in the presence of stannous gluconate was achieved at room temperature for 30-60 min or in a 100 degrees C water bath for 10 min. Up to 80% of the activity was eluted from the column with saline to give products with purity up to 99.8% as determined by HPLC. Amino acid analysis indicated as little as 100 pmol of peptide present in the (99m)Tc products, demonstrating that extremely high effective specific activity can be achieved without the need for purification.

Amino Acid Sequence↗

PubMedDate not supplied

Synthesis and evaluation of two technetium-99m-labeled peptidic 2-nitroimidazoles for imaging hypoxia.

The presence of hypoxic cells in solid tumors is a marker for therapy-resistant, aggressive disease. The noninvasive detection of hypoxic cells in tumors by radiolabeled 2-nitroimidazoles is a diagnostic technique under current evaluation. Two peptidic agents, dimethylglycyl-L-seryl-L-cysteinyl-lysyl{N(epsilon)-[1-(2-nitro-1H -im idazolyl)acetamido]}glycine (RP435) and dimethylglycyl-tert-butylglycyl-L-cysteinyl-glycine-[2-(2-ni tro-1H-im idazolyl)ethyl]amide (RP535) have been synthesized. Both agents contain an N(3)S class chelator for (99m)Tc and Re and a 2-nitroimidazole group which can be enzymatically reduced and selectively trapped in cells under hypoxic conditions. Two isomers of (99m)TcO-RP435, which are assumed to be syn and anti conformations, were observed on HPLC analysis. The interconversion of the two isomers in aqueous solution was investigated. In contrast, RP535 chelated (99m)Tc to form a single isomer and no conversion to its counterpart has been observed on HPLC analysis. The tert-butyl group on the chelator may inhibit the formation and interconversion of the syn and anti isomers of (99m)TcO-RP535. Both tracers showed a significant degree of hypoxia-specific accumulation in an in vitro assay, with (99m)TcO-RP535 showing higher selectivity for hypoxic cells than (99m)TcO-RP435. These results suggest that (99m)TcO-RP535 represents a lead compound worthy of further investigation as an agent for imaging hypoxia in tumors.

Animals↗

PubMedDate not supplied

Targeting hypoxia in tumors using 2-nitroimidazoles with peptidic chelators for technetium-99m: effect of lipophilicity.

Tumor hypoxia is an important prognostic factor for response to therapy. Radiolabeled 2-nitroimidazoles have been used for imaging hypoxia, and the octanol/water partition coefficient (P) of these compounds appears to play a crucial role in their suitability for imaging. A series of 11 2-nitroimidazoles coupled to peptidic chelators for (99m)Tc with divergent P was developed and evaluated in an in vitro system. Two classes of N(3)S chelators were used: dialkyl-Gly-Ser-Cys-linker-2-nitroimidazole (Class I) and dialkyl-Gly-Lys(2-nitroimidazole)-Cys (Class II). The chelators were prepared by automated solid-phase peptide synthesis. Xanthine oxidase was able to reduce the 2-nitroimidiazole moiety on the ligands, but the rate of reduction varied 5-fold among the different chelators. The chelators were labeled by transchelation from [(99m)Tc]gluconate at temperatures between 22 and 100 degrees C. The reaction mixtures were analyzed by HPLC and their P values determined. The accumulation of each complex in suspension cultures of Chinese hamster ovary cells incubated under aerobic or extremely hypoxic conditions was determined. Radiochemical yields ranged from 5 to 80% for the 11 compounds. HPLC showed that some of the compounds formed two complexes with (99m)Tc, possibly syn and anti conformations with respect to the Tc=O bond. In general, the Class I chelators labeled more readily than the class II chelators. The P values of the (99m)Tc complexes varied from 0.0002 to 5 and were generally in accordance with predictions based on structure. There were also differences in P as a function of pH; the free acids had a lower P at pH 7.4 than at pH 2.0 due to ionization, whereas the amides did not show this effect. Accumulation levels in aerobic cells were related to P but varied over a narrow range. Four of the 11 compounds showed selective accumulation in hypoxic cells. The peptidic class of 2-nitroimidazoles, with flexible design and convenient solid-phase synthesis, deserves further study as agents for imaging hypoxia in tumors.

Animals↗

PubMedDate not supplied

[Opiate addiction in gravidity - consequences for the newborn. Results of an interdisciplinary treatment concept].

AIMS: To evaluate the outcome of infants of drug dependent mothers (IDM) after establishing an interdisciplinary attention concept at the University Hospital in Vienna. To compare the influence of different maintenance agents on neonatal morbidity. PATIENTS AND METHODS: All newborns of opiate dependent mothers were prospectively included from III 1995 to IX 1999. The following data were collected: maintenance agent (methadone, slow release morphine, buprenorphine), infectious status, demographic data, congenital malformations, perinatal complications, as well as incidence and duration of the neonatal abstinence syndrome (NAS). Medical treatment with phenobarbital (1995 - 96) or morphine hydrochloride (MoHCl) (1997 - 99), respectively, was indicated when Finnegan score exceeded 10. RESULTS: 88 neonates (38 females/50 males) with a median gestational age of 39 weeks were included, 18 (20.5 %) were born prematurely. The median birthweight was 2905 g, 24 (27.3 %) infants were small for date (< 10th percentile), 15 (17 %) microcephalic. The malformation incidence was 7.4 %. 63 (72 %) of all newborns had to be treated due to abstinence syndrome: in the methadone group 76 %, in the morphine group 93 %, but in the buprenorphine group 19 % only (p < 0.01). Median duration of withdrawal was 15.1 days (d) with significant difference after antenatal buprenorphine exposure compared to methadone and morphine exposure (8.3 d versus 15 d and 16.5 d respectively). In neonates treated with phenobarbital duration of NAS was 17.6 d, whereas NAS in infants with MoHCl therapy lasted 12.8 d (p < 0.05). CONCLUSION: Incidence and duration of NAS after buprenorphine exposure was significantly lower than after methadone and morphine exposure. Withdrawal time under morphin-hydrochloride therapy was reduced by one third compared to treatment with phenobarbital.

Buprenorphine↗

PubMedDate not supplied

[Comparison of the acetylcholine receptor antibody titer and clinical course in neonatal myasthenia].

Ten to fifteen percent of infants of myasthenic mothers develop neonatal myasthenia independent of the severity of the maternal disease. The antiacetylcholin receptor-protein antibodytiter (AChR-AK) was followed through the first twelve months in a boy who's mother suffered from myasthenia gravis (M.G.) since twelve years. Only unspecific symptoms for an impaired neuromuscular transmission were found, the diagnosis however was confirmed by determination of AChR-AK (alpha-Bungarotoxin binding assay, Lindström 1979). Maternal AChR-AK did not change during the observation period: values were between 120 X 10(-9)mol/l and 140 X 10(-9)mol/l. The neonatal titer on day one was 100 X 10(-9) mol/l, somewhat below the corresponding maternal titer (120 X 10(-9)mol/l). By 7 months the AchR-AK had decreased to the reference value according to the half time for IgG (t/2 = 17 days). In contrast to Keesey and Donaldson we found no relationship between AChR-AK levels and clinical course.

Adult↗

PubMedDate not supplied

[Therapy refractory arterial hypotension after heart operation].

Adrenalin insufficiency associated with adrenal hemorrhage, is a rare complication after cardiac surgery in neonates. A boy suffering from transposition of the great arteries, who had an arterial switch-operation on day three of his life, acquired a bilateral adrenal hemorrhage. Clinically the situation resembled a septic shock. Despite large doses of catecholamines, he continued to have severe arterial hypotension, anuria, and kyperkalemia. The clinical condition did not change, although sepsis specific therapy was initiated. Consequently adrenal insufficiency, as a possible postoperative complication, was considered and prednisolon, initially in a dose of 15 mg/kg/d, was administered. The clinical condition improved dramatically. The diagnosis could be confirmed by ultrasound examination and determination of cortisol and ACTH plasma levels. Adrenal insufficiency was only transitory, adrenal sonography on day 135 returned to normal. The surgical procedure on heart-lung bypass, the obligatory anticoagulation and the perioperative stress have to be considered as pathogenetic factors.

Adrenal Insufficiency↗

PubMedDate not supplied

The cytogenetic basis for classifying ependymomas.

The phylogeny of ependymal cells and astrocytes can be traced to a single primitive progenitor the ependymoglia or the tanycyte, respectively. Ependymoglia cells have ependymal perikarya having astrocyte-like processes that terminate subpially in primitive glial footplates. Such cells prevail in primitive nervous systems, but they also persist regionally in the mature mammalian brain. Their fine structure has been studied in many species. An electronmicroscopic study of 8 ependymomas reveals that the neoplastic cells possess features characteristic of primitive ependymoglia; in particular they possess cell processes filled with glial filaments, terminating submesenchymally in a primitive, piston-shaped footplate. The perivascular pseudorosettes of ependymomas are the equivalents of these cell poles. The dominant phenomenon of ependymoma structure appears to be a reversion of cellular organization to the stage of primitive ependymoglia cells. On reviewing 43 ependymomas and 71 astrocytomas 11 neoplasms were found having a tissue structure reminiscent of the evolution of piloid astrocytes from ependymoglia or tanycytes, respectively. These features correspond to transitional stages seen in normal primitive brains. Tumors of this type may be characterized as a tanycytic variant of ependymomas. They appear to be relatively common in the spinal cord and present a source of confusion with piloid astrocytomas.

Adolescent↗

PubMedDate not supplied

Neonatal islet cell adenoma: a distinct type of islet cell tumor?

An encapsulated, compact-type islet cell adenoma of the pancreas, found in a newborn infant with hyperinsulinemic hypoglycemia, was investigated by conventional histology and immunofluorescence. Although the histologic structure of the tumor was indistinguishable from that of most islet cell tumors of adults, immunofluorescence revealed that the four islet cell hormones (insulin, glucagon, somatostatin, and pancreatic polypeptide) were all present in the tumor. They were stored in different cells that showed the same spatial distribution usually seen in normal islets. We conclude that neonatal islet cell adenoma can be distinguished from those of adults on the basis of the content and topographic distribution of their constituent endocrine cells.

Adenoma, Islet Cell↗

PubMedDate not supplied

[New aspects in the treatment of patent ductus arteriosus in premature newborns with respiratory insufficiency].

The efficacy of prolonged indomethacin treatment of sPDA was studied using a new, diagnostic method, the two-dimensional Doppler echocardiography (2-DDE). 35 ventilated preterm infants with sPDA (gestational age: 31.6 +/- 2.6; birth weight: 1535 +/- 565 gms) were studied prospectively. Therapy consisted of a loading and maintenance dose (3 x 0.3 mg/kg I. 12 h, 2 x 0.15 mg/kg I. 24 h). Therapy was initiated at postnatal age 1 to 17 days. Echocardiographycally verified closure of sPDA was achieved in 27/35 patients (77%), one patient had a relapse (4%), 8/35 (23%) did not respond to indomethacin. Responders were treated earlier (4.5 vs 9.6 days), were ventilated over a shorter period (30 vs 57 days) and exposure time to more than 30% of FiO2 was shorter (28 vs 56 days). Prolonged indomethacin is an effective treatment of sPDA in ventilated prematures. Early start of therapy increases rate of closure. For precise diagnosis of hemodynamic effectiveness 2-DDE method is mandatory.

Drug Administration Schedule↗