Two polychlorinated biphenyls (PCB) enzyme linked immunosorbent assays (ELISAs) were developed using goat PCB purified immunoglobulin (IgG) antibodies (Abs). The IgGs exhibited the highest affinity ...toward PCB-77 (24
ng
mL
−1) with sensitivities in the range of 6–11
ng
mL
−1. The Abs cross-reacted with PCB-126 and the heptachlorodibenzofuran 1,2,3,4,6,7,8-HpCDF but not with PCB-169, PCB-118, Aroclor 1232, 1248, 1260 or the hexachlorodibenzofuran 2,3,4,6,7,8-HxCDF. The IgGs were also used to develop a sol–gel-based immunoaffinity purification (IAP) method for cleanup of PCB-126. Recovery efficiencies depended on the sol–gel formats; a 1:12 format resulted in the highest binding capacity. Net binding capacity ranged from 112 to 257
ng, and 90% of the analyte could be eluted with only 2
mL of ethanol. The method was also very efficient in purifying PCB-126 from spiked soil and sediment samples from contaminated sites; and eliminating matrix interferences to a degree that enabled analysis of the purified samples by ELISA. The approaches developed in the course of the study form a basis for the development of additional IAP methods for other PCBs, and their implementation in high-throughput screening programs for PCB in food, soil, and other environmental and biological samples.
Childhood familial pheochromocytoma was investigated in four patients by abdominal computed tomographic scan, 131Imetaiodobenzylguanidine scan, and vena caval catecholamine sampling. Results ...conflicted with surgical findings. Computed tomographic scan identified all four adrenal tumors but missed two midline tumors in one patient. 131Imetaiodobenzylguanidine scan identified two of three adrenal tumors but also suggested extra-adrenal tumors not confirmed at operation in two of three patients. Vena caval sampling for catecholamines confirmed all adrenal tumors but suggested additional tumors not verified at operation in two of three patients. All patients are asymptomatic and have normal urinary catecholamines 15 to 51 months after operation. Because of the frequency of multiple tumors in familial pheochromocytoma, different diagnostic techniques were employed. False-positive results were more frequent with 131Imetaiodobenzylguanidine and vena caval sampling. Reinterpretation of the 131Imetaiodobenzylguanidine scans at a later date led to less false-positive interpretation, although the false-negative rate remained unchanged. More pediatric experience with 131Imetaiodobenzylguanidine scans and vena caval sampling in familial pheochromocytoma is needed. Confirmation of tumor and its localization rest with meticulous surgical exploration.
Progressive myoclonus epilepsy (PME) has a number of causes, of which Unverricht–Lundborg disease (ULD) is the most common. ULD has previously been mapped to a locus on chromosome 21 (EPM1). ...Subsequently, mutations in the cystatin B gene have been found in most cases. In the present work we identified an inbred Arab family with a clinical pattern compatible with ULD, but mutations in the cystatin B gene were absent. We sought to characterize the clinical and molecular features of the disorder. The family was studied by multiple field trips to their town to clarify details of the complex consanguineous relationships and to personally examine the family. DNA was collected for subsequent molecular analyses from 21 individuals. A genome-wide screen was performed using 811 microsatellite markers. Homozygosity mapping was used to identify loci of interest. There were eight affected individuals. Clinical onset was at 7.3 ± 1.5 years with myoclonic or tonic–clonic seizures. All had myoclonus that progressed in severity over time and seven had tonic–clonic seizures. Ataxia, in addition to myoclonus, occurred in all. Detailed cognitive assessment was not possible, but there was no significant progressive dementia. There was intrafamily variation in severity; three required wheelchairs in adult life; the others could walk unaided. MRI, muscle and skin biopsies on one individual were unremarkable. We mapped the family to a 15-megabase region at the pericentromeric region of chromosome 12 with a maximum lod score of 6.32. Although the phenotype of individual subjects was typical of ULD, the mean age of onset (7.3 years versus 11 years for ULD) was younger. The locus on chromosome 12 does not contain genes for any other form of PME, nor does it have genes known to be related to cystatin B. This represents a new form of PME and we have designated the locus as EPM1B.
We describe an application of the backbone cyclization and cycloscan concept for the design and synthesis of pheromone biosynthesis
activating neuropeptide (PBAN) antagonists capable of inhibiting ...sex pheromone biosynthesis in Heliothis peltigera female moths. Two backbone cyclic (BBC) sub-libraries were designed and synthesized. The structure of the first sub-library
(Arg 27 PBAN27â33NH 2 , termed the Ser sub-library) was based on the active C-terminal hexapeptide sequence (Tyr-Phe-Ser-Pro-Arg-Leu-NH 2 ) of PBAN1â33NH 2 , which was found to comprise its active core. The second sub-library (Arg 27 , d -Phe30PBAN27â33NH 2 , termed the d -Phe sub-library) was based on the sequence of the lead antagonist Arg-Tyr-Phe-( d )Phe-Pro-Arg-Leu-NH 2 . In both sub-libraries the Pro residue was replaced by an N
α (Ï-amino-alkyl)Gly building unit having various lengths of the alkyl chain. All the cyclic peptides in each sub-library had
the same primary sequence and the same location of the ring. The members of each library differed from each other by the bridge
size and bridge chemistry. Screening of the two libraries for pheromonotropic antagonists resulted in the disclosure of four
compounds that fully inhibited sex pheromone biosynthesis at 1 nmol and were devoid of agonistic activity. All antagonistic
peptides originated from the d -Phe sub-library. Substitution of the d -Phe30 amino acid with a Ser resulted in a loss of antagonistic activity. Agonistic activities were exhibited by peptides
from both sub-libraries.
We report the discovery of a linear lead antagonist for the insect pheromone biosynthesis activating neuropeptide (PBAN) which inhibits sex pheromone biosynthesis in the female moth
Heliothis ...peltigera. Two approaches have been used in attempting to convert PBAN agonists into antagonists. The first involved omission of the C-terminal amide and reduction of the sequence from the N-terminus in a linear library based on PBAN 1–33NH
2. The second involved replacement of L amino-acids by the D hydrophobic amino acid D-Phe in a linear library based on PBAN28–33NH
2. Screening of the two libraries for pheromonotropic antagonists resulted in the disclosure of one compound out of the D-Phe library (Arg-Tyr-Phe-D-Phe-Pro-Arg-Leu-NH
2) which inhibited sex pheromone production by 79 and 64% at 100 pmol in two moth colonies and exhibited low agonistic activity. Omission of the C-terminal amide in PBAN 1–33NH
2 and its shorter analogs did not lead to the discovery of an antagonistic compound.
The development of a new approach for the generation of a novel type of putative insect control agents based on backbone cyclic peptidomimetic antagonists of insect-neuropeptides is reported. The ...approach, termed the backbone cyclic neuropetide based on autogonist (BBC-NBA) was applied to the insect pyrokinin/pheromone biosynthesis activating neuropeptide (PBAN) family as a model, and led to the discovery of a potent linear lead antagonist and several highly potent, metabolically stable BBC peptidomimetic antagonists, devoid of agonistic activity, which inhibited in vivo PBAN-mediated activities in moths.
A radio-receptor assay (RRA) for the insect pyrokinin/PBAN family has been developed. The development involved examination of the ligand (
3H-tyrosyl-PBAN28–33NH
2)-receptor interaction under various ...incubation conditions and variations on sex pheromone gland membrane preparation. Application of the RRA for a partial characterization of the putative pyrokinin/PBAN receptor in the pheromone gland of
H. peltigera revealed age-dependence of its expression. Pharmacological characterization revealed a high correlation between the binding-affinity to the receptor of various PBAN-derived peptides and their in vivo pheromonotropic bioactivity, and shed light on the interaction of backbone cyclic and linear (Arg
27,D-Phe
30PBAN28–33NH
2) PBAN antagonists with the receptor.
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