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Papers by Michael Seiff

Hydrocephalus is a common disorder of cerebral spinal fl uid (CSF) physiology resulting in abnorm... more Hydrocephalus is a common disorder of cerebral spinal fl uid (CSF) physiology resulting in abnormal expansion of the cerebral ventricles. Infants commonly present with progressive macrocephaly whereas children older than 2 years generally present with signs and symptoms of intracranial hypertension. The classic understanding of hydrocephalus as the result of obstruction to bulk fl ow of CSF is evolving to models that incorporate dysfunctional cerebral pulsations, brain compliance, and newly characterised water-transport mechanisms. Hydrocephalus has many causes. Congenital hydrocephalus, most commonly involving aqueduct stenosis, has been linked to genes that regulate brain growth and development. Hydrocephalus can also be acquired, mostly from pathological processes that aff ect ventricular outfl ow, subarachnoid space function, or cerebral venous compliance. Treatment options include shunt and endoscopic approaches, which should be individualised to the child. The long-term outcom...

Molecular and General Genetics MGG, 1986

The DNA sequences of the mercuric resistance determinants of plasmid R100 and transposon Tn501 di... more The DNA sequences of the mercuric resistance determinants of plasmid R100 and transposon Tn501 distal to the gene (merA) coding for mercuric reductase have been determined. These 1.4 kilobase (kb) regions show 79% identity in their nucleotide sequence, and in both sequences two common potential coding sequences have been identified. In R100, the end of the homologous sequence is disrupted by an 11.2 kb segment of DNA which encodes the sulfonamide and streptomycin resistance determinants of Tn21. This insert contains terminal inverted repeat sequences and is flanked by a 5 base pair (bp) direct repeat. The first of the common potential coding sequences is likely to be that of the rnerD gene. Induction experiments and mercury volatilization studies demonstrate an enhancing but non-essential role for these merA-distal coding sequences in mercury resistance and volatilization. The potential coding sequences have predicted codon usages similar to those found in other Tn501 and R100 mer genes.

Gonococci and Meningococci, 1998

The λgtll expression vector was used to construct a gene bank of gonococcal DNA of strain RIO (se... more The λgtll expression vector was used to construct a gene bank of gonococcal DNA of strain RIO (serovar PIB-9). Upon screening with a rabbit antiserum containing antibodies to the H8 antigen a number of clones were isolated which produced products related to H8 antigen. DNA hybridization studies demonstrated that these clones were derived from three distinct gonococcal genes. The antigens produced by the clones were used to isolate antibodies from rabbit antiserum. Immunoblots of gonococcal lysates analyzed with the affinity purified antibodies and with H8 monoclonal antibody demonstrated that two of the H8 genes were expressed by the gonococcal strain studied and gave rise to products with apparent molecular weights of ca. 19,700 and 21,200.

Infection and Immunity, 1989

al. (1) have cloned and sequenced the structural gene for a class 1 meningococcal protein, and Ka... more al. (1) have cloned and sequenced the structural gene for a class 1 meningococcal protein, and Kawula et al. (16) have characterized the meningococcal azurin lipoprotein antigen. We report here the cloning and characterization of the structural gene for a meningococcal class 2 protein.

Infection and Immunity

The class 2 protein of Neisseria meningitidis is the major outer membrane protein and a porin. A ... more The class 2 protein of Neisseria meningitidis is the major outer membrane protein and a porin. A lambda gt11 bank of meningococcal chromosomal DNA was screened with monoclonal antibodies against gonococcal protein IB that cross-react with meningococcal class 2 protein. Three independent immunoreactive clones were isolated. DNA sequence analysis indicated that these clones included regions encoding the N-terminal portion of the class 2 protein. An oligonucleotide of 21 bases that was complementary to this sequence was synthesized and used as a probe for a second screening of the lambda gt11 bank. One of the positive clones isolated contained the complete gene, including the ribosome binding site, but lacked the promoter region. On the basis of the DNA sequence, a protein of 360 amino acids was predicted. Comparison of the predicted protein sequence with that of gonococcal protein I showed little homology in six regions constituting 29% of the total amino acids, while the remainder of...

Antonie Van Leeuwenhoek International Journal of General and Molecular Microbiology, 1987

We have purified protein III (PIII) from several strains of gonococcus by extractions with Zwitte... more We have purified protein III (PIII) from several strains of gonococcus by extractions with Zwittergent 3,14 followed by cation exchange chromatography and gel filtration. The pI of 8.6 determined by isoelectric focusing was in keeping with the high content of basic amino acids found. PIII from two strains had identical N-terminal sequence. In contrast to PIII in vivo, purified PIII

Proceedings of the National Academy of Sciences of the United States of America, 1987

The outer membrane porin molecule of Neisseria gonorrhoeae is known as protein I (PI). Among diff... more The outer membrane porin molecule of Neisseria gonorrhoeae is known as protein I (PI). Among different strains of gonococci there is variability of PI, and two main classes, PIA and PIB, have been recognized. A lambda gt11 bank of gonococcal DNA was screened using monoclonal antibodies directed to a PIB-type porin molecule of N. gonorrhoeae, and three immunoreactive clones were isolated. DNA sequence analysis indicated that each contained only portions of the PI structural gene, but that together they contained the complete gene, and its structure was determined. The DNA sequence predicts a protein of 348 amino acids with a typical 19 amino acid signal peptide. The PI protein resembles Escherichia coli porins in size, lack of long hydrophobic sequences, and absence of cysteine residues. Sequence homologies between PI and the E. coli porins were found, particularly in the 100 N-terminal and the 110 C-terminal amino acids. In addition to the coding sequence of PI, the complementary st...

American Journal of Surgical Pathology, 2008

Angiomatoid fibrous histiocytoma (AFH) is generally considered a soft tissue sarcoma of low malig... more Angiomatoid fibrous histiocytoma (AFH) is generally considered a soft tissue sarcoma of low malignant potential that occurs in children/young adults and most frequently affects the extremities. AFH infrequently recurs and rarely metastasizes. AFH has a characteristic histomorphology, and immunohistochemical reactivities for desmin and CD68 have led to myofibroblastic and fibrohistiocytic histogenetic hypotheses, respectively. Although only a limited number of AFH cases have been molecularly characterized, many have demonstrated evidence of an underlying translocation event. Reverse transcription-polymerase chain reaction and fluorescence in situ hybridization studies suggest that chromosomal rearrangement in AFH most frequently involve the EWS, CREB, ATF-1, and FUS genes. We report the first pathologically confirmed case of an AFH presenting as an intracerebral primary in a previously healthy 25-year-old man. Genetic analyses revealed a t(12;22)(q13;q12) and a unique underlying clear cell sarcomalike type 1 EWS/ATF-1 gene fusion.

Proceedings of the National Academy of Sciences, 1987

The outer membrane porin molecule of Neisseria gonorrhoeae is known as protein I (PI). Among diff... more The outer membrane porin molecule of Neisseria gonorrhoeae is known as protein I (PI). Among different strains of gonococci there is variability of PI, and two main classes, PIA and PIB, have been recognized. A Xgtll bank of gonococcal DNA was screened using monoclonal antibodies directed to a PIB-type porin molecule of N. gonorrhoeae, and three immunoreactive clones were isolated. DNA sequence analysis indicated that each contained only portions of the PI structural gene, but that together they contained the complete gene, and its structure was determined. The DNA sequence predicts a protein of 348 amino acids with a typical 19 amino acid signal peptide. The PT protein resembles Escherichia coli porins in size, lack of long hydrophobic sequences, and absence of cysteine residues. Sequence homologies between PI and the E. coli porins were found, particularly in the 100 N-terminal and the 110 C-terminal amino acids. In addition to the coding sequence of PI, the complementary strand contains a large open reading frame. At the 3' end of the PI gene, immediately following an inverted repeat (probably the transcription terminator), the clone contains an unusual sequence consisting of 31 perfect repeats of the heptamer CTGTTTT. Hybridization analysis suggests that there is a single structural gene for PI and that it is homologous to the gene found in a PIA-bearing strain of gonococcus.

Journal of Experimental Medicine, 1986

A bank of gonococcal DNA was constructed in the lambda gt11 expression vector. immunological scre... more A bank of gonococcal DNA was constructed in the lambda gt11 expression vector. immunological screening of the bank resulted in the isolation of a clone that contains the structural gene of protein III. In addition, several clones reactive with mAbs specific for the H8 antigen were isolated. DNA hybridization studies revealed that these H8-reactive clones were derived from three different gonococcal genes. When the products produced by these clones were used to absorb antibodies from a rabbit antiserum, and the eluted antibodies were used in immunological studies, it could be shown that the parent gonococcus expressed the product of two of these H8 genes, and in strain R10, these had Mr of approximately 19,700 21,200 respectively. The larger form has not been recognized hitherto because the epitope reactive with the H8 mAb may be masked in this product.

Journal of Experimental Medicine, 1987

The insert of a lambda gt11 clone expressing gonococcal protein III was sequenced. The deduced am... more The insert of a lambda gt11 clone expressing gonococcal protein III was sequenced. The deduced amino acid sequence showed a coding frame of 236 amino acids with a typical 22-amino-acid signal peptide, followed by the known NH2-terminal sequence of PIII. The mature protein has a molecular weight of 23,298. It was found that PIII had extensive and very striking homology to the carboxy-terminal portion of enterobacterial OmpA proteins. The homology encompasses the OmpA domain that is believed to be located in the periplasmic space. If the disposition of PIII across the OM is analogous, then the surface-exposed domain consists of less than 40 amino acids. These include a potential 15-amino-acid disulfide loop, a feature not found in OmpA proteins. Hybridization studies with the sequenced insert indicated that it contained a repetitive sequence that occurred at least 20 times in the genome. By additional hybridization studies the area containing the repetitive sequence was narrowed to a ...

FEMS Microbiology Letters, 1987

We have determined the DNA sequence of a cloned gonococcal gene and found that the predicted prot... more We have determined the DNA sequence of a cloned gonococcal gene and found that the predicted protein sequence is highly homologous to the class of blue copper-containing proteins known as azurins. However, the 127 amino acid sequence homologous to azurin is preceded by two unusual structural features. The gene possesses a typical 17 residue lipoprotein signal peptide and the Nterminal 39 amino acids are very rich in proline and alanine. The azurin gene of Pseudomonas aeruginosa has recently been characterized and possesses an ordinary signal peptide susceptible to signal peptidase I, causing export of a soluble protein to the periplasm. In gonococcus it would appear that the homologous product becomes an outer membrane protein. 2. INTRODUCTION Cannon et al. have produced a monoclonal antibody which recognizes an antigen on the surface of the pathogenic Neisseria species includ

FEMS Microbiology Letters, 2000

Antonie van Leeuwenhoek, 1987

The Journal of experimental …, 1987

Molecular and General Genetics MGG, 1986

Gonococci and Meningococci, 1998

Infection and Immunity, 1989

Infection and Immunity

Antonie Van Leeuwenhoek International Journal of General and Molecular Microbiology, 1987

Proceedings of the National Academy of Sciences of the United States of America, 1987

American Journal of Surgical Pathology, 2008

Proceedings of the National Academy of Sciences, 1987

The outer membrane porin molecule of Neisseria gonorrhoeae is known as protein I (PI). Among diff... more The outer membrane porin molecule of Neisseria gonorrhoeae is known as protein I (PI). Among different strains of gonococci there is variability of PI, and two main classes, PIA and PIB, have been recognized. A Xgtll bank of gonococcal DNA was screened using monoclonal antibodies directed to a PIB-type porin molecule of N. gonorrhoeae, and three immunoreactive clones were isolated. DNA sequence analysis indicated that each contained only portions of the PI structural gene, but that together they contained the complete gene, and its structure was determined. The DNA sequence predicts a protein of 348 amino acids with a typical 19 amino acid signal peptide. The PT protein resembles Escherichia coli porins in size, lack of long hydrophobic sequences, and absence of cysteine residues. Sequence homologies between PI and the E. coli porins were found, particularly in the 100 N-terminal and the 110 C-terminal amino acids. In addition to the coding sequence of PI, the complementary strand contains a large open reading frame. At the 3' end of the PI gene, immediately following an inverted repeat (probably the transcription terminator), the clone contains an unusual sequence consisting of 31 perfect repeats of the heptamer CTGTTTT. Hybridization analysis suggests that there is a single structural gene for PI and that it is homologous to the gene found in a PIA-bearing strain of gonococcus.

Journal of Experimental Medicine, 1986

Journal of Experimental Medicine, 1987

FEMS Microbiology Letters, 1987

FEMS Microbiology Letters, 2000

Antonie van Leeuwenhoek, 1987

The Journal of experimental …, 1987