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Biomedical subjects

S E Hunter

Publications and source records attributed to S E Hunter.

16 recordsLinked to original sources
PubMed1995

Atypical zeta-protein kinase c displays a unique developmental expression pattern in rat brain.

The expression of atypical zeta-protein kinase C (PKC) was examined during prenatal and postnatal rat brain development. Immunoblot as well as transcript analysis revealed a dramatic increase in expression at 2-3 days post-birth, which declined thereafter and remained at levels observed in the adult brain. The expression of zeta-PKC precedes that of the other PKC isoforms in developing rat brain. Subcellular fractionation of pup and adult brain documented distribution between all three distinct fractions (A,B,C), including the low speed pellet composed of nuclei. In adult brain, the kinase was enriched in the A fraction of the sucrose gradient. Specific substrate proteins of zeta-PKC were characterized in each of the subcellular fractions from both pup and adult brain. Four predominant proteins pp76, pp60-doublet, pp54 and pp45 were identified as zeta-PKC endogenous substrates. All four proteins were phosphorylated on serine residues, while the pp60-doublet was also phosphorylated on tyrosine. The pp60-doublet was the most predominant substrate, specifically enriched in the A fraction of a sucrose gradient of adult brain and immunoprecipitated by monoclonal antibody to pp60c-src.

Age Factors↗
PubMed1993

Molecular genetic analysis of beta-toxin of Clostridium perfringens reveals sequence homology with alpha-toxin, gamma-toxin, and leukocidin of Staphylococcus aureus.

Oligonucleotide probes designed on the basis of the N-terminal sequence of Clostridium perfringens beta-toxin were used to isolate the encoding gene (cpb). The nucleotide sequence of cpb was determined, and on the basis of DNA hybridization experiments it was shown that the gene is found only in type B and C strains of C. perfringens. The deduced amino acid sequence of the beta-toxin revealed homology with the alpha-toxin, gamma-toxin, and leukocidin of Staphylococcus aureus. The beta-toxin purified from C. perfringens appeared to exist in monomeric and multimeric forms. Recombinant beta-toxin, produced in Escherichia coli, appeared to be mainly in the multimeric form.

Amino Acid Sequence↗
PubMed1992

Comparison of the nucleotide sequence and development of a PCR test for the epsilon toxin gene of Clostridium perfringens type B and type D.

The sequence of the epsilon toxin gene of Clostridium perfringens type D was determined and compared with that of the previously reported type B sequence. It showed two nucleotide changes in the open reading frame, giving rise to one amino acid substitution. The promoter sequences were not homologous, and different putative -35 and -10 regions have been identified in each. The sequence information was used to develop PCR primers which were specific for the epsilon toxin gene. The utility of this system for identifying type B or D strains of C. perfringens was demonstrated.

Amino Acid Sequence↗
PubMed1992

Cloning and nucleotide sequencing of the Clostridium perfringens epsilon-toxin gene and its expression in Escherichia coli.

The sequence of 20 amino acids from the N terminus of Clostridium perfringens epsilon-toxin was determined. Some differences between this sequence and the previously published sequence (A. S. Bhown and A. F. S. A. Habeeb, Biochem. Biophys. Res. Commun. 78:889-896, 1977) were found. A degenerate 23-bp pair oligonucleotide probe was designed from the amino acid sequence data and used to isolate a DNA fragment containing the gene encoding epsilon-toxin (etx) from C. perfringens type B. The gene encoded a protein with a molecular weight of 32,981. Upstream of the gene, promoter sequences which resembled the Escherichia coli sigma 70 consensus sequences were identified. The gene was expressed in E. coli, and the cloned gene product reacted with epsilon-toxin-specific monoclonal antibodies and had a molecular weight and isoelectric point similar to those of the native protein. Downstream of etx, two overlapping open reading frames were identified. Each encoded part of a protein which was homologous to the transposase from Staphylococcus aureus transposon Tn4001. Southern hybridization experiments indicated that the etx gene was found only in C. perfringens types B and D, the types which produce epsilon-toxin.

Amino Acid Sequence↗
PubMed1989

Molecular cloning and nucleotide sequence of the alpha-toxin (phospholipase C) of Clostridium perfringens.

A fragment of DNA containing the gene coding for the phospholipase C (alpha-toxin) of Clostridium perfringens was cloned into Escherichia coli. The cloned DNA appeared to code only for the alpha-toxin and contained both the coding region and its associated gene promoter. The nucleotide sequence of the cloned DNA was determined, and an open reading frame was identified which encoded a protein with a molecular weight of 42,528. By comparison of the gene sequence with the N-terminal amino acid sequence of the protein, a 28-amino-acid signal sequence was identified. The gene promoter showed considerable homology with the E. coli sigma 55 consensus promoter sequences, and this may explain why the gene was expressed by E. coli. The cloned gene product appeared to be virtually identical to the native protein. A 77-amino-acid stretch that was close to the N terminus of the alpha-toxin showed considerable homology with similarly located regions of the Bacillus cereus phosphatidylcholine, preferring phospholipase C and weaker homology with the phospholipase C from Pseudomonas aeruginosa.

Amino Acid Sequence↗
PubMed1982

Selective limbotomy.

A method is designed dividing the limbic system into sectors. The method was tested by analyzing 50 procedures carried out by the authors. Rostral limbotomies, performed either by open techniques (cingulectomy) or by stereotactic surgery, showed similar results, although recurrence was more frequent with stereotaxis. Comparison with other described procedures on the same areas revealed similar results. Analysis suggests that the interruption of the cingulum was responsible for the permanent behavior modification and not the interruption of intersecting anatomical systems.

Follow-Up Studies↗
PubMed1982

Surgical treatment of 63 cases of conjoined nerve roots.

The operative results of 63 cases of lumbar disc disease with surgically confirmed conjoined nerve roots are reviewed. The first 55 patients were treated by standard hemilaminectomy and discectomy, with only 30% reporting a good result. Of the last eight patients treated by hemilaminectomy, pediculectomy, and discectomy, seven patients returned to work. Te rationale for and the technique of pediculectomy are discussed in detail. Clinical, radiological, and surgical clues indicating the presence of the conjoined nerve root anomaly are reviewed.

Adult↗
PubMed1981

Intraspinal extradural sensory rhizotomy in patients with failure of lumbar disc surgery.

Questionnaires were sent to 60 patients who had undergone an intraspinal extradural sensory rhizotomy after failure of back surgery to assess the efficacy of the procedure. Questionnaires were returned from 47 patients. The operative results were uniformly poor in improving the level of activity of the patient. However, nearly 60% of the patients obtained relief of their pain. Section of only one root, either L-5 or S-1, relieved pain in 50% of the cases. Section of both roots, L-5 and S-1, appeared more effective, since 66% of these patients were relieved of their pain. The technique of performing an intraspinal extradural sensory rhizotomy is discussed in detail.

Adult↗
PubMed1978

Assessment of the effects of cinglulate gyrus lesions by neuropsychological techniques.

Nineteen psychiatric patients undergoing bilateral cryogenic cingulate cortex lesions were extensively evaluated pre- and postoperatively with objective measures of intelligence, higher cortical functions, memory, and emotional status. Following surgery the patients as a group revealed no significant deterioration of functions; rather, they demonstrated improvement that could be interpreted as the result of decline in anxiety. Investigations of individual revealed that the overall test performance was improved in 13 and substantially unchanged in three, whereas three demonstrated some decline in performance. These results were discussed in terms of the characteristics of the changes across the various tests.

Adult↗
PubMed1975

Pain suppression by peripheral nerve stimulation. Part I. Observations with transcutaneous stimuli.

A systematic, strict appraisal was made of 100 patients, after preliminary clinical trials suggested that some patients with pain could be helped by peripheral nerve stimulation. Transcutaneous stimulation of different nerve trunks was done with a special electrical stimulation device with various selected electrical parameters. More than half of the patients experienced some relief; in many, this effect was obtained by stimulating nerves distant from the area of referred pain. Pain relief lasted for varying periods after stimulation. The maximum benefit was noticed after certain specific parameters were reached for each patient. A few patients had response decay, gain or worsening. Results differ to some degree from previous reports. The results seem encouraging for the treatment of certain forms of intractable pain.

Adolescent↗
PubMed1975

Pain suppression by peripheral nerve stimulation. Part II. Observations with implanted devices.

Twenty-three patients underwent implantation of a stimulator system and were followed for 6-20 months. Twenty patients estimated between 50% and 100% pain relief. The effect was largely consistent and reproducible. Reduced drug intake and improved social performance were associated with subjective improvement. The surgical technique is given, complications are analyzed and parameters are discussed.

Adult↗
PubMedDate not supplied

Pain suppression by peripheral nerve stimulation. Chronic effects of implanted devices.

This is a study of the long range effects of pain suppression obtained by electrical stimulation of peripheral nerves. These cases were followed during 12--46 months and evaluated personally and by questionnaires. Selection for surgery was done exclusively on the basis of the results of a preoperative peripheral nerve stimulation test. Of 37 cases observations, 18 were considered significantly relieved; that is, more than 50% of the intensity and/or duration of pain was consistently admitted. The results obtained in the acute preoperative trial could be reproduced indefinitely in some cases for as long as 46 months. Correlation of the results with the disease producing the pain revealed as benefitting for painful syndromes associated with peripheral nerve disorders, amputation, soft tissue injuries (nerves?), and some recurrent lumbar disc surgeries. Sciatic, ulnar and occipital nerve implantations were particularly rewarding. The best and worse results were analyzed. The complications appear to be largely preventable and of no serious consequences. Our analysis suggests that most failures take place within 2 years from implantation. Experience seems to be accumulating showing that a number of patients may receive sustained relief beyond this period.

Adult↗