Capturing nystagmus in the emergency room: posterior circulation stroke versus acute vestibular neuritis.

OBJECTIVES: To compare acute nystagmus characteristics of posterior circulation stroke (PCS) and acute vestibular neuritis (AVN) in the emergency room (ER) within 24 h of presentation. METHODS: ER-based video-nystagmography (VNG) was conducted, recording ictal nystagmus in 101 patients with PCS (on imaging) and 104 patients with AVN, diagnosed on accepted clinical and vestibular test criteria. RESULTS: Patients with stroke in the brainstem (38/101, affecting midbrain (n = 7), pons (n = 19), and medulla (n = 12)), cerebellum (31/101), both (15/101) or other locations (17/101) were recruited. Common PCS territories included posterior-inferior-cerebellar-artery (41/101), pontine perforators (18/101), multiple-territories (17/101) and anterior-inferior-cerebellar-artery (7/101). In PCS, 44/101 patients had no spontaneous nystagmus. Remaining PCS patients had primary position horizontal (44/101), vertical (8/101) and torsional (5/101) nystagmus. Horizontal nystagmus was 50% ipsiversive and 50% contraversive in lateralised PCS. Most PCS patients with horizontal nystagmus (28/44) had unidirectional "peripheral-appearing" nystagmus. 32/101 of PCS patients had gaze-evoked nystagmus. AVN affected the superior, inferior or both divisions of the vestibular nerve in 55/104, 4/104 and 45/104. Most (102/104) had primary position horizontal nystagmus; none had gaze-evoked nystagmus. Two inferior VN patients had contraversive torsional-downbeat nystagmus. Horizontal nystagmus with SPV ≥ 5.8 °/s separated AVN from PCS with sensitivity and specificity of 91.2% and 83.0%. Absent nystagmus, gaze-evoked nystagmus, and vertical-torsional nystagmus were highly specific for PCS (100%, 100% and 98.1%). CONCLUSION: Nystagmus is often absent in PCS and always present in AVN. Unidirectional 'peripheral-appearing' horizontal nystagmus can be seen in PCS. ER-based VNG nystagmus assessment could provide useful diagnostic information when separating PCS from AVN.

Spinal root and plexus hypertrophy in chronic inflammatory demyelinating polyneuropathy.

MRI was performed on the spinal roots, brachial and lumbar plexuses of 14 patients with chronic inflammatory demyelinating polyneuropathy (CIDP). Hypertrophy of cervical roots and brachial plexus was demonstrated in eight cases, six of whom also had hypertrophy of the lumbar plexus. Of 11 patients who received gadolinium, five of six cases with hypertrophy and one of five without hypertrophy demonstrated enhancement. All patients with hypertrophy had a relapsing-remitting course and a significantly longer disease duration. Gross onion-bulb formations were seen in a biopsy of nerve from the brachial plexus in one case with clinically evident nodular hypertrophy. We conclude that spinal root and plexus hypertrophy may be seen on MRI, particularly in cases of CIDP of long duration, and gadolinium enhancement may be present in active disease.

Musculoskeletal causes of spinal axis compromise: beyond the usual suspects.

The majority of cases of spinal canal compromise are caused by common pathologic conditions, including degenerative spondylosis, infection, trauma, and metastatic disease. However, there are other causes of spinal canal compromise that, though unusual, may be seen in everyday practice. Congenital abnormalities of the spine that may produce spinal canal compromise include the os odontoideum, hemivertebra, diastematomyelia, and achondroplasia. Arthritides and enthesopathies such as rheumatoid arthritis, ankylosing spondylitis, synovial cysts of the facet joint, calcium pyrophosphate dihydrate deposition or hydroxyapatite deposition, and ossification of the posterior longitudinal ligament or ligamentum flavum may lead to narrowing of the spinal canal. Primary spinal tumors and tumorlike lesions such as hemangioma, aneurysmal bone cysts, osteochondroma, and osteoblastoma may also cause spinal canal stenosis. Finally, Paget disease of bone may compromise the spinal cord. Radiologists should be aware of these unusual musculoskeletal causes of spinal canal compromise and their radiologic and clinical features.

Hypoglossal nerve palsy: a segmental approach.

Hypoglossal nerve (cranial nerve XII) palsy is uncommon. Damage to this nerve produces characteristic clinical manifestations, of which unilateral atrophy of the tongue musculature is the most important. When these features are recognized, the radiologist, armed with knowledge of the normal anatomy of the area, can focus on each segment of the nerve in search of a cause. The hypoglossal nerve is divided into five segments: the medullary, cisternal, skull base, nasopharyngeal/oropharyngeal carotid space, and sublingual segments. Because each segment is usually affected by different disorders, localizing a lesion to a particular segment allows the radiologist to narrow the differential diagnosis. In this way, the most efficient imaging strategy for evaluation of the symptoms can be developed. Both computed tomography and magnetic resonance imaging are useful in assessing dysfunction of the hypoglossal nerve; the choice depends on the status of the patient and the preference of the radiologist.

PCR amplification of partial mRNA sequences encoding the alpha- and beta-globin chains of the bivalve mollusc Anadara trapezia: correction of the C-terminal amino acid sequence of the alpha-chain.

1. PCR was carried out on cDNA which had been synthesized from poly(A)+ RNA extracted from A. trapezia red blood cells. 2. A 348 bp product encoding the C-terminal region of the alpha-globin chain and another product encoding a portion of the beta-globin chain were isolated. 3. The C-terminal alpha-chain sequence, encoded by the cDNA, differs from the previously published sequence and these changes improve the alignment of this chain with the other globin chains of this organism.

A minor globin gene of the bivalve mollusc Anadara trapezia.

A minor haemoglobin gene was isolated from an Anadara trapezia genomic library using a synthetic oligonucleotide probe based on the identical amino acid sequence of the F-helical region of all the major Anadara globins previously sequenced. The amino acid sequence inferred from the coding region of the gene indicated that it is different from that of the three major chains alpha, beta and gamma, but most like the beta-chain. This beta-variant sequence shows 100% homology in the conserved F-helix region. The minor gene was found to contain two long intervening sequences, 1214 bp and 1435 bp, longer than those present in the genes for vertebrate globins or leghaemoglobins but shorter than those in myoglobin genes.

Oestrogen sulfotransferase: isolation of a high specific activity species from bovine placenta.

During the course of a study of the control of expression of steroid-binding proteins in human mammary cancer oestrogen sulfotransferase was isolated from bovine placenta. By a combination of salt precipitation and ion-exchange and gel-permeation chromatography two forms of the enzyme were isolated. The forms, which apparently differ only in charge, have specific activities 100-300 times greater than has previously been reported for the enzyme. Partial peptide sequences of these enzymes are presented.

Oestrogen sulfotransferase: molecular cloning and sequencing of cDNA for the bovine placental enzyme.

The female sex hormone, oestrogen, plays a central role in breast cell proliferation in both the normal and malignant state. It controls transcription from several genes, including that for the progesterone receptor, and in endometrial tissue, via this receptor, it controls the gene for the enzyme oestrogen sulfotransferase. This enzyme may control the level of the oestrogen receptor by sulfurylating free oestradiol. To study the mode of transcriptional control exercised by oestrogen, bovine oestrogen sulfotransferase cDNA has been cloned and the nucleotide sequence determined. The message, of which 1812 bases have been sequenced, contains an open reading frame of 885 bases which encode a protein of 295 amino acids and a maximum apparent molecular weight of 34,600. The deduced protein sequence is supported by existing peptide sequence data and appears to contain a steroid-binding region. Some physico-chemical characteristics of the enzyme appear to differ markedly from those previously reported.

Amino acid sequence of the beta-chain of the tetrameric haemoglobin of the bivalve mollusc, Anadara trapezia.

The amino acid sequence of the beta-chain of the principal haemoglobin from A. trapezia has been determined. The sequence was deduced from the sequences of tryptic peptides, which were fractionated using highperformance liquid chromatography and peptide mapping. Additional sequence data, particularly for the large tryptic peptides, was obtained from enzyme digests of both cyanogen bromide fragments and large citraconyltryptic peptides. The beta-chain has 151 residues which is longer than all the other sequenced haemoglobin chains except the alpha-chain of A. trapezia, which is 153 residues in length. The residues corresponding to those normally in the D helix are absent in this beta-chain. The additional residues are contributed by an extension of the N-terminal region, which was also found to be acetylated. Comparison of the beta-chain amino acid sequence with that of the alpha-chain of A. trapezia, the dimeric chain of A. trapezia, and the dimeric chain of A. broughtonii showed 53% identity in each case. In the E and F helices, the homology is particularly noticeable. There is 100% homology in the F helix of all four chains. The dimeric globin of A. trapezia also shows 100% homology with the beta-chain in the E helix, while the alpha-chain shows 75%. If the tertiary structure of the alpha- and beta-chains of A. trapezia haemoglobin is the same as that of horse haemoglobin, then there are many changes in the alpha 1 and beta 2 contact site residues.

AIDS: today's vital challenge to dentistry.

PIP: This article suggests precautions that should be taken if dentists are to treat acquired immunodeficiency syndrome (AIDS) patients. Dentists are considered to be at higher risk of contracting AIDS than physicians. AIDS patients often present at dental offices seeking treatment for the oral symptoms sometimes associated with the virus. Identification of patients who may have AIDS is a critical factor in establishing treatment and protective guidelines; however, such identification is hindered by the prolonged incubation period. It is suggested that questions identifying symptoms of AIDS should be added to the Medical-Dental History Form (a sample form is included with the article). If responses to this form raise suspicion that a patient might have AIDS, the patient should be referred to his physician before an oral examination is scheduled. There is good evidence that AIDS patients can be safely treated in the dental office if the following precaustions are observed: 1) faithful use of an updated medical-dental history form with the follow-up measures suggested, 2) limitation to an absolute minimum of any dental operations; and 3) control of splashback. It is reasonable to assume that liquids that come from the mouth contain blood, infected fluids, saliva, sputum, and mucus that can act as carriers for the AIDS virus if they become droplets and/or aerosols and are transmitted to others through the mucuous membranes of the mouth or eyes. The use of face masks, washed-field dentistry, the rubber dam, protective eyeglasses, rubber gloves, disposable needles, autocleavable instruments, and disposable cap and gown is advocated to protect dentists from the AIDS virus.^ieng

Amino acid sequence studies on sheep liver fructose-bisphosphatase. II. The complete sequence.

The cyanogen bromide fragments of S-carboxymethylated fructose-bisphosphatase were purified. The amino acid sequences of the small fragments were determined by the dansyl-Edman method. The large fragments were subjected to proteolytic digestion to give smaller peptides more amenable for purification and sequencing by similar methods. Enzyme digests of the S-carboxymethylated enzyme gave overlap peptides containing the methionine residues. In conjunction with the amino acid sequence of the 60-residue N-terminal fragment previously determined on the S-peptide released by limited proteolysis with subtilisin the complete sequence of 336 residues was deduced. The sequence has been compared with the 335 residue sequence of pig kidney fructose-bisphosphatase and some areas of sequence for rabbit liver enzyme. The strong homology previously noted for the S-peptide sequence is maintained for the complete enzyme with only 34 changes in 336 residues when comparing the pig and sheep enzymes.

Carboxymethylation of thiol groups in ovalbumin: implications for proteins that contain both thiol and disulfide groups.

The cysteine residues of hen ovalbumin were S-carboxymethylated with non-radioactive iodoacetic acid under various conditions by altering the pH at which the protein was denatured in 8 M urea, by using different molar ratios of non-radioactive iodoacetic acid to cysteine and by varying the time at which carboxymethylation was commenced after denaturing conditions had been applied. Under the various conditions, the thiol groups were carboxymethylated to different extents, the residual thiol groups being measured by reaction with 5,5'-dithiobis(2-nitrobenzoic acid) in the presence of sodium dodecyl sulfate. When ovalbumin is carboxymethylated in alkaline urea, it unfolds slowly and the carboxymethylation is incomplete even with 150-fold excess iodoacetic acid. The known rapid thiol-disulfide exchange that occurs at alkaline pH values makes this method of carboxymethylation unsuitable as a preliminary step for blocking the native cysteine residues of ovalbumin before reduction and labelling the thiol groups formed by reduction of the disulfide bonds. Titration of the thiol groups of ovalbumin in 6 M guanidine hydrochloride or 1% (w/v) sodium dodecyl sulfate at pH 8.2 with 5,5'-dithiobis(2-nitrobenzoic acid) is more rapid than in 8 M urea and these solvents would be preferable for studies of the disulfide-bonded sequences. Denaturation of ovalbumin in acidic 8 M urea is a very rapid process, and under mild acid conditions thiol-disulfide interchange is much slower. Subsequent carboxymethylation of the cysteine residues at alkaline pH with 150-fold excess iodoacetic acid results in complete carboxymethylation and the carboxymethylated ovalbumin can be reduced and labelled with radioactive iodoacetic acid with specific labelling of the half-cystine residues involved in the disulfide bond. The results are discussed in relation to the allocation of half-cystine residues in other protein systems that contain both thiol and disulfide groups.

Uridine and inosine: pressor nucleosides from man, rat and dog.

Short-acting pressor compounds isolated from rat kidney, brain, heart and spleen have been identified as inosine and uridine by gas chromatography, mass spectrometry, high pressure liquid chromatography and analysis of ultraviolet spectra. Inosine was further identified by nuclear magnetic resonance. These compounds have also been found in kidneys from hypertensive man, rejected renal transplants and dog and beef kidney. Tissues were extracted by acid ethanol extraction followed by gel filtration and high voltage paper electrophoresis. Compounds found to be pressor in the anaesthetised rat resisted proteolytic enzymes, boiling for 10 min, extremes of pH and incubation with plasma from the source species for up to 20 min. The pressor effects of bolus injections of active gel filtration fractions, uridine and inosine were short-lived with a maximum effect at 5-6 s. Intravenous (I.V.) infusions of extracts gave a sustained pressor response without a concurrent change in heart rate. The effect on blood pressure was not accompanied by increased heart rate and persisted when the pressor effects of angiotensin II, noradrenaline and 5-hydroxy-tryptamine were blocked pharmacologically.

Myoglobins of cartilaginous fishes III. Amino acid sequence of myoglobin of the shark Galeorhinus australis.

Myoglobin isolated from the red muscle of the school shark Galeorhinus australis was purified by gel filtration and ion-exchange chromatography. The amino acid sequence was determined following digestion with trypsin and purification of the peptides by paper ionophoresis and chromatography. Sequences of purified peptides were determined by the dansyl-Edman procedure and the peptides aligned by homology with the sequence of the myoglobin of the gummy shark Mustelus antarcticus. The two myoglobin sequences showed a marked similarity (16 differences), but both sequences showed approximately the same number of differences (68) from myoglobin of the Port Jackson shark Heterodontus portusjacksoni. There are 19 residues unique to three shark myoglobin sequences. As found with other fish myoglobins there are 148 residues with deletions of four residues at the amino terminal end as well as one residue in the CD region. The amino terminal residue is acetylated. The distal E7 histidine residue was found to be replaced by glutamine, as only previously reported for the myoglobin sequence of gummy shark.

Amino acid sequences containing cysteine or cystine residues in ovalbumin from eggs of the quail Coturnix coturnix japonica.

Ovalbumin isolated from eggs of the Japanese quail, C. c. japonica, was subjected to limited proteolysis by subtilisin to give plakalbumin and then fractionated on Sephadex G75 in acid-urea to give plakalbumin S-protein and S-peptide. The plakalbumin peptide was recovered, oxidized with performic acid, and the sequence of amino acids determined from the peptides formed by enzyme digestion. There were two cysteine residues in the 33-residue sequence. The ovalbumin was also oxidized with performic acid and digested with thermolysin and pepsin before isolating, from a sulfonated polystyrene column, the acidic cysteic acid peptides, as well as acetylated N-terminal peptides and phosphorylated peptides, and determining their amino acid sequence. Additional peptide sequences containing cysteine or half-cystine were characterized. Quail ovalbumin was reduced and carboxymethylated with [2-14C]iodoacetic acid. Peptides containing labelled S-carboxymethylcysteine residues were isolated from thermolytic digests of the carboxymethylated ovalbumin by paper ionophoresis and chromatography. Their amino acid sequence was determined and five different sequences involving labelled S-carboxymethylcysteine residues were established. The presence of two half-cystine residues and the location of the disulfide bond were shown by blocking the cysteine residues with non-radioactive iodoacetic acid, reducing the disulfide bond and labelling the half-cystine residues with [2-14C]iodoacetic acid. After thermolytic digestion of the protein, radioactive peptides were isolated by paper ionophoresis and chromatography. These studies have thus shown that quail ovalbumin contains one cystine residue and three cysteine residues, which is one residue of cysteine less than in ovalbumin from the hen (Gallus gallus domesticus). There is strong homology in the amino acid sequences of hen ovalbumin and quail ovalbumin determined in these investigations.

Amino acid sequence studies on sheep liver fructose-bisphosphatase. I. The S-peptide.

Fructose-bisphosphatase has been isolated from sheep liver using affinity-elution chromatography from carboxymethylcellulose as the final purification step. The purified enzyme was homogeneous by disc gel electrophoresis. Digestion with subtilisin yielded the N-terminal S-peptide similar to that reported for the rabbit and pig. The peptide has an acetylated amino terminal residue and the following sequence deduced from a study of the tryptic and cyanogen bromide peptides: Ac-Thr-Asp-Glu-Ala-Pro-Phe-Asp-Thr-Asn-Ile-Val-Thr-Val-Thr-Arg-Phe-Val-Met-Glu-Glu-Gly-Arg-Lys-Ala-Arg-Gly-Thr-Gly-Glu-Met-Thr-Gln-Leu-Leu-Asn-Ser-Leu-Cys-Thr-Ala-Val-Lys-Ala-Ile-Ser-Thr-Ala-Val-Arg-Lys-Ala-Gly-Ile-Ala-His-Leu-Tyr-Gly-Ile-Ala. The sheep liver S-peptide sequence shows only six changes in 60 residues and three changes in 56 residues compared with the sequences of the rabbit and pig S-peptides respectively.

Amino acid sequences containing cysteine or half-cystine residues in beta-glucuronidase.

Amino acid analysis of oxidized or reduced and carboxymethylated beta-glucuronidase have shown the presence of 24 cysteic acid or S-carboxymethylcysteine residues respectively per mole of the tetrameric enzyme. Titration of sulfhydryl groups gave eight cysteine residues, and by difference 16 half-cystine residues per mole. Six peptides containing radiolabelled cysteine residues were isolated from pepsin and chymotrypsin digest of reduced and S-carboxymethylated beta-glucuronidase by ion-exchange chromatography or gel filtration, followed by paper ionophoresis and paper chromatography. The peptides were analysed for amino acids and sequenced by the dansyl-Edman procedure. Peptides containing cysteic acid were selectively recovered from thermolysin digests of performic acid-oxidized glucuronidase. The amino acid sequences confirmed that there were only six different peptide sequences containing either cysteine or half-cystine residues in the tetrameric enzyme, supporting the presence of four identical subunits. These sequences wer: (A)-Val-Asx-Val-Ile-Cys-Val-Asx-Ser-Tyr- (B)-Gly-Asx-Leu-Cys-Ser-Gly- (C)-Phe-Val-Val-Ile-Asx-Glx-Cys-Pro-Gly-Val-Gly- (D)-Val-Val-Cys-Leu- (E)-Gln-Ser-Gly-Cys-Leu-Val-Lys-Gly-Tyr- (F)-Cys-Asp-Arg-Tyr-Gly-Ile-Val-Val-.