Videofluoroscopic evaluation of dysphagia in motor neurone disease with modified barium swallow

The role of videofluoroscopy with the modified barium swallow in the assessment and management of motor neurone disease (MND) is discussed. Nine patients (age range 40-82) with dysphagia secondary to MND were assessed over a four-year period. The examinations were carried out by a multiprofessional team of radiologist, speech and language therapist and dietitian assessing the preoral, oral and pharyngeal phases of swallowing. Preoral feeding abnormalities were present in four out of nine patients, oral phase abnormalities in eight out of nine patients, while 33% of patients demonstrated abnormality in all three phases. Where aspiration occurred (four out of nine cases), no cough reflex was noted. On the basis of these examinations management changes were introduced in all patients. Nonoral feeding was continued or introduced in three patients. Videofluoroscopic examination with the modified barium swallow may be helpful in planning suitable feeding regimes for dysphagia in MND.

Quantitative trait loci contributing to phencyclidine-induced and amphetamine-induced locomotor behavior in inbred mice

Phencyclidine (PCP) and amphetamine (AMP) can induce psychotic syndromes in humans, whereas administration of these drugs to mice results in behavioral activation that is influenced by genetic factors. Quantitative trait loci (QTL) underlying genetic differences in response to PCP and AMP in mice were provisionally identified by correlating allelic variation at known marker loci in the BXD series of recombinant inbred (RI) mice and its progenitors (C57BL/6J and DBA/2J inbred strains) with the locomotor response of each strain to PCP and AMP. Total distance traveled for individual mice from each of the 26 BXD RI and two progenitor strains was measured after injections of normal saline and 7.5 mg/kg i.p. injection of PCP. This procedure was repeated after 1 week, using 5.0 mg/kg of AMP, instead of PCP. Markers significantly (p < .01) correlated with response to PCP map to murine chromosomes 1, 14, and 15. Response to amphetamine was correlated with markers mapping to chromosomes 4, 5, 6, 8, 14, and 18. Identification of the QTL underlying PCP-induced and AMP-induced behavior in mice may provide clues into the complicated genetics of psychosis in humans.

Perception of direction of visual motion. II. Influence of linear body acceleration

We investigated whether linear whole-body acceleration along the interaural y-axis influenced the concurrent perception of visual motion direction as has been shown for angular accelerations. A sled running on air bearings along a 7.5-m track was used to accelerate 18 subjects at two different linear accelerations. These young, healthy volunteers, aged 25.50 +/- 7.38 years, used a joystick to indicate whether or not they perceived visual motion to the left within a random-dot kinematogram continuously presented on a monitor moving with them. The percentage of coherently leftward moving pixels presented for a 640-ms period during acceleration was adjusted according to a Modified Binary Search (MOBS) procedure. Six conditions were tested, two acceleration levels of 1 and 2 m/s2 to both left and right with, at the higher acceleration, two different times of visual motion presentation. Conditions were sequenced by means of a 6 x 6 Latin square balanced for order and carry over. A MANOVA did not show any statistically significant effects either for the independent variables acceleration, velocity, and direction of motion of the sled or for their interactions. The results obtained are in clear contrast to those obtained under rotatory stimulation. We conclude that the otolithic contribution to vestibular-visual motion processing is negligible.

Molecular, functional and evolutionary characterization of the gene encoding HMG-CoA reductase in the fission yeast, Schizosaccharomyces pombe

The synthesis of mevalonate, a molecule required for both sterol and isoprene biosynthesis in eukaryotes, is catalysed by 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase. Using a gene dosage approach, we have isolated the gene encoding HMG-CoA reductase hmgl+, from the fission yeast Schizosaccharomyces pombe (Accession Number L76979). Specifically, hmgl+ was isolated on the basis of its ability to confer resistance to lovastatin, a competitive inhibitor of HMG-CoA reductase. Gene disruption analysis showed that hmgl+ was an essential gene. This result provided evidence that, unlike Saccharomyces cerevisiae, S. pombe contained only a single functional HMG-CoA reductase gene. The presence of a single HMG-CoA reductase gene was confirmed by genomic hybridization analysis. As observed for the S. cerevisiae HMGlp, the hmgl+ protein induced membrane proliferations known as karmellae. A previously undescribed 'feed-forward' regulation was observed in which elevated levels of HMG-CoA synthase, the enzyme catalysing the synthesis of the HMG-CoA reductase substrate, induced elevated levels of hmgl+ protein in the cell and conferred partial resistance to lovastatin. The amino acid sequences of yeast and human HMG-CoA reductase were highly divergent in the membrane domains, but were extensively conserved in the catalytic domains. We tested whether the gene duplication that produced the two functional genes in S. cerevisiae occurred before or after S. pombe and S. cerevisiae diverged by comparing the log likelihoods of trees specified by these hypotheses. We found that the tree specifying post-divergence duplication had significantly higher likelihood. Moreover, phylogenetic analyses of available HMG-CoA reductase sequences also suggested that the lineages of S. pombe and S. cerevisiae diverged approximately 420 million years ago but that the duplication event that produced two HMG-CoA reductase genes in the budding yeast occurred only approximately 56 million years ago. To date, S. pombe is the only unicellular eukaryote that has been found to contain a single HMG-CoA reductase gene. Consequently, S. pombe may provide important opportunities to study aspects of the regulation of sterol biosynthesis that have been difficult to address in other organisms and serve as a test organism to identify novel therapies for modulating cholesterol synthesis.

Colour-coded duplex assessment alone before carotid endarterectomy

This study assessed whether carotid colour-coded duplex imaging can provide sufficient information to investigate patients before carotid endarterectomy. One hundred patients with symptomatic carotid artery disease (amaurosis fugax 24, transient ischaemic attack 38 and established stroke 38) were assessed by both colour-coded duplex imaging and arch angiography. Stenoses were graded at angiography using the linear method from the European Carotid Surgery Trial and on duplex using peak systolic velocity criteria. Angiograms were also analysed for any arch or intracerebral pathology which would alter surgical management. In defining 70-99 per cent stenoses, duplex had a sensitivity of 98 per cent, specificity 96 per cent, positive predictive value of 96 per cent, negative predictive value 98 per cent and accuracy 97 per cent compared with angiography for both symptomatic and asymptomatic carotids (chi 2 = 1.22, 1 d.f., P = 0.25). With respect to the symptomatic carotid arteries angiography gave different information from duplex in six patients (6 per cent): definition of 70-99 per cent carotid stenosis was different (four), visualization was poor on duplex (one) and an intracerebral aneurysm was identified by angiography. One patient died following arch angiography as a result of mesenteric thrombosis. Carotid duplex imaging alone would appear to be sufficient to assess most patients before carotid endarterectomy as an accurate, safe and relatively cheap investigation compared with angiography. In cases where duplex assessment does not allow full visualization of the carotid bifurcation angiography is required.

Caulobacter Lon protease has a critical role in cell-cycle control of DNA methylation

CcrM, an adenine DNA methyltransferase, is essential for viability in Caulobacter crescentus. The CcrM protein is present only in the predivisional stage of the cell cycle, resulting in cell-cycle-dependent variation of the DNA methylation state of the chromosome. The availability of CcrM is controlled in two ways: (1) the ccrM gene is transcribed only in the predivisional. cell, and (2) the CcrM protein is rapidly degraded prior to cell division. We demonstrate here that CcrM is an important target of the Lon protease pathway in C. crescentus. In a lon null mutant, ccrM transcription is still temporally regulated, but the CcrM protein is present throughout the cell cycle because of a dramatic increase in its stability that results in a fully methylated chromosome throughout the cell cycle. Because the Lon protease is present throughout the cell cycle, it is likely that the level of CcrM in the cell is controlled by a dynamic balance between temporally varied transcription and constitutive degradation. We have shown previously that restriction of CcrM to the C. crescentus predivisional cell is essential for normal morphogenesis and progression through the cell cycle. Comparison of the lon null mutant strain with a strain whose DNA remains fully methylated as a result of constitutive expression of ccrM suggests that the effect of Lon on DNA methylation contributes to several developmental defects observed in the lon mutant. These defects include a frequent failure to complete cell division and loss of precise cell-cycle control of initiation of DNA replication. Other developmental abnormalities exhibited by the lon null mutant, such as the formation of abnormally long stalks, appear to be unrelated to altered chromosome methylation state. The Lon protease thus exhibits pleiotropic effects in C. crescentus growth and development.

Increased neural cell adhesion molecule in the CSF of patients with mood disorder

Neural cell adhesion molecule (N-CAM) is involved in cell-cell interactions during synaptogenesis, morphogenesis, and plasticity of the nervous system. Disturbances in synaptic restructuring and neural plasticity may be related to the pathogenesis of several neuropsychiatric diseases, including mood disorders and schizophrenia. Disturbances in brain cellular function may alter concentrations of N-CAM in the CSF. Soluble human N-CAM proteins are detectable in the CSF but are minor constituents of serum. We have recently found an increase in N-CAM content in the CSF of patients with schizophrenia. Although the pathogenesis of both schizophrenia and mood disorders is unknown, ventriculomegaly, decreased temporal lobe volume, and subcortical structural abnormalities have been reported for both disorders. We have therefore measured N-CAM concentrations in the CSF of patients with mood disorder. There were significant increases in amounts of N-CAM immunoreactive proteins, primarily the 120-kDa band, in the CSF of psychiatric inpatients with bipolar mood disorder type I and recurrent unipolar major depression. There were no differences in bipolar mood disorder type II patients as compared with normals. There were no significant effects of medication treatment on N-CAM concentrations. It is possible that the 120-kDa N-CAM band present in the CSF is derived from CNS cells as a secreted soluble N-CAM isoform. Our results suggest the possibility of latent state-related disturbances in N-CAM cellular function, i.e., residue from a previous episode, or abnormal N-CAM turnover in the CNS of patients with mood disorder.

A cell cycle-regulated bacterial DNA methyltransferase is essential for viability

The CcrM adenine DNA methyltransferase, which specifically modifies GANTC sequences, is necessary for viability in Caulobacter crescentus. To our knowledge, this is the first example of an essential prokaryotic DNA methyltransferase that is not part of a DNA restriction/modification system. Homologs of CcrM are widespread in the alpha subdivision of the Proteobacteria, suggesting that methylation at GANTC sites may have important functions in other members of this diverse group as well. Temporal control of DNA methylation state has an important role in Caulobacter development, and we show that this organism utilizes an unusual mechanism for control of remethylation of newly replicated DNA. CcrM is synthesized de novo late in the cell cycle, coincident with full methylation of the chromosome, and is then subjected to proteolysis prior to cell division.

Localized facial telangiectasias following frostbite injury

Two patients presented with localized facial telangiectasias a consequence of superficial frostbite injury. Trauma from frostbite resulted in the permanent formation of these telangiectasias. We review the morphology of the different degrees of frostbite and discuss the involvement of angiogenesis as a response to tissue insult.

In vivo examination of membrane protein localization and degradation with green fluorescent protein

To test the utility of green fluorescent protein (GFP) as an in vivo reporter protein when fused to a membrane domain, we made a fusion protein between yeast hydroxymethylglutaryl-CoA reductase and GFP. Fusion proteins displayed spatial localization and regulated degradation consistent with the native hydroxymethylglutaryl-CoA reductase proteins. Thus, GFP should be useful in the study of both membrane protein localization and protein degradation in vivo.

Culture of dialysis fluids on nutrient-rich media for short periods at elevated temperatures underestimate microbial contamination

Recommended culture methods for monitoring bacterial contamination of H2O, dialysate and bicarbonate concentrate in dialysis centers in the USA involves culturing these fluids for 48 h at 37 degrees C. A variety of media and commercial culture methods are accepted for monitoring these fluids. Over a 3-month a comparison was made between an acceptable culture method, tryptic soy agar (TSA) employing the pour plate (PP) technique at 37 degrees C for 48 h, and PP cultures on standard methods agar (SMA) and R2A agar, incubated at ambient temperature (23 degrees C) for 48, 72, 168 h. Increases in the colony counts over time occurred for all three fluids. However, counts wee greater on SMA and R2A than on TSA. The increases over the standard 48-hour TSA cultures ranged as high as 10(4) times for 23 degrees C cultures at 7 days of incubation. Endotoxin levels even in the most contaminated samples were found to be below the acceptable 5 EU/ml recommended for reprocessor water. Bacterial colonies that appeared at 48, 72 and 168 h were isolated and identified. Pseudomonas, Moraxella, Acinetobacter and CDC group VI C-2 were among some of the common bacteria isolated. This study indicates that the media utilized, the time and temperature of incubation may result in a significant underestimation of the bacterial population of water and dialysis fluids, thus potentially placing the patient at a higher risk.

Degradation of HMG-CoA reductase-induced membranes in the fission yeast, Schizosaccharomyces pombe

Elevated levels of certain membrane proteins, including the sterol biosynthetic enzyme HMG-CoA reductase, induce proliferation of the endoplasmic reticulum. When the amounts of these proteins return to basal levels, the proliferated membranes are degraded, but the molecular details of this degradation remain unknown. We have examined the degradation of HMG-CoA reductase-induced membranes in the fission yeast, Schizosaccharomyces pombe. In this yeast, increased levels of the Saccharomyces cerevisiae HMG-CoA reductase isozyme encoded by HMG1 induced several types of membranes, including karmellae, which formed a cap of stacked membranes that partially surrounded the nucleus. When expression of HMG1 was repressed, the karmellae detached from the nucleus and formed concentric, multilayered membrane whorls that were then degraded. During the degradation process, CDCFDA-stained compartments distinct from preexisting vacuoles formed within the interior of the whorls. In addition to these compartments, particles that contained neutral lipids also formed within the whorl. As the thickness of the whorl decreased, the lipid particle became larger. When degradation was complete, only the lipid particle remained. Cycloheximide treatment did not prevent the formation of whorls. Thus, new protein synthesis was not needed for the initial stages of karmellae degradation. On the contrary, cycloheximide promoted the detachment of karmellae to form whorls, suggesting that a short lived protein may be involved in maintaining karmellae integrity. Taken together, these results demonstrate that karmellae membranes differentiated into self-degradative organelles. This process may be a common pathway by which ER membranes are turned over in cells.

Oral immunization with attenuated Salmonella expressing human sperm antigen induces antibodies in serum and the reproductive tract

Induction of immune responses in the reproductive tract will be crucial for a functional gamete antigen-based antifertility vaccine. Here we describe the construction and development of an avirulent Salmonella as an oral vaccine delivery vector to elicit sperm-specific immune responses in reproductive tract secretions. A cDNA sequence encoding the human sperm antigen SP10 was cloned on an asd+vector and expressed to a high level in an avirulent delta cya, delta crp, and delta asd vaccine strain of Salmonella typhimurium. Oral immunization of female BALB/c mice with this recombinant Salmonella elicited high-titer anti-SP10 IgG antibodies in serum and IgA antibodies in vaginal secretions. Anti-SP10 antibody titers could be increased by secondary and tertiary oral administrations of the recombinant Salmonella. Induction of sperm-specific antibodies in the reproductive tract following oral administration of a recombinant Salmonella could lead to the development of a simple, safe, efficient, and easy-to-use antifertility vaccine.

Teleradiology

Advances in telecommunications and computer software have led to the development of radiology image transfer systems. Radiologists may now report radiographs at a site distant from that of the examination, in some cases almost instantaneously. Computed tomography, magnetic resonance imaging, and ultrasonography may also be supervised from afar. Developments over the past few decades are reviewed, allowing an understanding of the systems currently available. These include systems that transmit static images and real time video systems that enable interactive supervision from a radiologist at a distant site. The implications for the practice of radiology are discussed and the main areas of development over the next few years explored.

Critical threonine and aspartic acid residues within the I domains of beta 2 integrins for interactions with intercellular adhesion molecule 1 (ICAM-1) and C3bi

Integrins mediate signal transduction through interactions with multiple cellular or extracellular matrix ligands. Evidence is accumulating that the I (or A) domain, a approximately 200-residue inserted sequence in some integrin alpha subunits, mediates ligand binding. We have previously shown that Thr-221 of the putative ligand binding sites within alpha 2 I domain of alpha 2 beta 1 is critical for binding to collagen (Kamata, T., and Takada, Y. (1994) J. Biol. Chem. 269, 26006-26010). Here we report that the mutation of Thr-206 of alpha L blocks intercellular adhesion molecule 1 (ICAM-1) binding to alpha L beta 2 and mutation of Thr-209 of alpha M blocks ICAM-1 and C3bi binding to alpha M beta 2. The data indicate the Thr residues of alpha M and alpha L corresponding to Thr-221 of alpha 2 are critically involved in the ligand interaction with beta 2 integrins. The mutations of the Asp-137 and Asp-239 of alpha L also block ICAM-1 binding to alpha L beta 2, as do the corresponding Asp residues of alpha 2 or alpha M in collagen/alpha 2 beta 1 or C3bi/alpha M beta 2 interactions, respectively. These data suggest that these Thr and Asp residues, conserved among I domains, are critical for interaction with structurally distinct ligands (e.g. ICAMs, C3bi, and collagen).

Acetabular fractures: long-term follow-up of open reduction and internal fixation

Eight-seven acetabular fractures in eighty-seven patients underwent open reduction and internal fixation at Vanderbilt University Hospital from 1984 to 1989. Fifty-six were treated by orthopaedic traumatologists. Fifty-six patients returned for long-term follow-up (range 24-80 months, average 43). Harris hip ratings were used to clinically grade the results. Poor results were found in 43%. Eighty-three percent of the patients with poor results had satisfactory surgical reductions with < 3 mm of residual displacement. Factors other than surgical reduction contributed significantly to the poor results. These included hip dislocation associated with the fracture, class III or IV heterotopic ossification, development of avascular necrosis, and age > 40 years. These factors in addition to adequacy of surgical reduction allow us to better counsel patients as to long-term prognosis.