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Biomedical subjects

J G Morris

Publications and source records attributed to J G Morris.

At least 163 records · Page 9Linked to original sources

Postural tremor of Parkinson's disease.

Previous studies have reported the resting tremor (RT) of Parkinson's disease to occur at frequencies between 3-7 Hz and to be characterised by an alternating pattern of electromyographic (EMG) bursting activity between opposing muscles. A postural tremor (PT), of higher frequency (> 6 Hz) and with a synchronous pattern of EMG activity, has also been previously described in Parkinson's disease. We investigated the electrophysiological and pharmacological properties of both the RT and PT of 11 patients with Parkinson's disease and 10 patients with essential tremor in a double-blind, placebo-controlled study of L-Dopa/benserazide and propranolol. Tremor amplitude and frequency were assessed via bidirectional accelerometry, and the pattern of activation of the antagonist muscles of the forearm was determined with use of surface EMG. In the Parkinson's disease group studied, the frequency, EMG pattern of bursts, and response to L-Dopa were similar for the two tremors (median improvement of RT by 70% and PT by 61%). Despite some overlap between the Parkinson's disease and essential tremor groups in the electrophysiology of the tremor, there was no such dramatic pharmacological response in the latter group. These results suggest that the RT and PT of Parkinson's disease share a common pathophysiology and are distinct from essential tremor.

Adult↗

Vibrio cholerae O139 synonym bengal is closely related to Vibrio cholerae El Tor but has important differences.

Although Vibrio cholerae O139 synonym Bengal strains, from the current epidemics in India and Bangladesh, are closely related to seventh-pandemic strains, as shown by multilocus enzyme electrophoresis, Bengal strains are encapsulated and portions of the O1 antigen biosynthetic complex genes found in O1 strains are altered or lacking. Encapsulated Bengal strains showed resistance to killing by normal human serum. The presence of the capsule suggests the potential for bloodstream invasion in susceptible hosts and has profound implications for vaccine development.

Animals↗

The Sydney Multicentre Study of Parkinson's disease: a randomised, prospective five year study comparing low dose bromocriptine with low dose levodopa-carbidopa.

149 previously untreated patients with Parkinson's disease were recruited over a three year period and randomly allocated to either low dose levodopa-carbidopa (< or = 600/150 mg/day) or low dose bromocriptine (< or = 30 mg/day). A five year follow up is reported on the 126 patients who completed the dose titration and who have not developed features of atypical Parkinsonism. Levodopa-carbidopa in low dosage adequately controlled symptoms in most patients and delayed the appearance of dyskinesia and end of dose failure for about two years longer than conventional doses. Only a few patients could be managed for more than one year on low dose bromocriptine alone; these patients had mild disease and asymmetric signs. Patients randomised to bromocriptine did not develop dyskinesia or troublesome end of dose failure until levodopa-carbidopa was added. The prevalence of dyskinesia in this group was lower than in patients given levodopa-carbidopa alone. The prevalence of end of dose failure was similar in the two randomisation groups once levodopa was introduced.

Adult↗

Occurrence of necrotizing enterocolitis may be dependent on patterns of bacterial adherence and intestinal colonization: studies in Caco-2 tissue culture and weanling rabbit models.

Necrotizing enterocolitis (NEC) is one of the leading causes of death in neonatal intensive care units. The underlying pathophysiology of NEC is poorly defined, although there is a suggestion that bacterial agents play an important role in the process. In this study, we evaluated bacterial isolates from 17 NEC cases and matched asymptomatic control infants. Isolates from NEC patients were no more likely than control isolates to be adherent to enterocytes, as assessed by a Caco-2 cell tissue culture model. Adherent Escherichia coli isolates, from both NEC cases and controls, were able to cause pathologic changes typical of NEC in a weanling rabbit ileal loop model. Adherence of E. coli strains to Caco-2 cells, and subsequent production of disease in weanling rabbits, could be blocked by coinfection with Gram-positive isolates from control children. In contrast, in three of four instances, adherent E. coli from NEC cases retained their adherence and caused illness in rabbits when coinfected with Gram-positive isolates from the homologous child. Our data suggest that patterns of intestinal adherence, as influenced by the underlying intestinal microbial ecology, play a role in the pathophysiology of NEC.

Animals↗

An epizootic of feline herpesvirus, type 1 in a large specific pathogen-free cat colony and attempts to eradicate the infection by identification and culling of carriers.

This study describes the clinical course of an inadvertent feline herpesvirus, type 1 (FHV-1) outbreak in 2 specific pathogen-free (SPF) research and breeding colonies housing 690 cats and assesses a programme that was designed to eradicate the virus from the colonies. The clinical signs observed in these cats were milder, with more eye involvement than those previously described for FHV-1 infection and did not include abortion. FHV-1 eradication was based on the detection and elimination of both active and latent viral carriers. Carrier cats were detected by virus isolation from oral swabs before and after corticosteroid-induced reactivation of FHV-1 excretion. Four per cent of recovered cats were actively shedding virus prior to corticosteroid treatment; 21% of the virus negative cats shed virus after one corticosteroid injection, and 12% of remaining culture negative cats tested positive upon a second corticosteroid treatment 6 weeks later. The colony remained virus free for 8 months after all detectable virus carriers were culled and there was no seroconversion among new kittens. A second epizootic of FHV-1 then occurred among susceptible animals. At this time, all breeding cats that had tested negative after 2 injections of corticosteroids were treated a third time; 23% of them now tested positive for FHV-1. This study demonstrates that corticosteroid treatment can be useful in improving the rate of detection, essential as a basis for decreasing the incidence of enzootic disease, but it is unlikely to detect all possible FHV-1 carriers in large populations of cats.

Animals↗

Experimental induction of hepatic lipidosis in cats.

The effect of long-term voluntary fasting on hematologic variables, biochemical profiles, and liver histologic findings was assessed in 15 obese cats (> 40% overweight). Clinical signs and laboratory results consistent with hepatic lipidosis were observed in 12 of 15 cats after 5 to 7 weeks of fasting, and were associated with 30 to 35% reduction of initial body weight. Histologic examination of successive liver biopsy specimens revealed that obesity was not associated with liver parenchymal lipid accumulation, but that fasting resulted in lipidosis in all 15 cats. The long-term fast was associated with an early (after 2 to 4 weeks of fasting) and significant (P < 0.05) reduction in serum urea, glucose, and albumin concentrations, and RBC mass. Fasting for 5 to 7 weeks was associated with a significant (P < 0.05) increase in hepatic-associated enzyme activities and in total and direct serum bilirubin concentrations. Significant (P < 0.05) changes in serum alkaline phosphatase developed as early as 3 weeks before the onset of hyperbilirubinemia. Except for development of hepatic lipidosis, cats appeared to tolerate the fast without other adverse effect. This study confirmed that long-term fasting may induce clinical hepatic lipidosis in obese cats. Fasting appears to induce a syndrome of hepatic lipidosis that is indistinguishable from feline idiopathic hepatic lipidosis and may be an appropriate model to study the pathophysiologic features and treatment of hepatic lipidosis.

Alkaline Phosphatase↗

Endemic necrotizing enterocolitis: lack of association with a specific infectious agent.

We conducted a comprehensive analysis of bacterial, parasitic and viral agents present in stool samples of 23 necrotizing enterocolitis cases and 23 matched and 10 random controls. Enterococcus spp., Staphylococcus epidermidis, and Escherichia coli were the most common aerobic bacterial species isolated. Astrovirus was identified in a stool sample from one control. Eight infants were bacteremic; in 7 of 8 the same organism was also present in the stool. No one bacterial species or strain (as identified by plasmid profile analysis) was associated with occurrence of illness. Plasmid analysis further suggested that each infant was colonized with his or her own distinctive aerobic bacterial flora. With the exception of isolates from two control patients which hybridized with a probe for diffuse adherence, no diarrheagenic E. coli was identified. Five (45%) of 11 case infants were colonized with coagulase-negative staphylococci (all S. epidermidis) that produced delta-hemolysin in vitro, as compared with 13 (87%) of 15 control infants. Necrotizing enterocolitis was not associated with an increased ability to ferment carbohydrate, as measured by in vitro beta-galactosidase activity. Our data do not support the hypothesis that endemic necrotizing enterocolitis in our institution is caused by a single infectious agent, nor was there evidence that previously proposed virulence mechanisms such as production of delta-hemolysin or increased in vitro carbohydrate fermentation play a critical role in disease occurrence.

Bacteriological Techniques↗

Effects of protein, lipid, or carbohydrate supplementation on hepatic lipid accumulation during rapid weight loss in obese cats.

Effects of restricted tube-feeding (25% of energy requirements) of protein, lipid, or carbohydrates on body weight loss; hematologic and clinical chemical variables; plasma lipid and amino acid concentrations; nitrogen balance; and hepatic histologic features and lipid concentrations were compared with values in voluntary-fasting cats (control, CON). Twelve obese cats (6.1 +/- 0.1 kg, > 40% above optimal body weight) were randomly assigned to 4 matched treatment groups (n = 3)--protein (PRO), lipid (LIP), carbohydrate (CHO), and CON--and were offered a low-palatability diet for 4 weeks. Cats of the PRO, LIP, and CHO groups were also tube-fed isocaloric amounts (88 kcal of metabolizable energy) of a casein-soybean protein mixture, corn oil, or a dextrin-dextrose mixture, respectively, during the 4 weeks. All cats fasted, rather than eat the low-palatability purified diet. Cats of the PRO group lost weight at a lower rate (P < 0.05) than did cats of other groups. After 4 weeks of fasting, serum alkaline phosphatase activities were higher than reference values in all cats of the CON and LIP groups and in 2 cats of the CHO group. At that time, 1 cat of the LIP group had lethargy, hepatomegaly, and hyperbilirubinemia. Total hepatic lipid and triglyceride concentrations increased in all groups during the study, but the increase was significantly (P < 0.05) less in cats of the PRO group, compared with those of the CON and LIP groups, and those of the CHO group, compared with those of the LIP group.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗

Delayed cerebral radiation necrosis.

The clinical features and long-term outcome of seven patients with delayed cerebral radiation necrosis (DCRN) are described. Radiotherapy had been given for pituitary tumour (1), astrocytoma (2), pinealoma (2), craniopharyngioma (1) and parotid carcinoma (1). The mean latency to onset of the first neurological symptoms was 22 months (range 6-40 months), and mean duration of follow-up was 86 months (range 60-126). Three patients died at a mean of 84 months after radiotherapy (range 62-98). A fourth patient probably died from metastatic disease. Three patients remain alive, albeit severely disabled, after 5-10 years. The illness typically ran a stepwise course, with fits and stroke-like episodes occurring against a background of progressive dementia and somnolence. CT and MRI scans showed progressive ventricular dilatation associated with cerebral atrophy and diffuse or focal changes in the white matter. Four patients had had two or more neurosurgical procedures after the radiotherapy. In only one of the seven patients was the diagnosis made at presentation. DCRN produces a distinctive clinical picture, yet remains a poorly recognized complication of cranial irradiation.

Adolescent↗

Reliability of the Columbia scale for assessing signs of Parkinson's disease.

Inter- and intrarater reliability in scoring the signs of Parkinson's disease using the original Columbia scale and a modified version of this, the Sydney scale, were assessed in five neurologists participating in a long-term study of Parkinson's disease. Scoring was done on video recordings of 41 patients whose disability ranged from mild to severe. Although all the neurologists were familiar with the scales and had received training designed to produce uniformity of scoring, interrater reliability was poor. The mean score for the Columbia scale varied from 18.6 to 30 and for the Sydney scale from 15.2 to 23.2. By contrast, intrarater reliability was good. This study highlights the limitations of clinical rating scales in Parkinson's disease when more than one rater is used. In designing clinical trials, every effort should be made to ensure that the same patient is always assessed by the same rater.

Analysis of Variance↗

Capsular polysaccharide structure of a clinical isolate of Vibrio vulnificus strain BO62316 determined by heteronuclear NMR spectroscopy and high-performance anion-exchange chromatography.

Virulence of Vibrio vulnificus has been strongly associated with encapsulation. Capsular polysaccharide was purified from a virulent strain of Vibrio vulnificus BO62316, a clinical isolate, by dialysis, centrifugation, enzymatic digestion, and phenol-chloroform extraction. This polysaccharide shows partial reactivity with antibodies to the capsular polysaccharide of a related pathogenic strain of V. vulnificus (MO6-24) whose structure was recently reported. Nuclear magnetic resonance spectroscopic analysis of the purified polysaccharide from strain BO62316 showed that the polymer is composed of a repeating structure with four sugar residues per subunit: a residue of 2-acetamido-2,6-dideoxy-hexo pyranose in the alpha-gluco configuration (QuiNAc), a residue of 2-acetamido-2,6-dideoxy hexopyranose in the alpha-galacto configuration (FucNAc), a residue of 2-acetamido-2,6-dideoxy hexopyranose in the alpha-manno configuration (RhaNAc), and a residue of 2-acetamido-2,6-dideoxy hexouronate in the alpha-galacto configuration (GalNAcA). The complete carbohydrate structure of the capsular polysaccharide was determined by heteronuclear nuclear magnetic resonance spectroscopy and by high-performance anion-exchange chromatography. The 1H and 13C spectra were completely assigned, and vicinal coupling relationships were used to establish the stereochemistry of each sugar residue, its anomeric configuration, and the position of the glycosidic linkages. The complete structure is Formular; [see text]. This is the first reported occurrence of RhaNAc in a capsular polysaccharide.

Carbohydrate Conformation↗

Zoster sine herpete of the trigeminal nerve.

Zoster sine herpete infection that involves the trigeminal nerve is rarely reported. The present case details a case of varicella zoster virus infection of the mandibular division of the left trigeminal nerve without evidence of a vesicular eruption. The diagnosis was established on clinical findings and was supported by the demonstration of an IgG antibody titer of > 1:640 during the acute phase of the disease.

Adult↗

Bacterial shock responses.

Bacteria, very early in their history, developed protective 'shock responses', triggered when the organism was exposed to some acute environmental stress. At the heart of each response was the accelerated synthesis of both general and stimulus-specified intracellular proteins. So successful was this strategy that its basic mechanism and several of its components were highly conserved throughout the course of evolution. This was particularly true of heat shock proteins whose universal distribution has both good and bad consequences for man.

Animals↗

An outbreak of cholera in Maryland associated with imported commercial frozen fresh coconut milk.

In August 1991, the first outbreak of cholera associated with an imported commercial food product occurred among persons attending a private picnic. An epidemiologic investigation showed infection with toxigenic Vibrio cholerae O1, biotype El Tor, serotype Ogawa, in 4 of 6 persons who had consumed coconut milk imported from Thailand. In addition, the US Food and Drug Administration recovered toxigenic V. cholerae O1, biotype El Tor, serotype Ogawa, from 1 of 6 unopened bags of the same brand (but different shipment) of coconut milk as that consumed by infected persons. Investigation in Thailand of the manufacturing process of the implicated coconut milk showed several sanitary violations, suggesting that contamination had occurred during production. This outbreak suggests a model of entrance of V. cholerae into a population and shows the need to evaluate current methods of maintaining the safety of imported foods in the United States.

Adult↗