Basic study on hepatic resection under partial perfusion cooling

To improve liver quality after reperfusion following partial hepatectomy under total or partial cooling of the liver (HPC), a new perfusion solution containing 100 mM L-histidine (KM solution) was developed. The livers of Lewis rats were removed and perfused for 2 hours at 20 degrees C with lactated Ringer's (LR) solution (group A) or the KM solution (group B). They were reperfused with rat blood at 37 degrees C at a perfusion pressure of 5 cmH2O while monitoring the portal and peripheral tissue blood flows. At the end of reperfusion, bile production, lactate dehydrogenase (LDH) secretion, and tissue adenosine triphosphate (ATP) was measured. Recovery of portal and peripheral tissue blood flows of the group B livers after reperfusion were significantly better than those of group A. Viability of the group B livers, assessed by bile production, tissue ATP value, and LDH release, was preserved better than that of group A livers. In situ total liver perfusion with LR (group C) and KM (group D) solutions for 1 hour at 20 degrees C followed by partial hepatectomy of the left lateral lobe was performed. The 1-week survivals of the group C and D rats were 25% and 100%, respectively (p < 0.05). It was concluded that KM solution is suitable for HPC.

Dopaminergic functional supersensitivity: effects of chronic L-dopa and carbidopa treatment in an animal model of Parkinson's disease

We have evaluated the effects of L-Dopa and carbidopa treatment (30 days) on dopamine (DA) turnover, intracellular cyclic AMP (cAMP) accumulation and tetrahydrobiopterin levels in the nigrostriatal pathway of rats with a unilateral 6-OHDA lesions (greater than 90% lesions). We observed significant increase in the 3,4-dihydroxy-phenylacetic acid/DA and homovanillic acid/DA ratios, and in basal cAMP levels (92%) in the ipsilateral striatum, but not in the substantia nigra when compared to the contralateral intact hemisphere. After L-dopa/carbidopa treatment, the increased 3,4-dihydroxy-phenylacetic acid/DA, homovanillic acid/DA ratios and the elevated levels of cAMP in the ipsilateral striatum were reduced significantly and returned to the control levels of contralateral non-lesioned side. Tetrahydrobiopterin levels obtained on both sides remained unaffected after treatment. The D1 agonist SKF 38393 (10 microM) increased cAMP accumulation significantly in striatal slices from the lesioned and intact hemispheres in both vehicle and treatment group, which were completely inhibited by the D1 antagonist SCH 23390 (10 microM). In contrast, the ability of SKF 38393 to enhance the cAMP accumulation was blocked by the D2 agonist quinpirole (10 microM) in striatal slices from the intact hemisphere, but not from the lesioned side. In substantia nigra, no significant differences in cAMP accumulation were observed. Our data suggests that chronic L-dopa/carbidopa treatment reverses the increased dopaminergic activity and D1 receptor functional supersensitivity seen after 6-hydroxydopamine lesions, and indicates a D1 receptor-mediated action of L-dopa.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparative effects of electroconvulsive shock and haloperidol on in vivo tyrosine hydroxylation and tetrahydrobiopterin in the brain of rats with 6-hydroxydopamine lesions

We have evaluated the effects of electroconvulsive shock (ECS) and haloperidol treatment on the in vivo tyrosine hydroxylation rate and the tetrahydrobiopterin levels in the nigrostriatal system of 6-OHDA-lesioned rats. The rate of DOPA accumulation was significantly decreased by 96% in the ipsilateral striatum and by 50% in substantia nigra of the 6-OHDA-lesioned rats compared to the control activity of contralateral non-lesioned striatum and substantia nigra. The loss of total biopterin was found to be 75% and 50% in the ipsilateral striatum and substantia nigra, respectively. Following administration of haloperidol, the rate of DOPA accumulation increased significantly in the striatum and substantia nigra on the lesioned side compared to that in the vehicle treatment group. Application of ECS also significantly increased the rate of DOPA accumulation in the ipsilateral striatum and substantia nigra compared to that obtained in the non-shocked rats. The biopterin levels in the nigrostriatal system of 6-OHDA-lesioned were elevated significantly in the striatum after haloperidol treatment; in contrast the biopterin levels were unchanged in response to ECS. Our results show that both haloperidol and ECS significantly enhanced the rate of in vivo tyrosine hydroxylation in the striatum and substantia nigra of rats with greater than 90% lesions. These results suggest that the nigrostriatal system, although up-regulated following 6-OHDA lesions, still maintains the potential for further up-regulation of dopaminergic function in response to haloperidol and ECS treatment.

Effects of electroconvulsive shock on tetrahydrobiopterin and GTP-cyclohydrolase activity in the brain and adrenal gland of the rat

The effects of a single and repeated electroconvulsive shock (ECS) (300 mA, 0.2 s) on tetrahydrobiopterin (BH4) levels and GTP-cyclohydrolase activity in the brain and adrenal glands of rats were examined. Twenty-four hours after the last ECS treatment (one/day for 7 days), biopterin levels were significantly elevated in the locus coeruleus, hippocampus, frontal cortex, hypothalamus, ventral tegmental area, and adrenal gland. There were no changes in biopterin levels after a single application of ECS. GTP-cyclohydrolase activity was significantly increased in the locus coeruleus, frontal cortex, hippocampus, hypothalamus, and adrenal gland 24 h after repeated ECS and remained elevated in certain tissues up to 8 days after the last treatment. Kinetic analysis of adrenal and locus coeruleus GTP-cyclohydrolase 1 day after 7 days of ECS showed significant changes in both Km and Vmax values. These data suggest that the long-term increases in BH4 levels and GTP-cyclohydrolase activity after repeated ECS may play a part in the mediation of the antidepressant effects of ECS.

Incidence of Aeromonas isolated from diarrhoeal children and study of some virulence factors in the isolates

Stool samples from 305 children with diarrhoea and equal number of age and sex matched non-diarrhoeal control children, less than 5 years of age, were examined during the period from Sept 1988 to April 1989. Aeromonas spp. were isolated from 37 (12.1%) diarrhoeal and 05 (1.6%) control cases. Out of 37 diarrhoeal isolates 13 (35.1%) were A. hydrophila, 19 (51.1%) A. sobria and 05 (13.5%) A. caviae. All the isolated strains were tested for haem agglutination property and haemolysin production. Seventeen diarrhoeal and 05 control isolates were tested for cytotoxin production in He La cell line and enterotoxin production in rat ileal loop model and suckling mouse model. Chinese hamster ovary cell (CHO) assay and Gm-1 ELISA methods were also employed. Cytotoxin production was found in 82.5% of diarrhoeal and 40% of control isolates. Haemagglutination was found in 62.1% of Aeromonas isolated from diarrhoeal children and 20% from control children. Enterotoxin production was detected in 58.8% diarrhoeal and none of the control isolates by either of the methods. Of the virulence factors enterotoxin production was found to correlate well with enteropathogenicity but haemolysin, cytotoxin and haemagglutinin did not.

Campylobacter jejuni bacteraemia in children with diarrhoea in Bangladesh: report of six cases

Campylobacter jejuni was isolated from blood cultures from 6 of 6,275 diarrhoeal children seeking treatment at the Clinical Research Centre of the International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B) between April 1989 and December 1990. The clinical records of these 6 children were reviewed. All children were male; 5 were less than 1-year old and were severely malnourished. Five patients presented with watery diarrhoea and one with bloody diarrhoea. Two children died in the hospital. All strains of Campylobacter isolated from the 6 children were negative for cell invasive properties as tested by the Sereny test. Of the two strains tested for serum bactericidal activity, one strain was serum sensitive (growth inhibition), and the other resistant. The ability of C. jejuni to cause bacteraemia suggests that the organisms may be responsible for diarrhoeal diseases especially in young and malnourished children. An early attempt to detect Campylobacter and start effective antimicrobial therapy is indicated.

Antimicrobial resistance of Shigella isolates in Bangladesh, 1983-1990: increasing frequency of strains multiply resistant to ampicillin, trimethoprim-sulfamethoxazole, and nalidixic acid

The susceptibility to ampicillin and trimethoprim-sulfamethoxazole (TMP-SMZ) was determined for 15,824 isolates of Shigella obtained from patients attending a treatment center in Dhaka, Bangladesh, from 1983 through 1990 and for 520 isolates obtained during community surveys from 1988 through 1990. Susceptibility to nalidixic acid was determined for isolates obtained after 1985. In 1983 13% of isolates were resistant to ampicillin, 23.5% to TMP-SMZ, and 0.8% to both drugs. By 1990 51.2% of isolates obtained at the Diarrhea Treatment Centre were resistant to ampicillin, 47.7% to TMP-SMZ, and 40.5% to both drugs (for comparison with figures for 1983, P less than .001). Resistance to nalidixic acid increased from 0.8% in 1986 to 20.2% in 1990 (P less than .001). In 1990 71.5% of Shigella dysenteriae type 1 isolates were resistant to ampicillin, 68.5% to TMP-SMZ, 67.7% to both drugs, and 57.9% to nalidixic acid. The resistance pattern of isolates obtained during community surveillance was similar to that of Treatment Centre isolates. In Bangladesh ampicillin and TMP-SMZ are no longer useful for treatment of infection with any species of Shigella, and nalidixic acid is no longer useful for treatment of infections due to S. dysenteriae type 1.

Studies on virulence determinants of Plesiomonas shigelloides

Virulence determinants of nineteen strains of Plesiomonas shigelloides isolated from stool samples of diarrhoeal children were studied. Heat-labile toxin was detected in seven strains using rat ileal loop model and in none of the strains using Chinese hamster ovary cell assay system and by Enzyme-linked immunosorbent assay. Rat ileal loop model was used for the first time to assay toxin in P. shigelloides and is suggested to be a cheap and effective method of detecting labile toxin in the organism. Heat stable toxin, cytotoxin, hemolysin and hemagglutinin were not detected in the strains tested. Invasiveness could not be established by using HEp-2 cell assay system. The results of this study provide some experimental support for an etiological role for P. shigelloides in the production of diarrhoea.

Effect of duration of diarrhoea and predictive values of stool leucocytes and red blood cells in the isolation of different serogroups or serotypes of Shigella

Diarrhoeal stools from 11,358 patients were microscopically examined for the presence of white and red blood cells (WBC and RBC) and cultured for enteric pathogens. Of the 3895 patients who had Shigella as sole pathogens, 2681 (72.3%) showed the presence of both WBC and RBC and the remainder had only WBC (P less than 0.001). The presence of both WBC and RBC was as good a predictor of shigellosis as the presence of greater than 25 WBC per high power field (hpf) of the microscope with or without RBC. However, the best predictor of shigellosis (positive predictive value 85%, negative predictive value 83%) was the presence of greater than 25 WBC/hpf and the presence of RBC regardless of their number. More patients infected with S. dysenteriae 1, S. flexneri and S. boydii shed both WBC and RBC than those infected with S. sonnei, most of whom shed WBC only (P less than 0.001). A greater number of patients infected with S. dysenteriae 1 shed more WBC and RBC than those infected with S. flexneri (P less than 0.001). The same trend was found when patients infected with S. flexneri were compared with those infected with S. boydii (though the difference was not statistically significant) and when patients infected with S. boydii were compared with patients infected with S. sonnei (P less than 0.001). There was a progressive decline in the isolation rate of Shigella as the duration of dysentery, before stool culture, increased.

Survival of classic cholera in Bangladesh

During the present cholera pandemic the El Tor biotype of Vibrio cholerae has completely displaced the classic biotype, except in Bangladesh. We studied the distribution of these two biotypes in twenty-four rural districts during epidemics in 1988-89; there was clustering of the classic biotype in the southern region and of the El Tor biotype in all other regions. These findings suggest that the southern coastal region is now (and may always have been) the habitat of classic cholera. The selective distribution of V cholerae O1 biotypes in Bangladesh may have been affected by ecological changes occurring in the country.

Hafnia alvei, a probable cause of diarrhea in humans

Hafnia alvei, a member of the family Enterobacteriaceae, was the only species of bacteria cultured from the stool of a 9-month-old child who was admitted with a 3-day history of watery diarrhea. The isolated strain of H. alvei failed to produce heat-labile or heat-stable enterotoxins or Shiga-like toxin I or II and did not invade HeLa cells, nor did it cause keratoconjunctivitis (determined by the Sereny test) in a guinea pig's eye. The strain, however, induced diarrhea in 8 of 12 adult rabbits with removable intestinal ties (removable intestinal tie-adult rabbit diarrhea [RITARD] assay) and in 1 of 2 orally fed animals. No diarrhea could be induced with Escherichia coli K-12 in eight RITARD assay rabbits and three orally fed rabbits, respectively. Microscopic examination of affected animals revealed moderate inflammatory cellular infiltration of the intestinal mucosa, in which bacterial attachment to the surface epithelium and loss of the microvillus border were evident in the ileum and colon. Electron microscopy demonstrated cellular modifications of the apical surface, with cupping or pedestal formation and increased terminal web density at sites of bacterial "attachment-effacement," a well-known characteristic and mechanism of diarrhea of enteropathogenic E. coli. Identical lesions were also induced by H. alvei in rabbit ileal loops, which ruled out naturally occurring rabbit enteropathogenic E. coli strains, which are known to produce similar lesions. It is concluded that at least some strains of H. alvei have the potential to cause diarrhea and that attachment-effacement is a virulence characteristic shared by bacteria other than E. coli.

The effects of electroconvulsive shock on catecholamine function in the locus ceruleus and hippocampus

Repeated electroconvulsive shock (ECS) treatment (once per day for 7 days) produced a significant increase in tyrosine hydroxylase activity, GTP-cyclohydrolase activity and tetrahydrobiopterin (BH4) levels in the locus ceruleus and hippocampus from 1 to 4 days after the last treatment. These changes may be responsible for, or contribute to, the antidepressant effect of ECS treatment.

Epidemiology of shigellosis in Teknaf, a coastal area of Bangladesh: a 10-year survey

The epidemiological data on shigellosis in Teknaf, a coastal area of Bangladesh, were reviewed for a 10-year period (1975-84). Certain similarities and differences were observed in the epidemiology of the disease in Teknaf when compared with urban Dhaka and rural Matlab. Similarities included: round-the-year infection with two peaks, one in the monsoon period and the other in the winter period; high male to female attendance ratio at the treatment centre; the predominance of infection in the under-15-year age group; high mortality rate in the under-5-year age group of both sexes and in females of all age groups; the multiple drug resistance of organisms. Differences included the higher isolation rate of organisms in Teknaf (42.1% as against 11-12% in Dhaka and Matlab) and the preponderance of Shigella dysenteriae 1 infection in females in Teknaf. The unusually high isolation rate of shigella makes Teknaf the area with the highest incidence of shigellosis in Bangladesh.

Theoretical modeling of biodegradation and biotransformation of hydrocarbons in subsurface environments

Hydrocarbons such as TCE, PCE, TCA, gasoline and kerosene which are widely used in the industry, enter soils and groundwater from chemical waste disposal sites and from accidents. These types of substances are the most commonly encountered groundwater contaminants nationwide. Biotransformation of dissolved chlorinated hydrocarbons can provide complete mineralization to harmless end products such as CO2. It is the objective of this work to investigate the biodegradation and biotransformation, and transport of hydrocarbons in groundwater. This will be achieved first by defining and identifying relevant physical and biological processes which contribute to the fate of hydrocarbon contaminants in unsaturated/saturated soils, and providing a conceptual framework for incorporating these processes into a mathematical formulation. The conservation principles expressed in terms of quantifications of the physical, chemical and microbial processes described above lead to a system governing the phenomenon which consists of nonlinear partial differential equations. Microbial transformation conducted by both anaerobic and aerobic bacteria are considered.

Alpha 1 antitrypsin (PI) phenotypes in two rheumatic diseases: a reappraisal of the association of PI subtypes in rheumatoid arthritis

alpha 1 Antitrypsin phenotypes were determined by isoelectric focusing in 225 adult white patients with rheumatoid arthritis (RA), 60 patients with severe rheumatoid arthritis (grade III and IV), 17 sibling pairs--HLA identical but discordant for rheumatoid arthritis, and 122 random patients with Sjögren's syndrome. No significant increase in non-M phenotypes was found in either of the groups of patients with RA, but the association between M subvariants was striking. There was a significant increase in M1M2 phenotype and M2 allotype in both the RA and severe RA groups. This increase in M1M2 was also supported by DR4 positive patients with RA compared with DR4 positive siblings without RA. No apparent association of variant phenotype was found in four subgroups of patients with Sjögren's syndrome.

Gastro-oesophageal reflux in halothane anaesthetized sheep. The effects of feeding and positioning

The frequency of gastro-oesophageal reflux (GOR) in sheep anaesthetized with halothane was reduced by withholding food and water for 24 hours. The total reflux volume increased. The effect of body position on GOR was studied by inclining the operating table at angles to the horizontal and positioning the head up or down on sand bags. The operative positions investigated were: right and left lateral recumbency with head down, dorsal recumbency with head down and right lateral recumbency with head up. Least GOR occurred when the sheep was in right lateral recumbency with a head up tilt and the body inclined at 20 degrees from the horizontal. A cuffed oesophageal drainage tube increased the incidence of GOR but prevented the chances of the aspiration of rumen material.

Motility of the oesophagus and gastro-oesophageal junction during halothane anaesthesia in sheep

Electromanometry and electromyography were used to study gastro-oesophageal motility in two planes of halothane anaesthesia in sheep. Gastro-oesophageal motility when present was greater in light than in deep anaesthesia. The caudal thoracic oesophagus contracted more frequently and for longer than the rostral thoracic oesophagus. In light anaesthesia oesophageal movements were peristaltic in direction with a propagation velocity of 26-29 cm sec-1. Rumen pressures increased throughout anaesthesia and the rate of increase was greatest when the plane of anaesthesia was deep at the start. Gastro-oesophageal reflux (GOR) occurred in both planes of anaesthesia and must occur by passive mechanisms during deep anaesthesia because gastro-oesophageal motility was inhibited. A high pressure zone (HPZ) was demonstrated for a length of 2.9 cm at the gastro-oesophageal junction with a balloon-tipped catheter and a 'pull through' technique. Open-tipped catheters could detect the HPZ but were less sensitive. The pressure in the HPZ was not significantly influenced by the depth of anaesthesia used. In 80% of cases of light anaesthesia an increase in HPZ pressure preceeded the contraction of the cranial sac of the rumen. In deep anaesthesia the HPZ continued to have rhythmic changes in tone. Spontaneous GOR coincided with a maximum gastro-oesophageal pressure gradient in 24% of cases. Rumen insufflation with oxygen provoked GOR at a rumen pressure above 33 mmHg compared with 7.2 mmHg during spontaneous reflux. The study demonstrates that a gastro-oesophageal pressure gradient was not primarily responsible for the initiation of GOR during anaesthesia and that the HPZ at the gastro-oesophageal junction of sheep had some of the properties of a lower oesophageal sphincter and played an important role in the initiation of GOR during anaesthesia.

HLA and rheumatoid arthritis: an analysis of multicase families

In a study of multicase RA families, significantly raised frequencies of the HLA antigens DR4, DR1, Bw62, Cw3, A2, A31 and significantly lower frequencies of DR2, DR3, and B8 were found in probands compared to normal controls. When haplotype frequencies were compared between probands and controls, two haplotypes A2-B44-DR4 and A2-Bw62-DR4 were at higher frequency in probands. These differences no longer reached significance when only DR4-containing haplotypes were compared between probands and controls. A significantly lower haplotype frequency of A1-B8-DR3 was observed in probands compared to controls. This difference did not remain significant when only non-DR4 haplotypes were compared. Using an affected sibling pair ratio method, significant linkage between HLA and RA was found (P less than 0.01). Significant linkage was also observed between HLA and seropositivity. Analysis of Hardy-Weinberg equilibrium for the DR locus did not support the suggestion that DR4-associated RA susceptibility was inherited as a dominant trait. In addition it did not support the notion of an additive effect of DR4 and DR1 in RA susceptibility as these antigens were not found together more frequently than predicted by their individual gene frequencies.