Hyperammonemia with citrullinemia

Two cases of hyperammonemia with elevated citrulline are reported, one resulting from a deficiency of pyruvate carboxylase and the other from a partial deficiency of argininosuccinate synthetase. Diagnosis was based on clinical, biochemical and amino acid profiles. The utility of amino acid determinations in hyperammonemia suspected to underlie an inborn error of metabolism is emphasized.

Effect of asimadoline, a kappa opioid agonist, on pain induced by colonic distension in patients with irritable bowel syndrome

BACKGROUND

Visceral hypersensitivity plays a major role in irritable bowel syndrome pathophysiology. Opioid kappa receptors on afferent nerves may modulate it and be the target for new irritable bowel syndrome treatments.

AIM

This study evaluated the effect of the kappa opioid agonist asimadoline on perception of colonic distension and colonic compliance in irritable bowel syndrome patients.

METHOD

Twenty irritable bowel syndrome female patients (Rome II criteria; 40 +/- 13 years) and hypersensitivity to colonic distension (Pain threshold < or = 32 mmHg) were included in a randomized double-blind cross-over trial comparing the effect of a single oral dose of asimadoline 0.5 mg or placebo on sensory thresholds (defined as a constant and sustained sensation) elicited by left colon phasic distension (5 mmHg steps, 5 min) up to a sensation of abdominal pain. Colonic compliance was compared by the slope of the pressure-volume curves.

RESULTS

On asimadoline, pain threshold (mean +/- s.d.) (29.8 +/- 7.2 mmHg) was higher than on placebo (26.3 +/- 7.8 mmHg), difference not statistically significant (P = 0.1756, ANOVA). Area under curve of pain intensity rated at each distension step was significantly lower on asimadoline (89.3 +/- 33.9, ANOVA) than on placebo (108.1 +/- 29.7) (P = 0.0411). Thresholds of perception of nonpainful distensions were not altered on asimadoline, as compared with placebo. Colonic compliance was not different on placebo and asimadoline.

CONCLUSION

Asimadoline decreases overall perception of pain over a wide range of pressure distension of the colon in irritable bowel syndrome patients, without altering its compliance. These data suggest that further studies should explore the potential benefit of asimadoline in treatment of pain in irritable bowel syndrome patients.

Comparison of articaine and bupivacaine/lidocaine for sub-Tenon's anaesthesia in cataract extraction

BACKGROUND

Articaine is the most widely used local anaesthetic for dental anaesthesia in Germany, Italy and The Netherlands and has recently been introduced and licensed for dental use in the UK. We have previously shown articaine to be superior to a standard mixture of bupivacaine 0.5%/lidocaine 2% for peribulbar anaesthesia. Sub-Tenon's anaesthesia arguably provides a safer method of anaesthetic delivery for cataract surgery. A blunt cannula is used in this technique, thus greatly reducing the risk of globe perforation, intrathecal injection and sight-threatening periocular haemorrhage.

METHODS

We compared articaine and bupivacaine/lidocaine for sub-Tenon's anaesthesia in cataract surgery.

RESULTS

Sub-Tenon's anaesthesia using articaine 2% resulted in a more rapid onset of motor block compared with a bupivacaine/lidocaine (P=0.0076). Ocular movement scores were significantly lower from 2 min after injection until the end of surgery (P=0.031 ANOVA).

CONCLUSION

Articaine 2% is safe and effective for sub-Tenon's anaesthesia and is a suitable alternative to the traditional bupivacaine 0.5%/lidocaine 2% mixture.

Hepatic arterial infusion using pirarubicin combined with systemic chemotherapy: a phase II study in patients with nonresectable liver metastases from colorectal cancer

BACKGROUND

A prospective phase II study was performed to determine the feasibility, efficacy and safety of arterial hepatic infusion (HAI) using pirarubicin combined with intravenous chemotherapy.

PATIENTS AND METHODS

From December 1991 to April 1994, 75 patients with unresectable colorectal metastases confined to the liver were included in this multicenter study to receive intra-arterial hepatic pirarubicin and a systemic monthly regimen of 5-fluorouracil (5-FU) and folinic acid. Sixty-four patients were analyzed in the intention-to-treat analysis and 61 in the per-protocol analysis.

RESULTS

Tolerance of this regimen was rather good; however, functional catheter problems were observed in 29 patients (45%) resulting in failure of HAI in 21 cases (33%) after a median of three cycles; vomiting grade 3 was present in 12.5% of patients, neutropenia grade 4 in 23% and alopecia grade 3 in 19%. The overall response rate was 31.9% in intention-to-treat analysis, and 39.3% in per-protocol analysis. Extrahepatic progression was reported in only 21.7% of patients. Time to hepatic progression and extra-hepatic progression was 8.3 and 15 months, respectively, in intention-to-treat analysis, and 11 and 18 months, respectively, in per-protocol analysis. Median survival was 19 and 20 months in intention-to-treat analysis and per-protocol, respectively.

CONCLUSIONS

In our study, the combination of intra-arterial pirarubicin and intravenous chemotherapy demonstrated some efficacy and good tolerance in the treatment of isolated colorectal liver metastases. This treatment seems to prevent extra-hepatic spread and prolong survival time. The results of this study have to be confirmed by new trials using more active systemic chemotherapy.

The clinicopathological spectrum of Rosenthal fibre encephalopathy and Alexander's disease: a case report and review of the literature

Alexander's disease is a leucodystrophy that usually presents in early childhood, but can infrequently arise in adults. It is characterised pathologically by megalencephaly, demyelination, and the presence of numerous Rosenthal fibres. Most cases have been shown to be due to mutations in the gene encoding glial fibrillary acidic protein. In rare instances, numerous Rosenthal fibres have been found at autopsy in patients who have suffered protracted debilitating systemic illnesses, some with associated brain stem signs, and in very rare instances in patients with no apparent neurological abnormality. The term "Rosenthal fibre encephalopathy" is used to distinguish these cases from those of Alexander's disease. We report the first case of Rosenthal fibre encephalopathy in a young man with AIDS, and review the literature.

Delayed type hypersensitivity-associated disruption of splenic periarteriolar lymphatic sheaths coincides with temporary loss of IFN-gamma production and impaired eradication of bacteria in Brucella abortus-infected mice

A major problem of infections with facultative intracellular bacteria is their chronic course. We comprehensively evaluated the host response in murine brucellosis to study mechanisms contributing to bacterial persistence in the presence of an established immune response. Evidence is presented that the decrease in eradication kinetics, reproducibly occurring 18 d after infection of mice with Brucella abortus S19, is related to a state of downregulation of defense mechanisms. This is not due to a Th1 to Th2 switch or prostaglandin-mediated suppression by macrophages but is most probably caused by a severe disruption of spleen morphology at the height of Brucella-induced delayed type hypersensitivity. This results in a profound depletion of both CD4(+) and CD8(+) T cells in periarteriolar lymphatic sheaths, a consecutive deleterious shift in the relation of permissive macrophages and protective lymphocytes and an impaired capacity of splenocytes to produce IFN-gamma in response to soluble Brucella antigen.

Pulmonary volume recruitment manoeuvre restores pulmonary compliance and resistance after apnoea in anaesthetized lambs

BACKGROUND

We studied the effects of an episode of induced apnoea on the dynamic compliance (Crs) and resistance (Rrs) of the respiratory system in anaesthetized lambs and investigated the mechanisms underlying the effectiveness of a timed reexpansion inspiratory manoeuvre (TRIM).

METHODS

Following 2 min of apnoea, three manoeuvres were randomly performed: (i) control: reventilated without TRIM using initial settings and gas composition of 30% oxygen in 70% nitrous oxide; (b) T1: TRIM with 30% oxygen in 70% nitrous oxide, followed by reventilation with the initial settings; and (c) T2: preoxygenate with 100% oxygen, apnoea, then TRIM with 100% oxygen, then reventilation with 100% oxygen at the initial settings. The percentage change in Crs and Rrs was calculated at first breath, second breath, 10, 20, 40, 60, 90, 120 and 180 s postapnoea.

RESULTS

Mean control decreased 15% and did not return to baseline during the study period. TRIM increased mean Crs in T1 and T2 by 8% and 9%, respectively, at first breath and returned to baseline and did not deteriorate for the remainder of the study period. Mean Rrs in the control group increased 20% and did not return to baseline during the study period. Mean Rrs in T1 and T2 initially increased 17% and 27%, respectively, at first breath and returned to baseline within 40 s.

CONCLUSIONS

These results demonstrate that significant deterioration occurs in Crs and Rrs following 2 min of apnoea in anaesthetized lambs, which is not corrected with normal ventilation but is rapidly and completely reversed with a TRIM. This supports our hypothesis that volume recruitment of alveoli is an effective manoeuvre in restoring lung function. The practice of preoxygenation is also reinforced as the lambs maintained maximal oxygen saturation if they were ventilated with 100% oxygen prior to the 2 min of apnoea.

Longitudinal study of a cohort of people with diabetes screened by the Exeter Diabetic Retinopathy Screening Programme

PURPOSE

To evaluate the long-term outcome of a cohort of people with diabetes screened by the Exeter Diabetic Retinopathy Screening Programme.

METHOD

The cohort comprised of diabetic patients from nine market town General Practices around Exeter who first attended the diabetic retinopathy screening programme in 1992. Screening was carried out by a combination of dilated fundoscopy by a screening technician and a single 45 degrees Polaroid photograph of each eye. The prevalence of diabetic retinopathy at the baseline, the incidence of sight threatening diabetic retinopathy (STDR) in the next two rounds of screenings, and the long-term visual outcome are described.

RESULTS

The cohort consisted of 775 patients (104 Type I, 517 Type II non-insulin-requiring and 154 Type II insulin-requiring). The mean age was 72.1 years (15-100), with mean disease duration of 13.0 years (1-79). Baseline prevalence was as follows: background retinopathy: 21.4%, proliferative: 2.8%, clinically significant macular oedema: 6.1%. The incidence of proliferative disease was 2.20% and 2.25% respectively in the next two rounds of screening (P > 0.05, chi2 test). The incidence of clinically significant macular oedema was also constant over next two rounds of screening, at 4.79% and 5.18% respectively (P > 0.05, chi2 test). Ninety-five (12.3%) patients were deceased and a further 179 (23%) patients were lost to follow-up by the third round. Only two patients with newly diagnosed STDR suffered deterioration of visual acuity to 6/60 or worse as a result of diabetic retinopathy.

CONCLUSION

The incidence of STDR remained constant throughout the period of screening, reflecting the chronic progressive nature of the disease. Significant numbers of patients were lost to follow-up. Screening seemed effective in preserving vision in those patients with newly diagnosed STDR.

Significance of a prenatally diagnosed del(10)(q23)

Structural chromosome mosaicism is rare. We report a case of prenatal mosaicism for a deletion of chromosome 10(q23). To our knowledge, there are only three reports of prenatally diagnosed cases of del(10)(q23). Two of these cases were due to an inherited fragile site. In the present case amniocentesis revealed 46,XY,del(10)(q23)[9]/46,XY[45]. Follow-up chromosome analysis of peripheral blood and placental tissue from a phenotypically normal liveborn male revealed the del(10)(q23) in only 3/100 blood cells grown in low-folate medium. It appears that prenatally diagnosed deleted (10q) mosaicism represents culture artifact and is not clinically significant.

Trapping efficiency of Ugglan traps and Longworth traps for house mice in south-eastern Australia

Small mammal studies require traps that efficiently capture the target species, are cheap, and preferably have no adverse effects on the animals. We compared the trapping efficiency of Ugglan multiple-capture live-traps with Longworth single-capture live-traps in field studies of house mice (Mus domesticus) in the Victorian Mallee of south-eastern Australia. More captures and recaptures were made with Longworth traps and fewer mice died while in these traps. There was no difference in mean body mass of captured mice between Ugglan and Longworth traps but relatively more males were trapped with Ugglan traps. The trapping mechanism that requires the mouse to activate a trap door, and open mesh wire along the sides of the Ugglan trap may be the main reasons for low trappability. In addition, the open sides could have contributed to the lower survival observed for mice in Ugglan traps. Although Ugglan traps have the potential for multiple captures, are cheaper, and their trapping mechanism is less prone to failure than Longworth traps, they were not as efficient in trapping house mice at low and medium densities.

Retention of the bait marker Rhodamine B in wild house mice

We investigated the retention of the systemic bait marker Rhodamine�B (RB) in house mice (Mus domesticus) that were fed RB in pellet bait (0.5% RB) and in water solutions (1.6%). Wild mice fed RB baits (3 mg RB) or provided with treated water (0.3 mg RB) were screened for traces of RB in whiskers, blood, urine, faeces, and the digestive tract. The dye was detectable in all tissues and excretions tested 12 h after its uptake in pellet bait or solution. RB was detectable under ambient light in urine and the digestive tract for up to four days and in faeces for up to two days. RB was detectable in blood sera for up to 84 h using a fluorometer. RB-bands were found in whiskers for up to seven weeks after ingestion of RB. There was no difference between males and females regarding the presence of RB in blood and whiskers. A second dose of RB (1.8 mg) one week after the first dose resulted in two bands in mouse whiskers. Fewer mice were scored RB positive when uptake of RB was low. In contrast to whiskers, analysis of blood sera provided quantitative results and allowed rapid screening of animals. We conclude that RB is an appropriate marker for short- and medium-term studies on bait uptake in house mice.

X-deficient woodchuck hepatitis virus mutants behave like attenuated viruses and induce protective immunity in vivo

The X protein (HBX) of the hepatitis B virus (HBV) has been shown to be important for the establishment of HBV infection in vivo. Our previous studies suggested that interaction of HBX with the proteasome complex may underlie the pleiotropic functions of HBX. In this study, we generated a series of woodchuck hepatitis virus (WHV) X mutants, including mutants of the domain interacting with the proteasome, and studied their infectivity in woodchucks. Many of the mutants were defective in transactivation but none of them were completely replication defective in vitro. In vivo, all the wild-type and some X mutant-transfected animals demonstrated evidence of infection with anti-WHc and/or anti-WHs seroconversion. Most of the wild-type- and X mutant-transfected animals had transient viremia. Some animals were later challenged with infectious WHV. Animals inoculated with X mutants, including those with no serologic evidence of infection, were protected from the challenge, suggesting previous infection with resulting protective immunity. Our study demonstrates that the previously described functional domains of HBX are biologically important and the X-defective mutants, possibly as attenuated viruses, are not completely replication defective in vivo.

Hydrogen-bond network in cyclodecaamylose hydrate at 20 K; neutron diffraction study of novel structural motifs band-flip and kink in alpha-(1-->4)-D-glucoside oligosaccharides

A single-crystal neutron diffraction study of cyclodecaamylose (CA10) was carried out at 20 K. CA10 crystallizes with 27.18 water molecules [(C(6)H(10)O(5))(10).27.18H(2)O] in space group C2 with unit-cell constants a = 29.31 (5), b = 9.976 (10), c = 19.34 (2) A, beta = 121.07 (2) degrees. The asymmetric unit contains a half molecule of CA10 and 13.59 water molecules, the other half being related by a crystallographic twofold rotation axis. All H atoms except two water H atoms could be located from difference neutron-density maps; structure refinement converged at R = 0.635. Two of the five CH(2)-O6 groups and one of the 15 O2, O3 hydroxyl groups of CA10 are twofold orientationally disordered. A total of 13.59 water molecules in the asymmetric unit are distributed over 23 positions; 20 of which are in the CA10 cavity, and the other three occupy intermolecular interstices. Of the 123 symmetry-independent hydrogen bonds, 25 (= 20%) are three-centered and 7 (= 6%) are four-centered. Water molecules and O-H groups of CA10 form an extended network with cooperative O-H...O-H...O-H hydrogen bonds. They are arranged in 11 polygons with three, four, five, six and eight O-H bonds and in homodromic, antidromic and heterodromic arrangements. Nine polygons are located within the cavity and the others are outside.

X-deficient woodchuck hepatitis virus mutants behave like attenuated viruses and induce protective immunity in vivo

The X protein (HBX) of the hepatitis B virus (HBV) has been shown to be important for the establishment of HBV infection in vivo. Our previous studies suggested that interaction of HBX with the proteasome complex may underlie the pleiotropic functions of HBX. In this study, we generated a series of woodchuck hepatitis virus (WHV) X mutants, including mutants of the domain interacting with the proteasome, and studied their infectivity in woodchucks. Many of the mutants were defective in transactivation but none of them were completely replication defective in vitro. In vivo, all the wild-type and some X mutant-transfected animals demonstrated evidence of infection with anti-WHc and/or anti-WHs seroconversion. Most of the wild-type- and X mutant-transfected animals had transient viremia. Some animals were later challenged with infectious WHV. Animals inoculated with X mutants, including those with no serologic evidence of infection, were protected from the challenge, suggesting previous infection with resulting protective immunity. Our study demonstrates that the previously described functional domains of HBX are biologically important and the X-defective mutants, possibly as attenuated viruses, are not completely replication defective in vivo.

Lipid and lipoprotein levels in premenopausal systemic lupus erythematosus patients

The purpose of this study was to assess the prevalence of dyslipoproteinemia and to analyze the clinical variables that are associated with it in a sample of premenopausal systemic lupus erythematosus (SLE) patients. We studied 53 premenopausal (34.5 y) SLE outpatients and 45 controls. Clinical variables studied included patient age, weight, height, body mass index (BMI), age at disease onset, disease duration, clinical activity of SLE, renal involvement and drug therapy. Total cholesterol (TC), high- and low-density lipoprotein cholesterol (HDL-C and LDL-C), and triglycerides were measured using standard enzymatic techniques. Apolipoproteins (apo) A-I and B were determined by radial immunodiffusion. Twenty-nine patients (55%) and 14 controls (30%) had dyslipoproteinemia. An increase in TC, triglycerides, HDL3-C, apo A-I and apo B, and a decrease in HDL2-C and HDL-C/TC index was found in SLE patients in comparison with controls. TC (P = 0.007), apo B (P = 0.02), LDL-C (P = 0.03) and triglycerides (P = 0.0001) were significantly correlated with proteinuria. Patients on prednisone therapy had higher triglycerides levels (P = 0.03) than untreated patients. TC (P = 0.01), LDL-C (P = 0.006) and triglycerides (P = 0.04) were also correlated with the dose of prednisone. Dyslipoproteinemia is a common feature in adult SLE premenopausal patients which is characterized by an increase in TC, triglycerides and apo B, and an abnormal distribution of HDL subclasses. Corticosteroid therapy and proteinuria are the best predictors of dyslipoproteinemia in these patients.

Disulfide-mediated dimerization of L1 Ig domains

The neural cell adhesion molecule L1 contains immunoglobulin-like (Ig) domains in its extracellular region that mediate homophilic binding, neurite outgrowth and other activities relevant to CNS development. To correlate conformations of these domains to biological function, several L1-Fc fusion proteins whose bioactivities were previously characterized were analyzed by rotary shadowing electron microscopy. We found that bioactive L1-Fcs containing Ig domains 1-4 or 1-6 exhibited extended, branched structures. In contrast, inactive L1-Fcs containing only the first two or three Ig domains assumed compact shapes that suggested interactions between the L1 arms of these proteins. Analysis of an untagged L1 fragment composed of Ig domains 1-3 demonstrated a mixture of monomeric and dimeric forms. Surprisingly, these dimers were stabilized by intermolecular disulfide bonds. Finally, cell surface L1-GFP fusion proteins containing only the first two or three Ig domains in the extracellular region also engaged in disulfide-mediated dimerization. These results suggest a novel mechanism by which mutations in L1 could interfere with its biological functioning.

Light scattering and crossover critical phenomena in polymer solutions

An accurate photon-correlation spectrometer capable of measuring scattered light at two fixed scattering angles simultaneously in the temperature range from 10 to 120 degrees C is described. For the detection of the correlation function of the scattered light both an original correlator (PhotoCor-SP) with a linear-time-scale channel spacing and an ALV GmbH correlator (Model ALV-5000) with a logarithmic-time-scale channel spacing are used. High-resolution static and dynamic light-scattering measurements near the critical point of a polystyrene solution were performed with this instrument. The static-intensity measurements reveal that the crossover from mean-field to Ising behavior occurs at a temperature at which the correlation length of the critical fluctuations becomes equal to the radius of gyration of the polymer molecule. We found that the wave-number dependence and the temperature dependence of the diffusion coefficient of the concentration fluctuations are not consistent with existing theory for critical dynamics in low-molecular-weight liquid mixtures.

Mechanisms and molecules in motor neuron specification and axon pathfinding

The vertebrate nervous system performs the most complex functions of any organ system. This feat is mediated by dedicated assemblies of neurons that must be precisely connected to one another and to peripheral tissues during embryonic development. Motor neurons, which innervate muscle and regulate autonomic functions, form an integral part of this neural circuitry. The first part of this review describes the remarkable progress in our understanding of motor neuron differentiation, which is arguably the best understood model of neuronal differentiation to date. During development, the coordinate actions of inductive signals from adjacent non-neural tissues initiate the differentiation of distinct motor neuron subclasses, with specific projection patterns, at stereotypical locations within the neural tube. Underlying this specialisation is the expression of specific homeodomain proteins, which act combinatorially to confer motor neurons with both their generic and subtype-specific properties. Ensuring that specific motor neuron subtypes innervate the correct target structure, however, requires precise motor axon guidance mechanisms. The second half of this review focuses on how distinct motor neuron subtypes pursue highly specific projection patterns by responding differentially to spatially discrete attractive and repulsive molecular cues. The tight link between motor neuron specification and axon pathfinding appears to be established by the dominant role of homeodomain proteins in dictating the ways that navigating motor axons interpret the plethora of guidance cues impinging on growth cones.