Histopathological findings from the investigation of paediatric acute hepatitis of unknown aetiology, United Kingdom 2022

In 2022, there were global reports of increased numbers of acute hepatitis not explained by hepatitis A-E virus infection in children. This manuscript summarises histopathology results from 20 patients in the United Kingdom who underwent liver transplant or had a liver biopsy as part of aetiological investigations. All available histopathological samples were reviewed centrally as part of the outbreak investigation. A working group comprised of infection specialists, hepatologists and histopathologists met virtually to review the cases, presentation, investigations and histopathology. All 20 liver samples had evidence of inflammation without significant interface activity, and submassive confluent pan-lobular or multilobular hepatocellular necrosis. Overall, the predominant histopathological findings were of acute nonspecific hepatitis with submassive hepatic necrosis and central vein perivenulitis and endothelitis. Histopathological findings were a poor indicator of aetiology.

Favipiravir in patients hospitalised with COVID-19 (PIONEER trial): a multicentre, open-label, phase 3, randomised controlled trial of early intervention versus standard care

BACKGROUND

COVID-19 has overwhelmed health services globally. Oral antiviral therapies are licensed worldwide, but indications and efficacy rates vary. We aimed to evaluate the safety and efficacy of oral favipiravir in patients hospitalised with COVID-19.

METHODS

We conducted a multicentre, open-label, randomised controlled trial of oral favipiravir in adult patients who were newly admitted to hospital with proven or suspected COVID-19 across five sites in the UK (n=2), Brazil (n=2) and Mexico (n=1). Using a permuted block design, eligible and consenting participants were randomly assigned (1:1) to receive oral favipiravir (1800 mg twice daily for 1 day; 800 mg twice daily for 9 days) plus standard care, or standard care alone. All caregivers and patients were aware of allocation and those analysing data were aware of the treatment groups. The prespecified primary outcome was the time from randomisation to recovery, censored at 28 days, which was assessed using an intention-to-treat approach. Post-hoc analyses were used to assess the efficacy of favipiravir in patients aged younger than 60 years, and in patients aged 60 years and older. The trial was registered with clinicaltrials.gov, NCT04373733.

FINDINGS

Between May 5, 2020 and May 26, 2021, we assessed 503 patients for eligibility, of whom 499 were randomly assigned to favipiravir and standard care (n=251) or standard care alone (n=248). There was no significant difference between those who received favipiravir and standard care, relative to those who received standard care alone in time to recovery in the overall study population (hazard ratio [HR] 1·06 [95% CI 0·89-1·27]; n=499; p=0·52). Post-hoc analyses showed a faster rate of recovery in patients younger than 60 years who received favipiravir and standard care versus those who had standard care alone (HR 1·35 [1·06-1·72]; n=247; p=0·01). 36 serious adverse events were observed in 27 (11%) of 251 patients administered favipiravir and standard care, and 33 events were observed in 27 (11%) of 248 patients receiving standard care alone, with infectious, respiratory, and cardiovascular events being the most numerous. There was no significant between-group difference in serious adverse events per patient (p=0·87).

INTERPRETATION

Favipiravir does not improve clinical outcomes in all patients admitted to hospital with COVID-19, however, patients younger than 60 years might have a beneficial clinical response. The indiscriminate use of favipiravir globally should be cautioned, and further high-quality studies of antiviral agents, and their potential treatment combinations, are warranted in COVID-19.

FUNDING

LifeArc and CW+.

Phenolic potential of new red hybrid grape varieties to produce quality wines and identification by the malvin

The hybrids are new varieties that are resistant to the cryptogamic diseases of vines, and they may be a good solution to the reduction of pesticide use. However, these new varieties have appeared recently and only few studies have been conducted to check the quality of the wine that they produce. In this study, wines originated from hybrids were chemically characterized (polyphenols, tannins, anthocyanins, and color analysis). Results show that their oenological parameters were close to those of the Vitis vinifera wines. The wines made from Vinifera (100%), with Vidoc, and all the resistant Bouquets studied are malvidin-3 glucoside dominant, and all the others hybrids varieties are cyanidin dominant. Furthermore, the hybrid wines had a higher concentration in condensed tannins and a lower one in molecular tannins compared with the Vitis vinifera wines, except for the Vidoc wines. As far as the anthocyanin content is concerned, the samples contained anthocyanin diglucosides, with the malvidin-3,5-diglucoside (malvin) the most abundant one. Also, their concentration in molecular anthocyanins were higher than the concentration in normal wines. The Vidoc wines do not contain any malvin. For the other wines, malvin co-eluted with cyanidin-3-O-glucoside and in this case, the cyanidin’s concentration was impressively higher than the Vidoc wines. The current OIV method gives different results for malvidol diglucoside compared to the use of an HPLC chromatography method (HPLC-DAD-QQQ). The current OIV method does not appear reliable in comparison with the HPLC method for detecting malvin. Finally, the hybrid wines had a darker blue/purplish color than the Vitis vinifera wines.

P11.64.A Long-term follow up and translational data from the ReoGlio phase Ib trial of GM-CSF and intravenous pelareorep (Reovirus) alongside standard of care in GBM

BACKGROUND

We previously reported safety data from a phase Ib, open-label study of intravenous oncolytic virus pelareorep with GM-CSF alongside standard chemoradiotherapy in newly diagnosed glioblastoma confirming that the combination is well tolerated. We now report on long-term follow up and analysis of translational samples from tumour and blood in a subset of patients.

METHODS

15 patients with newly diagnosed GBM were treated with GM-CSF 50μg subcutaneously on days 1-3 and intravenous pelareorep on days 4-5 in weeks 1 and 4 of chemoradiotherapy, and subsequently in week 1 of each adjuvant temozolomide course: 7 patients received 1x1010TCID50 (dose level 1); 8 received 3x1010TCID50 (dose level 2). The primary objective was to determine the maximum tolerated dose of pelareorep and GM-CSF with standard chemoradiotherapy. Following a protocol amendment we also collected survival data in all patients up to August 2021. Serial blood samples were taken from three patients, at baseline, during chemoradiotherapy and in the first adjuvant cycle. Peripheral blood mononuclear cells were analysed for immune checkpoint expression by flow cytometry, RNAseq gene expression and T-cell receptor clonality, whilst plasma cytokines were quantified by Luminex.

RESULTS

This combination was well tolerated with 87% of patients completing treatment as planned. Survival data analysis showed that median OS was 12.6 months in dose level 1 and 16.1 months in dose level 2, median OS for all patients was 13.1 months. The 24-month survival estimate for all patients was 25.0%, 16.7% for dose level 1 and 33.3% for dose level 2. One patient in dose level 1 remains alive at 43 months post registration without further treatment. Laboratory data showed that pelareorep infusion resulted in inflammatory cytokine and chemokine secretion, immune checkpoint modulation, and upregulation of inflammatory pathways. There was also increased peripheral clonal tumour-specific T-cell proliferation following pelareorep infusion.

CONCLUSION

Although based on small numbers, these long-term follow up data suggest this may be an active combination in a subset of GBM patients. Translational data confirm that pelareorep potentially activates tumour-targeting immune pathways in GBM, with consequential immune checkpoint modulation. These data support a combination clinical trial of pelareorep, radiotherapy and immune checkpoint blockade in GBM.

Sixty-eight consecutive patients assessed for COVID-19 infection: Experience from a UK Regional infectious diseases Unit

Background

Assessment of possible infection with SARS‐CoV‐2, the novel coronavirus responsible for COVID‐19 illness, has been a major activity of infection services since the first reports of cases in December 2019.

Objectives

We report a series of 68 patients assessed at a Regional Infection Unit in the UK.

Methods

Between 29 January 2020 and 24 February 2020, demographic, clinical, epidemiological and laboratory data were collected. We compared clinical features between patients not requiring admission for clinical reasons or antimicrobials with those assessed as needing either admission or antimicrobial treatment.

Results

Patients assessed were aged from 0 to 76 years; 36/68 were female. Peaks of clinical assessments coincided with updates to the case definition for suspected COVID‐19. Microbiological diagnoses included SARS‐CoV‐2, mycoplasma pneumonia, influenza A, non‐SARS/MERS coronaviruses and rhinovirus/enterovirus. Nine of sixty‐eight received antimicrobials, 15/68 were admitted, 5 due to inability to self‐isolate. Patients requiring admission on clinical grounds or antimicrobials (14/68) were more likely to have fever or raised respiratory rate compared to those not requiring admission or antimicrobials.

Conclusions

The majority of patients had mild illness, which did not require clinical intervention. This finding supports a community testing approach, supported by clinicians able to review more unwell patients. Extensions of the epidemiological criteria for the case definition of suspected COVID‐19 lead to increased screening intensity; strategies must be in place to accommodate this in time for forthcoming changes as the epidemic develops.

Positron emission tomography and reframing vasculitis as a spectrum of disease when investigating a patient with a fever of unknown origin

A retired businessman presented to the infectious diseases department with a history of ongoing fevers and myalgia and raised inflammatory markers. This continued despite adequate antibiotic treatment of an epididymo-orchitis. Extensive investigations, including bone marrow and liver biopsies and a positron emission tomography, did not reveal a cause but showed reactive change in the bone marrow. Later, he developed a vasculitic rash and vision loss due to non-arteritic anterior ischaemic optic neuropathy. High-dose steroids were immediately initiated. A temporal artery biopsy was performed, which confirmed a healing large vessel vasculitis, possibly giant cell arteritis. He has responded very well to therapy. We must better appreciate the limitations of positron emission tomography in investigating a fever of unknown origin. The case also encourages awareness of autoimmune disorders as the leading category of causative diseases for this in older age groups.

<b>A pre­liminary report on the impact of road kills on the herpetofauna species in Nilgiris, Tamil Nadu, India</b>

To know the situation of road hits of amphibians and reptile species, a survey was conducted during the period 02 June 2013 to 25 May 2014.  A total of 172 incidents of road kill of different species were noticed, representing 12 species of herpetofauna, including five amphibian species of the families Bufonidae, Dicroglossidae, Microhylidae and Rhacophoridae, and seven species of reptiles of the families Scincidae, Agamidae, Uropeltidae, Colubridae, Natricidae and Xenodermatidae.  Reptiles were the most affected group (60%), of which more than 79.61% of the road kills were snakes.  The most affected snake species were endemic Xylophis perroteti (64.63%). 

Road kills of the endemic snake Perrotet’s Shieldtail Plectrurus perrotetii, Dumeril, 1851 (Reptilia: Squamata: Uropeltidae) in Nilgiris, Tamil Nadu, India

Twenty seven road killed specimens of Plectrurus perrotetii were recorded in Emerald and its surrounding areas in the Nilgiris. Among the road kills, fourteen of them were females, seven were males and six are juveniles. Among the road kill female specimens of this species, it was observed that seven were gravid with fully developed young. Three to six developing young ones were observed

Effect of vehicular traffic on wild animals in Sigur Plateau, Tamil Nadu, India

The construction of a road, directly and indirectly, impacts on the ecosystems where the road is built.  Highways passing through national reserves/wildlife sanctuaries have an adverse impact on wild animals.  The present survey was conducted to estimate the road kills on the state highways passing through the Nilgiri north territorial forest division (19km) and Mudumalai Tiger Reserve (15km) in Sigur Plateau, Tamil Nadu, India.  The road kills were monitored three times a month between July 2013 and December 2013 (six months) and a total of 176 road kills belonging to 30 species were recorded.  Reptiles were the most affected taxa (39%), followed by mammals (33%) and birds (21%).  Amphibians were least affected by vehicular traffic and comprised 7% of the total kills.  According to road stretch category, the overall road kill was N=135 in the forested area and N=41 in human habitations.  A total of 812 food materials were encounterd  612km with average of  1.32 food materials / km. Conservation and management implications are essential to prevent the local extinction of wildlife. 

Living with the BRCA1 and BRCA2 genetic mutation: learning how to adapt to a virtual chronic illness

The objective of this study was to understand how women living with the BRCA1 and BRCA2 genetic mutation adapt to this life transition and to identify the main adaptive tasks. A qualitative inquiry inspired by grounded theory revealed that participants cognitively appraised their test result in the same manner as women who have been diagnosed with breast cancer. Consequently, participants had to adapt to a condition that they perceived as a chronic illness. The following three main tasks were identified: Physical Task: Attempting to Limit the Impact of the Test Result, Psychological Task: Living with Uncertainty, and Social Task: Finding Effective Support. In conclusion, although these women live with the possibility of developing breast cancer, their experiences mirror those of individuals living with a chronic illness, and they must therefore adapt accordingly in a physical, psychological, and social manner.

Individual predictions based on nonlinear mixed modeling: application to prenatal twin growth

The assessment of growth during fetal life and childhood commonly relies upon cross'sectional reference ranges or centiles. However, individual sequential predictions may help the timewise assessment of a growth process. In twin pregnancies for example, which are at risk of growth restriction, such predictions may improve the detection of abnormal trajectories. In this article, we present a simple forecasting method, assuming that a given normal individual behaves in the same way as a reference population. We consider, as a prediction in a given individual, the forecast of a future observation conditional to any previous observation and a set of population parameters obtained by nonlinear mixed modeling in a reference population. We suggest an estimator for this prediction without resorting to linear approximation and show that it enjoys interesting asymptotics when the amount of observations increases over time. We use two independent real datasets of twin pregnancies with normal growth and outcome to illustrate the application of such predictions in prenatal growth. We consider the first dataset as a reference dataset and model it using a two'level nonlinear model. We perform illustration and validation of predictions on the second dataset.

Living with the BRCA genetic mutation: an uncertain conclusion to an unending process

Women carrying a BRCA1 or BRCA2 genetic mutation have an up to 80% lifetime risk of developing breast cancer. It is especially important to understand the experiences of these women, as their lives are permeated with the threat of cancer. This qualitative study examined the experiences of six young women of reproductive age (age < 45 years) who were identified as carriers. The analysis of the semi-structured interviews inspired by grounded theory methodology, showed that participants experienced the same type of uncertainty demonstrated by women who have already been diagnosed with breast cancer.

Density estimation of a biomedical variable subject to measurement error using an auxiliary set of replicate observations

Correcting for measurement error when estimating the density of a routinely collected biomedical variable is an important issue when describing reference values for both healthy and pathological states. The present work addresses the problem of estimating the density of a biomedical variable observed with measurement error without any a priori knowledge on the error density. Assuming the availability of a sample of replicate observations, either internal or external, which is generally easily obtained in clinical settings, we propose an estimator based on the non-parametric deconvolution theory with an adaptive procedure for cutoff selection, the replicates being used for an estimation of the error density. We illustrate this approach in two applicative examples: (i) the systolic blood pressure distribution density, using the Framingham Study data set, and (ii) the distribution of the timing of onset of pregnancy within the female cycle, using ultrasound measurements in the first trimester of pregnancy.

Implementation of an integrated cancer care network

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Background: In 1998, the province of Quebec adopted its cancer control program (CP). Its goal was to establish a hierarchical and integrated cancer network of interdisciplinary teams. In 2004, a team evaluation process was initiated by the Direction de la lutte contre le cancer (ministry of health) to help implement this program. Methods: The evaluation consisted of completion of a matrix by the requesting team, a visit by a multidisciplinary group of experts and a report card. Three levels of expertise were assessed: core (all), regional (regional hospitals), and supraregional (tumor specific/complex situations). The matrix was based on the fundamental orientations of the CP, thus setting the framework for patient centered care. The conformity indicators were mainly structural and process oriented. In order to be evaluated for the subsequent mandates, teams had to conform to the core mandate. Those who did not succeed had one year to reapply. Mandates are for 4 years. Results: Teams were able to comply with most of the elements of the evaluation matrix. Sessions for clarification and coaching about this new interdisciplinary approach were necessary and helpful. A total of 153 visits were done:70 for core, 8 for regional and 75 for supraregional mandates respectively. Major health institutions such as university hospitals applied for multiple supraregional team designation. In all, 130 teams had their designation confirmed. This process highlighted some common weaknesses such as the lack of use of data for quality control. Conclusions: Acceptance of this hierarchical cancer care model was facilitated by the fact that it was in line with the integrated health care network of Quebec. The evaluation process has had an impact on the way cancer care is delivered in Quebec. This initial phase has helped implement an interdisciplinary patient centered model of care in line with the CP. Participation of different experts has also helped foster knowledge transfer and appropriation of the process. Impact on patient care and satisfaction remains to be assessed. An initial patient's questionnaire has been completed in 2008 and will serve as a control to future surveys.

No significant financial relationships to disclose.

Optometrist referrals for cataract and 'Action on Cataracts' guidelines: are optometrists following them and are they effective?

PURPOSE

To assess the information included in optometrist referrals for cataract to the Hospital Eye Service with reference to the recommendations made by the Department of Health in "Action on Cataracts" and the resultant surgical listing rates.

METHODS

We prospectively collected and analysed the information included in three different types of optometrist referrals for cataract over 8 weeks. Referrals containing "full information" as recommended in "Action on Cataracts" confirmed cataract as the cause of visual loss with a detrimental effect on the patient's lifestyle, and a willingness for surgery. The referral outcomes were assessed in terms of listing rate and the reasons for not listing, for each type of referral form.

RESULTS

A total of 412 referrals were analysed. Of these, 50% (208) were "conventional" referrals via the general practitioner (GP) [39% (n = 162) using the General Ophthalmic Services (GOS) 18 referral form and 11% (n = 46) an optometrist's custom letter]; 35% (n = 143) were direct referrals and 15% (n = 61) were GP referrals with no optometrist information (these results were excluded from further analysis). The listing rates for optometric referrals were 78% (n = 272) overall, 83% (n = 119) for direct and 74% (n = 153) for conventional referrals. "Full information" was included in 17% (n = 8) of letter referrals and 10% (n = 16) of GOS 18 referrals. The listing rates were 83% for referrals with full information and 73% for referrals specifying only that cataracts were the cause of visual loss. The listing rates for referrals with partial information were 78% for "cataract" plus "effect on lifestyle" and 67% for "cataract" plus "willingness for surgery". The most common reason for not listing a patient for surgery was "no effect on lifestyle", accounting for 42% (n = 32).

CONCLUSION

We recommend that all referrals for cataract should confirm a detrimental effect on lifestyle and the patient's willingness for surgery, in addition to confirming cataract as the main cause of visual loss.

Transformation-associated recombination (TAR) cloning of tumor-inducing Xmrk2 gene from Xiphophorus maculatus

We modified the TAR methodology of YAC clone construction for application to fish genomic DNA isolated from Xiphophorus maculatus. YAC libraries were developed using the XIR1 repeat sequence as the recombinational hook. Construction of these libraries demonstrates that Xiphophorus DNA sequences can function as hooks in the yeast recombination system and that X. maculatus genomic DNA contains sequences that provide origin of replication function in yeast. By screening a subset of Xiphophorus YAC clones, we isolated a clone harboring the Xmrk2 locus that is associated with spontaneous and induced melanomagenesis. Modifications of the TAR technique allowed the targeted cloning of specific genes from genomic regions ranging in size from cDNAs to several hundred kilobases. Specific genomic regions can be isolated in a directional manner from fixed map locations to saturate these areas with physical markers. We discuss the applications of these and other yeast recombinational processes to fish genetics.

Anti-sickling, analgesic and anti-inflammatory properties of 3,5-dimethoxy-4-hydroxy benzoic acid and 2,3,4-trihydroxyacetophenone

Effects of 3,5-dimethoxy-4-hydroxybenzoic acid and 2,3,4-trihydroxyacetophenone were studied on haemoglobin S (Hb S) polymerisation, analgesia and inflammation using Hb S solution, rats and mice. UV spectrophotometric procedure was used to monitor the polymerization of the Hb S. Acetic acid induced writhing in mice and egg albumin induced rat paw edema procedures were used to evaluate analgesic and anti-inflammatory activities of the compounds respectively. The results indicate that both drugs inhibit the process of polymerization significantly, possibly by direct action on the Hb S molecules. The drugs inhibited acetic acid induced pain and decreased egg albumin induced oedema. It is concluded that 3,5-dimethoxy-4-hydroxybenzoic acid and 2,3,4-trihydroxyacetophenone may have some value in the management of sickle cell disease.

Effect of somatostatin on electrogenic ion transport in the duodenum and colon of the mouse, Mus domesticus

In this study, we have used the mouse intestine and the Ussing short circuit technique to compare the effects and mechanism of action of somatostatin (SST, 0.1 microM) on cAMP- and Ca(2+)-mediated ion secretion in the duodenum and colon of the Swiss-Webster mouse. The cAMP-dependent secretagogues, prostaglandin E(2) (1 microM) and dibutyryl-cAMP (150 microM) increased short circuit current (I(sc)) in both regions, but only the colonic response was inhibited by SST. This inhibition was independent of enteric nerves, suggesting a direct action on the epithelial cells. The Ca(2+)-dependent secretagogue carbachol (10 microM) stimulated a transient increase in I(sc) in both intestinal segments. In the duodenum, SST partially inhibited this increase in I(sc) and both the responses to carbachol and SST were independent of enteric nerves. In the colon, while SST inhibited the carbachol induced increase in I(sc), pre-treatment with tetrodotoxin (750 nM) profoundly inhibited the carbachol induced increase in I(sc), thus markedly reducing the inhibitory effect of SST. This indicates an involvement of the enteric nervous system in the response to carbachol and the action of SST in the colon. These data indicate marked regional differences within the mouse intestine of the effects of SST on ion secretion and demonstrate different mechanisms of action of SST in the duodenum and colon.

Evaluation of Nigerian traditional medicine: effects of Gakani, a herbal anti-asthmatic drug

The anti-asthmatic potential of Gakani, a popular herbal drug in Nigeria was investigated. The LD50 values of the freeze-dried aqueous extract in mice and rats were 20.9 +/- 2.4 mg/kg and 18.6 +/- 4 mg/kg, respectively. The extract unsurmountably blocked the effects of histamine and isoprenaline on the guinea pig tracheaL chain. It produced initial dose-related contractions of the isolated guinea pig ileum and rat stomach strip, which was followed by persistent autoinhibition and inhibition of histamine- and 5-hydroxytryptamine (5-HT)-induced responses of the two preparations, respectively. The extract had good anti-inflammatory effect in rats, causing a dose-related inhibition of the increase in the paw circumference (acute inflammation) induced by subplantar injection of fresh egg albumin. These results highlight the anti-asthmatic and toxic potential of this preparation and the need for a systemic approach in the study of traditional medicines.

A novel rapid hybridization technique: paper chromatography hybridization assay (PACHA)

A new DNA hybridization technique, based on chromatographic migration of DNA on a nitrocellulose strip passing through an immobilized probe area, is described. The new paper chromatography hybridization assay (PACHA) is faster and simpler to use than the conventional dot hybridization assay. In this assay, an aliquot of biotinylated, PCR-amplified target DNA is applied to one end of a nitrocellulose strip. The DNA migrates to the opposite end of the strip by capillary forces and hybridizes to a specific DNA probe immobilized in a reaction zone (RZ), located in the middle of the strip. Unhybridized DNA migrates away from the RZ. The biotinylated hybrid is visualized by a color reaction employing a streptavidin-alkaline phosphatase (SA-AP) conjugate and a specific chromogenic substrate. The new PACHA technique allows for detection of as little as 1-5 pg of specific human papilloma virus 16 (HPV16) DNA in 25 min of hybridization. In this system, the hybridization efficiency is controlled by the flow velocity of the hybridization solution (HS) and by the volume of the amplified labeled DNA migrating across the immobilized probe. Glycerol (30%) or polyvinyl pyrrolidone (PVP) (1%) reduces the flow rate by a factor of 2.5-3 and increases the sensitivity of the assay by a factor of 5.2 for glycerol and 2.6 for PVP. This novel method ensures efficient hybridization to multiple probes and appears to be superior to currently available solid-phase hybridization techniques.

Binocular interaction and disparity coding in area 19 of visual cortex in normal and split-chiasm cats

Binocular disparity, resulting from the projection of a three-dimensional object on the two spatially separated retinae, constitutes one of the principal cues for stereoscopic perception. The binocularity of cells in one hemisphere stems from two sources: (1) the ganglion cells in the homonymous temporal and nasal hemiretinae and (2) the contralateral hemisphere via the corpus callosum (CC). The objectives of this study were, on one hand, to determine whether disparity-sensitive cells are present in a "higher order" area, namely area 19 of the visual cortex, of the cat and, on the other hand, to ascertain whether the CC contributes to the formation of these cells. As in areas 17-18, two types of disparity-sensitive neurons were found: one type, showing maximal interactive effects around zero disparity, responded with strong excitation or inhibition when the stimuli presented independently to the two eyes were in register. These neurons are presumed to signal stimuli situated about the fixation plane. The other type, also made up of two subtypes of opposed valencies, gave maximum responses at one set of disparities and inhibitory responses to the other set. These are presumed to signal stimuli situated in front of or behind the fixation plane. Unlike areas 17-18, however, disparity-sensitive cells in area 19 of the normal cat were less finely tuned and their proportion was lower. In the split-chiasm animal, very few cells were sensitive to disparity. These results, when coupled with behavioral data obtained with destriate animals, indicate that (1) area 19 is probably less involved in the analysis of disparity information than area 17, (2) the disparity-sensitive neurons that are sensitive to disparity are not involved in the resolution of very fine three-dimensional spatial detail, and (3) the CC only determines a limited number of these cells in the absence of normal binocular input.

Binocular interaction and disparity coding at the 17-18 border: contribution of the corpus callosum

Binocular disparity, resulting from the projection of a three-dimensional object on the two spatially separated retinae, constitutes one of the fundamental cues for stereoscopic perception. The binocularity of cells in one hemisphere stems from two sources: i) from the ipsilateral ganglion cells in the temporal retina which converge with inputs coming from the contralateral nasal retina; the latter axons cross at the chiasma; ii) from inputs originating in the opposite hemisphere which cross in the corpus callosum. The objective of this study was to demonstrate that interactions from both types of inputs can result in the formation of disparity sensitive neurons and presumably that either type could mediate stereoperception based on disparity cues. Two types of disparity sensitive neurons were found in the normal cat: one type, showing maximal interactive effects around zero disparity responded with strong excitation or inhibition when the stimuli were in register. These neurons are presumed to signal stimuli situated about the fixation plane. The other type, also made up of two subtypes of opposed valencies, gave maximum responses at one set of disparities and inhibitory responses to the other set. These were presumed to signal stimuli situated in front of or behind the fixation plane. In the split-chiasm cat, whose cortical binocularity is presumably assured by converging ipsilateral and callosal inputs, three of the four subtypes of disparity sensitive neurons were found, the uncrossed disparity cells being absent in these animals. Moreover, stimulating each eye individually indicated that nearly 80% of the cells in normal and about 40% in split-chiasm cats were binocularly driven. However, both these figures underestimated the amount of binocular interaction in the callosal recipient zone, since stimulating both eyes simultaneously showed that a proportionately larger number of cells were binocularly driven. Disparity sensitive cells also varied as a function of ocular dominance, i.e., cells signaling the fixation plane tended to have balanced dominance whereas units preferring stimuli situated in front of or behind the fixation plane were dominated by the ipsilateral and contralateral eyes, respectively.

Infective complications associated with the use of the Quinton 'Permcath' for long-term central vascular access in haemodialysis

The major complication of central venous catheterization for immediate access for haemodialysis is infection. The Quinton Permcath is a tunnelled, double lumen, flexible silastic catheter with a Dacron cuff, and is claimed to be associated with a low rate of infection. In a two-year study we have monitored all complications including catheter-associated infection related to this device in haemodialysis patients while following a simple aseptic programme for the care of the catheter exit wound. Thirty four Permcaths were inserted in 30 patients for a mean duration of 6.2 months (SD +/- 5.7; range 2 days to 23 months). Catheter use amounted to a total of 197 months. Of twenty-seven catheter wound infections, 6 (22%) were caused by Staphylococcus aureus, and 15 (56%) by coagulase-negative staphylococci or corynebacteria. These occurred in 19 patients, giving an exit site infection rate of one episode per 7.4 catheter months. Catheter-associated septicaemia occurred in three patients (two S. aureus, one S. epidermidis), at a rate of one episode per 66 months. It was possible to correlate three episodes of infection with breakdown in aseptic care. This study confirms the low rate of infection associated with the use of the Permcath, and we conclude that the design of the device and aseptic care of the catheter and its wound contribute to this.

Acute haemodialysis during the Armenian earthquake disaster

On the 7 December 1988 an earthquake struck a densely populated region in northern Armenia. Up to 50,000 people were killed and many thousands were seriously injured. At least 385 of these casualties developed acute renal failure secondary to crush syndrome and required dialysis. The Armenian renal unit at Yerevan, in common with units elsewhere, was already overstretched to cope with the dialysis requirements of their patients with chronic renal failure before the earthquake. Most of the patients requiring dialysis were transferred to other hospitals in the USSR but 120 patients remained in Yerevan, the majority at the regional renal unit, overwhelming the resources. We assisted by taking a team of dialysis personnel, equipped with portable haemodialysis machines, to Yerevan. We performed 57 haemodialysis sessions and treated 15 patients, 13 of whom ultimately survived. Valuable lessons were learnt about the medical management of disasters abroad.

Dialysis for acute renal failure due to crush injuries after the Armenian earthquake

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