Oral fluid collection by post for viral antibody testing

BACKGROUND

The objective of this study was to estimate the prevalence of hepatitis B virus exposure (HBV) in the population of the Republic of Ireland, by using oral fluid (saliva) collection by post for hepatitis B anti-core antibody (anti-HBc). This paper discusses the methodological approach used and the strategies that were adopted to improve response rates.

METHODS

The sampling frame used was the Register of Electors for Irish parliamentary elections. A multistage stratified cluster sample was taken, and a total of 962 households were selected nationally. A four-letter approach was employed for sample collection. Households received an initial letter outlining the purpose of the study. This was followed by a letter containing six swabs for oral fluid collection, along with easy-to-follow instructions. Non-respondents received two reminder letters, and were also telephoned where possible. A telephone helpline was provided. All testing was anonymous and unlinked.

RESULTS

The study achieved a good household response rate (60.4%), and more than 98% of the 1738 specimens received were suitable for testing. The prevalence of anti-HBc in the Irish population was estimated to be 0.51%. The observed design effect was 1.29.

DISCUSSION

From a review of the literature, this is the first study where a representative sample of a national population was asked to self-collect oral fluid samples and return these by post for serological testing. The technique may have many future applications in epidemiological research.

In-vitro cyclosporin sensitivity of proliferating lymphocytes is predictive of in-vivo therapeutic response in ulcerative colitis

BACKGROUND

The efficacy of cyclosporin in the management of ulcerative colitis is recognized. Not all patients respond to this treatment. Existing clinical and laboratory parameters are of little use in identifying those most likely to respond.

AIMS

To determine whether in-vitro sensitivity to cyclosporin as measured by a lymphocyte proliferation assay is predictive of in-vivo response to therapy.

METHODS

The study comprised seven responders with ulcerative colitis, seven non-responders, and 14 healthy matched controls. A lymphocyte proliferation assay was carried out in the presence of a range of concentrations of cyclosporin and a dose-response curve constructed for each subject. The IC(50) value, the concentration of cyclosporin that resulted in 50% inhibition of proliferation, was calculated for each subject. IC(50) values for responders, non-responders and controls were compared using a Mann-Whitney test.

RESULTS

There was a wide range of values obtained for the study group as a whole. IC(50) values for non-responders were significantly higher than those of responders (P < 0.05).

CONCLUSIONS

There is a population-wide variation of in-vitro sensitivity to cyclosporin. This is reflected in in-vivo sensitivity as measured by clinical response to cyclosporin treatment. Future therapeutic strategies need to address this inherent variability of individual response to therapy.

Transjuglar liver biopsy: a review

Transjugular liver biopsy is advocated as the technique of choice for use in those with contraindications to standard transabdominal biopsy. This technique was introduced to our unit in 1995. We audited our experience in performing transjugular liver biopsies over a three year period. Eighty-eight biopsies were performed in seventy-eight patients. We identified no major procedure related complications, despite the presence of coagulopathy and thrombocytopenia in 85% and 47% of cases respectively. Biopsy provided histological diagnosis in 97.7% of cases. Availability of the technique allowed us to perform liver biopsy safely and quickly in patients with both acute and chronic liver problems in whom standard techniques were contraindicated. We conclude that transjugular liver biopsy is a safe and effective technique, invaluable in the investigation and management of patients in a liver diseases referral unit.

Prevalence of hepatitis B anti-core antibody in the Republic of Ireland

The aim of this study was to estimate the prevalence of hepatitis B exposure in the population of the Republic of Ireland, by measuring the prevalence of hepatitis B anti-core antibody in oral fluid collected by postal survey. A random multi-stage stratified sample of Irish households was obtained, using the Irish electoral register as the sampling frame. A total of 962 households were selected, and a household response rate of 60.4% was achieved. Oral fluid specimens totalling 1714 were tested for antibody to hepatitis B core antigen (anti-HBc), using an Immune Capture Enzyme Immuno-Assay. Five specimens (0.29%) were found to contain anti-HBc. Adjusting for study design, the estimated anti-HBc prevalence in the Republic of Ireland is 0.51%. This study demonstrates that self-collection of oral fluid samples is acceptable to the public, and based upon the data generated, that the Republic of Ireland has a low prevalence of hepatitis B infection.

Metallothionein is expressed in adipocytes of brown fat and is induced by catecholamines and zinc

Metallothionein (MT) is thought to have an antioxidant function and is strongly expressed during activation of thermogenesis and increased oxidative stress in brown adipose tissue (BAT). Localization and regulation of MT expression in BAT was therefore investigated in rats and mice. Immunohistochemical analysis of BAT from rats exposed to 4 degrees C for 24 h showed that MT and uncoupling protein 1 (UCP1) were coexpressed in differentiated adipocytes, and both cytoplasmic and nuclear localization of MT was observed. Cold induction of MT-1 expression in BAT was also observed in mice. Administration of norepinephrine to rats and isoproterenol to mice stimulated MT and UCP1 expression in BAT, implying a sympathetically mediated pathway for MT induction. In mice, zinc, and particularly dexamethasone, induced MT-2 expression in BAT and liver. Surprisingly, zinc also induced UCP1 in BAT, suggesting that elevated zinc may induce thermogenesis. We conclude that expression of MT in mature brown adipocytes upon beta-adrenoceptor activation is consistent with a role in protecting against physiological oxidative stress or in facilitating the mobilization or utilization of energy reserves.

The cause of neuronal degeneration in Alzheimer's disease

Alzheimer's disease is associated with a specific pattern of pathological changes in the brain that result in neurodegeneration and the progressive development of dementia. Pathological hallmarks common to the disease include beta-amyloid plaques, dystrophic neurites associated with plaques and neurofibrillary tangles within nerve cell bodies. The exact relationship between these pathological features has been elusive, although it is clear that beta-amyloid plaques precede neurofibrillary tangles in neocortical areas. Examination of the brains of individuals in the preclinical stage of the disease have shown that the earliest form of neuronal pathology associated with beta-amyloid plaques resembles the cellular changes that follow structural injury to axons. Thus, the development of beta-amyloid plaques in the brain may cause physical damage to axons, and the abnormally prolonged stimulation of the neuronal response to this kind of injury ultimately results in the profound cytoskeletal alterations that underlie neurofibrillary pathology and neurodegeneration. Therapeutically, inhibition of the neuronal reaction to physical trauma may be a useful neuroprotective strategy in the earliest stages of Alzheimer's disease.

A practical guide to the management of oesophageal varices

Bleeding oesophageal varices are a frequent and sometimes fatal complication of portal hypertension. Prompt resuscitation and arrest of haemorrhage are the immediate short term priorities. Vasoactive therapy to reduce portal pressure is administered on presentation. Early endoscopy is necessary to make a definitive diagnosis and initiate appropriate therapy; usually emergency sclerotherapy or banding. After the acute bleeding episode, follow-up therapy is instituted either to obliterate the varices by sclerotherapy or banding, or to chronically lower portal pressure and hence reduce the risk of bleeding pharmacologically; a combination of both strategies may be also used. Active surveillance of those at risk of developing varices is advocated. Long term beta-blocker therapy has been demonstrated to be effective in both the primary prevention of variceal haemorrhage and the prevention of rebleeding in those who have already bled. Despite a multitude of therapeutic regimes and ongoing clinical trials, mortality from this condition remains disappointingly high.

The source of disparity vergence innervation determines prism adaptation

A physiological model of prism adaptation argues that adaptation magnitude and rate are functions of the magnitude of reflex vergence innervation. It has also been shown that there is reduced prism adaptation magnitude for a given disparity stimulus where only peripheral sensory fusion is present (the 'eccentricity effect'). This study attempted to determine whether the eccentricity effect is attributable to reduced reflex vergence innervation in peripheral fusion. Experiments were run in a Maxwellian view haploscope. Convergence and divergence adaptation to 6 delta disparity stimuli were quantified for seven binocularly normal subjects using subjective heterophoria measurements. Vergence response during central or peripheral fusion was quantified objectively by infrared oculography. Six of seven subjects revealed an eccentricity effect. However, in three of seven subjects the eccentricity effect was not predictable from the manifest vergence response. The results suggest that the source of reflex vergence innervation affects prism adaptation. A model is proposed whereby different sources of reflex disparity vergence innervation stimulate prism adaptation by way of separate neurological pathways of differing responsiveness.

Infant VEP and preferential looking acuity measured with phase alternating gratings

Previously, infants' grating acuity was found to be temporally tuned, but adults' grating acuity was not. In infants, acuity was higher for gratings phase alternating at 7.5 and 14 reversals/sec than for stationary gratings and gratings alternating at 2.5 or 23 reversals/sec. Also, when preferential looking (PL) and visually evoked potential (VEP) acuity were estimated with phase alternating gratings (14 reversals/sec), the acuity difference between the two techniques was smaller than that obtained when phase alternating gratings were used to estimate VEP acuity and stationary gratings were used to estimate PL acuity. In the present study, it was determined if PL grating acuity was tuned in older children and if the smaller difference between VEP and PL acuity found when infants were tested with phase alternating gratings was independent of temporal rate. Grating acuity in infants older than 2 yr was found to be not tuned, and the smaller difference between VEP and PL grating acuity in infants when both were measured with phase-alternating gratings was not rate dependent. VEP acuity and PL acuity for phase alternating gratings developed at different rates, converging to nearly equivalent levels by 12 mo of age.

Differences in tests of aniseikonia

The New Aniseikonia Test (NAT), a hand-held direct-comparison test using red/green anaglyphs, has several potential advantages as a screener. We compared the validity of the NAT to that of the Space Eikonometer in three experiments: (1) aniseikonia was induced by calibrated size lenses in a double-blind study of 15 normal subjects; (2) habitual aniseikonia was measured with both instruments in four patients; and (3) eight of the normal subjects were retested with a computer-video simulation of the NAT. The NAT underestimated induced aniseikonia by a factor of 3 in the normal subjects and underestimated habitual aniseikonia in four patients. The Space Eikonometer correctly measured the magnitude of induced aniseikonia in the normal subjects. The simulation test did not show underestimation in the eight normal subjects. We could not attribute the NAT's underestimation of aniseikonia to the red/green anaglyph method, printing error, psychophysical method, or the direct-comparison test format. We speculate that the NAT induces a different sensory fusion response to aniseikonia than do the other tests, and that this altered sensory fusion response diminishes measured aniseikonia. We conclude that the NAT is not a valid measure of aniseikonia.

Retinal eccentricity of fusion detail affects vergence adaptation

Adaptation of tonic vergence ("vergence adaptation" or "prism adaptation") may be produced by sustained accommodative, disparity, or proximal vergence innervation. Phoria measures were used in the present study as indices of tonic vergence adaptation to convergence and divergence stimuli in five subjects. Amblyoscope targets stimulated fusion either over the central or peripheral retina while holding accommodative and proximal stimuli constant. The magnitude and rate of tonic vergence adaptation were greater under the central fusion condition than under the peripheral fusion condition, even though the vergence stimuli were matched between central and peripheral fusion conditions. These results show that tonic vergence adaptation is influenced by the retinal eccentricity of target fusional patterns. However, additional work is required to identify the mechanism(s) underlying this eccentricity effect.

Normal retinotopic mapping in human strabismus with anomalous retinal correspondence

Burian proposed that a functional retinotopic remapping of the deviated eye on striate visual cortex may be the physiologic basis for the perceptual phenomenon of anomalous retinal correspondence (ARC) in human strabismus. This investigation searched for this type of retinotopic remapping in five esotropes and one exotrope with ARC by means of visual evoked potential (VEP) topographic mapping. Uniocular stimulation of the foveas (corresponding points) during binocular vision in a normal subject yielded identical VEP scalp topographies from each eye. Stimulation of anomalously corresponding points produced different VEP scalp topographies from each eye in the six strabismic subjects. Uniocular stimulation of the anatomic foveas of each eye (noncorresponding points) in a strabismic subject during binocular vision produced identical VEP scalp topographies. These results suggest that there is no significant functional binocular realignment of retinotopic mapping in the visual cortex of human strabismics with ARC.

Signal to noise ratio considerations in the analysis of sweep visual-evoked potentials

More investigators are recommending rapid sweep displays to estimate visual-evoked potential (VEP) sensory thresholds. Theoretically, phase-sensitive analysis offers a higher signal to noise ratio (SNR) than phase-insensitive techniques and, therefore, a more reliable and equally valid threshold estimate. Phase-sensitive analysis assumes that the VEP phase does not change over the period of one sweep. This study tests the assertion that the VEP phase is sufficiently stable for valid and reliable phase-sensitive detection. Mathematical analysis shows that phase-sensitive detection yields a lower SNR than phase-insensitive analysis if the phase error is < 45 degrees . We recorded the VEP to contrast reversing sinusoidal gratings of sweeping spatial frequency (12.5-0.2 epd) from 26 subjects. In most, phase varied > 180 degrees Over one sweep. Moreover, these large phase shifts could not be diminished by modifying contrast reversal rate, direction of spatial frequency sweep, or sweep time. We conclude that when using spatial frequency sweeps, phase-insensitive detection is superior to phase-sensitive. The filter's bandwidth and the effect of SNR on sensory threshold estimations also are discussed.

Infant grating acuity is temporally tuned

Studies of infant visual development have shown that acuity estimated with pattern visually evoked potential (VEP) techniques is higher than acuity estimated with preferential looking (PL) techniques. A major difference is that VEP stimuli are temporally modulated while PL stimuli are typically stationary. We measured PL acuity in 2-10-month-old infants for stationary gratings and for gratings phase alternating at 2.5, 7.5, 14 and 23 reversals/sec using a computer generated staircase method. The acuity functions were temporally tuned at 7.5 or 14 rev/sec for infants 3 months and older. Acuity for 7.5 and 14 rev/sec gratings was 0.5 to 1.0 octave higher than for stationary, 2.5 and 23 rev/sec gratings. When adults' grating acuity was measured foveally and 5 deg eccentrically, tuning occurred only for the eccentric targets, suggesting that the retinal area used by the infants to detect gratings acts like the adult perifovea. In a second experiment, VEP and PL acuity were both measured from the same infants using 14 reversals/sec gratings. The VEP/PL acuity difference was less for phase alternating gratings than for stationary gratings. The magnitude of the difference was age dependent, decreasing from 2 octaves at 2 months to 0.5 octave at 12 months. Even though the use of phase alternating gratings results in improved PL acuity, temporal modulation does not completely account for the difference between VEP and PL acuity.

Blink vergence in an antimetropic patient

A patient with uncorrected antimetropia was found to attain motor fusion through blinking. Although this patient was also able to attain motor fusion through saccadic vergence and slow fusional vergence, he usually relied on blink vergence. In this patient, blink vergence was an efficient alternative to slow fusional vergence.

Stress management as a component of occupational therapy in acute care settings

The recent explosion of stress literature in the medical community has created a new awareness of "stress" as a potentially destructive force in itself. Contributing the physical and psychological dysfunction, stress has now been linked with a wide range of diagnoses including cancer, cardiac disease and arthritis. The importance of incorporating stress management activities into daily life is increasingly apparent. Occupational therapists concerned with patients' ability to achieve health enhancing independent living skills are in a key position to help patients master stress management skills and incorporate them into activities of daily living. This article will explore the incorporation of stress management into occupational therapy programming for a variety of acute care patients. It will review the components of stress, the stress cycle, the relaxation response, the occupational therapy role based on a model of human occupation, and will review current programs through case study of four patients: one diagnosed with cancer (leukemia), one with anorexia nervosa, one with chronic pain and the fourth, a patient in medical intensive care.

Randomized phase II studies in advanced colorectal carcinoma: a North Central Cancer Treatment Group study

5-FU, semustine (MeCCNU), triazinate (TZT), and razoxane (ICRF-159) have each shown activity against advanced colorectal cancer in studies by at least two investigative groups. Objective response rates, however, have been low, without evidence of increased patient survival. The hope of this study was that enhanced activity might result from giving these agents in two-drug combinations. There were 167 eligible and evaluable patients randomized among the programs: 5-FU at a dose of 500 mg/m2/day by iv push X 5 (F); 5-FU at a dose of 400 mg/m2/day iv X 5 plus TZT at a dose of 175 mg/m2/day iv X 3 (FT); 5-FU at a dose of 400 mg/m2/day plus ICRF-159 at a dose of 600 mg/m2/day orally X 3 (FI); MeCCNU at a dose of 150 mg/m2/day orally plus TZT at a dose of 200 mg/m2/day iv X 3 (MT); MeCCNU at a dose of 150 mg/m2 orally plus ICRF-159 at a dose of 500 mg/m2/day orally X 3 (MI); and ICRF-159 at a dose of 425 mg/m2/day orally X 3 plus TZT at a dose of 125 mg/m2/day iv X 3 (IT). Patients with limiting conditions (serum creatinine greater than 1.5 mg/dl or elevated bilirubin) were randomized among programs F, FI, and MI. Objective response rates by treatment arm were: F--13% (four of 31 patients); FT--13% (four of 31); FI--15% (four of 27); MT--11% (three of 28); MI--13% (four of 32); and IT--6% (one of 17). Response rates of combination arms were not significantly larger than those of 5-FU alone. With regard to survival, patients initially treated with 5-FU alone had the most favorable experience (median, 10.8 mos). Multivariate analysis showed the following factors to have a significant and independent influence on survival: Eastern Cooperative Oncology Group performance score, grade, site of indicator lesion, and the presence of 5-FU in the treatment regimen. Toxic effects most frequently seen were nausea, vomiting, thrombocytopenia, leukopenia, diarrhea, stomatitis, alopecia, and dermatitis. The incidence and severity of toxicity were roughly comparable among the six treatment arms.

Dynamics of cover test eye movements

The dynamics of unilateral cover test eye movements, never before systematically investigated with an objective recording system, are shown to be more complex than textbook accounts of them. We administered the cover test to nine heterophoric subjects by means of electromechanical occluders. Eye movements were recorded using the infrared photoelectric technique. Saccadic and vergence movements of the fixating eye were observed in almost all records when the occluded eye was uncovered. These movements were found in esophores and exophores and in both large and small phoria cases. Such movements were previously described in other asymmetric vergence tasks and appear to obey Hering's law of equal innervation. Uncovering the dominant eye, in cases of clear dominancy, resulted in shorter latency and larger amplitude saccades than did uncovering the nondominant eye. These large saccades were frequently of unequal amplitude in each eye. Trained subjects appear to use dynamic overshoots to increase this saccadic inequality and thereby attain vergence during saccades. Movements after the application of a cover to one eye, while grossly similar to textbook descriptions of them, are found to contain small vergence drifts and refixation (correcting) saccades in the nonoccluded eye.