Sequential follow up observations of a patient with rubella associated persistent arthritis

In 1985 a patient was described whose persistent polyarthritis was found to be aetiologically linked to rubella virus infection through the detection of repeated maximal synovial lymphocyte proliferative responses to rubella virus antigen and by isolation of rubella virus from her synovium. Follow up over the succeeding seven years has shown continuing chronic polyarthritis and persistent synovial lymphocyte responses to rubella virus antigen with the additional observation that she has a defective humoral immune response against rubella virus.

An estimate of the future size of the tuberculosis problem in sub-Saharan Africa resulting from HIV infection

The impact of the human immunodeficiency virus (HIV) on tuberculosis is well documented. Its effect in populations with a high proportion of dually infected individuals is likely to be significant. Sub-Saharan Africa is one such region and to better document the effect of HIV infection on tuberculosis there we developed a mathematical model to predict the likely extra numbers of tuberculosis cases due to it. A mathematical model was developed using a variety of scenarios giving a range of risks for the period 1980-2000. The four scenarios included (1) a low rate of 1% risk of tuberculosis infection in year 0 (1980) with 45% tuberculosis infection prevalence, and an HIV prevalence of 2% in 1989; (2) a 2% risk of tuberculosis infection in year 0 with 60% tuberculosis infection prevalence, and a 2% HIV prevalence in 1989; (3) a 2% risk of tuberculosis infection in year 0 with 60% tuberculosis infection prevalence, and a 10% HIV prevalence in 1989; and (4) a 2% risk of tuberculosis infection in year 0 with 60% tuberculosis infection prevalence and a 20% HIV prevalence in 1989. Under scenarios 1 and 2, a 50-60% increase in smear-positive rates in the subpopulation (15-45 years old) is predicted for the year 2000, under scenario 3, smear-positive rates in the subpopulation in the year 2000 are expected to increase four-fold from the 1980 baseline. Under scenario 4, a 10-fold increase in smear-positive rates in 2000 is expected in the subpopulation. Under this scenario, total disease will have increased 12-fold in the subpopulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Preservation techniques for heart transplantation: comparison of hypothermic storage and hypothermic perfusion

Preservation of the donor heart is an important and controversial subject in heart transplantation. This study compares simple hypothermic storage and hypothermic perfusion in a swine model of heart transplantation (n = 14). The donor hearts of group A (n = 7) were placed in simple hypothermic storage for 5 hours. The donor hearts of group B (n = 7) were placed onto a perfusion apparatus for 5 hours, with pressure maintained at 28 cm of H2O and a myocardial temperature of 8 to 10 degrees C. In both groups the hearts were initially protected with isosmolar potassium cardioplegic solution. The perfusate in group B contained moderate sodium, mannitol, glucose, insulin, and oxygen. The ischemic interval within both groups was 6 hours including orthotopic transplantation. Investigation was conducted at three time periods: prepreservation, postpreservation, and immediately after loading. For both groups there was nonsignificant depression of myocardial function (cardiac index, stroke index, stroke work index, ejection fraction, and wall stress) at the postpreservation period. After volume loading, for the hypothermic perfusion group there was significant improvement of myocardial function (cardiac index, p less than 0.01; stroke index, p less than 0.01) with no significant change in heart rate, systemic vascular resistance, and systolic blood pressure. There was also significant improvement in myocardial performance (p less than 0.05) for the hypothermic perfusion group after volume loading. Ultrastructural changes were minimal for both groups, and there were no major heart transplantation after 6 hours of ischemia; however, hearts retain their contractile capacity better after hypothermic perfusion than after simple hypothermic storage.(ABSTRACT TRUNCATED AT 250 WORDS)

Age-dependent decline in motor evoked potential (MEP) amplitude: with a comment on changes in Parkinson's disease

Peak-to-peak measurement of the maximum amplitude motor evoked potential (MAXMEP) elicited by 20 consecutive transcranial magnetic stimuli recorded from the contracting thenar and hypothenar muscles measured 9.8 +/- 2.0 mV and 7.25 +/- 2.9 mV respectively (P less than 0.01). The ratio of MAXMEP/CMAP measured 92.6 +/- 25.8% and 54.8 +/- 12.3% respectively (P less than 0.001). Repeat studies showed good individual reproducibility. Amplitudes declined linearly with age (r = -0.836 for thenar MAXMEP P less than 0.001). It is argued that MAXMEP related to age is more meaningful than the MEP/CMAP wave ratio and is proportional to the number of fast conducting cortical motor neurons excited. In 7/18 patients with Parkinson's disease (PD) MAXMEP was increased; in 2 other patients MAXMEP was decreased for their age.

A comparison of treated and untreated glaucoma suspects

One hundred forty-three patients with intraocular pressures (IOPs) above 22 mmHg and without visual field defects or any obvious evidence of optic nerve damage were randomly assigned to either a timolol treatment group or no treatment in a 6-year prospective clinical trial. Endpoints were defined as reproducible visual field defects on automatic perimetry, disc hemorrhages, or stereophotographically documented optic nerve head changes. Endpoints developed in 42 patients: 28 visual field defects, 8 changes in disc appearance, and 6 disc hemorrhages. Of the 42 patients, 20 were treated and 22 were not. Survival analysis showed no statistically significant differences in failure time to any endpoints between the two groups. In the untreated group, the time to failure of disc change was related to the mean IOP during the study and also to the changes in the IOP from baseline. A significant correlation was found between initial cup-to-disc ratio and survival time to visual field defects in the untreated group.

Comparison of functional and metabolic assessments in preservation techniques for heart transplantation

The present study compares simple hypothermic storage and hypothermic perfusion in a swine model of heart transplantation using metabolic and functional assessments. In both groups the hearts were initially protected with iso-osmolar potassium Tyers' cardioplegia. The donor hearts of group A were placed in simple hypothermic storage for 5 h. The donor hearts of group B were placed onto a perfusion apparatus for 5 h with perfusion pressure maintained at 28 cm of H2O and a myocardial temperature of 8-10 degrees C. The perfustate consisted of Tyers' solution with the addition of 2 mg/L of mannitol, 12.5 mg/L of glucose, 5 units/L of insulin, and 95% oxygen. The ischemic interval within both groups was 6 h, including orthotoipic transplantation. Investigation was conducted at three time periods: prepreservation (T1) in the donor, and postpreservation (T2) and immediately after loading (T3) in the recipient. Following volume loading for the hypothermic perfusion group there was significant improvement of myocardial function (cardiac index, p less than .05; stroke index, p less than .05) with no significant change in systemic vascular resistance, systemic blood pressure, and heart rate. There was also significant improvement in myocardial performance (p less than .05) for the hypothermic perfusion group following volume loading. Results of fatty acid turnover using 15-p-iodo (123I)-phenylpentodecanoic acid indicate significantly greater increase in metabolic rate for the perfusion group than for the hypothermic storage group. (p less than .05). This indicates improved metabolic status of the heart treated with the hypothermic perfusion technique. We conclude that a combination of functional and metabolic assessments is a good method for deduction of ischemic-reperfusion injury. We also conclude that hypothermic perfusion is superior to hypothermic storage for in vitro preservation of hearts for heart transplantation.

Relation between optic nerve axon number and axon diameter to scleral canal area

To determine whether there are more axons present in eyes with larger optic discs, the authors studied 16 eyes from 16 individuals whose eyes were donated for corneal transplantation. For each nerve, the axon count, axon diameter, and scleral canal area was measured. Total axon count decreased with age. Mean axon diameter increased with age. There was no statistically significant relation detected between axon count and scleral canal area. Multiple regression revealed that when corrected for the effect of age, eyes with smaller scleral canal areas had larger number of axons.

Sensitivity and specificity of a diagnostic test determined by repeated observations in the absence of an external standard

Traditionally, the sensitivity and specificity of a new diagnostic test are derived from its application to two groups of individuals known to have or not to have met the criterion to be detected as judged by means of a "gold standard", some external time-honored test. In this study, a test with unknown accuracy parameters was used to detect an end-point criterion in an ongoing ophthalmological clinical trial. Since no external test method was available to assess the accuracy of this test, equations were derived relating the unknown sensitivity and specificity of the test to data frequencies based on replicate measurements. The solutions to these equations also provided estimates of the incidence rate of the criterion under investigation in the group tested, and of the predictive values of the test. The validity of this method of estimation is discussed, and applications to other situations are suggested.

Adrenergic and adrenolytic effects on intraocular pressure

We compared the pressure-lowering effects of timolol, pindolol, epinephrine and the mixture of timolol and epinephrine with that of placebo over a 12-h period. All agents reduced the pressure significantly but with varying time courses. The mixture of timolol and epinephrine reduced the pressure significantly more than did timolol or epinephrine alone, especially at 12 h after the last administration of the drops.

Characteristics of the normal central visual field measured with resolution perimetry

The ring perimeter is an innovative device that measures the resolution threshold at 50 locations in the central visual field in approximately 6 min. This study was undertaken to define the characteristics of the resolution visual field in normal eyes using this instrument and to check the repeatability of the measurement. A total of 114 perimetrically naive, normal subjects aged from 20 to 79 years were prospectively enrolled; 55 randomly chosen subjects were tested twice, with a rest period of less than or equal to 60 s elapsing between examinations. The resolution threshold increased towards the periphery in all subjects. A small but significant decline in sensitivity occurred with age; this loss was greatest in the inner part of the field. Variability in threshold between subjects was not found to increase towards the periphery or in the upper field as compared with the lower. The field was highly repeatable when reexamined in the same subject. This study defines the resolution visual field in normal subjects, along with its inter- and intra-observer variability, and gives age-corrected predictive confidence intervals for each location of the field using the ring perimeter.

Choice of anesthetic agents for peribulbar anesthesia

To determine the effectiveness of various combinations of lidocaine, epinephrine, and hyaluronidase with bupivacaine, a prospective, randomized, masked study on 117 patients having cataract extraction under local anesthesia was undertaken. All patients were given a 9 ml peribulbar block by one surgeon, and a graded assessment of analgesia and akinesia was made in a masked fashion one hour later. A mixture using all these agents gave significantly better results than any of the combinations (P = .001). No single agent was shown to be the major determinant of effectiveness. The result suggests a synergistic effect found only when all the agents are combined.

Possible significance of cilioretinal arteries in low-tension glaucoma

Cilioretinal arteries arise from the short posterior ciliary artery circulation or directly from the choroidal circulation. The presence of a cilioretinal artery may in compromised discs steal flow from the peripapillary circulation and account for worsening glaucoma damage. We reviewed the records of 33 patients with unilateral cilioretinal arteries admitted for investigation of low-tension glaucoma. We looked for absolute difference between the affected and unaffected eyes as well as percent difference relative to the mean value for the two eyes and to the value for the unaffected eye in the following variables: mean defect, corrected loss variance or corrected pattern standard deviation, and adjusted neuroretinal rim area. No statistically significant differences were found. The mean disc area for the eyes with cilioretinal arteries was significantly larger than that previously reported for normal eyes. The results suggest that if vascular steal exists because of the presence of this artery, it is not of major clinical importance.

Lens opacity as a predictor of visual field impairment due to cataract

The contribution of cataract to the decrease of visual field in patients with glaucoma is difficult to ascertain. To attempt to quantitate the change in visual field due to cataract, we examined 27 eyes of 26 patients before and after cataract extraction. The examination consisted of measurement of best refraction with visual acuity, visual field testing with the pupil dilated, measurement of lens opacity, determination of the intraocular pressure, and evaluation of the character of the cataract before surgery and of the posterior capsule after surgery. The results reaffirmed the detrimental effect that cataract may have on the visual field but also showed that the heterogeneity of cataracts limits the usefulness of the lens opacity meter in quantitating the extent of visual field loss due to cataract.

Adoption of guidelines for Universal Precautions and Body Substance Isolation in Canadian acute-care hospitals

The impact of recently recommended hospital infection control guidelines on Canadian acute-care hospitals is unknown. A confidential cross-sectional mailed survey of all acute-care Canadian hospitals was conducted to determine rates of receipt and adoption of published guidelines for Universal Precautions (UP) or Body Substance Isolation (BSI), rationale for adoption and knowledge of costs and benefits. Five hundred and seventy-nine of 943 sites (61%) responded (exceeding 80% in urban centers); 94% among hospitals with at least 300 beds and 57% among those under 300 beds. Seventy-four percent of responders claimed adoption of UP (65%) or BSI (9%), staff protection being their primary motivation. Adoption of either UP or BSI was associated with size (p less than .001), increasing progressively from 45% in the smallest group (less than 25 beds) to 84% in the largest (greater than or equal to 500 beds). Many hospitals introduced modifications and some substituted names other than UP or BSI in adopting a new strategy. In practice, UP and BSI now mean different things in different hospitals, and the distinction between them has become blurred. Furthermore, only 5% claiming adoption of a new strategy adopted all of the fundamental policies expected under UP or BSI. Receipt of guidelines was also correlated with size: one-third of hospitals under 200 beds had not received key publications defining UP and BSI. Only 19% claiming adoption of a new strategy indicated knowledge of cost implications. These results suggest a need for closer collaboration among hospitals and government agencies in developing uniform infection control policies, and for systematic evaluation of the cost and effectiveness of new strategies.

Covert orienting attention in Parkinson's disease

We examined covert orienting attention in twenty patients with Parkinson's disease using Posner's reaction time (RT) method. Patients were divided according to the grade of severity (Hoehn and Yahr), the P1 group was grade I-II and P2 group grade II-IV. Each group of patients was compared with an equal number of age-matched controls. In controls, and in the less disabled younger P1 group, a significant RT difference was shown between "valid" and "crossed" conditions, that is, when the cue and target appeared in the same square or in equivalent squares in opposite visual fields. In the P2 group, however, there was no advantage of the "valid" over "crossed" conditions. Furthermore, the RT difference seen in controls between "valid" and "towards the fovea" or "away from the fovea" (conditions where cue and target were in adjacent squares) disappeared in the Parkinsonian groups. These results suggest that the covert shift of attention from initial focus to the cue is very weak, or does not occur in more disabled Parkinsonian patients, resulting in only a shift of attention to the target. In considering the elementary mental operations involved in covert orienting attention, this deficit may be attributable to a disturbance of moving attention.

Determination of luteal phase length by quantitative basal temperature methods: validation against the midcycle LH peak

Basal temperature data are known to provide unreliable assessments of luteal phase length when they are evaluated by qualitative, visual-pattern methods. This study of 24 cycles in 24 women compared the serum LH peak day with the luteal phase onset day determined by three quantitative basal temperature methods: a) a new computerized least mean square method developed by the authors; b) the mean temperature method reported by Vollman; and c) a computerized version of the World Health Organization cumulative sum method of Royston. The luteal phase onset day determined by the three quantitative basal temperature methods, (a, b, and c) correlated well with the midcycle LH peak (r = 0.879, 0.891, and 0.791, respectively, all p less than 0.001). The cumulative sum method, however, was only able to analyze 19/24 cycles. The mean delay between the LH peak day and the luteal phase onset day determined by thermal shift was 2.4 +/- 1.5, 2.7 +/- 1.4, and 4.1 +/- 2.0 d (mean +/- SD), respectively. The mean temperature method, but not the other two methods, showed an increasing delay between the LH peak day and the thermal shift day with longer follicular phase lengths. Rectal and oral temperature data from the same cycle give identical luteal onset days when analyzed by the least mean square and mean temperature methods, but discrepant days by the cumulative sum analysis. The least mean square technique is a reliable and precise method for population documentation of luteal phase lengths.

Estimation of the short-term fluctuation from a single determination of the visual field

The short-term fluctuation in regular grid threshold static fields is commonly determined from repeated observations of a number of threshold points. In this study we estimated the short-term fluctuation from a single determination of the field. Sixty-two eyes of 62 patients were tested, using three consecutive repetitions of a Humphrey 24-2 full threshold program. The resulting grid patterns were examined using a modified version of the statistical technique of trend-surface analysis. Polynomial surfaces of increasing degree were fitted to the data over the grid. The residual variances after detrending the surface correlated very well with the direct estimates based on the triple observations at each point (correlation coefficients of log-transforms of 0.8 and better). We conclude that short-term fluctuation (the square root of the variance) can be estimated with good reliability from grids of single threshold determinations.

Biostatistical evidence for two distinct chronic open angle glaucoma populations

Twenty-six eyes of 26 patients with low-tension glaucoma and 34 eyes of 34 patients with high-tension glaucoma were studied. Fifty-one measurements were available on each patient, including visual field indices, finger blood flow measurements, as well as haematological, coagulation, and biochemical and rheological variables. Multivariate analysis revealed two statistically distinct groups of patients, with low and high tension glaucoma cases equally distributed in both. The smaller group (15 patients) showed a suggestion of vasospastic finger blood flow measurements, and had a high positive correlation between the mean deviation (MD) index of field severity and the highest intraocular pressure (r = 0.715, p = 0.0008). The second, larger group (45 patients) showed disturbed coagulation and biochemical measurements, suggestive of vascular disease, and had no correlation between the MD index and the highest intraocular pressure.

Control of intraocular pressure after cataract extraction

We carried out a prospective randomized study in 172 patients undergoing cataract extraction and lens implantation to compare the effects of pilocarpine gel, 1% acetylcholine chloride and 0.01% carbachol on early postoperative intraocular pressure (IOP), to determine the effect of sodium hyaluronate on IOP and to compare the effects of 0.01% carbachol (full-strength) and 0.005% carbachol (half-strength) on IOP, pupil size and brow ache. IOP was measured 3, 6, 9 and 24 hours after surgery, and in the full- and half-strength carbachol groups pupil size and subjective complaints of brow ache were recorded. The mean IOP 3 and 6 hours after surgery was significantly lower in all the treatment groups than in the control groups. At 9 and 24 hours it was significantly lower only in the carbachol groups. The use of sodium hyaluronate was not found to affect the postoperative IOP. There was no difference in postoperative IOP or miosis between the full- and half-strength carbachol groups, but fewer patients in the half-strength group than in the full-strength group reported brow ache at 9 and 24 hours. The results suggest that carbachol is the most effective agent currently available for the management of IOP after cataract extraction.

The effect of refractive blur on the visual field using the ring perimeter

To determine the effect of optically induced blur on the visual field measured with high pass spatially filtered targets, 10 normal subjects had field examinations with 0 diopter + 1.00 diopter or + 2.00 diopter of overcorrection in the cyclopleged state. All subjects showed a significant loss of sensitivity when defocussed, but not with pupil dilation. Mean thresholds for the central field rose from 4.79 +/- 0.68 dB (Mean +/- SD) with the image focussed and pupil dilated, to 7.16 +/- 0.72 dB with two diopters of image blur (P less than 0.001). The effects of defocussing did not differ significantly between the central and peripheral parts of the field. The great influence of defocussing the image on sensitivity should be considered during clinical perimetry as the 2.37 dB decline shown would place the group's mean sensitivity below the fifth percentile for age corrected normals.

Unequal intraocular pressure and its relation to asymmetric visual field defects in low-tension glaucoma

Fifty-nine low-tension glaucoma patients were reviewed with respect to asymmetry of intraocular pressure (IOP) and visual field defects. In the presence of unequal IOP the visual field damage is almost always greater on the side with higher mean IOP. However, only 13 of 47 patients with asymmetric visual field defects had a mean IOP difference between the two eyes of greater than or equal to 1 mmHg. Although in the case of IOP asymmetry visual field damage is greater in the eye with higher mean IOP, other factors must also play an important role in the development of visual field defects in low-tension glaucoma.

The normal human optic nerve. Axon count and axon diameter distribution

Computerized image analysis was used to determine the normal axonal count and axon diameter distribution in 12 normal human eyes. Mean axon count per nerve was 969,279 +/- 239,740 and mean axon diameter was 0.72 +/- 0.07 micron. Multiple linear regression disclosed 4909 axons lost yearly (P = 0.08). Statistical analysis did not show a relationship between axon diameter and age or time to fixation. The inferotemporal sector of the nerve had the highest fiber density (P = 0.02). The superonasal nerve had higher mean diameters (P = 0.02). This study may provide a baseline for future pathologic studies.

Persistent synovial lymphocyte responses to mumps and adenovirus antigens

A man in his 50s with rheumatoid arthritis showed maximal synovial lymphocyte reactivity to mumps antigen on 9 of 10 testings over a period of 6 years; peripheral blood lymphocytes showed no significant responses to mumps antigen in 5 testings over 5 years. A boy of 15 with recurrent arthritis of the right knee showed maximal synovial lymphocyte reactivity to adenovirus antigen. This reactivity was again present during a subsequent episode more than 3 years later; peripheral blood lymphocytes showed no such response to adenovirus antigen.