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Biomedical subjects

M Schulzer

Publications and source records attributed to M Schulzer.

At least 109 records · Page 6Linked to original sources
PubMed1991

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.

Animals↗
PubMed1990

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.

Body Fluids↗
PubMed1990

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.

Adult↗
PubMed1990

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.

Aged↗
PubMed1990

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.

Aged↗
PubMed1990

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.

Adult↗
PubMed1990

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.

Ciliary Body↗
PubMed1990

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.

Adolescent↗
PubMed1990

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.

Acetylcholine↗
PubMed1990

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.

Adult↗
PubMed1989

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.

Adolescent↗
PubMed1989

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.

Glaucoma↗
PubMed1988

Correlation between color vision and highest intraocular pressure in glaucoma patients.

We examined 75 glaucoma patients to determine the relationship between losses in color vision and their highest intraocular pressure. The losses of blue chromatic (P less than .0001) and achromatic (P = .0006) sensitivity were strongly related to highest intraocular pressure. The dysfunction of blue chromatic and achromatic pathways may therefore indicate damage from increased intraocular pressure.

Color Perception↗
PubMed1988

Response of blood flow to warm and cold in normal and low-tension glaucoma patients.

We measured blood flow in the finger in 38 control subjects with normal ocular findings without migraine, 13 control subjects with normal ocular findings with classic migraine, 17 patients with low-tension glaucoma with classic migraine, and 29 patients with low-tension glaucoma without migraine. Three blood flow measurements were recorded: one at baseline, one after immersion in warm water (40 C), and one after ten seconds' exposure to cold water (4 C). The mean baseline flow and the mean flow after exposure to cold was lower in patients with low-tension glaucoma (P = .013 and P less than .001, respectively).

Cold Temperature↗
PubMed1988

The pattern electroretinogram and visual-evoked potential in glaucoma.

The pattern electroretinogram (PERG) may reflect ganglion cell or inner retinal layer activity. The most sensitive spatial and temporal variables for testing patients with glaucoma have not yet been identified. Fifty-two glaucoma suspects, 51 glaucoma patients, and 28 normal subjects were studied with the PERG and VEP, using three repetition rates and three spatial frequencies. Fast Fourier transforms were calculated at each spatial frequency and reversal rate. An analysis of variance revealed that normals could be differentiated from ocular hypertension and glaucoma patients using the amplitude of the PERG (second and fourth harmonic). Abnormalities in phase of the PERG between groups were also detected. A discriminant analysis of all amplitude and phase data revealed that the phase shift of the response of the second harmonic at 11 alternations/s (15-min checks) and at 5.5 alternations/s (15-min checks) correctly identified 81% of the normal and 75% of the glaucoma patients. The phase shift determinations of the VEP revealed significant abnormalities using 2 and 1/2 standard deviation confidence limits. There was significant overlap in the pattern ERG amplitude and phase shift in all three groups.

Analysis of Variance↗
PubMed1988

Reproducibility of computerized pallor measurements obtained with the Rodenstock Disk Analyzer.

Computerized pallor measurements of the optic nervehead were performed by global analysis with the Rodenstock Disk Analyzer. Total intervideographic and intravideographic variability was calculated. The coefficients of variation ranged from 8.3% to 20.08% for intervideographic variability of different pallor histogram values. The intravideographic variability for pallor histogram values ranged from 0.82% to 2.94%.

Analysis of Variance↗