Prospective evaluation of mild to moderate pediatric acetaminophen exposures.

STUDY OBJECTIVE: To determine whether pediatric patients with acute, mild to moderate acetaminophen exposures, treated with home monitoring alone, develop systemic signs of hepatic injury. METHODS: A prospective, observational study of calls to a regional poison center over a 25-month period was performed. Patients were eligible for the study if they were younger than 7 years and had an acute maximum possible acetaminophen exposure of up to 200 mg/kg. Exclusion criteria included previous decontamination measures, possibility of ingestion of an extended-release preparation, health or medication issues that could increase susceptibility to hepatotoxicity, current symptoms of hepatotoxicity, and indeterminable ingestions. Study protocol included reviewing the signs and symptoms of early and late acetaminophen toxicity, a 4- to 6-hour follow-up call, and a 72-hour follow-up call. Outcome measures were defined as a verbal report by the patient's parent or guardian of the presence or absence of signs or symptoms of hepatotoxicity. RESULTS: A total of 1,039 patients were enrolled in the study, including 519 girls and 520 boys, with exposures ranging from 20 to 200 mg/kg. Eighteen patients were lost to follow-up; data were incomplete for 2 patients. At 72-hour follow-up, the remaining 1,019 patients were all doing well, without signs or symptoms of hepatotoxicity. CONCLUSION: On the basis of these data, pediatric patients with acute acetaminophen exposures of up to 200 mg/kg, treated with home monitoring alone, do not develop signs or symptoms of hepatic injury.

Loosening rates and bone lysis with rough finished and polished stems.

In the senior author's 27-year experience in cementing femoral components, stems with smooth and rough surfaces were implanted. Prospective data have been kept on all patients allowing extensive long term followup. The polished Charnley stem was implanted in 168 hips from 1971 to 1975. To date, only four (2.4%) stems have required revision for aseptic loosening and four others for fracture. None showed significant bone lysis. The experience with the T-28 and TR-28 allows comparison of stems of similar geometry, but with different surface finishes. From 1972 to 1977, 209 polished T-28 stems were inserted and to date 18 (14 for fracture and four for loosening, 1.9%) have required revision. None had associated bone lysis. From 1977 to 1982, 227 second generation TR-28 matte surface finish stems (Ra 30) were implanted. Five required revision, three (2.2%) with major bone lysis. Radiographic review revealed minimal lysis in four (1.9%) polished T-28 stems and in 11 (4.9%) TR-28 stems, three of which showed major bone destruction. From 1980 to 1993, 1061 Iowa stems were implanted. In 1986 proximal precoat was added, which required additional roughening of the surface. In 1995 a 1.5% early loosening rate was reported with significant bone lysis, complicating revision. By 1998 34 (3.2%) stems have required revision, all associated with significant bone loss. Revision of one of 12 original Iowa (Ra 30) and 12 of 22 (Ra 80) grit blasted stems was needed before 5 years postoperatively. These early failures prompted the author to return to a polished stem with a geometry almost identical to the Charnley stem.

Early loosening of the femoral component at the cement-prosthesis interface after total hip replacement.

Between 1980 and 1990, 1941 total hip replacements were performed with use of the Iowa femoral component fixed with cement. Twenty-seven of these patients (twenty-nine hips) had early loosening of the femoral component two to ten years (average, five years) after the operation. The average age of these patients at the time of the operation was fifty-nine years (range, forty-one to seventy-seven years). The acetabular cup had been inserted without cement in seventeen hips, and the cup had been inserted with cement in twelve. The femoral stems had a matte finish; twenty had been precoated with polymethylmethacrylate and nine had not been precoated. The pattern of loosening of the femoral stem was unique: in each hip, the loosening was initially reflected by debonding (a superolateral lucency between the cement and the prosthesis in zone 1 of Gruen et al.), and this was followed by progressive loosening at the cement-prosthesis interface with maintenance of the bone-cement interface. In twenty hips, the debonding was followed by extensive osteolysis. Twenty patients (twenty-one hips) had a revision, and one was considering a revision at the time of writing. The average time from the onset of the symptoms to the revision for the nineteen hips for which this information was available was nine months. We believe that both the geometry (a cylindrical shape distal to the proximal cobra shape) and the surface finish of the Iowa femoral component were responsible for the pattern of progressive loosening.(ABSTRACT TRUNCATED AT 250 WORDS)

Conjoined twins.

Conjoined twins, otherwise known as Siamese twins, have fascinated physicians and laymen alike for centuries. The minimal diagnostic criteria for conjoined twins is the fusion of some portion of mononuclear or monozygotic twins.

Total hip replacement with insertion of an acetabular component without cement and a femoral component with cement. Four to seven-year results.

One hundred and fifty-three so-called hybrid total hip replacements were performed in 142 patients from 1985 to 1987 at Rush-Presbyterian-St. Luke's Medical Center. A hemispherical porous-coated acetabular component was inserted without cement and was fixed with screws, and a femoral stem was inserted with the use of so-called third-generation cementing techniques. The average age of the patients at the time of the operation was sixty-seven years (range, thirty-nine to eighty-five years). The average preoperative Harris hip score was 46 points (range, 9 to 73 points). One hundred and eleven patients (120 hips) were available for clinical review; 100 of these patients (109 hips) had a complete set of radiographs available. The average Harris hip score was 86 points (range, 29 to 100 points) at the time of follow-up (average duration, sixty-two months; range, forty-eight to eighty-five months). There was progressive migration of one cup (1 per cent); another cup migrated one centimeter in the first two years after the operation, with no additional migration evident after that time. The remaining acetabular components were stable. Two femoral components (2 per cent) were determined to be definitely loose. The remaining femoral components were stable. This population of patients had a good result after so-called hybrid total hip replacement with insertion of a porous-coated acetabular component without cement and a femoral component with cement for the reconstruction of a painful hip.

[Dose-response relation of gallopamil in comparison with nifedipine, diltiazem and tiapamil in patients with coronary heart disease]. / Dosis-Wirkungsbeziehung von Gallopamil im Vergleich zu Nifedipin, Diltiazem und Tiapamil bei Patienten mit koronarer Herzkrankheit.

For effective treatment of coronary heart disease with calcium antagonists, knowledge of both the dose-response relationship of a remedy and equipotent dosage for comparison of different drugs is necessary. We performed controlled studies to evaluate the influence of single oral doses of calcium antagonists on ischemic ST-depression (calculated as the mean of all exercise and recovery minutes = mean ST-depression) in exercise ECGs of patients with proven CHD and stable angina pectoris. Ergometries were carried out under constant conditions, particularly with individually constant work load and duration. All calcium antagonists reduced ischemic ST-depression during ergometry dose-dependent when compared to placebo. Diltiazem: 90 mg: 6% (n.s.), 120 mg: 19% (n.s.) und 180 mg: 26% (p less than 0.025); gallopamil: 25 mg: 19% (n.s.), 50 mg: 34% (p less than 0.01) und 100 mg: 57% (p less than 0.0025); nifedipine-Cps.: 5 mg: 17%, 10 mg: 33% und 20 mg: 42%; nifedipine-Tbl.: 20 mg: 8% (p less than 0.05), 40 mg: 23% (p less than 0.057 und 60 mg: 31% (p less than 0.05); tiapamil: 300 mg: 30% (p less than 0.05) und 600 mg: 60% (p less than 0.01). As the result of our findings, comparable antiischemic effects can be expected with 120 mg diltiazem, 50 mg gallopamil, 20 mg nifedipin as capsule or 60 mg nifedipin as tablet and 600 mg tiapamil.

Seed dispersal and seedling emergence in an old field community in central New York (USA).

Seed dispersal and seedling emergence of common taxa growing in a Solidago-dominated old field in central New York (USA) were monitored from May 1982 to June 1984. Over 3.5x104 seeds per m2 were captured on seed traps in each of the two years, with peaks occuring in July (due to Hieracium) and in November (due to Solidago). About 4.0x103 seedling/m2 emerged beneath the intact community in each of the two years. Although seedlings emerged predominantly in the early spring, a secondary peak occurred in September and October when many seedlings of introduced grasses appeared. Two additional aspects of the reproductive biology of the major taxa were related to the seasonal timing of seed dispersal: As the date of peak seed dispersal (among taxa) became progressively later in the season, (1) the duration of dispersal increased from about one week to about one-half year, and (2) the delay between the peak of seed dispersal and the peak of seedling emergence increased from a few days to about one-half year.

A clinicopathological case report of retinopathy of pancreatitis.

A 32-year-old black woman with pancreatitis developed visual loss in both eyes. On ophthalmoscopic examination she had extensive ischaemic infarcts at the posterior poles of both eyes, a clinical picture which has been reported previously in patients with pancreatitis and noted to be similar to Purtscher's retinopathy. On histopathological examination of the eyes after death there were arteriolar occlusions in both the choroid and retina and inner ischaemic infarctions with inner retinal oedema. Owing to the 23-day interval from arteriolar occlusion until death the exact nature of the original occlusion could not be determined. However, either fat emboli or activated complement C5-induced granulocyte embolus formation are possible causes.

Long-term evaluation of patients with Best's vitelliform dystrophy.

We examined 91 patients with Best's dystrophy and followed 54 affected individuals for five years. Most eyes with normal maculas, minimal pigment epithelial changes, atrophic maculae, or fibrous macular scars did not change stage. Eyes with vitelliform or pseudohypopyon lesions progressed to later atrophic macular stages. Visual acuity decreased after age 40 and was worse for patients with atrophic maculas and fibrous scars. Nineteen percent of patients with atrophic maculas or fibrous scars who were followed for 8 to 10 years were the only patients to lose vision.

Role of striate cortex and superior colliculus in visual guidance of saccadic eye movements in monkeys.

1. We studied the effect of lesions placed in striate cortex or superior colliculus on the detection of visual stimuli and the accuracy of saccadic eye movements. The monkeys (Macaca mulatta) first learned to respond to a 0.25 degrees spot of light flashed for 150-200 ms in one part of the visual field while they were fixating in order to determine if they could detect the light. The monkeys also learned in a different task to make a saccade to the spot of light when the fixation point went out, and the accuracy of the saccades was measured. 2. Following a unilateral partial ablation of the striate cortex in two monkeys they could not detect the spot of light in the resulting scotoma or saccade to it. The deficit was only relative; if we increased the brightness of the stimulus from the usual 11 cd/m2 to 1,700 cd/m2 against a background of 1 cd/m2 the monkeys were able to detect and to make a saccade to the spot of light. 3. Following about 1 mo of practice on the detection and saccade tasks, the monkeys recovered the ability to detect the spots of light and to make saccades to them without gross errors (saccades made beyond an area of +/-3 average standard deviations). Lowering the stimulus intensity reinstated both the detection and saccadic errors...

Organization of monkey superior colliculus: intermediate layer cells discharging before eye movements.

1. We investigated the characteristics of cells in the intermediate layers of the superior colliculus that increase their rate of discharge before saccadic eye movements. Eye movements were repeatedly elicited by training rhesus monkeys to fixate on a spot of light and to make saccades to other spots of light when the fixation spot was turned off. 2. The eye movement cells showed consistent variations with their depth within the colliculus. The onset of the cell discharge led the eye movement by less time and the duration of the discharge was shorter as the cell was located closer to the dorsal edge of the intermediate layers. The movements fields (that area of the visual field where a saccade into the area is preceded by a burst of cell discharges) of each successive cell also became smaller as the cells were located more dorsally. The profile of peak discharge frequency remained fairly flat throughout the movement field of the cells regardless of depth of the cell within the colliculus. 3. A new type of eye movement-related cell has been found which usually lies at the border between the superficial and intermediate layers. This cell type, the visually triggered movement cell, increased its rate of discharge before saccades made to a visual stimulus but not before spontaneous saccades of equal amplitude made in the light or the dark. A vigorous discharge of these cells before an eye movement was dependent on the presence of a visual target; the cells seemed to combine the visual input of superficial layer cells and the movement-related input of the intermediate layer cells. The size of the movement fields of these cells were about the same size as the visual fields of superficial layer cells just above them...

Organization of monkey superior colliculus: enhanced visual response of superficial layer cells.

1. Cells in the superficial layers of monkey superior colliculus respond more vigorously to a spot of light falling in their receptive fields when the monkey uses that spot of light as the target for a saccadic eye movement. Our purpose in these experiments was to investigate the characteristics of this enhancement effect. While monkeys fixated, we determined the response of a cell to a stimulus falling in its receptive field. Then we determined the response of the cell to the same stimulus when the monkey made a saccade to the stimulus or near to it. 2. The enhancement of the visual response is spatially limited. The receptive field of a cell always shows enhancement throughout its extent and frequently shows a slight expansion. Saccades made near to a stimulus in the visual receptive field, but not to it, also lead to an enhancement of that visual stimulus; an area around the excitatory center of the receptive field where such enhancement occurs was referred to as the enhancement field of the cell. An enhanced response in one part of the visual field was not accompanied by depressed responses associated with saccades to other parts of the visual field. 3. The enhancement effect is temporally limited; it begins 200-300 ms before the eye movement, as determined by the increasing response to 50-ms light pulses presented at varying intervals before the eye movement. The degree of enhancement intensifies when the visual stimulus is turned on closer in time to the onset of the saccade. A buildup of the enhancement also occurs on successive trials as does the response of eye movement-related cells in the intermediate layers. 4. The enhancement response is not present in the upper quarter-millimeter of the superficial layers, suggesting that the effect is not present in retinal afferents which terminate primarily in this area of the superficial layers. The enhancement effect is seen throughout the visual field; the foveal area was not tested. 5. In order to determine the relation of the enhancement effect to the monkey's behavioral response, we required the monkey to make a hand response rather than an eye movement-response to the visual stimuli. Cells did not show a clear enhancement with such a hand response. Results of these experiments indicate that the enhancement effect is dependent on the type of response the monkey makes to the stimulus and is probably specifically related to eye movements. Since the enhancement of visual response seems likely to be related specifically to eye movements both on physiological and behavioral grounds, the response-free term "attention" is probably inappropriate for the phenomenon. 6. The hypothesis advanced in the preceding paper that eye movement-related activity from intermediate and deep colliculus layers is directed upward to converge with visually related activity in the superficial layers is extended to include an input from cells in these deeper layers (or their afferents) to the superficial layer cells...

Enhancement of visual responses in monkey striate cortex and frontal eye fields.

1. We have studied the visual enhancement effect in two areas of the cerebral cortex of monkeys. The response of the cells to a visual stimulus was determined both when the monkey used the visual stimulus as the target for a saccadic eye movement and when he did not. 2. In striate cortex cells with nonoriented, simple, complex, and hypercomplex receptive-field types were studied. Clear enhancement of the response to the appropriate visual stimulus was seldom seen when the monkey used the stimulus as a target for a saccade. In addition, any enhancement effect seen was nonselective; it occurred whether the monkey made a saccade to the receptive-field stimulus or some other stimulus at a point distant from the receptive field. The enhancement also occurred whether the monkey made a saccade to the stimulus or just released the bar when the stimulus dimmed. 3. This nonselective enhancement in striate cortex is in striking contrast to the selective enhancement of the visual response seen in the superior colliculus. The different characteristics of the enhancement in striate cortex and the observation of enhancement in the colliculus following ablation of striate cortex suggest that this cortical area is an unlikely source of the collicular enhancement. 4. These observations reinforce the distinction between striate cortex and superior colliculus. Striate cortex is an excellent analyzer of stimulus characteristics but a poor evaluator of stimulus significance. The superior colliculus is an excellent evaluator but a poor analyzer. 5. The area of frontal eye fields in which cells have clear visual responses has been better localized. Enhancement of the visual response of these cells also occurs and, at least for some cells, the response enhancement is selective. The response enhancement, like the visual properties of these frontal eye field cells, appears to be more closely related to the properties of superior colliculus cells than to striate cortex cells.