Laparoscopic appendectomy

Laparoscopy offers the surgeon better visibility for performing an appendectomy, which is to the advantage of the child. When the appendix is normal, the offending etiology usually can be managed through the same cannulas. With proper judgment and training, the laparoscopic technique can be used on almost any patient suspected of appendicitis. The ease of the technique, coupled with the decreased postoperative morbidity and shorter hospitalization, make the laparoscopic operation an important addition to the surgical armamentarium for managing acute appendicitis.

Influence of age on clinical and psychometric assessment of subjects with very mild or mild dementia of the Alzheimer type

OBJECTIVE

The influence of age on performance on clinical and psychometric assessments is examined in groups of nondemented persons and individuals with either very mild or mild dementia of the Alzheimer type (DAT).

DESIGN

Initial clinical and psychometric assessments of persons enrolled in longitudinal studies of DAT and nondemented control subjects.

SETTING

Alzheimer's Disease Research Center at Washington University, St Louis, Mo.

PARTICIPANTS

Volunteer samples of 108 people (44 men, 64 women) with mild DAT, 61 people (30 men, 31 women) with very mild DAT, and 122 healthy nondemented people (45 men, 77 women) were recruited between 1979 and 1991. Age ranged from 54 to 87 years. Persons with confounding medical, neurologic, or psychiatric disorders were excluded. Dementia severity was staged using the Clinical Dementia Rating scale.

MAIN OUTCOME MEASURES

Five brief quantitative clinical tests included in the 90-minute clinician administered protocol, as well as 14 tests included in a 2-hour psychometric test battery.

RESULTS

Dementia severity affected performance on all measurements. Age did not influence performance on clinical assessments. There was a significant interaction between age and dementia severity on 10 of 14 psychometric measures. In general, older nondemented individuals performed less well than younger nondemented individuals while older mildly demented persons performed about the same as, or slightly better than, their younger counterparts.

CONCLUSIONS

Age does not affect performance on brief clinical assessment instruments. However, age affects psychometric performance differently in cognitively intact persons when compared with persons with DAT. As a result, psychometric differentiation between cognitively normal and demented individuals is more difficult in older populations.

Neuropathological indexes of Alzheimer's disease in demented and nondemented persons aged 80 years and older

Subjects with clinically diagnosed senile dementia of the Alzheimer type (n = 37) and healthy controls (n = 5) were assessed clinically until death. Postmortem examination of the brain was performed at age 80 years or older. The brains of all of the group with dementia (except one that was found to have a non-Alzheimer dementia) had substantial densities of neocortical senile plaques regardless of dementia severity; the control brains had very few senile plaques. In those subjects with Alzheimer's disease, moderate correlations were found between dementia duration and severity (cognitive portion of the Blessed Dementia Scale and the Sum of Boxes from the Clinical Dementia Rating) and certain neuropathological lesions, both gross and microscopic. Densities of neocortical neurofibrillary tangles were related to degree of dementia; densities of neocortical senile plaques were unrelated. We conclude that (1) neocortical senile plaque densities differentiate very old subjects with Alzheimer's disease from nondemented controls, but there is a need for more postmortem studies of older persons who are free of dementia; and (2) among the microscopic lesions studied, densities of neocortical neurofibrillary tangles were most closely related to the degree and duration of dementia.

Frailty and injuries in later life: the FICSIT trials

Physical frailty and fall-related injuries present two of the biggest threats to older people's functioning and quality of life. The Frailty and Injuries: Cooperative Studies of Intervention Techniques (FICSIT) trials represent a set of eight different clinical trials concerning physical frailty and injuries in later life. This report documents the history and organization of the trials and provides an overview of the measures being collected at multiple sites and the analytic strategies to be used for multi-site investigations.

Duchenne dystrophy: randomized, controlled trial of prednisone (18 months) and azathioprine (12 months)

Prednisone has been shown to improve strength in Duchenne dystrophy. Azathioprine often benefits corticosteroid-responsive diseases and can reduce the dose of prednisone needed. The present study reports a randomized, controlled trial of prednisone and azathioprine designed to assess the longer-term effects of prednisone and to determine whether azathioprine alone, or in combination with prednisone, improves strength. Ninety-nine boys (aged five to 15 years) with Duchenne dystrophy were randomized to one of three groups: (I) placebo; (II) prednisone 0.3 mg/kg/d; or (III) prednisone 0.75 mg/kg/d. After 6 months, azathioprine 2 to 2.5 mg/kg/d was added in groups I and II and placebo added in group III. The study showed that the beneficial effect of prednisone (0.75 mg/kg/d) is maintained for at least 18 months and is associated with a 36% increase in muscle mass. There was weight gain, growth retardation, and other side effects. Azathioprine did not have a beneficial effect. This study suggests that prednisone's beneficial effect is not due to immunosuppression.

Interlaboratory histopathologic assessment of Alzheimer neuropathology: different methodologies yield comparable diagnostic results

Three investigators have applied different histopathologic methods (modified Bielschowsky silver methods, Congo red-gallocyanin) to differentiate Alzheimer's disease (AD) (n = 7 subjects; four with very mild dementia and three with moderate to advanced dementia) neuropathology from brain changes associated with aging in three nondemented individuals who had been evaluated using a validated dementia severity staging instrument [Washington University Clinical Dementia Rating (CDR)] generally within a year of death. The presence of elevated numbers of neocortical (frontal and temporal) diffuse, mature, and total senile plaques (SP) was strongly correlated with the presence of clinical AD but did not equate with CDR dementia severity. Neocortical neurofibrillary tangle (NFT) density as well as hippocampal NFT and SP density in this small series did not differentiate statistically between AD and controls. NFT density appeared to correlate with CDR better than SP density. Quantitative histopathologic assessment of AD markers in only a few brain regions can accurately predict the presence of clinical AD, including the very mild form of the disease. This is especially true for SP in the neocortex.

Use of a modified shell vial technique to quantitate cytomegalovirus viremia in a population of solid-organ transplant recipients

A quantitative modification of the shell vial assay was used to investigate cytomegalovirus viremia in solid-organ transplant recipients. The level of viremia detected in 109 of 407 specimens ranged from 0.02 to 28 infectious foci per 100,000 leukocytes. By using a Poisson model, a technique was developed to determine 95% confidence limits for the measured levels of viremia. These confidence limits were used to determine the level of viremia that could be excluded by culturing a given number of cells. Longitudinal assessment of two transplant recipients revealed different patterns of viremia and demonstrated that significant disease sometimes occurred with low-level viremia. On the basis of the results of the studies, culture of at least 4 x 10(6) leukocytes is recommended for the sensitive detection of cytomegalovirus viremia.

Difficulties in diagnosing hypertension: implications and alternatives

OBJECTIVE

To estimate the magnitude of misclassification rates with commonly used algorithms for the detection of hypertensives and to suggest a sequential approach to screening.

DESIGN

A conventional statistical model was used with several different algorithms to determine the number and types of errors made in categorizing two different populations, a general population sample and a population with a high risk of hypertension.

METHODS

The calculations were made for single-visit screens, similar to those used in epidemiologic studies, for three-visit screens commonly used in clinical practice and clinical trials for cutoff points of 85, 95 and 105 mmHg. A sequential probability ratio screen was proposed and the error rates estimated.

RESULTS

Perhaps only one-third to two-thirds of people whose measured diastolic pressures exceed 95 mmHg actually have average pressures that high. The disparity between a single measured diastolic pressure and the mean of many pressure values also leads to errors in identifying individual subjects with mild hypertension. In a general population, single measurements of diastolic pressure exceed 95 mmHg in approximately equal numbers of normotensive, borderline and hypertensive subjects; moreover, one-third of those who are usually in the hypertensive range are not identified. All commonly used screening algorithms give too many false-positive and/or false-negative results. A sequential screening algorithm averaged 3.8 visits per subject and identified 95% of the hypertensives, with only 2.5% of those identified having usual diastolic pressures below 90 mmHg.

CONCLUSIONS

Population-based surveys like the National Health and Nutrition Examination Survey (NHANES) may markedly overestimate the true prevalence of hypertension. This overestimate is greatest for mild hypertension and could significantly affect the cost/benefit analyses of public health policy. Alternative screening methods, such as the sequential algorithm proposed, may have significant benefits in providing a correct classification.

Mild senile dementia of the Alzheimer type. 4. Evaluation of intervention

The design of trials of interventions intended to slow or arrest the progression of senile dementia of the Alzheimer type must be based on analysis of the natural history of the disease. Using a random coefficients statistical model, we analyzed the natural history of senile dementia of the Alzheimer type in carefully defined subjects with mild disease (n = 68) for periods of up to 10 years. Subject performance was assessed longitudinally on batteries of clinical and psychometric measures. The characteristics of these measures were analyzed relevant to their utility as outcome measures for long-term trials in patients with senile dementia of the Alzheimer type. Estimates were made of sample sizes required to show arrest, and 50% or 25% slowing in the progression of mild disease. We suggest that a clinically relevant global measure, such as the Sum of Boxes of the Clinical Dementia Rating scale, and a performance-based clinical scale or psychometric measure would be appropriate in a 12- or 24-month trial enrolling subjects with mild senile dementia of the Alzheimer type.

Laboratory facilities for investigating lipid disorders in the United Kingdom: results of the British Hyperlipidaemia Association survey

AIMS

To determine the availability of facilities for the investigation of hyperlipidaemia in the United Kingdom.

METHODS

A questionnaire was sent to all health districts in the United Kingdom.

RESULTS

The response rate was 81%. All laboratories used enzymatic techniques to measure serum triglyceride and cholesterol concentrations, although there were differences in standardisation procedures. Reference ranges for serum lipids were quoted by 58% of laboratories while 50% quoted "desirable limits". Almost half specified that fasting blood samples were required. High density lipoprotein cholesterol concentrations were estimated by 75% and apolipoproteins AI and B by 14% of laboratories; there were differences in specimen type and considerable diversity in procedures used for measurement.

CONCLUSIONS

Many laboratories were unaware of current recommendations for screening for hypercholesterolaemia in the community. The present survey indicated an urgent need for the introduction of better reference methods, standardisation, and quality assurance procedures before apolipoproteins become a routine part of coronary heart disease risk assessment.

Intrarater reliability of manual muscle test (Medical Research Council scale) grades in Duchenne's muscular dystrophy

The purpose of this study was to document the intrarater reliability of manual muscle test (MMT) grades in assessing muscle strength in patients with Duchenne's muscular dystrophy (DMD). Subjects were 102 boys, aged 5 to 15 years, who were participating in a double-blind, multicenter trial to document the effects of prednisone on muscle strength in patients with DMD. Four physical therapists participated in the study. Two identical (duplicate) evaluations were performed within 5 days of each other by the same examiner initially and after 6 and 12 months of treatment. A total of 18 muscle groups were tested on each patient, 16 of them bilaterally, using a modification of the Medical Research Council scale. Reliability of muscle strength grades obtained for individual muscle groups and of individual muscle strength grades was analyzed using Cohen's weighted Kappa. The reliability of grades for individual muscle groups ranged from .65 to .93, with the proximal muscles having the higher reliability values. The reliability of individual muscle strength grades ranged from .80 to .99, with those in the gravity-eliminated range scoring the highest. We conclude the MMT grades are reliable for assessing muscle strength in boys with DMD when consecutive evaluations are performed by the same physical therapist.

A comparison of two computer-administered versions of the NIMH Diagnostic Interview Schedule

This study compared three versions of the NIMH Diagnostic Interview Schedule (DIS): "traditional" interviewer-administered DIS; computer-administered DIS (subject interacting alone with computer); computer-prompted DIS (interviewer using computer program as a guide). Kappas for 20 diagnoses ranged from .15 to .94, and averages for the three method pairs ranged from .57 to .64, which are comparable to other DIS reliability studies. Agreement between pairs of methods were comparable. Subjects' attitudes toward the computer interview were positive. While they felt they could better describe their feelings and ideas to a human, they found the computer contact less embarrassing. Overall, subjects had no preference for one method over another. Measures of social desirability and deviant response biases were correlated with diagnostic results. Reading ability did not affect subject's ability to respond to the DIS, although subjects with lower reading levels preferred the computer interview more.

Long-term benefit from prednisone therapy in Duchenne muscular dystrophy

Two successive, 6-month, randomized, double-blind, controlled trials of prednisone showed that 0.75 mg/kg/d was the optimal dose to improve strength in boys with Duchenne muscular dystrophy (DMD). We attempted to maintain 93 boys on that dose for an additional 2 years. During the 3 years of observation, the decline in average muscle strength scores of all boys taking prednisone was 0.072 units/yr, as compared with an expected decline of 0.341 units/yr from natural history controls. The occurrence of side effects in some boys prevented maintenance of the full dose, which may have lessened the response. At the time of last visit, dosages ranged from 0.15 mg/kg to 0.75 mg/kg. In addition to maintaining their strength, several of the boys actually improved their performance in lifting kilogram weights and in some timed function tests. Treatment of DMD with prednisone significantly slows the progression of weakness and loss of function for at least 3 years.

The newborn with hydrops and sacrococcygeal teratoma

The combination of fetal hydrops and sacrococcygeal teratoma (SCT), is considered to be lethal. We report two such babies who survived. Case 1 exhibited oliguric acute renal failure (ARF) immediately after birth, and severe respiratory insufficiency despite maximal ventilatory support and vasodilator infusions. Tumor resection on the 2nd day of life resulted in an immediate improvement in pulmonary function as reflected by the ratio of arterial to alveolar oxygen. Renal function returned in a pattern typical of recovery from acute tubular necrosis. Case 2, less desperately ill, developed nonoliguric ARF, in part due to deliberate fluid restriction during the 7 days that followed birth and preceded surgery. This resolved following liberalization of fluid intake that occurred at the time of tumor removal on the 7th day of life. The baby also had respiratory insufficiency that improved after surgery. Respiratory insufficiency may be a severe and life-threatening complication of SCT and hydrops fetalis. Pulmonary function may improve dramatically by removal of the tumor. Why this improvement occurs is unclear. Improvement of respiratory function may result from the elimination of excess tumor blood volume with an improvement of the ventilation-perfusion ratio. Alternatively, the tumor may be a source of vasoactive substances or extremely desaturated blood that leads to pulmonary hypertension and right-to-left shunting. Uncertainties in postnatal fluid shifts and exaggerated fluid compartment volumes demand close attention to details of renal function.

Representation of sensory information in the cricket cercal sensory system. I. Response properties of the primary interneurons

1. Six different types of primary wind-sensitive interneurons in the cricket cercal sensory system were tested for their sensitivity to the orientation and peak velocity of unidirectional airflow stimuli. 2. The cells could be grouped into two distinct classes on the basis of their thresholds and static sensitivities to airflow velocity. 3. Four interneurons (the right and left 10-2 cells and the right and left 10-3 cells) made up one of the two distinct velocity sensitivity classes. The mean firing frequencies of these interneurons were proportional to the logarithm of peak stimulus velocity over the range from 0.02 to 2.0 cm/s. 4. The other two interneurons studied (left and right 9-3) had a higher air-current velocity threshold, near the saturation level of the 10-2 and 10-3 interneurons. The slope of the velocity sensitivity curve for the 9-3 interneurons was slightly greater than that for the 10-2 and 10-3 interneurons, extending the sensitivity range of the system as a whole to at least 100 cm/s. 5. All of the interneurons had broad, symmetrical, single-lobed directional sensitivity tuning curves that could be accurately represented as truncated sine waves with 360 degree period. 6. The four low-threshold interneurons (i.e., left and right 10-2 and 10-3) had peak directional sensitivities that were evenly spaced around the horizontal plane, and their overlapping tuning curves covered all possible air-current stimulus orientations. The variance in the cells' responses to identical repeated stimuli varied between approximately 10% at the optimal stimulus orientations and approximately 30% at the zero-crossing orientations. 7. The two higher threshold interneurons (left and right 9-3) had broader directional sensitivity curves and wider spacing, resulting in reduced overlap with respect to the low-threshold class.

Age-related sensitivity to kainate neurotoxicity

Domoate, a glutamate analog, is believed to be responsible for a seafood poisoning incident that caused acute neurological disturbances and chronic memory impairment in some victims, with the incidence of mortality and neuropsychological morbidity being highest among the aged. Domoate expresses neurotoxic (excitotoxic) activity in vitro by an action at the kainate subtype of glutamate receptor, and when administered to adult rats, it mimics kainate in causing status epilepticus and a severe seizure-brain damage syndrome. Because domoate is exceedingly expensive, we explored the feasibility of using kainate to study the age-linked features of domoate neurotoxicity. We administered kainate subcutaneously in various doses to young (5-6 months), middle-aged (12-13 months), and old (22-25 months) rats and found the middle-aged and old rats significantly more sensitive than young rats to the neurotoxic actions of kainate. Low doses of kainate, which were nontoxic to young rats, frequently triggered status epilepticus, associated brain damage, and precipitous death in old rats. Middle-aged rats were more sensitive than young rats, but less sensitive than old rats to kainate neurotoxicity. These results suggest that the kainate-treated rat may be a useful model for studying mechanisms underlying age-related aspects of the human domoate neurotoxic syndrome.

Representation of sensory information in the cricket cercal sensory system. II. Information theoretic calculation of system accuracy and optimal tuning-curve widths of four primary interneurons

1. Principles of information theory were used to calculate the limit of accuracy achievable by a subset of the wind-sensitive primary interneurons in the cricket cercal sensory system. For these calculations, an ensemble of four neurons was treated as an information channel, which encoded the direction of air-current stimuli for a defined range of air-current velocities. The specific information theoretic parameter that was calculated was the "transin-formation" or "mutual information" between the air-current directions and the neuronal spike trains, which were characterized in the preceding report. Under the assumptions used for these calculations, the ensemble of four interneurons was demonstrated to be capable of encoding between 4.2 and 3.5 bits of information about wind direction. This corresponds to an average directional accuracy of 4.7 and 7.7 degrees, respectively. 2. The same principles were applied to estimate the extent to which any variation in the width of the tuning curves would affect the transfer of information. As the widths of simulated tuning curves were varied, the mean ensemble accuracy showed a clear global maximum. This maximum corresponds to tuning curves widths of 110 degrees wide (at half maximum), which was remarkably close to the actual mean widths of the tuning curves observed in the cricket of 130 degrees. 3. The effect of varying the parametric "spacing" of the tuning curves within the stimulus range was also examined through a series of simulations. The configuration allowing the maximum information transfer corresponded to equal spacing of the tuning curves around the stimulus range (i.e., 90 degrees separation of peak sensitivity points). This theoretically optimum spacing corresponded exactly to the values observed in the experiments presented in the preceding report. 4. These simulations also showed that the degradation in the accuracy resulting from a shift in the tuning-curve spacing would depend on the plasticity of the higher order decoder of directional information. If there were no plasticity in the interneurons making up the higher order decoder, then the accuracy would be degraded by 50% for a mean tuning-curve shift of only 3.5 degrees. However, if the higher order decoding network were capable of being reoptimized to any arbitrary shift in tuning curves, the degradation in attainable accuracy would be much less severe as shifts of up to 10 degrees would result in virtually no degradation in the accuracy. 5. From these results, two general conclusions can be drawn about the coding of specific stimulus parameters by arrays of sensory cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Medications and multiple falls in elderly people: the St Louis OASIS study

The purpose of this study was to identify associations between the use of commonly taken medications and groups of medications and the risk of falls in elderly people living in the community. A stratified random sample of 1358 persons aged 65 years and over was selected from the 15,000 members of an educational organization for functionally independent, community-dwelling elderly people in St Louis, Missouri. Twenty-seven per cent of subjects reported at least one fall in the past year and 8% reported two or more falls. After adjusting for potential confounders (including age, sex, relevant medical conditions, health status, cognitive impairment, use of alcohol, depression and use of other medications), the following medications were found to be important risk factors for multiple falls: diazepam [odds ratio (OR): 3.7, 95% confidence interval (CI): 1.5-9.3], diltiazem (OR: 1.8, 95% CI: 0.8-4.1), diuretics (OR: 1.8, 95% CI: 1.2-2.8) and laxatives (OR: 2.1, 95% CI: 1.0-4.5). We conclude that caution is needed before prescribing diuretics and psychotropics, especially diazepam, for elderly people. The safety of diltiazem in this age group should be assessed further.

A controlled clinical trial of local anesthesia for lumbar punctures in newborns

To evaluate the efficacy of subcutaneous administration of lidocaine for reducing physiologic instability in acutely ill newborns during clinically required procedures, 81 neonates who required lumbar punctures within the first month of life were stratified by birth weight and respiratory support and randomly assigned to an experimental or a control group. The experimental group received an injection of 0.1 mL/kg of 1% lidocaine prior to the lumbar puncture. The control group received a nonanesthetized lumbar puncture without placebo. Changes in heart rate, respiratory rate, transcutaneous oxygen and carbon dioxide tensions, and heart rate variability from baseline, preparatory (positioning/handling), lumbar puncture, and recovery periods were measured. The administration of lidocaine did not minimize physiologic instability in response to the lumbar puncture nor was it associated with any detectable adverse effects other than prolonging the duration of the lumbar puncture. Although significant physiologic changes were observed in response to preparatory procedures, few additional changes beyond those occurred in response to lumbar punctures in either the experimental or control group. It is concluded that local anesthesia failed to influence manifestations of physiologic instability during neonatal lumbar punctures and that preparatory procedures were more destabilizing than either the administration of lidocaine or the lumbar puncture itself. The results suggest that the management of newborns requires emphasis on minimizing the destabilizing effects of required and frequent handling procedures.