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Biomedical subjects

J S Katz

Publications and source records attributed to J S Katz.

At least 19 recordsLinked to original sources
PubMed2005

Bilateral isolated phrenic neuropathy causing painless bilateral diaphragmatic paralysis.

The authors report four patients with a syndrome of painless bilateral isolated phrenic neuropathy. Electrophysiologic testing demonstrated active denervation restricted to the diaphragm. Long-term recovery was poor. The authors conclude that bilateral isolated phrenic neuropathy is a cause of painless diaphragmatic paralysis distinguishable from immune brachial plexus neuropathy and other neuromuscular disorders with similar clinical presentation.

Adult↗
PubMed2005

Myopathy with skeletal asymmetry and hemidiaphragm elevation is caused by myotubularin mutations.

The authors report two families with a myopathy phenotype affecting only women, marked by asymmetric weakness, skeletal asymmetry, and an elevated hemidiaphragm. One family had a mutation in a stop codon in exon 9 of the myotubularin gene, and the other had a splice site mutation in exon 13. Both families had manifesting and nonmanifesting carriers. Skewed X-inactivation appeared to explain the clinical manifestations in only one of the two families.

Adult↗
PubMed2002

Axonal multifocal motor neuropathy without conduction block or other features of demyelination.

BACKGROUND: Conduction block is considered an essential finding for the distinction between motor neuropathies and lower motor neuron disorders. Only a small number of reports describe patients with multifocal motor neuropathies who lack overt conduction block, although in these cases other features of demyelination still suggest the presence of a demyelinating disorder. In contrast, a purely axonal multifocal motor neuropathy has not been described. METHODS: This report describes nine patients with slowly or nonprogressive multifocal motor neuropathies who had purely axonal electrodiagnostic features. RESULTS: GM1 antibodies titers were normal in all nine cases. Six patients were treated with either prednisone or IV immunoglobulin and three showed convincing improvement. CONCLUSIONS: These findings suggest an immune-mediated motor neuropathy with axonal electrophysiologic features that appears to be distinct from both multifocal motor neuropathy and established motor neuron disorders.

Adolescent↗
PubMed2001

Clinical spectrum of chronic acquired demyelinating polyneuropathies.

A number of presentations of chronic demyelinating polyneuropathy have been identified, each distinguished by its phenotypic pattern. In addition to classic chronic inflammatory demyelinating polyneuropathy (CIDP), which is characterized clinically by symmetric proximal and distal weakness and sensory loss, several regional variants can be recognized: multifocal motor neuropathy (MMN: asymmetric and pure motor), multifocal acquired demyelinating sensory and motor (MADSAM) neuropathy (asymmetric, sensory, and motor), and distal acquired demyelinating symmetric (DADS) neuropathy (symmetric, distal, sensory, and motor). There are also temporal, pathological, and disease-associated variants. This review describes a clinical scheme for approaching the chronic acquired demyelinating polyneuropathies that leads to a rational use of supportive laboratory studies and treatment options. In addition, we propose new diagnostic criteria for CIDP that more accurately reflect current clinical practice.

Humans↗
PubMed2001

Cervicobrachial involvement in diabetic radiculoplexopathy.

Diabetic radiculoplexopathy is commonly viewed as a condition affecting the lower extremities. However, other regions may also be affected and the presence of upper extremity involvement has rarely been emphasized. Our goal was to illustrate the clinical features of arm involvement in this condition. Of 60 patients with diabetic lumbosacral radiculoplexopathy, we identified 9 who also had upper extremity involvement. The study included 8 men and 1 woman, ranging in age from 36 to 71 years. Upper limb involvement developed simultaneously with the onset of lower limb disorder in 1 patient, preceded it by 2 months in another patient, and occurred between 3 weeks and 15 months later in the remaining 7. In 5 cases, arm involvement developed after symptoms in the legs began to improve. The upper extremity weakness affected the hands and forearms most severely. It was unilateral in 5 patients and bilateral but asymmetric in 4. Pain was often present, but it was not a prominent feature. In most patients, neurologic deficits in the arms improved spontaneously after 2-9 months. We conclude that diabetic radiculoplexopathy may involve the cervical region before, after, or simultaneously with the lumbosacral syndrome. The upper limb process is similar to that in the legs, with subacutely progressive weakness and pain followed by spontaneous recovery.

Adult↗
PubMed2001

Malnutrition-induced myopathy following Roux-en-Y gastric bypass.

A 42-year-old man developed a myopathy in the setting of malnutrition following Roux-en-Y gastric bypass for the treatment of morbid obesity. No specific vitamin or electrolyte deficiency was identified. Muscle biopsy revealed type II fiber atrophy. He recovered after the initiation of continuous enteral feeding. We suggest that malnutrition was the underlying cause of his myopathy.

Adult↗
PubMed2001

Physical and occupational therapy undergraduates' stereotypes of one another.

Literature suggests that increased interaction between physical therapy and occupational therapy students may improve their understanding of each other's profession. This cross-sectional study examined positive and negative stereotypes in an educational setting in which physical and occupational therapy students take over 25% of their curricular courses together. The aim of the study was to assess whether interaction between these students in and out of the classroom positively affected their views of each other, as compared with physical and occupational therapy students in previous studies who did not take classes together. Senior students, 25 physical therapy and 28 occupational therapy, completed two copies of the Health Team Stereotype Scale questionnaire exploring attitudes concerning their own chosen profession and the other participants' profession. They also completed an extracurricular activities survey to indicate how much they participated in activities outside of the classroom with students from the other profession. On the stereotype scale, physical therapy students' self-assessment compared with their assessment of occupational therapy students yielded 28 significantly (p<.05) different adjective pairs; occupational therapy students' self-assessment compared with their assessment of physical therapy students yielded 26 significantly (p<.05) different adjective pairs. The students rarely or never participated in extracurricular activities with each other. When comparing present results with those of previous studies, present subjects selected significantly fewer negative adjective pairs to describe the other profession. The results indicate a more positive view of each other's profession than in the previous studies. The interdisciplinary education model examined in our institution may have fostered positive attitudes among students in these programs.

Adult↗
PubMed2000

Distal acquired demyelinating symmetric neuropathy.

OBJECTIVE: To characterize an acquired, symmetric, demyelinating neuropathic variant with distal sensory or sensorimotor features. BACKGROUND: Classic chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) patients have prominent proximal and distal weakness. However, chronic demyelinating neuropathies may present with different phenotypes. An approach that distinguishes these disorders primarily according to the pattern of weakness may be useful to the clinician. METHODS: A total of 53 patients with acquired symmetric demyelinating polyneuropathies were classified primarily according to the pattern of the neuropathy and secondarily according to the presence and type of monoclonal protein (M-protein) in this retrospective review. The authors distinguished between patients with distal sensory or sensorimotor involvement, designated as distal acquired demyelinating symmetric (DADS) neuropathy, from those with proximal and distal weakness, who were designated as CIDP. RESULTS: M-proteins were present in 22% of patients with CIDP. There were no features that distinguished clearly between CIDP patients with or without an M-protein, and nearly all of these patients responded to immunomodulating therapy. In contrast, nearly two-thirds of the patients with DADS neuropathy had immunoglobulin M (IgM) kappa monoclonal gammopathies, and this specific combination predicted a poor response to immunomodulating therapy. Antimyelin-associated glycoprotein (anti-MAG) antibodies were present in 67% of these patients. CONCLUSION: Distinguishing acquired demyelinating neuropathies by phenotype can often predict the presence of IgM kappa M-proteins, anti-MAG antibodies, and responses to immunomodulating therapy.

Adult↗
PubMed2000

Stimulus repetition effects on texture-based visual search by pigeons.

Four experiments investigated the effects of within-session stimulus repetition on texture discrimination. Six pigeons (Columba livia) searched for a contrasting target region (color or shape) randomly embedded within a larger distractor region for food reinforcement. Experiment 1 found that repeating features of the distractors, but not those of the target, across trials increased the accuracy of target localization relative to baseline. Experiment 2 found that subsequently switching the identity of a repeated distractor feature to the target decreased accuracy. Experiment 3 found that the effects of repeating a distractor feature influenced search performance for at least 60 trials after this learning. Experiment 4 found that differential stimulus-outcome relations can produce control by repeated target features. The results are discussed in terms of the factors and strategies involved in the control of avian visual search behavior.

Animals↗
PubMed1999

Brachial amyotrophic diplegia: a slowly progressive motor neuron disorder.

OBJECTIVE: To describe a sporadic motor neuron disorder that remains largely restricted to the upper limbs over time. BACKGROUND: Progressive amyotrophy that is isolated to the upper limbs in an adult often suggests ALS. The fact that weakness can remain largely confined to the arms for long periods of time in individuals presenting with this phenotype has not been emphasized. METHODS: We reviewed the records of patients who had a neurogenic "man-in-the-barrel" phenotype documented by examination at least 18 months after onset. These patients had severe bilateral upper-extremity neurogenic atrophy that spared lower-extremity, respiratory, and bulbar musculature. RESULTS: Nine of 10 patients meeting these criteria had a purely lower motor neuron disorder. During follow-up periods ranging from 3 to 11 years from onset, only three patients developed lower-extremity weakness, and none developed respiratory or bulbar dysfunction or lost the ability to ambulate. CONCLUSION: Patients presenting with severe weakness that is fully isolated to the upper limbs, without pyramidal signs, may have a relatively stable variant of motor neuron disease.

Adult↗
PubMed1999

Outcome in severe pediatric Guillain-Barré syndrome after immunotherapy or supportive care.

We reviewed duration of illness in 26 children with severe pediatric Guillain-Barré syndrome (GBS) during two contiguous 8-year periods that represent a "non-treatment era" of supportive care alone or a "treatment era" of supportive care plus either plasma exchange or intravenous immunoglobulin intervention. Our findings of similar recovery times in each treatment group suggest that immunotherapy in severe pediatric GBS may be less effective than in adult GBS, or effective only when given to certain patients very early in the course of the illness.

Adolescent↗
PubMed1999

The exercise test in Andersen syndrome.

BACKGROUND: Andersen syndrome is a rare form of periodic paralysis (PP) associated with dysmorphic features and potentially fatal cardiac dysrhythmias. To date, no electrodiagnostic abnormalities have been reported that can be used to confirm the presence of PP in this condition. OBJECTIVES: To determine if the exercise test could be used to confirm the diagnosis of PP in Andersen syndrome. To evaluate the exercise test as a means to assess neuromuscular status during treatment. METHODS: We performed the exercise test on 2 patients with Andersen syndrome. In 1 patient, we used a modified version of the test to document responsiveness to treatment with tocainide. RESULTS: Studies in both patients demonstrated a progressive decline in the compound muscle action potential amplitude after exercise that was characteristic of the phenomenon seen in other forms of PP. In 1 patient, improvement in interattack strength and a reduction in the number of attacks of weakness correlated with improvement in the test results. CONCLUSIONS: Our cases demonstrate that the exercise test can confirm the diagnosis of PP in Andersen syndrome. A modified version of exercise testing may also be considered as an objective method for documenting treatment responses in PP.

Abnormalities, Multiple↗
PubMed1999

Chronic cryptogenic sensory polyneuropathy: clinical and laboratory characteristics.

BACKGROUND: Chronic sensory-predominant polyneuropathy (PN) is a common clinical problem confronting neurologists. Even with modern diagnostic approaches, many of these PNs remain unclassified. OBJECTIVE: To better define the clinical and laboratory characteristics of a large group of patients with cryptogenic sensory polyneuropathy (CSPN) evaluated in 2 university-based neuromuscular clinics. DESIGN: Medical record review of patients evaluated for PN during a 2-year period. We defined CSPN on the basis of pain, numbness, and tingling in the distal extremities without symptoms of weakness. Sensory symptoms and signs had to evolve for at least 3 months in a roughly symmetrical pattern. Identifiable causes of PN were excluded by history, physical examination findings, and results of laboratory studies. We analyzed clinical and laboratory data from patients with CSPN and compared findings in patients with and without pain. RESULTS: Of 402 patients with PN, 93 (23.1%) had CSPN and stable to slowly progressive PN syndrome. These patients presented with a mean age of 63.2 years and a mean duration of symptoms of 62.9 months. Symptoms almost always started in the feet and included distal numbness or tingling in 86% of patients and pain in 72% of patients. Despite the absence of motor symptoms at presentation, results of motor nerve conduction studies were abnormal in 60% of patients, and electromyographic evidence of denervation was observed in 70% of patients. Results of laboratory studies were consistent with axonal degeneration. Patients with and without pain were similar regarding physical findings and laboratory test abnormalities. Only a few patients (<5%) had no evidence of large-fiber dysfunction on physical examination or electrophysiologic studies. All 66 patients who had follow-up examinations (mean, 12.5 months) remained ambulatory. CONCLUSIONS: Cryptogenic sensory polyneuropathy is a common, slowly progressive neuropathy that begins in late adulthood and causes limited motor impairment. Isolated small-fiber involvement is uncommon in this group of patients. Management should focus on rational pharmacotherapy of neuropathic pain combined with reassurance of CSPN's benign clinical course.

Adult↗
PubMed1999

Multisystem neuronal involvement and sicca complex: broadening the spectrum of complications.

We report two patients with multisystem neuronal involvement associated with sicca complex. One had a lower motor neuron syndrome combined with a flaccid bladder and rectum. The second patient had unilateral hearing loss, sensory neuronopathy, Adie's pupils, upper motor neuron signs, and autopsy-proven anterior horn cell degeneration. Our cases lead us to propose that the spectrum of neuronal involvement occurring with sicca syndrome may be wider than is currently appreciated.

Adie Syndrome↗
PubMed1999

Multifocal acquired demyelinating sensory and motor neuropathy: the Lewis-Sumner syndrome.

We report 11 patients with multifocal acquired demyelinating sensory and motor (MADSAM) neuropathy, defined clinically by a multifocal pattern of motor and sensory loss, with nerve conduction studies showing conduction block and other features of demyelination. The clinical, laboratory, and histological features of these patients were contrasted with those of 16 patients with multifocal motor neuropathy (MMN). Eighty-two percent of MADSAM neuropathy patients had elevated protein concentrations in the cerebrospinal fluid, compared with 9% of the MMN patients (P < 0.001). No MADSAM neuropathy patient had elevated anti-GM1 antibody titers, compared with 56% of MMN patients (P < 0.01). In contrast to the subtle abnormalities described for MMN, MADSAM neuropathy patients had prominent demyelination on sensory nerve biopsies. Response to intravenous immunoglobulin treatment was similar in both groups (P = 1.0). Multifocal motor neuropathy patients typically do not respond to prednisone, but 3 of 6 MADSAM neuropathy patients improved with prednisone. MADSAM neuropathy more closely resembles chronic inflammatory demyelinating polyneuropathy and probably represents an asymmetrical variant. Given their different clinical patterns and responses to treatment, it is important to distinguish between MADSAM neuropathy and MMN.

Adult↗
PubMed1999

Dynamic object perception by pigeons.

Three experiments examined pigeon discrimination of computer-generated three-dimensional (3-D) projections of cube and pyramid objects. Four pigeons were tested using a go/no-go procedure involving static and dynamically rotating presentations of these stimuli. Transfer tests with different types of rotational and featural transformations suggested the pigeons may have used a 3-D representation of the objects as their primary means of performing the discrimination. The comparative implications for object and motion perception in animals are considered.

Animals↗
PubMed1999

Power laws and athletic performance.

In a previous study, we showed that the 1992 men's world record running times in the 100 m to 200 km could be represented accurately by the equation T = cDn, where T is the calculated record time for distance D, and c and n are positive constants. Here, we extend that to cover the years 1925-65 at 10-year intervals and 1970-95 in 5-year intervals for distances of 100 m to 10 km. Values of n for all years lie along a straight line with a small negative slope. A regression analysis yields an equation for values of n covering the period 1925-95. Values of c from 1925 to 1995 were fitted by a quadratic equation. These two equations define a surface in three-dimensional space (log(T), log(D), data) for all men's world record runs over the 70-year period for distances of 100 m to 10 km. We also demonstrated previously that event times, t, do not scatter randomly with respect to the values of T but form a consistent pattern about the straight lines in log(T) versus log(D) plots. In this study, we show that the pattern of (t-T)/t as a function of date has remained constant for the past 70 years.

Adult↗