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Biomedical subjects

R B Lipton

Publications and source records attributed to R B Lipton.

At least 217 records · Page 12Linked to original sources
PubMed1991

Commentary: the affected sib-pair method in the context of an epidemiologic study design.

The purpose of this commentary is to provide a framework for using the well-known sib-pair methodology in the context of epidemiologic study designs. Using examples from the Pittsburgh family studies of insulin-dependent diabetes mellitus, we illustrate that the sib-pair method can be used in family-based epidemiologic studies. In a cohort study, unaffected relatives of probands ascertained from well-defined populations are followed for disease development. Disease risks are then stratified according to the number of alleles at one or more loci (0, 1, 2) that are identical by descent (ibd) with the proband. In the absence of linkage between the marker locus and the disease locus, disease risks are expected to be identical in the three groups. Measures of relative risk can be computed (with share-0 as baseline group). In a case-control study, relatives of probands that become affected (cases) are compared to a sample of relatives of probands that stay unaffected (controls) with respect to the number of alleles ibd with the proband. Measures of odds ratio can be computed (with share-0 as baseline group). In both cohort and case-control approaches, covariates including other genetic markers and environmental exposures can be evaluated in relation to disease risk and also for evidence of interaction with the specific marker of interest using stratified and multivariate analyses. Family-based epidemiologic studies allow investigators to study, in a single design, the role of environmental factors and specific gene loci in the etiology of diseases.

Alleles↗
PubMed1991

Bilateral burning foot pain: monitoring of pain, sensation, and autonomic function during successful treatment with sympathetic blockade.

We describe a patient with burning pain in both feet associated with local autonomic disturbances following bilateral traumatic sciatic mononeuropathies. The diagnosis of a sympathetically maintained pain was confirmed through a prompt response to sympathetic blockade. Although a mild alcohol-nutritional neuropathy was found, the clinical findings strongly suggested a diagnosis of bilateral causalgia. Clinical evaluation and quantitative sensory testing were performed prior to and after successive unilateral lumbar sympathetic nerve blocks. After unilateral blockade, bilateral improvement was recorded in measures of pain, sudomotor function, and foot temperature. Other measures of autonomic function showed variable responses to sympathetic blockade. Quantitative sensory testing revealed a dramatic alteration in the contralateral limb's thermal sense following unilateral block. This case underscores the potential for bilateral causalgia and provides additional evidence for a central mechanism operating in this disorder. The relationship between bilateral causalgia and the "burning feet syndrome" in alcoholic neuropathy is discussed.

Adult↗
PubMed1991

Criteria for the diagnosis of migraine in clinical practice.

Criteria for the diagnosis of migraine have evolved from generalized descriptions to specific rules designed to ensure the selection of homogenous groups of patients for research studies. For clinical practice, the former are insufficiently specific and the latter are too complex. For care of headache patients by primary care physicians, we propose that the diagnosis of migraine without aura (common migraine) is warranted if any two of the following symptoms are present: unilateral site, throbbing quality, nausea, photophobia or phonophobia. These criteria are derived from a study comparing the features of 100 patients with migraine without aura and 100 patients with chronic daily headache. The proposed criteria for the diagnosis of migraine without aura were highly sensitive and adequately specific in discriminating groups. These simple criteria should facilitate the diagnosis of migraine by primary care physicians.

Cluster Headache↗
PubMed1991

Myocardial ischemia related to ergot alkaloids: a case report and literature review.

Ergotamine tartrate and methysergide are widely used headache treatments with important vasoconstrictive properties. We report a 31-year-old man with cluster headaches who developed severe, prolonged myocardial ischemia following combination therapy with ergotamine tartrate and methysergide. We reviewed the cardiovascular complications of each agent alone and in combination. Given the pharmacologic similarity of these agents, we propose that they may have additive or synergistic cardiac toxicity, at least in vulnerable individuals. We recommend caution when these agents are used together.

Adolescent↗
PubMed1991

Headache in HIV-1-related disorders.

To define the causes, clinical significance and characteristics of headaches in HIV-1-related disorders, we studied 49 consecutive HIV-1 infected patients who presented with headache. Work-up included CT scans, cerebrospinal fluid examinations (in the absence of a contraindication) and serologic studies. Overall, 40 of 49 patients (82 percent) had an identifiable serious cause of headache. Cryptococcal meningitis (39 percent) and CNS toxoplasmosis (16 percent) were the leading headache etiologies. Serious causes were more likely in patients diagnosed with AIDS prior to presentation but also occurred in most patients in early stages of infection. Based on this study, we suggest that patients with HIV-1 infection must be managed with a high index of suspicion when they present with new onset headaches.

Adult↗
PubMed1991

Large and small fibre type sensory dysfunction in patients with cancer.

Quantitative sensory testing was used to assess the prevalence of sensory dysfunction in patients with cancer, carefully screened for other risk factors for neuropathy. Large fibre type sensory function was evaluated using vibration threshold (VT) determinations while small fibre type sensory function was assessed by thermal threshold (TT) determinations. Mean VT and TT were significantly elevated in the toes but not the fingers of cancer patients. VT elevations in the toes occurred in 31% of cancer patients and in 6% of control subjects. TT elevations in the toes occurred in 43% of cancer patients and 4% of control subjects. Based on these findings it is concluded that large and small fibre type sensory dysfunction is much more common in carefully screened cancer patients than in control subjects. This sensory dysfunction is most likely to represent a neuropathy related directly or indirectly associated with cancer.

Adult↗
PubMed1991

The interface between epidemiology and molecular biology in the search for the causes of insulin-dependent diabetes mellitus.

Epidemiological techniques have been utilized to accumulate new knowledge about insulin-dependent diabetes mellitus (IDDM), leading to important insights into the disease process and the alteration of these mechanisms when viewed from a geographic or population base. More recently, highly powerful and sophisticated techniques of molecular biology have been added to the research arsenal, extending the knowledge on the genetic basis for IDDM and the probable environmental factors involved. The development and growth of the new discipline of epidemiological genetics promises exciting new developments for the future of our field as well as that of other major medical problems having a genetic base, but significantly influenced by environmental factors. This review stresses the importance of carefully validated diabetes registries in the study of the epidemiology of IDDM. The Children's Hospital of Pittsburgh and the University of Pittsburgh Medical Center have spear-headed the development of such registries, worldwide. The first international meeting on IDDM epidemiology in 1983 gave as a result, i.e., the finding that there were truly remarkable differences in the risk of developing IDDM depending upon the geographic location of the individual. Later collaborative work via the Diabetes Epidemiology Research International (DERI) group has confirmed the previous finding and added the description of secular trends and epidemics of IDDM. It is remarkable that the incidence rate of IDDM in children below 15 years vary from 1/100,000/yr in the Orient to 35/100,000/yr in Finland. The epidemiological approach in the study of IDDM has also stimulated research into the various facets of the etiology of the disease, genetic factors, autoimmune mechanisms and environmental factors.(ABSTRACT TRUNCATED AT 250 WORDS)

Autoantibodies↗
PubMed1991

The evaluation of patients with human immunodeficiency virus-related disorders and brain mass lesions.

In patients at risk for acquired immunodeficiency syndrome who present with a mass lesion, a dilemma arises as to whether to treat empirically for toxoplasmosis or perform a brain biopsy. We present data that further define the indications for performing brain biopsy vs empiric treatment. We reviewed charts on 59 patients with acquired immunodeficiency syndrome--related disorders and cerebral mass lesions. Thirty-two patients met diagnostic criteria for toxoplasmosis. Bayesian analysis demonstrated that the prior probability of toxoplasmosis was increased by the presence of contrast enhancement on computed tomographic scans (0.68) and toxoplasmosis titers greater than 1:64 (0.81). Features associated with decreasing probabilities of toxoplasmosis included the absence of contrast enhancement on computed tomographic scans (0.29) and toxoplasmosis titers less than or equal to 1:64 (0.14). Ten percent of patients had complications of brain biopsy. Treatment with pyrimethamine and sulfadiazine produced complications in 29% and serious complications in 8% of treated patients. These data favor empiric therapy for patients with typical features of toxoplasmosis and brain biopsy for defined subsets of patients with atypical features.

Bayes Theorem↗
PubMed1990

Arterial stenosis in migraine: spasm or arteriopathy?

Segmental arterial narrowing has rarely been angiographically demonstrated in patients with migraine. One new case is reported and 12 previous cases are reviewed. Though often referred to as vasospasm, arteriographic stenosis may result from edema of the vessel wall, arterial dissection, the effects of puerperium or arteritis. A biphasic course of spasm, similar to the pattern noted with subarachnoid hemorrhage, has been recorded in some migraineurs. The current neurogenic and biochemical concepts of "spasm" developed for subarachnoid hemorrhage are reviewed. Arterial narrowing may be important in several phenomena associated with migraine. It may account for migrainous cerebral infarction or hemorrhage. Vasoconstriction has also been invoked to explain the aura and other features of migraine. But the site of stenosis does not always correlate with the headache or focal neurologic features in location or timing. The angiographic changes are probably an epiphenomena rather than a primary mechanism of migraine. These changes may result from altered sympathetic neuronal activity; factors supporting that concept are reviewed.

Adolescent↗
PubMed1990

Nuchal features of cluster headache.

Nuchal symptoms were found in the majority of 100 consecutive patients with cluster headache. In 10%, pain was experienced in the neck with the initial typical orbitotemporal pain; in 37%, pain radiated from the orbit or temple to the ipsilateral side of the neck. Sometimes, neck pain heralded the onset of the attack by a few minutes. During an attack, neck stiffness was reported in 40% and tenderness in 29%. Movement of the neck, especially flexion, precipitated cluster headache in 9% of patients. This was particularly true of patients with chronic cluster headache. Neck movement aggravated the headache in 16 of 100 patients and an equal number reported amelioration of pain by neck movement, especially extension. The nuchal features did not necessarily accompany every attack and were usually overshadowed by the severity of the typical headache. Nevertheless, symptoms referable to the neck occur more commonly than is generally appreciated.

Adult↗
PubMed1990

Neurosyphilis in AIDS patients: initial CSF VDRL may be negative.

We report 2 HIV-seropositive patients with neurosyphilis whose initial CSF VDRL tests were negative. The CSF VDRL became positive after 12 days of IV penicillin treatment for syphilitic meningitis in the 1st patient. The 2nd patient developed syphilitic polyradiculopathy and a positive CSF VDRL 3 months after treatment with IV penicillin. Serial CSF VDRL determinations may be required in AIDS patients when a diagnosis of neurosyphilis is suspected.

Adult↗
PubMed1990

Apoplectic headache and oculomotor nerve palsy: an unusual presentation of multiple sclerosis.

A patient with a history of facial myokymia presented with apoplectic headache and a 3rd nerve palsy. Initial CT, lumbar puncture, and cerebral angiogram were unremarkable, but subsequent CSF examination revealed oligoclonal bands. MRI displayed over 30 white matter lesions. This case demonstrates that multiple sclerosis may present with severe headache and a 3rd nerve palsy, simulating the clinical picture of a posterior communicating artery aneurysm.

Adult↗
PubMed1990

Facial pain.

This article presents differential diagnosis and treatment of facial pain. Facial pain is classified in accordance with the recent work of the Headache Classification Committee of the International Headache Society. The two major divisions are facial pain associated with disorders of the head and neck, including their parts, and disorders of cranial nerves, including their central connections. Special attention is paid to the controversial topics of temporomandibular joint dysfunction and atypical facial pain.

Diagnosis, Differential↗