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Biomedical subjects

D G Sherman

Publications and source records attributed to D G Sherman.

17 recordsLinked to original sources
PubMed1992

Solid-phase time-resolved fluorescence detection of human immunodeficiency virus polymerase chain reaction amplification products.

A new assay system for the detection of polymerase chain reaction (PCR) amplification products is presented. This single-pot sandwich assay system employs solid-support oligonucleotide-coated capture beads, a rare earth metal chelate-labeled probe, and a time-resolved fluorescence detection. The new assay system was evaluated for various reaction conditions including, DNA denaturation time, hybridization salt concentration, probe concentration, and hybridization time, all of which are important in designing an assay with a high level of sensitivity for the detection of duplex DNA. This nonisotopic assay system was applied to the detection of purified human immunodeficiency virus (HIV) DNA and sensitivity was compared with agarose gel electrophoresis and slot blot hybridization using a 32P-labeled probe. We were able to detect the amplified product from one copy of HIV DNA after 35 cycles of PCR amplification in less than 30 min using this assay, which compared with one copy by gel electrophoresis after 40 cycles of PCR amplification and one copy by slot blot hybridization after 35 cycles of PCR amplification and an overnight exposure of the autoradiogram. Thus, this assay is rapid, sensitive, and easy to use.

Base Sequence↗
PubMed1992

Detection of human immunodeficiency virus type 1 RNA in plasma samples from high-risk pediatric patients by using the self-sustained sequence replication reaction.

There is an urgent need for rapid and sensitive methods to assess human immunodeficiency virus (HIV) infection in infants and children. We evaluated an approach by using the self-sustained sequence replication reaction (3SR) to amplify HIV type 1 (HIV-1) RNA directly. The amplified RNA product was then detected by bead-based sandwich oligonucleotide capture hybridization and rare earth metal chelate time-resolved fluorescence. The sensitivity of this technology was determined to be less than 12 HIV-1 RNA copies with an amplification level of 10(10)-fold with purified HIV-1 RNA. Plasma samples from 19 high-risk pediatric patients younger than 5 years of age were examined, and results were compared with viral culture of patient plasma. Results from plasma culture and 3SR amplification agreed for 14 of these patients and disagreed for 5. Of the five samples which did not agree, four were positive by 3SR and negative by culture and one was positive by culture and negative by 3SR but became positive by 3SR at a subsequent testing. We conclude that 3SR amplification coupled with time-resolved fluorescence is a promising technology for investigating the relationship between the presence of HIV-1 RNA in plasma and progression of disease in HIV-infected pediatric patients. This technology should be important in the assessment of HIV-1 infection, in evaluating drug therapies, and in understanding the pathogenesis and transmission of the virus.

Base Sequence↗
PubMed1991

Stroke prevention in nonvalvular atrial fibrillation.

There has been considerable uncertainty about the best way to prevent stroke in patients with nonvalvular atrial fibrillation. Recent studies have suggested that low-dose warfarin therapy, in addition to producing fewer bleeding complications, may be as effective as higher-dose therapy in preventing thromboembolic events. Four large, prospective, randomized trials have examined the risks and benefits of warfarin therapy for stroke prophylaxis in patients with nonvalvular atrial fibrillation. All four studies showed a substantially reduced incidence of stroke and a low incidence of significant bleeding in patients treated with warfarin. One of these studies also showed that aspirin reduced the incidence of stroke. The benefits associated with long-term low-dose warfarin therapy appear to exceed the risks for serious bleeding in most patients with atrial fibrillation. Aspirin may be a viable therapeutic option for patients who are unable to take warfarin or for those in subgroups at a low risk for stroke.

Aspirin↗
PubMed1991

Stroke prevention in nonvalvular atrial fibrillation: a review of prospective randomized trials.

Patients with atrial fibrillation are at risk for cerebral embolism; however, the roles of chronic anticoagulation or antiplatelet therapy for stroke prevention in patients with nonvalvular atrial fibrillation have been controversial. Recently, the results of three large prospective randomized trials that examined the risks and benefits of warfarin or aspirin for stroke prophylaxis in patients with nonvalvular atrial fibrillation were reported. All three studies revealed a reduction in the stroke rate for patients treated with warfarin and a small incidence of major bleeding. One of the studies also reported a reduced stroke rate in aspirin-treated patients. The reduction of thromboembolic events associated with chronic warfarin therapy appears to outweigh the risks of significant bleeding for most patients with nonvalvular atrial fibrillation. Aspirin may offer an alternative for subgroups of patients who are at low risk for stroke or those who are not good candidates for anticoagulation.

Anticoagulants↗
PubMed1991

Detection of Escherichia coli rRNA using target amplification and time-resolved fluorescence detection.

The development of technology to increase the sensitivity and speed of detection of bacterial pathogens in samples is important for diagnosis and monitoring of illness. We have developed a sensitive and rapid method for the detection of bacteria, using Escherichia coli as a model, which combines transcription-based target amplification with a bead-based sandwich hybridization assay using rare earth metal chelate labelled probes and time-resolved fluorescence detection. Using these methods as little as 100 copies (0.00016 attomoles) of purified native Escherichia coli rRNA or just one bacterial cell in a spiked sample could be detected. These results demonstrate that amplification of rRNA by transcription-based amplification and detection by time-resolved fluorescence provide a sensitive technology for the direct detection of micro-organisms without the requirement for prior cultivation.

Base Sequence↗
PubMed1990

Cardiac embolism: the neurologist's perspective.

Cardioembolic stroke represents a major healthcare challenge in the United States, accounting for significant morbidity and mortality, as well as economic and social costs. Determining the cause of ischemic stroke is often difficult because multiple potential etiologies are often present and available diagnostic tools are relatively insensitive. The diagnosis of cardioembolic stroke is based on a variety of clinical and laboratory clues that are significant, although not invariable, predictors of stroke etiology. Computed tomography scans help suggest etiology, and scans performed at 48 hours after stroke onset are essential to identify hemorrhagic infarctions. Cerebral angiograms may be helpful if performed early. Echocardiography is indicated only for selected patients who are more likely to demonstrate cardiac abnormalities on an echocardiogram. The management of acute cardioembolic stroke involves weighing the benefits of reducing stroke recurrence by anticoagulation against the risk of symptomatic brain hemorrhage. A management algorithm is provided that can help reduce both the risk of symptomatic brain hemorrhage and the incidence of potentially disabling stroke recurrence.

Coronary Disease↗
PubMed1990

Antiphospholipid antibodies and cerebral ischemia in young people.

The importance of a prothrombotic state as a cause of ischemic stroke in young adults is ill defined. We examined 46 unselected patients under age 50 years with cerebral ischemia for anticardiolipin antibody (aCL) and lupus anticoagulants (LA), over a 3-year-period. Age- and sex-matched patients with other neurologic diseases served as a noncerebral ischemia comparison group to test whether (1) stroke/transient ischemic attacks (TIA) in young people is associated with aCL and/or LA, and (2) their presence is specific to cerebral ischemia. In the stroke/TIA group, 21 patients had aCL or LA and 25 had neither, whereas in the control group, 2 patients had aCL and 24 had neither. Equal numbers of stroke/TIA patients with and without antiphospholipid antibodies (aPL) had other stroke risk factors. Patients with aPL and cerebral ischemia, however, had a more frequent history of multiple events than those without them. These antibodies occur with undue frequency in young patients with stroke/TIA and are not associated with a concurrent diagnosis of systemic lupus in most cases. A coexistent aPL-associated prothrombotic state may be a key determinant of whether patients with atherosclerosis, mitral valve prolapse, or other structural lesions experience recurrent ischemia.

Adult↗
PubMed1977

Dieting and peroneal nerve palsy.

In seven patients, peroneal nerve palsies developed while they were on weight-reduction diets. Five palsies were unilateral; two, bilateral. All patients recovered following diet modification. Therapeutic weight loss, of itself, can cause foot-drop. The prognosis is uniformly good.

Adult↗
PubMed1977

Ocular bobbing with superior cerebellar artery aneurysm. Case report.

A teen-age girl became comatose after the sudden onset of headache. Initial angiography did not reveal the site of bleeding. The subsequent onset of ocular bobbing directed attention to the region of the pons. Repeated angiography showed an aneurysm of the superior cerebellar artery. At surgery, the fundus of the aneurysm was adherent to the pons and there was a small hematoma within the pons. Ocular bobbing is rare, but is most commonly seen in association with destructive lesions of the pontine tegmentum, and is a useful localizing sign.

Adolescent↗
PubMed1976

Somatic anxiety attacks and propranolol.

Patients with acute anxiety-like attacks are often evaluated for various medical conditions, and, when nothing is found, their symptoms are attributed to psychogenic causes. "beta-Adrenergic hyperactivity" should be considered in these patients. Six patients are described who, we believe, are suffering from this condition. Low rates of isoproterenol hydrochloride infusion-precipitated symptoms that mimicked their spontaneous somatic anxiety attacks. Treatment with propranolol hydrochloride produced longterm symptomatic relief.

Adult↗
PubMed1976

Syncope.

Syncope is usually easily diagnosed, but sometimes it is confused with hypoglycemia, epilepsy, cerebral vascular disease, "drop attacks", hyperventilation attacks, and hysterical faints. Syncope is usually a benign disorder, but sometimes it is a manifestation of a serious neurologic or cardiac disease. This paper provides an approach to the evaluation and management of patients with this disorder.

Adolescent↗
PubMedDate not supplied

Stroke and mortality rate in carotid endarterectomy: 228 consecutive operations.

A retrospective study of 228 consecutive carotid endarterectomies was conducted to determine the operative stroke and mortality rate in two 600-bed community hospitals. The combined stroke-mortality rate for the series was 21.1% (48 of 228). Eleven endarterectomies were performed for asymptomatic bruits and the combined stroke-mortality rate was 18.2% (2 of 11). Fifty-seven endarterectomies were performed for transient ischemic attach(s) in the symptomatic carotid artery distribution and the combined stroke-mortality rate was 21.1% (12 of 57). Seventy-one endarterectomies were performed following a mild-moderate stroke in the symptomatic carotid artery distribution and the combined stroke-mortality rate was 21.1% (15 of 71). Twelve endarterectomies were performed following a severe stroke in the symptomatic carotid artery distribution and the combined stroke-mortality rate was 41.7% (5 of 12). There was no trend toward more or less operation strokes or deaths from 1970 to 1976. The similarity of results among the eleven board-certified neurological and vascular surgeons who performed the 228 endarterectomies suggests that the operative stroke and mortality rates for carotid endarterectomy reported here are likely to be representative of those in many other community hospitals in this country in the 1970s.

Aged↗
PubMedDate not supplied

Cervical manipulation and stroke.

Three patients are described who experienced vertebro-basilar distribution infarctions associated with neck manipulation. Two of the manipulations were chiropractic. Twenty-two previously reported cases are reviewed. Evidence favoring the use of anticoagulation in these patients is discussed along with the relative risk of such therapy.

Adult↗