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Biomedical subjects

J W Hurst

Publications and source records attributed to J W Hurst.

At least 19 recordsLinked to original sources

R. Bruce Logue.

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Cardiology

Direct detection of Molluscum contagiosum virus in clinical specimens by in situ hybridization using biotinylated probe.

Molluscum contagiosum virus (MCV) is an unclassified poxvirus which has recently become recognized as causing a major sexually transmitted disease. At present no assay is available for specific detection of MCV because the virus cannot be serially propagated in cell culture. Since MCV produces an abortive, limited growth with some cytopathic effect in certain cell lines, we were able to develop an in situ hybridization assay for detection of MCV genome in clinical specimens. Human fetal diploid lung cell monolayers were infected with clinical specimens, and after proper incubation and fixation in paraformaldehyde, hybridization was performed under full stringency conditions with a molecularly cloned biotinylated probe. Only MCV infected cells showed homology to the MCV probe with a purple-brown cytoplasmic staining. Additionally, we have described an in situ hybridization assay for direct detection of MCV genome in formalin-fixed, paraffin-embedded biopsies. Characteristic intracytoplasmic Molluscum bodies (Henderson-Paterson bodies) were detected in stratum spinosum cells of the epidermis. Striking staining similarities have been observed between in situ hybridization and haematoxylin-eosin cytostaining. These procedures are the first successful identification of MCV genome in clinical samples by molecular hybridization, with sensitivity and specificity equal to or greater than electron microscopy.

Blotting, Southern

Detection of the human immunodeficiency virus genome with a biotinylated DNA probe generated by polymerase chain reaction.

A non-radiolabelled DNA probe was developed for detection of the human immunodeficiency virus type 1 (HIV-1) genome using the polymerase chain reaction (PCR) technology. Primers amplifying a 395 base pair segment of a portion of the polymerase region of the HIV-1 genome were used both to amplify sample target DNA and to generate a biotinylated DNA probe used in Southern blot hybridization. This probe performed as well as one produced by nick translation using biotinylated nucleotides or an enzyme labelled oligonucleotide probe.

Bacterial Proteins

Advantages of a human immunodeficiency virus type 1 (HIV-1) persistently infected HeLa T4+ cell line for HIV-1 indirect immunofluorescence serology.

A HeLa T4+ cell line persistently infected with human immunodeficiency virus type 1 (HIV-1) was used in an indirect immunofluorescent antibody assay (IFA) system to explore its potential suitability as an alternative source of viral antigen for confirmatory IFA in HIV serology. In a study of 121 serum samples chosen because they were reactive on repeat examination by enzyme immunoassay but nonspecific by IFA by using HIV-1-infected H9 cells (H9 IFA) or gave discrepant results by enzyme immunoassay and H9 IFA, the specificity and sensitivity of the HeLa T4+ IFA were comparable to those of Western blot (immunoblot), and identification of the true positive samples among these discrepant or nonspecific samples by HeLa T4+ IFA was approximately twice that by H9 IFA. The primary advantages of using the HeLa cell line rather than lymphoid cell lines in IFA are that cells can be grown as a monolayer and that the individual cells are much larger. The cell membrane, cytoplasm, and nucleus are easily discernible; this allows specific and nonspecific staining to be distinguished. At least eight different nonspecific nuclear and cytoplasmic staining patterns were identified in this study by using T4+ cells.

Evaluation Studies as Topic

Comparison of biotinylated DNA and RNA probes for rapid detection of varicella-zoster virus genome by in situ hybridization.

We describe a general method for the production of nonisotopic DNA and RNA probes for the detection of the varicella-zoster virus (VZV) genome by in situ hybridization. VZV DNA was extracted from purified viral nucleocapsids, cleaved with restriction enzyme (RE) BamHI, and cloned into plasmid pBR322 by the standard vector insert procedure. We cloned over 85% of the VZV genome and obtained 18 recombinants. Plasmids containing the B, F, G, H, and J fragments of VZV DNA were labeled by the nick translation method with biotin-11-dUTP as the dTTP analog. Additionally, the B fragment was cleaved with RE AvaI, subcloned into the plasmid pGEM-4 transcription vector, and subsequently linearized with REs PstI and EcoRI. RNA was transcribed with T7 or SP6 polymerase, with a substitution of allylamine-UTP as the UTP analog, and labeled with epsilon-caproylamidobiotin-N-hydroxysuccinimide ester. The DNA and RNA probes were used under full-stringency conditions for in situ hybridization with alkaline phosphatase as the detector and 5-bromo-4-chloro-3-indolyl phosphate-Nitro Blue Tetrazolium as the substrate. When tested under comparable conditions, the RNA probe was slightly more sensitive than was the DNA probe: both probes showed homology only with VZV-infected cells and clinical tissues and not with the other herpesviruses. Probes prepared from variable regions of the genome (fragments F and J) performed as well as did those from conserved regions (fragments B. G. and H). Biotinylated probes have distinct advantages over isotopic probes and retain their full potency for more than 2 years when stored properly.

Biotin

Direct detection of molluscum contagiosum virus in clinical specimens by dot blot hybridization.

A dot blot hybridization protocol was developed for the direct detection of molluscum contagiosum virus (MCV) DNA in clinical specimens submitted for virus isolation. Samples were concentrated by high-speed centrifugation and treated with proteinase K; this was followed by a single phenol-chloroform extraction step. The DNA was denatured, and the entire volume was spotted onto a nitrocellulose membrane. A biotinylated DNA probe specific for the BamHI-C region of MCV type 1 was used for hybridization. Evidence of MCV DNA was visualized by using streptavidin alkaline phosphatase conjugate and 5-bromo-4-chloro-3-indolyl phosphate-nitroblue tetrazolium as the substrate. Results showed that nonspecific hybridization does not occur with herpes simplex virus- or orf virus-infected clinical specimens and that dot blotting is more sensitive and reproducible than electron microscopy.

DNA Probes

The examination of the heart: the importance of initial screening.

The screening examination of the heart and blood vessels require the use of the history, physical examination, electrocardiogram, and chest x-ray film. The relevant anatomy, pathology, and physiology responsible for the abnormalities found by using these methods of examination must be understood. The abnormalities that can be detected by the use of these methods of examination are discussed in this monograph. The techniques themselves are referred to as being low technology. The skill required in the use of these methods must be developed to its fullest. The data collected by using the history, physical examination, electrocardiogram, and chest x-ray film must be carefully analyzed in order for the examiner to diagnose the patient's cardiac problem. When possible, a complete cardiac diagnosis should be made according to guidelines formulated by the New York Heart Association. The four elements of a complete diagnosis are: Etiology, anatomy, physiology, and cardiac status and prognosis. In many cases, no additional data are needed and no additional data should be collected. When it is not possible to create a complete cardiac diagnosis from this information, the examiner must determine if it is wise and proper, given the patient's other health problems, to collect additional data that would permit a complete cardiac diagnosis. This effort hones the judgmental skill of the physician. When the cardiac diagnosis remains incomplete, or when a complete cardiac diagnosis is made but additional information is needed for follow-up purposes, carefully selected high technology should be used. With the unanswered questions in mind, the procedure used should be the one that answers the question with a predictive value that permits a defensible clinical decision. A complete medical problem list should be created for every patient. The cardiovascular problem must always be viewed in the context of other medical problems; there is no other way to make a sound judgment regarding the care of the patient with heart disease. When low technology, consisting of the history, physical examination, electrocardiogram, and chest x-ray film, is used poorly it is very likely that high technology will be used poorly. It is not possible to take a second step (high technology) without taking a well placed first step (low technology).

Electrocardiography

Monoclonal antibody to immediate early protein encoded by varicella-zoster virus gene 62.

Monoclonal antibodies (mAbs) were prepared against varicella-zoster virus (VZV)-infected cell proteins, and 10 mAbs which reacted with nuclear antigens were selected. These mAbs recognized a major 175-180 kDa and three minor VZV-specific phosphoprotein species. Immunofluorescence staining of VZV-infected cells showed that the 175-180 kDa protein was synthesized within 6 h after infection. The synthesis of this protein was inhibited by cycloheximide (CH); however, reversal of CH treatment and addition of actinomycin D (ActD) resulted in the synthesis of the 175-180 kDa protein. To determine whether the 175-180 kDa protein seen in the infected cells is encoded by VZV immediate early (IE) gene 62, the predicted open reading frames of VZV genes 61 and 62 were cloned into pGEM transcription vectors. RNA was transcribed from each gene, translated in vitro and immunoprecipitated with a mAb which recognizes a major 175-180 kDa and three minor proteins. The reactivity of the in vitro translation products encoded by gene 62 with this mAb suggested that the 175-180 kDa protein is encoded by VZV IE gene 62.

Animals

Writing.

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Writing

Hyperthyroid-induced atrial flutter-fibrillation with profound sinoatrial nodal pauses due to small doses of digoxin, verapamil, and propranolol.

Atrial fibrillation due to hyperthyroidism is characterized by a rapid ventricular response which is typically resistant to digoxin therapy. We report a patient with atrial flutter-fibrillation who developed cyclic sinus node dysfunction with profound ventricular pauses in response to small doses of digoxin, verapamil, and propranolol, which resolved with discontinuation of the medications. Caution is necessary to avoid paradoxical ventricular slowing when treating hyperthyroid-induced atrial fibrillation.

Arrhythmias, Cardiac

Comparison of immunofluorescence, enzyme immunoassay, and Western blot (immunoblot) methods for detection of antibody to human T-cell leukemia virus type I.

A total of 3,349 serum samples were screened by the immunofluorescence (IF) method for antibody to human T-cell leukemia virus type I (HTLV-I). Only 9 of 2,409 specimens from selected individuals, blood bank donors, patients with encephalitis-meningitis, and human immunodeficiency virus antibody-positive homosexual or bisexual men were reactive by IF. In addition, 940 serum samples from intravenous drug abusers were tested by IF and also by an HTLV-I enzyme immunoassay (EIA) method. Of these, 222 (24%) were positive for both HTLV-I and HTLV-II antigens by IF, and 191 of these 222 were also reactive in the HTLV-I EIA. Of the 31 IF-positive, EIA-negative serum samples, 20 exhibited optical density readings greater than or equal to 70% of the positive cutoff in the EIA, and 29 samples reacted with 1 or more bands in the Western blot (immunoblot) test. An additional 10 specimens that were EIA negative reacted only with HTLV-I by IF. Differences in staining morphology and in reactions on HTLV-I and HTLV-II antigens before and after absorption of the serum specimens with HTLV-I and HTLV-II-infected cell pellets revealed six distinct serological patterns by IF. These results indicate that infections by HTLV-I or by another closely related retrovirus(es) occur in California. Further studies utilizing statistically valid sampling methods are needed to estimate true prevalence rates among various groups. IF and Western blot tests should supplement the EIA method to maximize sensitivity and specificity of test procedures.

Blotting, Western

Clinical outcome 5 years after attempted percutaneous transluminal coronary angioplasty in 427 patients.

This study was performed to define the 5 year clinical status of 427 patients who underwent percutaneous transluminal coronary angioplasty (PTCA) in 1981. Their mean age was 54 +/- 10 years (+/- 1 SD). Sixty-one percent had unstable angina, 23% had prior myocardial infarction, 86% had one-vessel disease, and 92% had normal left ventricular function. Sixty-seven percent of patients had left anterior descending artery stenosis. Angiographic success was achieved in 84% of patients. Coronary bypass surgery was required in 9.6% of patients, in 5.9% as an emergency procedure. There were no in-hospital deaths. Follow-up at 5 years was 100% complete. There were 15 late deaths (96.3 +/- 1.0% survival), including seven of cardiac cause (98.1 +/- 0.7% cardiac survival). Myocardial infarction occurred in 24 patients (94% freedom from myocardial infarction), coronary bypass surgery was required in 63 (84% freedom from bypass surgery), and 365 patients (85%) were asymptomatic at follow-up. At 5 years, 83 patients (20%) had required an additional PTCA. Unstable angina pectoris and proximal left anterior descending coronary artery stenoses were present in 162 patients. The overall survival and cardiac survival in this subset was 94.4 +/- 1.8% and 98.1 +/- 1.1%, respectively. The excellent survival and low event rates over 5 years in this population support the concept that PTCA is safe and effective for patients with symptomatic angina pectoris, single-vessel disease, and normal left ventricular function.

Actuarial Analysis