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Biomedical subjects

B L Johnson

Publications and source records attributed to B L Johnson.

At least 91 records · Page 5Linked to original sources
PubMed1988

The characterization of Ia+ cells in human parathyroid and islets.

Recent studies in animals have shown prolonged survival of endocrine allografts after treatment of the graft with Ia antibody prior to transplant. In this study, we documented the presence of Ia bearing passenger cells in human parathyroid and islets of Langerhans. Furthermore, we characterized these cells with regard to their expression of HLA-DQ and HLA-DR molecules using indirect immunofluorescence. We found that passenger cells in parathyroid express both HLA-DQ and HLA-DR. In contrast, islets express only HLA-DR. Parathyroid tissue treated first with polyclonal anti-DR or anti-DQ and complement eliminated cells that reacted with monoclonal anti-DR or -DQ probes, respectively. Similarly, islets treated with polyclonal anti-DR and complement eliminated cells that reacted with monoclonal anti-DR reagents. We believe that further characterization of Ia+ cells in human endocrine tissue will provide information that could be used to enhance allograft survival.

Cytotoxicity Tests, Immunologic↗
PubMed1987

Use of curettage and shave excision in office practice. Microscopic confirmation of removal.

The technic of curettage and shave excision can be learned by the general dermatologist as a useful office procedure. With its roots in Mohs' surgery, its chief characteristic is that it provides microscopic confirmation of complete removal. The procedure appears to have certain indications and definite limitations. An effort has been made to define these. In general, curettage and shave excision will be most useful as a substitute for curettage and electrodesiccation in locations and for skin cancers for which the curettage and electrodesiccation procedure is being considered but is not quite adequate. Nineteen cases are presented. They fall into two groups, according to the timing of the procedure. Although the technic is not difficult, it is more time consuming than curettage and electrodesiccation, and it requires much more attention to detail. The interpretation of horizontal sections presents certain pitfalls that must be recognized.

Adult↗
PubMed1987

Chromatic imbalance due to commonly used red-green filters reduces accuracy of stereoscopic depth perception.

This study was designed to determine the effect on stereopsis of interocular retinal chromatic and illuminance imbalance in 30 subjects with normal binocularity. A Randot 3 Circle Stereotest, viewed through polarizing glasses only, was the control condition. In each of three additional conditions, illuminance and chromatic imbalances were created by commonly used red and green filters and neutral density filters combined with the polarizing filters. The effect of each of these experimental conditions on stereopsis was determined by comparing total stereo judgement errors on the Randot Circle Stereotest for each condition to the control condition. Total average flux through the filter combinations was held constant by adjusting the luminance level of light reflected from the target. The chromatic imbalance created by the red-green filters significantly increased the number of stereo judgment errors (37%, p less than 0.05). However, illuminance imbalance (0.2 log units) of the magnitude created by the red-green filters did not significantly increase the number of errors (2.9%, p less than 0.65). Finally, the combined illuminance and chromatic imbalance created by the red-green filters significantly increased the error frequency (46%, p less than 0.05). The chromatic imbalance caused by red-green glasses significantly degrades stereopsis, whereas the illuminance imbalance caused by these filters has no significant effect on stereopsis.

Adolescent↗
PubMed1987

Health risk communication at the Agency for Toxic Substances and Disease Registry.

I have described areas for which ATSDR has responsibilities that we see as involving risk communication. I conclude by indicating, based on our professional experience and from meetings with the public where we have presented health information, what we consider to be five elements required of successful risk communication. The first element we suggest is the credibility of the source. If you have no credibility, no matter how accurate, how truthful, how up-to-date, how important, how dramatic your message is, you are not going to be heard. So you start with credibility. The quality of the message is the second building block of successful risk communication. By quality of the message, I mean whether it is accurate, truthful, up-to-date, and based on current scientific knowledge. The third element is the degree of involvement of the receiver of the message in the shaping of the message. If the receiver has not been involved in the process, then the likelihood of successful risk communication is going to be diminished. Get the receivers involved up front. That means, in the case of community health studies, get those persons involved in the community who have been most concerned about the health issues. To the extent possible, involve community leaders, citizen groups, physicians, the news media, and concerned individual citizens in the design, conduct, and evaluation of community health surveys and studies. The fourth element is the quality of the delivery. If you present the message in government jargon and do not speak with, but to, the audience, you are going to find difficulties in successful communication.(ABSTRACT TRUNCATED AT 250 WORDS)

Communication↗
PubMed1987

The keratotic tumors of Cowden's disease: an electronmicroscopic study.

Cowden's disease is characterized by multiple hamartomas of the skin, breast, thyroid, and gastrointestinal tract. In the past, a viral hypothesis for the keratotic lesions of the skin has led to much controversy. The present study describes the results of a detailed fine structural analysis of 10 hyperkeratotic extremity lesions and 2 keratotic lesions from the face of a patient with Cowden's disease. Increases in the keratinocyte population were primarily confined to the basal and suprabasal regions. Differentiation products characteristic of keratinization were normal in both quantity and appearance. Nuclear remnants and numerous lipid droplets, markers of abnormal keratinization, were noted within horny cells. However, viral particles and/or virus-like particles were not observed in keratinocytes. Melanocytes and Langerhans cells were numerous. The latter contained membrane-bound pigment vacuoles in addition to the characteristic Birbeck granules. These unusual Langerhans cells were observed in the dermis as well as the epidermis. A large number of fully granulated "resting" mast cells was uniformly distributed throughout the dermis, associated with a prominent cellular infiltrate. Our observations do not support the concept of a viral etiology for these tumors.

Female↗
PubMed1986

Hyperoxemic retinal neuronal necrosis in the premature neonate.

A cytologically distinctive type of acute hyperoxemic injury of retinal neurons occurs in premature neonates. Ganglion cells in the central well-vascularized neonate retina are susceptible to excessive oxygen and this is expressed morphologically by karyorrhexis of their nuclei. We observed retinal neuronal necrosis in neonates who had hyperoxemia of greater than 150 torr for two hours or longer in the first week of life. Neuronal necrosis was strikingly associated with immaturity as determined by gestational age and birth weight: of 30 involved neonates, all were below 2,000 g; of 47 autopsied premature infants with birth weights under 1,500 g who survived for at least two days, 26 (55%) had acute retinal necrosis. When gestational age was used as a measure of prematurity, the highest incidence occurred in the 24- to 27-week group where 13 of 21 (62%) were involved. Hyperoxemic karyorrhectic changes, most prominent in the ganglion cells of the macula, are distinct from the classic peripheral mesenchymal vascular abnormalities of retinopathy of prematurity.

Birth Weight↗
PubMed1986

Cyclophosphamide in the treatment of orbital vasculitis.

When vasculitis, an angiocentric and angiodestructive process, occurs in the orbit, the clinical presentation and radiographic findings resemble those of idiopathic inflammatory pseudotumor. Three patients, two men and a woman, 28 to 72 years old, initially thought to have "pseudotumor" failed to response to corticosteroid therapy. Orbital biopsy specimens in all patients disclosed vasculitis. There was no evidence of systemic vasculitis. High-dose prednisone effectively eliminated pain and reduced inflammation but did not adequately control fibrosis formation leading to ultimate loss of function. Each patient eventually lost an eye to this process. Therapy with cyclophosphamide, a B-cell cytotoxic drug, produced a prompt response in terms of eliminating pain, inflammation, and formation of fibrous tissue. Cyclophosphamide therapy has been instrumental in preserving sight in each patient's remaining eye. In such cases we believe the benefits of cyclophosphamide therapy outweight the known risks.

Adult↗
PubMed1986

Ptosis associated with fatty infiltration of Müller's muscle and levator muscle.

Prominent fatty infiltration of Müller's muscle and the anterior levator muscle was noted at the time of surgery in nine of 115 patients undergoing external levator resection for ptosis. This distribution of adipose tissue was confirmed by light microscopy. Fatty infiltration appeared to be a degenerative change found in adults with congenital and acquired ptosis. Preoperatively these patients exhibited moderate to severe ptosis, fair to good levator function, and no elevation of the lid crease. The desired postoperative results were achieved with standard external levator resection and advancement techniques. The fatty appearance may lead to difficulty in identifying customary anatomical landmarks during surgery. With the exception of Horner's syndrome, abnormalities of Müller's muscle have not previously been described in association with ptosis, to these authors' knowledge.

Adipose Tissue↗
PubMed1986

Neurobehavioral evaluation of soil and structural fumigators using methyl bromide and sulfuryl fluoride.

Neurobehavioral functions affected by methyl bromide exposure were evaluated in California structural and soil fumigators using methyl bromide and sulfuryl fluoride. Sampling data revealed that structural fumigators are exposed for up to 1.5 hrs/day to 0-2.2 ppm methyl bromide and/or 10-200 ppm sulfuryl fluoride, and soil fumigators can be exposed to 2.3 ppm methyl bromide over an 8-hr day. Subjects were grouped for statistical analysis on the basis of exposure history: Those exposed primarily (80% or more of the work period with exposure potential) to methyl bromide (N = 32), primarily to sulfuryl fluoride (24), or to a combination of methyl bromide and sulfuryl fluoride (40-60% of each) for a minimum of one year (18), and those not exposed to high concentrations of any chemicals (29 Referents). Fumigators using methyl bromide reported a significantly higher prevalence of 18 symptoms consistent with methyl bromide toxicity than did Referents. Methyl bromide fumigators did not perform as well as Referents on 23 of 27 behavioral tests (chosen to reflect methyl bromide effects), and were significantly lower on one test of finger sensitivity and one of cognitive performance. These consistent differences suggest that even the low levels of methyl bromide found in fumigation today may produce slight neurotoxic effects. found in fumigation today may produce slight neurotoxic effects. The greater number of symptoms and reduced performance on all cognitive tests in sulfuryl fluoride fumigators compared to the Reference Group plus the absence of published research on this compound suggest that the data base for sulfuryl fluoride is inadequate.

Adult↗
PubMed1985

Orbital fine-needle aspiration biopsy.

Fine-needle aspiration was used as a primary orbital diagnostic technique in 156 patients. A 20-mm syringe, a 22-gauge, 3.75-cm needle, and a plastic pistol grip were used. Local anesthetic was not necessary. When the needle is in the lesion, small to-and-fro movements with a minimum of angulation are helpful. The aspirate is spread on slides fixed with alcohol. Positive cytologic identification was made in 125 of 156 cases. Commonly identified lesions included metastatic carcinoma, inflammatory lesions, and lymphoid lesions. Small posterior apical lesions are difficult to aspirate, but are often the most rewarding diagnostically. Fine-needle aspiration was not successful in tumors of fibrous consistency, in those located in the orbital apex, or in lymphocytic lesions with specimens inadequate for diagnosis.

Biopsy, Needle↗
PubMed1985

Export defect adjacent to the processing site of staphylococcal nuclease is suppressed by a prlA mutation.

Plasmids have been constructed in which the Escherichia coli alkaline phosphatase promoter and signal sequence have been fused to the staphylococcal nuclease gene to promote the high-level expression and secretion of this gene product in E. coli. We determined that the first amino acid residue after the signal sequence can determine whether this protein was processed and exported to the periplasmic space. Fractionation and protease accessibility studies were used to show that the export-defective, nuclease precursor is internal to the cytoplasmic membrane barrier of the cell. Furthermore, this export defect was suppressed in a strain containing a prlA mutation. These findings are novel in that this region of the polypeptide chain has been implicated in processing but not export and that prlA mutations have not been previously known to suppress such defects.

Alkaline Phosphatase↗
PubMed1984

Mycobacterium avium: a pathogen of patients with acquired immunodeficiency syndrome.

Mycobacterium avium complex has been isolated with increasing frequency from humans during the last few decades. Thirteen patients admitted to the UCLA Medical Center with the diagnosis of acquired immunodeficiency syndrome (AIDS), in addition to having Kaposi's sarcoma, Pneumocystis pneumonia, and other opportunistic infections, also had M. avium complex isolated from a variety of tissues and fluids submitted for culture. Of these patients, 10 had histologic and bacteriologic evidence of disseminated mycobacterial infection, and M. avium complex was isolated from the blood of 5. The organisms were isolated from routine bacteriologic and diphasic fungal blood culture bottles. Periodic cultures of sputum, urine, and other body fluids and tissues should be performed for mycobacterial infections in all such patients. Routine blood cultures should be kept for at least 8 weeks to check for the presence of acid-fast bacteria in general and for M. avium complex in particular from all patients with immune deficiencies.

Acquired Immunodeficiency Syndrome↗
PubMed1984

New biphasic culture system for isolation of mycobacteria from blood of patients with acquired immune deficiency syndrome.

A new biphasic medium consisting of a 7H11 agar slant and brain heart infusion broth liquid phase has been used for the past 10 months at the University of California at Los Angeles for isolation of Mycobacterium avium complex from blood. In 12 patients whose blood cultures were grown on this medium, the median time for isolation of M. avium complex was 7 days (range 6 to 15 days) compared with 21 to 27 days on a fungal medium and 28 to 38 days on routine blood culture medium. The system has provided a reliable and rapid way to obtain morphology and rapid identification of colonies produced from blood samples of patients with acquired immune deficiency syndrome, who are at high risk for M. avium complex mycobacteremia.

Acquired Immunodeficiency Syndrome↗
PubMed1984

A review of public health regulations on lead.

A review of public health regulations pertaining to lead exposure is the subject of this paper. Although lead had been used for centuries in the fabrication of a host of products, it was not until the mid-nineteenth century that the clinical pattern of lead poisoning was described in the medical literature. With this recognition gradually came government health regulations designed to limit human exposure to lead from occupational and environmental sources. The British, in particular, developed during the period 1890 to 1920 comprehensive rules and regulations pertaining to occupational lead exposures. The development and imposition of U.S. health regulations occurred later in the twentieth century; federal regulations not generally appearing until the 1970's. At present, several U.S. government agencies have promulgated regulations intended to prevent lead poisoning from paint; limit lead in ambient air, drinking water, workplace environments and consumer products; and reduce lead in fuels and fuel additives used in motor vehicles. These regulations are reviewed in terms of their extent of coverage. There is evidence, in some instances indirect in nature, that human exposure to lead in U.S. populations has been reduced, though comprehensive data are lacking. The Centers for Disease Control has reported that the mean blood lead level in the U.S. has decreased 36%, paralleling a reduction in the lead content of gasoline. For occupational lead exposure, comprehensive morbidity data do not exist, but an evaluation of NIOSH health hazard evaluations (HHE's) specific to lead show a gradual reduction since 1977 in the percentage of HHE's for which airborne lead exceeded 0.20 mg/m3, which at one time had been the federal standard for occupational lead exposure, prior to reduction of the U.S. standard to 0.05 mg/m3.

Adult↗