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Biomedical subjects

J Bloom

Publications and source records attributed to J Bloom.

At least 19 recordsLinked to original sources
PubMed1992

Clinical pathology testing recommendations for nonclinical toxicity and safety studies. AACC-DACC/ASVCP Joint Task Force.

Clinical pathology testing in nonclinical toxicity and safety studies is an important part of safety assessment. In recent years, clinical laboratory testing has rapidly expanded and improved. Some government regulatory agencies provide guidelines for clinical pathology testing in nonclinical toxicity and safety studies. To improve these testing guidelines and the resultant safety assessments, the American Association for Clinical Chemistry's Division of Animal Clinical Chemistry and the American Society for Veterinary Clinical Pathology formed a joint committee to provide expert recommendations for clinical pathology testing of laboratory species involved in subchronic and chronic nonclinical toxicity and safety studies. These recommendations include technical recommendations on blood collection techniques and hematology, serum chemistry, and urinalysis tests.

Animals↗
PubMed1991

Characterization of the mycotoxin fumonisin B1: comparison of thermospray, fast-atom bombardment and electrospray mass spectrometry.

The utility of thermospray mass spectrometry (TSMS), fast-atom bombardment mass spectrometry (FABMS), and electrospray mass spectrometry (ESMS) for the analysis of Fumonisin B1 is investigated. In addition, the analysis of two different standards of Fumonisin B1 as well as an inoculated corn culture extract that contained Fumonisin B1 is reported. The results of these efforts show that ESMS, as well as FABMS and a combination of FAB and tandem mass spectrometry (FABMS/MS), provide useful data for the characterization of Fumonisin B1. The detection limit was 50 pg for Fumonisin B1 when analyzed by full scan FABMS, and 5 pg when analyzed by single-reaction monitoring FABMS/MS.

Electrochemistry↗
PubMed1991

Cervical necrotizing fasciitis of odontogenic origin.

Necrotizing fasciitis is a severe soft tissue infection caused by both aerobic and anaerobic bacteria and is characterized by a rapid extension along fascial planes and by necrosis of soft tissues. The disease rarely occurs in the head and neck. Three cases of necrotizing fasciitis of the neck after a dental infection are presented. The difficulty in diagnosing the early stage of this condition in relation to other soft tissue infections of odontogenic origin in the neck is discussed. The importance of an early diagnosis followed by an appropriate combination of medical, surgical, and dental treatment is emphasized.

Adult↗
PubMed1991

Smoking, social support, and hassles in an urban African-American community.

BACKGROUND: Despite public health efforts, the prevalence of smoking among African Americans remains high. The determinants of smoking behavior in this population must be elucidated so that interventions can be better targeted and more effective. METHODS: As part of a prospective community intervention trial to reduce cancer mortality, we conducted a random household survey of 1137 African-American adults in San Francisco and Oakland between November 1985 and July 1986. The survey instrument included questions about social network characteristics, instrumental and emotional aspects of social support, smoking behavior, and stressors. RESULTS: The overall prevalence of smoking (41.9%) was higher than that reported in national surveys. Logistic models revealed that persons reporting high levels of stress, represented by an abbreviated hassles index, were more likely to smoke than those reporting less stress. Women with poor social networks were more likely to smoke (odds ratio = 3.1) than women with optimal networks; however, this relationship did not hold among men. Indeed, men lacking emotional support from friends or family were less likely to smoke (odds ratio = 0.5) than men receiving such support. No interaction between social support and hassles was observed. CONCLUSIONS: Stressful environments may contribute to high-risk smoking behavior among urban African Americans.

Black or African American↗
PubMed1990

Analysis of rat urine for metabolites of pyrilamine via high-performance liquid chromatography/thermospray mass spectrometry and tandem mass spectrometry.

Combined high-performance liquid chromatography/thermospray mass spectrometry (HPLC/TSMS) and HPLC/thermospray tandem mass spectrometry (HPLC/TSMS/MS) were utilized for the analysis of rat urine for metabolites of pyrilamine. The sample was analyzed via HPLC/TSMS/MS in the parent ion mode in order to identify potential metabolites of pyrilamine. Then HPLC/TSMS/MS analysis in the daughter ion mode was performed to provide additional analytical selectivity plus enhanced fragmentation of suspected protonated molecules. By this methodology, suspected pyrilamine metabolites were confirmed to be in the sample and several novel metabolites of pyrilamine were discovered and tentatively identified.

Aminopyridines↗
PubMed1990

Auditory brain-stem responses in guinea pigs following middle ear implantation of Ceravital.

The effects on auditory function caused by implantation of the bioactive glass ceramic Ceravital in the middle ear of guinea pigs was investigated. Auditory brain-stem responses (ABR) were used to measure hearing function. A threshold shift due to a conductive hearing loss was observed immediately post-operatively. This threshold shift increased towards the 20th post-operative day and improved thereafter. Surgical manipulation of the middle ear and biochemical reactions between the Ceravital granules and the middle ear wall may have contributed respectively to the immediate and late temporary ABR threshold shift recorded. However, cochlear function was not affected by middle ear implantation of Ceravital. These results correlate well with morphological studies of Ceravital implanted in the middle ear and give further support to the safe use of Ceravital as an implantation material in middle ear reconstructive surgery.

Animals↗
PubMed1990

Victims of fraud: comparing victims of white collar and violent crime.

Mental health professionals have focused attention on the psychiatric sequelae of criminal victimization. This article compares the experience of white collar and violent crime victims on several parameters including statistical risk of victimization and psychiatric outcome after victimization. Emphasis is given to data obtained from interviewing 77 victims of a fraudulent financial scheme.

Adaptation, Psychological↗
PubMed1989

Paroxysmal positional vertigo in the elderly.

In a retrospective study of 806 patients 70 years of age or older complaining of dizziness, 328/806 (40.7%) patients gave a history strongly suggestive of paroxysmal positional vertigo. This prevalence was higher than in other age groups of 7,269 patients seen in our Dizziness Clinic (33.7% in patients 50 years of age or younger; 26.6% in patients 40 years of age or younger). In 158/328 patients, the paroxysm was elicited and nystagmus occurred; in 135/158 patients, the observed nystagmus, during the paroxysm, was identified and in 131/135 patients, it was of the type described by Barany. It is concluded that: (a) the prevalence of paroxysmal positional vertigo increases with advancing age; (b) the usually observed nystagmus, during the paroxysm, in the elderly is of the type described by Barany, and similar to the nystagmus observed in other age groups.

Aged↗
PubMed1989

Electron microscopic study of the unique features and structural-morphologic relationship of canine bone marrow.

Electron microscopy revealed several unique features in canine bone marrow, compared with that of other species. The marrow was fatty and extensively trabeculated and was enclosed by a complete layer of endosteal bone-lining cells. Branched reticular cells were closely associated with each other and, occasionally, covered part of the sinus wall as an adventitial layer. The extent of adventitial coverage varied markedly and was less extensive, compared with that of other species. On average, only 23% of the sinus wall was covered by adventitial layer, in contrast to 65% reported in laboratory animals. Unilaminar sinuses, with no adventitial coverage, accounted for greater than 38% of all sinuses. Quantitative analysis indicated that 60% of the latter sinuses contained apertures, as opposed to 35% of sinuses with adventitial coverage (P less than 0.05). Moreover, the number of apertures in unilaminar sinuses was significantly (P less than 0.009) greater than that in multilaminar sinuses. Apertures were observed every 59 microns in unilaminar sinuses, in contrast to every 109 microns in multilaminar sinuses. Approximately 75% of the apertures were occupied by cells in transit, and only 25% were free of cells. Macrophages were distributed throughout the marrow and were closely associated with all blood cell lines. Occasionally, cells that entered the lumen were not fully mature. Erythroblasts were seen migrating across the wall and within the lumen of sinuses. The less-extensive adventitial coverage in canine bone marrow might indicate that the rate of cell delivery from the marrow into the circulation was relatively high in this species.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Tissue-specific expression and dietary regulation of a chimeric phosphoenolpyruvate carboxykinase/bovine growth hormone gene in transgenic mice.

A series of transgenic mice was produced by microinjection of a segment of DNA, containing 460 base pairs of the phosphoenolpyruvate (P-enolpyruvate) carboxykinase promoter-regulatory region ligated to the bovine growth hormone structural gene, into the male pronucleus of fertilized mouse eggs. Founder animals which contained the gene were selected for further analysis and for breeding. The concentration of bovine growth hormone in the serum of animals which were shown to contain the gene ranged from a low of 5 ng/ml serum to approximately 2300 ng/ml serum. Mice with high levels of bovine growth hormone had growth rates double that of their litter mates which did not contain the transgene. The transgene was expressed only in the liver and kidney of the animals studied, and the level of specific mRNA for bovine growth hormone in these tissues could be regulated by diet in a manner similar to the endogenous P-enolpyruvate carboxykinase gene. Feeding the animals a diet high in carbohydrate for 1 week caused a 90% decrease in the concentration of bovine growth hormone in the blood, suggesting that the expression of the chimeric P-enolpyruvate carboxykinase/bovine growth hormone gene is sensitive to insulin. When the same animals were then refed a diet high in protein, but devoid of carbohydrate, the concentration of bovine growth hormone in their blood was induced 30-fold within a week. The administration of dibutyryl cyclic AMP to the transgenic mice caused a 2-fold induction in the level of bovine growth hormone in the serum within 90 min. Thus the region between -460/+73 in the P-enolpyruvate carboxykinase promoter-regulatory region contains sequences which can direct the tissue-specific expression, as well as hormonal and dietary responsiveness, of a linked structural gene.

Amino Acid Sequence↗
PubMed1988

Cephalosporin-induced alterations in erythroid (CFU-E) and granulocyte-macrophage (CFU-GM) colony-forming capacity in canine bone marrow.

Cephalosporins are among the safest antibiotics. Nevertheless, hematologic abnormalities ranging from mono- to pancytopenia do occur, albeit infrequently, following their therapeutic use. Similar abnormalities to those reported in people have been seen in dogs given high doses of cephalosporins. As part of a study to define the latter thoroughly, we explored the effects of long-term, high-dose cephalosporin administration on canine marrow erythroid (CFU-E) and granulocyte-macrophage (CFU-GM) progenitor cells. Cefazedone (Refosporen, E. Merck, Darmstadt) was administered intravenously at doses of 540 to 840 mg/kg daily to 14 healthy beagle dogs for up to 4 months, or less if hematologic effects were evident earlier. Within 6 to 10 weeks, treated dogs developed pancytopenia (5/14), thrombocytopenia (11/14), moderate to severe neutropenia (8/14), and/or normocytic anemia (8/14). There was evidence of immune-mediated destruction of peripheral blood cells. All treated dogs exhibited a significant reduction in marrow colony-forming capacity, irrespective of whether peripheral cytopenia was present, with 12/14 showing decreased CFU-GM and 14/14 decreased CFU-E activity. Within a week following cessation of dosing, all affected dogs achieved hematologic remission as defined by restoration of the peripheral blood counts. However, despite this apparent recovery, both CFU-E and CFU-GM activities of the bone marrow remained depressed for at least another 8 months. We conclude that in dogs prolonged administration of high doses of cefazedone induced a persistent deficit of CFU-E and CFU-GM progenitor cells. The clinical relevance of this, if any, remains to be established.

Animals↗
PubMed1988

Cephalosporin-induced changes in the ultrastructure of canine bone marrow.

Fourteen healthy dogs were given 540 to 840 mg/kg of cefazedone (Refosporen) intravenously for up to 4 months or until peripheral blood cell count were depressed. Within 6 to 10 weeks treated dogs developed pancytopenia (5/14), thrombocytopenia (11/14), moderate to severe neutropenia (8/14), and/or normocytic anemia with erythroblastemia (8/14). Ultrastructural changes in bone marrow of severely cytopenic dogs included mitochondrial damage in hematopoietic and nonhematopoietic cells, thickening of endosteal bone lining layers, increased adventitial coverage of vascular sinuses, and an increased number of active macrophages. Swollen, ruptured mitochondria were in erythroid, granulocytic, and megakaryocytic cells, and, to a lesser extent, in macrophages, reticular endothelial, and bone lining cells. Maturation arrest was evident in both erythroid and granulocytic cell lines. There was also evidence of ineffective erythropoiesis and granulopoiesis. None of these changes were observed in bone marrow of controls, treated dogs that did not develop cytopenia, or dogs allowed to recover after cessation of dosing.

Anemia↗
PubMed1988

Reproducible cloning assays for in vitro growth of canine hematopoietic progenitor cells and their potential applications in investigative hematotoxicity.

A variety of in vitro cloning assays have been used for studying hematopoiesis in mice and human beings. However, these techniques have had limited use in dogs, a species used extensively as a model for hematopoietic research, particularly hematotoxicity. We have adopted cloning assays for in vitro growth of canine colony-forming unit-erythroid (CFU-E) and colony-forming unit-granulocyte/macrophage (CFU-GM) progenitor cells, using modified microplasma clot and soft agar culture systems, respectively. Marrow mononuclear cells separated by density-gradient centrifugation were added to the aforementioned culture systems. Erythroid colonies were stimulated with sheep plasma erythropoietin and incubated at 37 C in 5% CO2 for 2 days. The CFU-E colonies were fixed with 5% glutaraldehyde, stained with benzidine, counted, and expressed as a mean of 8 replicates. The CFU-GM colonies were stimulated with pooled serum from endotoxin-treated dogs and incubated for 8 days at 37 C in 10% CO2. Using an inverted microscope, the CFU-GM colonies were counted and expressed as a mean of 6 replicates. The number of colonies was proportional to the plated cell concentrations. The addition of 10% autologous serum to CFU-GM cultures increased the number of colonies by 80 to 100%, but markedly reduced the size and number of CFU-E colonies. The marrow cloning capacity among dogs of comparable age was similar, and little variation was noticed when bone marrow cells from the same dogs were cultured repeatedly over a period of 3 to 4 months. We concluded that these cloning assays are fast, reliable, and reproducible and that they allow quantitative determination of canine hematopoietic progenitor cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Dairy products containers as a source of unusual esophageal foreign bodies.

Seven patients were treated during a period of three years in the Otolaryngology department of Tel-Aviv Medical Centre, Israel, for the ingestion of a strange, previously unknown foreign body. The objects had been inadvertently swallowed while eating certain dairy products such as yogurt or sour cream. This rigid, sharp pointed plastic object is a waste product which is punched out from the production line of the foods and their containers. The plastic object is radiolucent and, therefore, difficult to identify on standard roentgenograms. Fluoroscopic examination with a contrast medium was needed for its demonstration. Five patients underwent rigid esophagoscopy under general anesthesia for removal of the foreign body. In two other cases the object was extracted from the piriform sinus under topical anesthesia. This unusual foreign body, although uncommon, poses a potential medical hazard. A high index of suspicion is necessary to make the diagnosis when a patient presents with a history of foreign body ingestion while eating dairy products of soft consistency.

Aged↗
PubMed1988

Duplication methods for replacement of broken orthoses.

The methods presented for replacement of broken orthoses have proved very effective (Fig. 9). In more than 5 years of employing such duplication techniques, we have found patient satisfaction in the product to be commensurate with that for their originally prescribed devices. The techniques presented are not the only methods by which orthoses can be duplicated. We recognize that the clinician should refabricate the same orthosis only when the cause of breakage has been determined to be material fatigue or stress. Should the patient's weight, foot structure, or activities have changed, new orthoses should be fabricated with those factors in mind.

Equipment Design↗