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Biomedical subjects

C Baker

Publications and source records attributed to C Baker.

At least 37 records · Page 2Linked to original sources
PubMed1990

Arthrocutaneous haemangiomatosis with destructive arthritis.

A case of synovial haemangiomatosis of the knee joint with associated severe destructive arthritis is reported. The patient also had widespread cutaneous port wine stains and a bilateral Naevus of Ota. The interesting association between cutaneous and synovial haemangiomatosis is discussed. A pathogenic association of synovial haemangiomatosis and destructive arthritis is offered. Patients presenting with port wine stains and joint symptoms should be considered for the investigation of synovial haemangiomatosis.

Aged↗
PubMed1989

Human disease associated with "Campylobacter upsaliensis" (catalase-negative or weakly positive Campylobacter species) in the United States.

Catalase-negative or weakly positive (CNW) thermotolerant campylobacteria, first isolated from dogs in 1983, were recently recognized as a new species, "Campylobacter upsaliensis," but their association with human illness has not been established. Twelve human isolates received at the Centers for Disease Control between 1980 and 1986 were identified as CNW campylobacteria by biochemical tests, cellular fatty acid composition, and antimicrobial susceptibility patterns. Eleven CNW Campylobacter strains tested by DNA-DNA hybridization (hydroxyapatite method) were all highly related and were related to two "C. upsaliensis" strains at the species level (86% under optimal conditions and 76% under stringent conditions). Clinical information was obtained for 11 human isolates from three stool and eight blood specimens. They were isolated from four female and seven male patients 6.5 months to 83 years of age residing in 10 different states. The patients had a wide spectrum of illnesses. The stool isolates were obtained from two previously healthy persons during episodes of acute gastroenteritis and from one immunocompromised patient with persistent diarrhea and fever. The blood isolates were obtained from two infants with fever and respiratory symptoms; a young woman with a ruptured ectopic pregnancy; three elderly men with underlying chronic diseases; and two immunocompromised adults. In a bactericidal assay to assess sensitivity to serum, seven of eight blood isolates showed some resistance to killing by pooled normal human serum. These observations suggest that "C. upsaliensis" is a potential human pathogen associated with both gastroenteritis and bacteremia in normal hosts and with opportunistic infection in immunocompromised individuals.

Adult↗
PubMed1989

Injurious effect of the eosinophil peroxide-hydrogen peroxide-halide system and major basic protein on human nasal epithelium in vitro.

Tissue injury is observed in allergic and nonallergic eosinophilic rhinitis, but the mechanism of this injury is unclear. Because eosinophils are prominent in biopsy specimens in these conditions, we hypothesized that they may participate in the injury process. Initially, we developed techniques to isolate and purify human nasal epithelial cells from turbinate biopsies to use as target cells for eosinophil granule products. Primary cultures from explants were characterized by electron microscopy and indirect immunofluorescence with a panel of primary monoclonal and polyclonal antibodies. These studies revealed the homogeneity of the cells and confirmed their epithelial nature. Cultured nasal epithelial cells were then exposed to either purified human eosinophil peroxidase, bromide, and glucose plus glucose oxidase, as a continuous source of hydrogen peroxide, or eosinophil major basic protein. Neither eosinophil peroxidase alone nor glucose plus glucose oxidase in the absence of eosinophil peroxidase were injurious, but the combined addition of eosinophil peroxidase, glucose/glucose oxidase, and bromide produced marked target cell lysis. This effect was time- and eosinophil peroxidase dose-dependent. Catalase and azide significantly inhibited the lysis of these cells, suggesting the eosinophil peroxidase-catalyzed products of halide oxidation mediated this form of injury. The addition of purified human eosinophil major basic protein also caused dose- and time-dependent lysis of the nasal epithelial cells but required longer incubation periods to effect injury. We hypothesize that the eosinophil peroxidase-hydrogen peroxide-halide system and major basic protein may injure the nasal epithelium in inflammatory conditions such as allergic and nonallergic eosinophilic rhinitis.

Blood Proteins↗
PubMed1989

Human nasal epithelium: characterization and effects of in vitro exposure to sulfur dioxide.

Human nasal turbinate tissue from surgical specimens was dissected free of connective tissue, and primary epithelial cultures were established by explant techniques. Transmission electron microscopy revealed that cultured cells retained homogeneous cytoplasmic granules, tonofilaments, and desmosomes and formed a homogeneous monolayer. The epithelial cells stained positively with cytokeratin antibodies AE1, AE3, and 35BH11 but failed to stain with two other cytokeratin antibodies, AE2 and 34BE12. Staining was also positive with anti-desmoplakin I and II but negative with antivimentin (43BE8), anti-desmin, and anti-human factor VIII antibodies. Cultured cells were exposed to filtered air or sulfur dioxide at 1-5 ppm for 30-60 min. Although there was no increase in cell lysis as measured by chromium-51 release, SO2 exposure significantly inhibited [3H]leucine incorporation compared to air exposure. This effect was dependent on both SO2 concentration and exposure duration. Control experiments revealed that these SO2 effects were not caused by the [H+] load produced by SO2 exposure. Electron microscopy of cells exposed to air or SO2 did not show any significant morphological differences.

Adolescent↗
PubMed1988

Antisense oligodeoxyribonucleotide-directed cleavage of maternal mRNA in Xenopus oocytes and embryos.

We have investigated the effect of specific antisense oligodeoxynucleotides (oligos) on endogenous histone H4 mRNA in Xenopus oocytes, eggs and embryos. In unfertilised eggs and non-matured oocytes, one 20-mer oligo (H4-1) mediated the RNAse H-like cleavage of up to 95% of H4 mRNA (which included polysomal mRNA), and cleavage was still obtained when the size of the oligo was reduced to a 10-mer; no cleavage was observed with 6- and 8-mers. The residual uncleaved mRNA appeared to be completely inaccessible to H4-1 since a second injection caused no further cleavage. A second 20-mer (H4-2) directed against a different region of H4 mRNA was much less effective (less than 5% cleavage). In fertilised embryos, injections of H4-1 and an oligo directed against the localised Vg1 mRNA caused less cleavage than in oocytes and also showed signs of inducing localised, non-specific mRNA cleavage. However we have been able to prepare fertilised embryos devoid of Vg1 mRNA by maturing and fertilising oligo-injected oocytes in vitro.

Animals↗
PubMed1988

Alteration of monocyte function following major injury.

The macrophage exerts its stimulatory and regulatory functions within the specific immune response via the interleukin 1 (IL-1) and prostaglandin E2 (PGE2), respectively. In a screening study of macrophage-related variables following injury, a total of 58 patients (mean age, 32 years; mean injury Severity Score, 38), macrophagic phenotyping with the monoclonal antibody Leu M3 and serial measuring of the antagonistic monokines IL-1 and PGE2 and of the macrophage-activating lymphokine interferon gamma were carried out on posttrauma days 0, 1, 3, 5, 7, 10, 14, and 21. The posttraumatic course was characterized by significant monocytosis, showing a peak value of 32% of Leu M3-positive cells compared with 15% of these cells in normal control subjects. During the posttrauma course, the macrophagic PGE2 output was significantly elevated up to eightfold on days 5 and 7 compared with that of control subjects (0.441 +/- 0.14 ng/mL vs 0.052 +/- 0.01 ng/mL). Conversely, macrophagic IL-1 synthesis was significantly suppressed until day 10. Levels of interferon gamma were suppressed to a significant degree during the two-day observation period, with a trend to slow recovery at the end of week 3. These data suggest that a negative regulatory macrophagic function may be the event initiating posttraumatic immunosuppression. To restore impaired macrophagic T-helper cell interaction, cyclo-oxygenase inhibition and substitution of interferon gamma may be useful to potentiate facilitatory macrophagic function and to block inhibitory macrophagic activity.

Adolescent↗
PubMed1988

Asymptomatic Chlamydia trachomatis infections in teenage males.

This study examined the prevalence of Chlamydia trachomatis infections of the urethra in asymptomatic teenage males in a juvenile detention setting. Gonorrhea cultures, chlamydia smears using the direct immunofluorescent antibody (DFA) technique, and 15-20 ml of a first-catch urine (FCU) sample were obtained. Of the 227 adolescent males screened, 205 had experienced sexual intercourse. Twenty-seven (13.2%) of the sexually active adolescents had positive DFA smears for C. trachomatis. Three (1.5%) had positive Neisseria gonorrhoeae cultures. A urine leukocyte count of greater than 10 per high-power field gave a 91% specificity but only a 26% sensitivity for a positive DFA. The high prevalence of chlamydia in this population and the relative low cost of the DFA screen for chlamydia make this a useful procedure for discovering unsuspected disease, particularly in a high-risk population. The FCU screen for leukocytes was of limited value in identifying asymptomatic infection.

Adolescent↗