Biomedical subjects
Publications and source records attributed to Z Samra.
A 40-year-old patient with no immune deficiency was admitted because of severe bilateral pneumonia and pleural effusion. The diagnosis of Chlamydia trachomatis pneumonia was confirmed by isolation of the pathogen and the appearance of serum antibodies to Chlamydia species.
Inbred guinea pigs selected for high (IMM/S) respectively low (IMM/R) responsiveness to ovalbumin (OA) as measured by induced respiratory anaphylaxis, were investigated for atopic immune responses of their conjunctival mucosa. IMM/S animals sensitized either by inhalation of OA, or by instillation of antigen into the conjunctival sac, developed regularly an acute ocular inflammatory response to topical (conjunctival) challenge with the allergen. A minimum of 1 microgram OA dropped repeatedly into the conjunctival sac was enough for both ocular and systemic sensitization of the animals, but the minimal dose of effective challenge was considerably higher. In IMM/R animals, ocular hypersensitivity was not achieved by inhalation of OA, but after topical administration of the antigen some of the IMM/R strains could be challenged to ocular anaphylactic responses of the same intensity as observed in IMM/S animals. The conjunctivae of both IMM/S and IMM/R animals could be sensitized passively by intraperitoneal injection of guinea pig sera containing homocytotropic antibodies to OA, but topical administration of such sera had no effect.
The relationship of capsular types of Staphylococcus aureus to type of infection, carrier state, and phage type was studied in a collection of 477 isolates from 380 infection sites. Capsular polysaccharides were demonstrated by precipitation and agglutination with 11 monospecific antisera. When only one isolate from each infection was considered, 63% were of type 8 and 16% were of type 5. Of all the isolates tested, over 90% were encapsulated. We did not demonstrate any marked difference in the distribution of capsular types between isolates from the blood stream or purulent processes and isolates from healthy carriers or food. Most isolates from bovine mastitis milk had nontypeable capsules. The capsular type seemed stable in culture, and encapsulation had no apparent influence on susceptibility to phages. Of 27 phage-propagating strains maintained via culture transfer on artificial media over many years, 16 (59%) produced capsules. A striking association between certain phage patterns and capsular types was demonstrated.
Low genital tract infectious agents were examined 411 times in 386 young women. Each examination included anamnesis, physical examination and broad-spectrum microbiologic analysis for the detection of: Ureaplasma urealyticum, Chlamydia trachomatis, Trichomonas vaginalis, Candida species, Mycoplasma hominis, Streptococcus beta hemolyticus Group B, Hemophilus vaginalis, Neisseria gonorrhoeae and syphilis serology. Three hundred and six patients were symptomatic for low genital tract infection and 80 were asymptomatic. Most patients were young, 19.6 +/- 1.7 (SD) years old, single (84.7%) and sexually active (87.4%). U. urealyticum and C. trachomatis were the most common agents recovered in 43.9 and 40.8% of symptomatic patients, respectively. All agents were isolated more frequently in the symptomatic group, but statistically significant group comparisons were obtained only for Candida sp. (P less than 0.001), T. vaginalis (P less than 0.005) and M. hominis (P less than 0.05). N. gonorrhoeae was isolated in only one case (0.3%), which may reflect technical difficulties or a true very low prevalence of this agent. Clinical diagnoses of candidiasis and trichomoniasis in symptomatic patients were confirmed by laboratory results in only 34.9 and 54.9%, whereas negative clinical diagnoses were confirmed in 83.9 and 73.2%, respectively.
A patient with erythema multiforme developed septicemia with two strains of Staphylococcus aureus. Six blood cultures, obtained during 14 days, yielded a mixture of both strains. The strains differed in the ability to hemolyze human erythrocytes, in the production of beta-lactamase and in the susceptibility to antibiotics and bacteriophages. Following therapy with gentamicin, a Dwarf colony variant auxotrophic for vitamin K, tryptophan and p-aminobenzoic acid appeared in some of the blood cultures. This variant was apparently derived from one of the offending strains (phage Type 55/71). From other blood cultures, a different type of Dwarf colony variant was obtained; this variant was of the same phage type as the other offending S. aureus strain (Type 85). The metabolic deficiencies of this strain were not unraveled. Both events, the double infection with distinct S. aureus strains, and the emergence of Dwarf variants during antibiotic therapy, are unusual in clinical practice, and will be detected only if laboratory staff pays particular attention to the possible occurrence of such events.
Vernal keratoconjunctivitis (VC) is an inflammatory disorder of the outer eye, probably of allergic etiology. The present study was performed on patients with a typical clinical appearance of VC and examined periodically for serum and tear IgE and albumin (HSA). The geometric mean of serum and tear IgE was 219 and 18 IU/ml, respectively, for the patients, but about 100 and less than 1 IU/ml for serum and tears of healthy controls and of parents of VC patients. A positive correlation between variations in tear IgE and tear HSA was observed, indicating that tear IgE levels have a significant influence on the intensity of the inflammatory process.
Tears and sera of 53 patients of vernal conjunctivitis were examined for antibodies of the IgE type to a panel of 18 allergens. In 18 of the patients (34.0%) allergen-specific IgE was demonstrated in both tears and serum, in 3 (5.7%) in tears only, and in 4 (7.5%) in serum only. The antigen-specific reactions with tear fluid were found in patients with the highest total IgE levels, not only in tears but also in serum. This is evidence for a specific, local allergic reaction in these patients. Most positive reactions were to perennial allergens, particularly house dust mites, cat epithelium and Bermuda grass. This fact is in harmony with the lack of season-linked symptoms in most patients in this geographical area.
Serum and tear levels of IgE were compared in patients with contact lens papillary conjunctivitis (CLPC), vernal keratoconjunctivitis (VC), healthy contact lens wearers (CLW), and healthy controls without lenses. The mean of serum IgE was elevated only in the VC group. Tear IgE levels were significantly higher for CLPC and VC than for CLW and healthy controls. Tear IgG levels were also increased in CLPC patients. With serum albumin (HSA) as a marker for leakage of proteins from the circulation to the tear fluid, the data indicated, that tear IgG was blood-borne whereas tear IgE was essentially a product of local synthesis. In one of the 10 CLPC patients, high titers of IgE type antibodies to housedust mites and cat epithelium were demonstrated in both serum and tears. We conclude that CLPC is usually an IgE mediated reaction to the lens material or to contaminations of allergenic material that sticks to the lenses.
Two clinically similar cases of vernal keratoconjunctivitis with dissimilar immunological data are reported. One patient had strikingly elevated IgE levels in both serum and tears, and his tear fluid contained specific IgE antibodies to a number of allergens. Conjunctival scrapings and peripheral blood samples showed marked eosinophilic reactions. The other patient showed normal values for tear and serum IgE; no IgE type antibodies to allergens were detected; and no local or systemic eosinophilic reactions were observed. The immunopathogenesis of these cases is discussed.
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Vernal keratoconjunctivitis (VKC) is usually considered as an allergic eye disorder of type I, and in most therapeutic trials it has been shown to yield to topical treatment with sodium cromoglycate. This has been confirmed in the present study of VKC patients from Israel. However, some of the cases seemed not to benefit from this treatment. In a survey of IgE levels in VKC patients in Israel tear IgE levels were significantly increased in 63.5%, but in 29% of the patients both tear and blood IgE levels were normal to low. The possibility that some of the cases diagnosed as VKC might have another cause than IgE-mediated atopy is discussed.
A general concept is proposed to explain the mechanism of bacterial resistance to tetracycline, and is essentially based on experimental date and a review of recently of recently published studies. It is assumed that tetracyclines are accumulated in the bacterial cell by an energy-demanding, carrier-mediated influx-mechanism, at a rate depending on the concentration of the antibiotic in the medium. Tetracyclines seep out of the cell by facilitated diffusion at a rate depending on the concentration inside the cell. At steady state, when no net alteration of the intracellular concentration is evident, the molecules of the antibiotic, inside and outside the cell, are exchanged by influx and efflux. In the resistant organism, an additional energy-demanding and carrier-mediated efflux-mechanism is assumed. The total efflux rate is therefore increased, and the steady state is obtained at a lower intracellular level of tetracyclines. It is possible that, in addition, the influx is decreased in the resistant organism.
The levels of total protein in tears from healthy donors, conjunctivitis vernalis patients, and conjunctivitis follicularis patients, were 625, 1370 and 1160 mg% respectively. Serum albumin accounted for 3.3%, 43% and 67% of the total protein of tears from these groups, and the level of proteins probably synthesized by the lacrimal gland, was in tears from conjunctivitis follicularis patients only half the level in normal tears. By crossed immunoelectrophoresis with intermediate gel, 10 antigenic species could be recognized in normal tears, and of these the following were identified: Lysozyme, IgA, lactoferrin and serum albumin. In tears from patients with conjunctivitis vernalis three more immunoprecipitates were observed, of which one was due to IgG. No lysozyme could be demonstrated in tears from a case of conjunctivitis sicca by immunoelectrophoresis. In tears from healthy donors the mean level of IgA was 20 mg%, of IgG 3 mg%, and IgM could not be demonstrated. Rabbit anti-tear immunoglobulin did not precipitate a standard of human IgM in double immunodiffusion. In cases of conjunctivitis vernalis and follicularis the mean levels were increased to 80 and 114 mg% IgG, and 11 and 14 mg% IgM, but IgA was increased only to 32 and 41 mg%. It is assumed that the level of IgA in normal tears is almost entirely due to local synthesis, while serum albumin and other immunoglobulins may have escaped from the circulation by molecular sieving. The increased levels of immunoglobulins in inflammatory diseases is probably due to transudation. However, in blepharoconjunctivitis patients several tear samples with a high IgM and a low or zero level of IgG could be demonstrated. Possible explanations for this phenomenon are discussed.
In crude water-soluble extracts of Pseudomonas aeruginosa 64 antigens can be demonstrated by crossed immunoelectrophoresis in agarose with polyvalent Pseudomonas-immunoglobulin. One of these antigens cross-reacts with antigens prepared from bacteria of a wide range of taxonomic groups. Monospecific immunoglobulins to this antigen (Common Antigen) were produced by immunization with the appropriate immunocomplex extracted from agarose. Common Antigen was purified by the combination of two fractionation methods: Precipitation of the crude extract with 18% (w/v) sodium sulfate, followed by gel filtration of the supernatant on a Sephadex G-200 column. By this method, 35% of Common Antigen from the crude extract was recovered, more than half of the fractions electrophoretically pure. Electrophoresis of reduced Common Antigen on a dodecyl sodium sulfate polyacrylamide gel revealed two protein bands with apparent molecular weights of 59-62 000 and 62-65 000, respectively. The untreated antigen, however, passed a column of Sephadex G-200 with the void volumen, indicating a substance of high molecular weight (> 4-600 000).
Common Antigen (CA) of Pseudomonas aeruginosa has been shown to be a protein composed of polypeptide subunits of a molecular weight (MW) of about 62 000. The MW of this protein was estimated to 665 000 by gel filtration on sepharose CL-6B, to 800 000 by electrophoresis on polyacrylamide gradient gels and to about 900 000 by ultracentrifugation, on a sucrose gradient. By analytical ultracentrifugation with Schlieren optics a sedimentation coefficient (S20 degrees, W) of 22.65 was calculated. The isoelectrical point was determined to pH 4.4. The antigen was decomposed on exposure to proteolytic enzymes. Polysaccharide, lipid, deoxyribonucleic acid or ribonucleic acid were not demonstrated in CA. The amino acid content of CA was determined, and no hexosamine or abnormal residues were observed. The amino acid content of CA was determined, and no hexosamine or abnormal residues were observed. The antigen was degraded when heated to 100 degrees C for 4 min or when exposed to pH below 4 or above 11 at 4 degree C. CA has been isolated from the cytoplasmic water-soluble fraction of disintegrated bacteria and only trace-amounts could be obtained from envelope fractions after solubilization with Triton X-100.
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Explore the source record for details and available documents.