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Biomedical subjects

L Johnson

Publications and source records attributed to L Johnson.

At least 289 records · Page 16Linked to original sources
PubMed1990

Primary biliary cirrhosis in the mouse: induction by human mycoplasma-like organisms.

Human intraocular and orbital chronic inflammatory disease with autoimmune features has been reported to be caused by mycoplasma-like organisms (MLO). MLO are intracellular cell-wall deficient pathogenic bacteria, closely related to rickettsia, with a characteristic ultrastrural pleomorphic tubulo-spherical and filamentous appearance. No culture system has been developed for MLO and diagnosis of MLO disease is made by detecting these bacteria within infected cells using a transmission electron microscope. In human MLO ocular and orbital disease the organisms are found in parasitized leucocytes at the disease site. Inoculation of human MLO into mouse eyelids produces a high incidence of orbital and introcular disease. MLO disseminate to produce randomly distributed lethal systemic disease with infected leucocytes found in all disease sites and with similar histologic features in all disease sites. Microvasculitis is the initial lesion. Disease progression results in lysis of vascular and parenchymal structures, stromal lymphocytic infiltrates, granulomas, and fibrosis. This report describes the hepatic portal chronic progressive inflammatory disease in 11 of 100 of those mice versus 0 in 200 controls. MLO parasitized portal leucocytes are present in all 11 inflamed livers versus 0 in 5 control livers (P less than 0.05). The resemblance of the animal liver disease induced by MLO to human primary biliary cirrhosis and rifampin treatment of MLO disease are discussed.

Animals↗
PubMed1990

Sequencing products of the polymerase chain reaction directly, without purification.

An improvement over current protocols for sequencing products of the polymerase chain reaction is described. This method allows sequencing products of the reaction without performing costly, time-consuming purification steps which often result in unacceptable loss of product. Conservation of small amounts of polymerase chain reaction products which can be obtained from limited DNA sources, such as tissue biopsies, is achieved. Clarity of autoradiograms obtained utilizing this adaptation is comparable to that obtained with the original method. In addition to streamlining the amplification-sequencing procedure, this procedure can potentially be subjected to total automation.

Base Sequence↗
PubMed1990

Ulcerative colitis associated chronic uveitis. Parasitization of intraocular leucocytes by mollicute-like organisms.

Uveitis is inflammation of the ocular vascular coats. Most uveitis is chronic, idiopathic, and considered to have an endogenous, possibly autoimmune pathogenesis. Chronic idiopathic uveitis occurs in isolation or with various systemic diseases including inflammatory bowel diseases. Using a transmission electron microscope vitreous leucocyte parasitizing and destroying mollicute-like organisms (MLO) are often found to cause chronic uveitis. Mollicutes are cell wall deficient bacteria. Mollicutes have a characteristic ultrastructural appearance. Extracellular mollicutes are fastidious, lipid-rich, and contain various potent cytotoxins. They cause human and animal diseases with autoimmune features. Morphologically similar organisms are intracellular non-cultivable pathogens that bear the eponym MLO. MLO are cytopathogenic, and cause host cell proliferation, destruction, and dysfunction. Uveitis producing MLO are detectable within parasitised vitreous lymphocytes, monocytes, and polymorphonuclear leucocytes. They appear as intracytoskeletal 0.005-0.01 micron diameter filaments and undulating pleomorphic trilaminar membrane bound 0.01-1.0 micron tubulo-spherical bodies. Cell wall deposition to form distinctive 'spore-like' cocci may also be seen. Inoculation of human uveitis MLO into mouse eyelids produces chronic uveitis. MLO also disseminate to produce chronic inflammatory disease in all organs including the gut. MLO are detectable in all the diseased organs. This report describes MLO parasitised vitreous and aqueous leucocytes in five ulcerative colitis patients with chronic uveitis. No microorganisms were cultivated using a wide variety of cultural techniques. The results indicate that MLO caused the uveitis of these patients. The possible role of this pathogen in human gut disease and Rifampin treatment of MLO disease are discussed.

Adult↗
PubMed1989

Blindness and sexual dimorphism associated with vitamin A deficiency in feedlot cattle.

Clinical, ophthalmoscopic, and histopathologic findings of vitamin A deficiency in a group of 535 feedlot cattle are described. Liver vitamin A content and results of histologic examination of ocular and osseous (optic canal) tissue confirmed the diagnosis. Blindness was the only clinical sign observed. Even though the steers and heifers in this feedlot were approximately the same age and were fed the same ration for an equal period, none of the heifers had overt clinical signs of hypovitaminosis A. Production of vitamin A by the bovine corpus luteum may account for the sexual dimorphism observed in vitamin A-deficient cattle.

Animals↗
PubMed1989

Epidermolysis bullosa simplex superficialis. A new variant of epidermolysis bullosa characterized by subcorneal skin cleavage mimicking peeling skin syndrome.

We report a new variant of epidermolysis bullosa simplex (EBS), termed EBS superficialis, which is characterized by the development of skin cleavage just beneath the level of stratum corneum. In two of seven patients identified, a second and more focal cleft within the lower third of the epidermis was also detected. Epidermolysis bullosa simplex superficialis appears to be transmitted as an autosomal dominant trait. It differs from other autosomal dominant forms of EBS by the common findings of milia and atrophic scarring, as well as involvement of oral and/or ocular surfaces. Epidermolysis bullosa simplex superficialis is further differentiated from peeling skin syndrome by the presence of blisters and the absence of spontaneous continual exfoliation or peeling.

Adult↗
PubMed1989

Autosomal recessive epidermolysis bullosa simplex. Generalized phenotypic features suggestive of junctional or dystrophic epidermolysis bullosa, and association with neuromuscular diseases.

With few exceptions, epidermolysis bullosa (EB) simplex is an autosomal dominant disorder characterized by rather localized and recurrent nonscarring blister formation; mucous membranes and other organs are usually uninvolved. Recently, two patients were described with an autosomal recessive form of EB simplex associated with muscular dystrophy. We now describe four additional patients with autosomal recessive EB simplex, three of whom had associated muscular dystrophy or congenital myasthenia gravis. These patients had generalized cutaneous findings, including milia, atrophic scarring, nail dystrophy, and scalp alopecia, which have been classically attributed to either junctional or dystrophic EB. Each patient had significant oral cavity involvement, and in two, marked growth retardation and anemia were also present. Our findings suggest that autosomal recessive EB simplex may be characterized by rather severe cutaneous and extracutaneous disease activity, and may be associated with at least two distinct neuromuscular diseases.

Adult↗
PubMed1989

H and 13C n.m.r. studies of serum from normal and Echinococcus multilocularis infected jirds.

The major components of the 13C and high field region of the 1H nuclear magnetic resonance (n.m.r.) spectra of normal and Echinococcus multilocularis infected jirds were identified and compared. Substantial depletion of the glucose and fatty acid chains from lower density lipoproteins was detected in sera from infected animals. In addition, this proliferating metacestode markedly changed the appearance of the spectral region recently assigned to N-acetyl protons of carbohydrate side chains of N-acetylated glycoproteins.

Animals↗
PubMed1989

Relationship between preexposure to prey and PCPA-induced filicidal activity in Sprague-Dawley rats.

Experiments, involving para-chloro-D,L-phenylalanine-induced pup-killing (filicide), were conducted to determine the effect of preexposure to the goal entity on the initial development and long-term expression of PCPA-induced filicide. Three groups of Sprague-Dawley rats (n = 50) were either preexposed/not preexposed, or preexposed for varying periods (5, 8, or 13 days) prior to receiving PCPA. Two major results were obtained: 1) preexposed animals were less filicidal than those not preexposed; and 2) there was an inverse relationship between the number of preexposures and filicide occurrence. The results are interpreted in reference to a serotonin-depletion habituation hypothesis.

Aggression↗
PubMed1989

Effects of postparturient uterine lavage on uterine involution in the mare.

Eighteen postparturient mares were used to evaluate effects of uterine lavage on uterine involution. Mares were randomly assigned to one of three treatment groups: Group 1 (seven mares), no lavage; Group 2 (five mares), lavage on Day 3 post partum; and Group 3 (six mares), lavage on Days 3, 4, and 5 post partum. Five liters sterile physiologic saline, prewarmed to 42 degrees C, were used for each lavage. Transrectal ultrasound examination of the reproductive tract was performed on Day 11 post partum to detect the presence of free fluid in the uterine lumen, to estimate the cross-sectional diameter of the uterine horns and body, and to determine if ovulation had occurred. Endometrial biopsies were also taken on Day 11 post partum to evaluate endometrial histologic characteristics. Lavage had no effect (P>0.05) on diameter of the uterine body or previously gravid uterine horn, presence of fluid in the uterine lumen, or number of mares which had ovulated by Day 11 post partum. Histologic characteristics of the endometrium (height of luminal epithelium, gland depth, relative gland vclume, and inflammatory-cell score) were not affected by treatment (P>0.05). Postpartum uterine lavage did not significantly affect uterine involution by the parameters measured in normal-foaling mares at Day 11 post partum.

Journal Article↗
PubMed1989

Effect of sustained pharmacologic vitamin E levels on incidence and severity of retinopathy of prematurity: a controlled clinical trial.

The incidence and severity of retinopathy of prematurity (ROP) as affected by vitamin E prophylaxis at pharmacologic serum levels (5 mg/dl) were evaluated in a double-masked clinical trial of infants with a birth weight less than or equal to 2000 gm or a gestational age less than or equal to 36 weeks. The infants were enrolled by age 5 days and randomly assigned to receive parenterally administered, and later orally administered, free alpha-tocopherol (vitamin E) or its placebo. Study medication was continued until retinal vascularization was complete or active ROP had subsided, except in infants with a diagnosis of severe disease, in whom vitamin E was substituted for study medication. Acute ROP data were collected on 755 infants. Logistic regression analysis, with control for immaturity, oxygen exposure, and other illness risk factors, showed a decrease in incidence of ROP in vitamin E-treated infants (p = 0.003, all infants; p = 0.035, infants weighing less than or equal to 1500 gm at birth). Among the 424 infants weighing less than or equal to 1500 gm at birth, the age at enrollment influenced treatment effect (age day 0 to 1, p = 0.006 (n = 288) vs age day 2 to 5, p greater than 0.1 (n = 136]. Overall, 77.6% of infants with ROP had mild disease. Moderate to severe ROP was confined to infants weighing greater than or equal to 1500 gm at birth (25 given placebo, 25 given vitamin E), with progression to severe disease in nine placebo-treated versus three vitamin E-treated infants (p = 0.048). The incidence of severe ROP per se was not significantly decreased (all birth weights, p = 0.086; less than or equal to 1500 gm birth weight, p = 0.080); the sample size was too small, however, to assess this end point adequately. An increased incidence of sepsis and late-onset necrotizing enterocolitis was found among vitamin E-treated infants weighing less than or equal to 1500 gm at birth who received study medication for greater than or equal to 8 days (p = 0.006). Because most ROP is mild in degree and regresses completely, the risk/benefit ratio of pharmacologic prophylaxis for ROP is unfavorable. Treatment of moderate and severe ROP with vitamin E above physiologic serum levels (greater than 3 mg/dl) appears promising and should be further investigated. The interpretation of cicatricial outcome was confounded by the small number of patients involved and by subsequent treatment of severe ROP in placebo-treated infants with vitamin E.

Age Factors↗
PubMed1989

Temporal appearance of seasonal changes in numbers of Sertoli cells, Leydig cells, and germ cells in stallions.

The temporal appearance of seasonal changes in numbers of Leydig, Sertoli, and germ cells was evaluated to determine if seasonally increased daily spermatozoan production might be preceded by changes in numbers of either of two somatic testicular cells. A significant increase in numbers of spermatogonia and Sertoli cells preceded the significant increase in number of Leydig cells in the approaching breeding season. Seasonal changes in parenchymal weight and in numbers of Sertoli cells, Leydig cells, and germ cells were maximal in May and June. Numbers of A or B spermatogonia in June were 2.4 to 2.5 times the number present in January. During the same time period, numbers of other germ cells, as well as Leydig cells and Sertoli cells, were increased by 1.5 to 1.9 times. The magnitude of change between January and March (first time period that the change was significant) was greater for A spermatogonia (1.7-fold) than for other cell types (1.3-fold to 1.5-fold). Hence, the need to accommodate more spermatogonial progeny might cause increased testicular size and number of somatic cells, including Sertoli cells. Season did not influence the rate of degeneration between A and B spermatogonia. However, in the breeding season, the conversion of B spermatogonia to primary spermatocytes was reduced. The lack of a seasonal difference in the ratio of primary spermatocytes per Sertoli cell was consistent with a limited capacity of individual Sertoli cells to accommodate primary spermatocytes.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Epidermolysis bullosa simplex: identification of a kindred with autosomal recessive transmission of the Weber-Cockayne variety.

With few exceptions, epidermolysis bullosa simplex (EBS) is transmitted as an autosomal dominant trait. All cases of autosomal recessive EBS reported to date have been associated with significant extracutaneous disease (including anemia, marked growth retardation, dentition abnormalities, and/or concurrent neuromuscular disease), early infant mortality, or often, rather extensive cutaneous involvement. In some, the cutaneous morphology has even suggested junctional or dystrophic disease. We cared for a kindred in which four individuals were affected with an autosomal recessive form of EBS with cutaneous findings most often suggestive of Weber-Cockayne disease. Except for scattered oral erosions in one patient, there was no evidence of associated extracutaneous disease. These findings demonstrate the increasing complexity of even the simplex forms of inherited epidermolysis bullosa. This obviously has implications for genetic counseling.

Adolescent↗
PubMed1989

Sarcoidosis associated uveitis. Parasitization of vitreous leucocytes by mollicute-like organisms.

Mollicute-Like Organisms (MLO) have been reported to be a cause of uveal tract and orbital chronic inflammatory disease. MLO are intracellular cytopathogenic cell wall deficient bacteria. No culture system exists for MLO, MLO disease diagnosis is based chiefly on direct detection of the organisms within diseased cells using a transmission electron microscope. Uveitis producing MLO are detectable within vitreous leucocytes as 0.005-0.01 micron filaments and undulating pleomorphic 0.01-1.0 micron tubulo-spherical bodies. Human uveitis producing MLO can be passed to laboratory animals. Inoculation into mouse eyelids produced intraocular, orbital, and lethal systemic chronic progressive inflammatory disease. MLO parasitised lesional leucocytes were found in all the disease sites. The MLO induced mouse chronic interstitial pneumonitis displayed 'sarcoid-like' granulomas. This report describes MLO parasitised vitreous leucocytes in the chronic uveitis of four sarcoidosis patients. The results indicate that MLO caused the uveitis. The implications of the results and Rifampin treatment of MLO disease are discussed.

Adult↗
PubMed1989

Chronic orbital inflammatory disease: parasitisation of orbital leucocytes by mollicute-like organisms.

Chronic orbital inflammatory disease (COID) is usually considered non-infectious and idiopathic. Treatment is empirical, palliative, and may not prevent disease progression. COID occurs in isolation or in association with various systemic diseases. Exophthalmos may be an important presenting sign. Vasculitis, lymphoid infiltrates, and granulomas are common. Mollicute-like organisms (MLO) parasitising and destroying vitreous leucocytes are often found to cause human chronic uveitis when an appropriate search is made. Inoculation of these MLO into mouse eyelids produced chronic uveitis and exophthalmic orbital inflammatory disease. Mollicutes are cell wall deficient bacteria. Extracellular mollicutes cause human and animal diseases characterised by lymphoid infiltrates, immunosuppression, and autoantibody production. Intracellular morphologically similar bacteria are non-cultivable pathogens termed MLO. Identification is based on direct detection in diseased cells by transmission electron microscopy. MLO are cytopathogenic and detection is aided by the alterations they produce. MLO replace the cytoplasm, destroy the organelles, and alter the nucleus. This results in cell proliferation, destruction, and dysfunction. MLO parasitise lymphocytes, monocytes, and polymorphonuclear leucocytes. This report describes orbital leucocytes parasitised by MLO in three patients with isolated COID. Rifampicin treatment of MLO disease is discussed.

Adolescent↗
PubMed1989

The effect of a 5 alpha-reductase inhibitor on androgen physiology in the immature male rat.

To provide insight into the role of 5 alpha-dihydrotestosterone (DHT) in postnatal androgen physiology, we administered the 5 alpha-reductase inhibitor finasteride to male rats from birth through the onset of puberty. In 4-week-old control rats serum testosterone levels averaged 0.21 ng/ml, and DHT levels averaged 0.64 ng/ml. By 7 weeks of age, testosterone levels increased more than 7-fold to 1.57 ng/ml, while the circulating DHT level declined to 0.26 ng/ml. In both the 4- and 7-week-old inhibitor-treated animals, circulating DHT levels were 25-50% of control values, and circulating testosterone levels were higher than control values. In 7-week-old inhibitor-treated rats, the weights of prostate, penis, seminal vesicles, and epididymal tissues were only 30-50% those of the controls. However, DHT formation is apparently not critical for postnatal development of the preputial glands or the androgen-dependent perineal muscles, since the weights of these tissues were not affected by treatment with inhibitor. Treatment with the 5 alpha-reductase inhibitor had no apparent effect on testicular histology or daily sperm production despite the fact that testicular DHT content was lower (70%) and testosterone content was higher (250%) than those in controls. We conclude that DHT formation is important for the normal postnatal growth of the prostate, seminal vesicles, epididymis, and penis and may be important for normal feedback control of testosterone production in rats, but that its formation is not critical for the onset of spermatogenesis or the development of the preputial glands or the androgen-dependent perineal muscles.

5-alpha Reductase Inhibitors↗
PubMed1989

Temporary paralysis of cranial nerves III, IV, and VI after a Gow-Gates injection.

A case of temporary complete paralysis of cranial nerves III, IV, and VI, after a Gow-Gates injection is reported. The proposed explanations for the mechanisms of occurrence are described. Although the Gow-Gates technique has many advantages, it is not without complications. To avoid such complications, it is important to take the following precautions when using the Gow-Gates technique: because of the proximity of the internal maxillary artery (accessory and middle meningeal) and the pterygoid plexus of veins, and because the anesthetic is injected quickly, it is paramount that careful aspiration be performed before administration of the local anesthesia; injections should be on or within 1 mm to 2 mm of the condylar neck.

Abducens Nerve↗
PubMed1989

Juvenile rheumatoid arthritis inflammatory eye disease. Parasitization of ocular leukocytes by mollicute-like organisms.

Patients with juvenile rheumatoid arthritis (JRA) commonly develop serious eye disease, particularly chronic uveitis. Most chronic uveitis is idiopathic. Mollicute-like organisms (MLO) were recently reported to be a common cause of chronic uveitis. MLO are pathogenic intracellular cell wall deficient bacteria. No culture system exists for MLO. Disease diagnosis is based on detection using a transmission electron microscope. Uveitis producing MLO are detectable within parasitized intraocular leukocytes. They appear as intracytoskeletal 0.005-0.01 micron diameter filaments and undulating pleomorphic 0.01-1.0 micron tubulospherical bodies. This report describes MLO parasitized lesional leukocytes in the inflammatory eye disease of 5 patients with JRA. Our results indicate that MLO caused the uveitis of these patients. The significance of these findings and rifampin treatment of MLO disease are discussed.

Actin Cytoskeleton↗