MICROVASCULAR ANGIOPATHY IN ADVANCED PERIODONTAL DISEASE

Previous studies have shown a perivascular hyaline thickening affecting restricted regions of the microcirculation in gingivitis and moderate periodontitis and in the pulpal vessels in chronic pulpitis. In the present study of the lesion of advanced periodontitis, immunostaining for type IV collagen and laminin demonstrated widespread deposition of basement membrane material, with manifest involvement of the venous network. Some vessels were associated with an increased deposition of both basement membrane proteins, while others showed preferential deposition of either laminin or type IV collagen. Immunostaining also revealed an extensive trabecular network of type IV collagen throughout the affected gingival tissue that was not related to recognizable vessels but was co-extensive with less intense staining for laminin. This network was not associated with viable endothelial cells demonstrable by staining with the endothelial marker Ulex agglutinin (UEA-1). The results indicate extensive vascular pathology in advanced periodontitis that could explain the attenuation of the inflammatory reaction and the restricted ability to develop reparative granulation tissue in this disease.     

Phonological development: a normative study of British English‐speaking children

This paper reports a normative study on the phonological development of British English‐speaking children. Speech samples of 684 children, aged between 3;0 and 6;11 years, randomly selected from nurseries and schools in eight different areas throughout the UK, were collected and analysed to obtain normative data. This paper reports on two aspects of speech development: the age of acquisition of sounds (phonetic acquisition) and the age that error patterns were suppressed (phonemic acquisition). It discusses the effects of age, gender and socio‐economic status on speech sound development. The study found that older children had more accurate production and fewer error patterns in their speech. It found no gender differences in the younger age groups. However, in the oldest age group, it found the phonological accuracy measures of girls' better than boys. It found no significant effects of socio‐economic status on any of the phonological accuracy measures.     

A Family with Hemoglobin I

Hemoglobin I was recently found in a Negro family. The amino acidsubstitution was shown to occur in the sixteenth residue of the chain (lys asp) and to be identical with hemoglobin I described by Murayama.¹⁰ Theminor component, I₂, was demonstrated by agar gel electrophoresis.

Submitted on January 9, 1963 Accepted on April 3, 1963     

EFFECT OF PROLONGED ADMINISTRATION OF RANITIDINE ON PITUITARY AND THYROID HORMONES, AND THEIR RESPONSE TO SPECIFIC HYPOTHALAMIC-RELEASING FACTORS

We have studied, in a double blind controlled trial, 30 male patients with duodenal ulcer to evaluate the effect of prolonged oral administration of ranitidine (150 mg bd for 4 weeks), a new H2-receptor antagonist, on basal PRL, LH, FSH and TSH concentrations, on their response to specific releasing hormones, and on basal and TRH-stimulated levels of thyroid hormones. Neither the basal levels of PRL, FSH, LH and TSH, nor their response to stimulation with appropriate releasing hormone were affected by ranitidine. Basal concentrations of T4 and its levels after TRH stimulation at 40 min (but not at 20, 60 and 120 min) were lower after ranitidine treatment (P < 0·05); basal and stimulated T3 and rT3 were unaffected. These results could suggest a possible role of histamine in thyroxine regulation but further studies are required.     

The value of bacteriology and serology in the diagnosis of cellulitis and erysipelas

Patients diagnosed as suffering from erysipelas or cellulitis were subjected to bacteriological and serological investigations. The serological tests used included the anti-streptolysin O reaction (ASO), the anti-deoxyribonuclease B test (ADB) and the anti-hyaluronidase tests (AHT) that are specific both for the group A streptococcus (Streptococcus pyogenes) and for the human pyogenic streptococci of group C or group G. Antibody tests to the alpha-lysin and the nuclease of Staphylococcus aureus were also employed. Conventional bacteriological culture methods were used plus needle aspiration of injected saline in most patients with erysipelas, but recognized pathogens were isolated in only 42% of cases. Our results indicate the limitations of these tests for making initial diagnoses and deciding treatment. Serial serological testing was very successful in differentiating cellulitis due to group A, C or G haemolytic streptococci, or occasionally Staphylococcus aureus, but was positive in only 40% of cases of erysipelas.     

Increased Activity of Some Folic Acid Enzyme Systems in Infectious Mononucleosis

Increased levels of activity for the formate activating enzyme and N⁵,N¹⁰-methylene FH₄ dehydrogenase have been found in the leukocytes from patients with infectious mononucleosis; in addition dihydrofolic reductase, anenzyme not found in mature circulating leukocytes, has been detected in infectious mononucleosis cells. Glucose-6-phosphate dehydrogenase activity isless in infectious mononucleosis leukocytes than in normal leukocytes.

These findings are similar to the results obtained in acute and chronic myelogenous leukemia and indicate that the leukocytes seen in infectious mononucleosis have the enzymatic apparatus associated with synthesis of DNA.

Submitted on November 6, 1961 Accepted on January 12, 1962     

Fish and Amphibian Embryos -- A Model System for Evaluating Teratogenicity

Fish and Amphibian Embryos—A Model System for EvaluatingTeratogenicity. Birge, W.J., Black, J.A., Westerman, A.G. andRamey, B.A. (1983). Fundam. Appl. Toxicol. 3: 237–242.Developmental stages of fish and amphibians were used to evaluatereproductive impairments produced by environmental contaminants.Using static-renewal and flow-through procedures, exposure wasinitiated at, or soon after, fertilization and maintained through4 days posthatching. Trace concentrations of many environmentaltoxicants produced high frequencies of mortality and teratogenesis.When developmental stages of the trout were exposed to inorganicmercury, 10% control-adjusted mortality was observed at 1 µg/Land frequencies of terata in hatched populations ranged from8% to 43% for exposure concentrations of 2 to 25 µg/L-In similar tests with the narrow-mouthed toad, 45% mortalityoccurred when mercury was administered at 1 µg/L; frequenciesof teratogenesis ranged from 8% to 17% at exposure concentrationsof 1 to 5 µg/L; and complete mortality occurred at 7 µg/L.Boron-induced teratogenesis in trout ranged from 5% at 1 µg/Lto 51% at higher exposure levels. When catfish embryos wereexposed to atrazine at 0.06, 4.8, and 46.7 mg/L, terata appearedin surviving populations at frequencies of 4%, 69%, and 100%,respectively. Fish and amphibian developmental stages constitutesimple and effective models for 1) investigating mechanismsof teratogenesis, 2) evaluating the impact of environmentaltoxicants on aquatic biota, and 3) identifying environmentalteratogens which may be of concern to human health.     

Erythropoietin in Children I. Findings in Various Types of Anemia

Erythropoietin assays were carried out on the plasma of 39 children with various blood dyscrasias. Increased erythropoietin activity was found primarily in those patients with depressed bone marrow function and severe anemia. No direct relationship could be found between the severity of the anemia and the erythropoietin level. No erythropoietin was found in the plasma of patients with hemolytic anemia or renal disease with the exception of one patient with bilateral Wilm's tumor.