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Biomedical subjects

C M Allen

Publications and source records attributed to C M Allen.

At least 19 recordsLinked to original sources
PubMed1992

Fibric acid derivatives: effects on the synthesis of isoprenoid lipids in cultured human lymphocytes.

Fibric acid derivatives have been demonstrated to reduce circulating lipoprotein and triacylglycerol concentrations and to inhibit hydroxymethylglutaryl CoA reductase, a key regulatory enzyme of cholesterol biosynthesis. This study describes the effect of four fibric acid derivatives on the biosynthesis of isoprenoid products from acetate and mevalonate in Molt-4 cells, a human leukemic T-lymphocyte cell line. The isoprenoids analyzed were cholesterol as well as dolichol and ubiquinone, alternative products of the branched isoprenoid biosynthetic pathway. None of the fibric acid derivatives showed significant effects on the synthesis of cholesterol from acetate or mevalonate and there was little change in the flux of these metabolites into either dolichol and ubiquinone compared to cells grown in drug-free medium. Therefore, in contrast to the reported inhibitory effects of fibric acids on hepatic sterol synthesis in rats and humans and on hydroxymethylglutaryl CoA reductase activity in human nonmalignant lymphocytes, our results show that these drugs do not significantly affect any of the post-reductase enzymes in the branched metabolic pathways leading from acetate to dolichol, ubiquinone and cholesterol in short term culturing of human malignant lymphocytes.

Acetates↗
PubMed1992

Central odontogenic fibroma, WHO type. A report of three cases with an unusual associated giant cell reaction.

Three cases of central odontogenic fibroma, WHO type, that exhibited a prominent giant cell granuloma-like histopathologic component are described in this report. All three lesions occurred in women, and all were located in the mandibular premolar-molar region. One lesion recurred after conservative excision, and the recurrence displayed the two histologically distinct tissues of the original lesion. The authors think that this pathologic process does not represent a "collision lesion" but, instead, is a unique presentation of a central odontogenic fibroma, WHO type.

Adolescent↗
PubMed1992

Diagnosing and managing oral candidiasis.

The red to white lesions of oral candidiasis are easily treated with any of several antifungal medications. But predisposing systemic conditions, such as diabetes mellitus or human immunodeficiency virus infection, should be ruled out as contributing factors.

Antifungal Agents↗
PubMed1991

Inhibition of farnesyl transferases from malignant and non-malignant cultured human lymphocytes by prenyl substrate analogues.

Cytosolic prenyl transferases from two human lymphoid tissue-derived cell lines, IM-9 and Molt-4 cells, are shown to isoprenylate recombinant p21H-ras. Isoprenylation was inhibited by an N-acetylated pentapeptide (N-Ac-Lys-Cys-Val-Leu-Ser), c,t-farnesyl diphosphate, c,t,t-geranylgeranyl diphosphate, t,t,t-geranylgeranyl diphosphate and a photolabile farnesyl diphosphate analogue. c,t-Farnesyl and t,t,t-geranylgeranyl monophosphates were also effective inhibitors of the Molt-4 enzyme but not the IM-9 enzyme.

Alkyl and Aryl Transferases↗
PubMed1991

Dolichol biosynthesis in human malignant cells.

Cholesterol, ubiquinone and dolichol biosynthesis from mevalonic acid was measured in non-malignant and malignant cultured human lymphocytes, freshly isolated human mononuclear leucocytes and in cultured human hepatoma cells. The relative flux of mevalonate into ubiquinone, dilichol and cholesterol was not significantly different between malignant and non-malignant cells, although the extent of labelling of each product was an order of magnitude greater in the malignant cultured cells. The most prominent dolichol isolated from total cellular lipid and synthesized in short-term labelling of cultured leukaemic cells had a chain length one isoprene unit shorter than that observed in normal human cells. Cultured human hepatoma cells and mononuclear leucocytes isolated from the peripheral blood of individuals with lymphoblastic and myelogenic leukaemia similarly synthesized shorter-chain dolichols. The dolichols made in cultured non-tumorigenic cells, freshly isolated mononuclear leucocytes from a normal individual or a patient with non-haematological malignancy had normal chain length.

Carcinoma, Hepatocellular↗
PubMed1991

Restraint stress differentially affects anti-viral cellular and humoral immune responses in mice.

Physical restraint administered to C57BL/6 mice significantly altered the inflammatory response to influenza virus infection and depressed anti-viral cellular immunity. Restraint-stressed animals showed a pattern of reduced mononuclear cell infiltration and lung consolidation which coincided with elevated plasma corticosterone levels. Furthermore, cellular immunity to virus was significantly depressed; interleukin-2 secretion was reduced by 96% and 59% in the mediastinal lymph nodes and spleens, respectively, as compared to a non-restrained group. However, the magnitude of the humoral immune response to influenza virus was unaffected by restraint stress. Anti-viral IgG antibody levels in restrained/infected mice did not differ when compared to a non-restrained/infected control group 14 days post-infection.

Animals↗
PubMed1991

Tuberculous broncho-oesophageal fistula in the acquired immunodeficiency syndrome.

Mycobacteria are the most common bacterial infections occurring in AIDS patients. Although the gastrointestinal tract is commonly involved, there has been only one case report of oesophageal infection. We report a patient in whom oesophageal tuberculosis was the presenting feature of AIDS and review the features of mycobacterial infections in AIDS. The incidence of extrapulmonary infection is common and mycobacterial oesophagitis should be considered in the differential diagnosis of oesophagitis in AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Cheilitis granulomatosa: report of six cases and review of the literature.

Six cases of cheilitis granulomatosa, a rare inflammatory disorder of unknown origin, are reported. The condition produces nontender, persistent swelling of one or both lips and affects primarily young adults. Histologically, nonnecrotizing granulomatous inflammation is seen. The clinical findings and results of therapy in these six cases are presented. One patient was treated with hydroxychloroquine sulfate (Plaquenil) that stabilized the process. One of our patients had vesicular-appearing lesions. Microscopic examination showed the lesions to be dilated superficial lymphatic channels, a finding that to our knowledge has not been previously described.

Adult↗
PubMed1990

A method for counting leukocytes in filtered components.

Leukocyte-depleted components are being used more frequently. Quantitation of residual WRCs is needed for quality control and for establishing the critical level required to prevent alloimmunization. Electronic counting is not accurate at WBC levels below 100/microL (1) and previously proposed techniques are either tedious or require sophisticated equipment. We describe a simple hemacytometer procedure using Türks solution that gives 87-93% recovery at WBC levels below 40/microL.

Filtration↗
PubMed1990

Diphtheritic polyneuritis in an elderly woman: clinical and neurophysiological follow-up.

A 71-year-old English lady initially presented with a bulbar paralysis and, six weeks later, developed a generalised sensori-motor neuropathy. Corynebacterium diphtheriae mitis was cultured from her throat swab. Despite a good clinical recovery at one month, nerve conduction velocity was at its lowest. As far as the authors are aware, this is one of the few cases of neurophysiological and clinical follow-up in a British subject with diphtheritic peripheral neuropathy. This case emphasises the importance of giving antitoxin early.

Adrenocorticotropic Hormone↗
PubMed1989

Dehydrodolichyl diphosphate synthase in Sertoli and spermatogenic cells of prepuberal rats.

The specific activity of 2,3-dehydrodolichyl diphosphate synthase in homogenates of protease-treated seminiferous tubules, enriched spermatogenic cells, and Sertoli cells changed as a function of the age of prepuberal rats. The highest enzymatic activity occurred in each case in 23-day-old rats. Homogenates of pachytene spermatocytes, spermatids, or Sertoli cells had higher synthase activity than a whole testicular homogenate prepared by protease treatment of tubules. Enzymatic activity in pachytene spermatocytes expressed per mg of protein was about 1.7-fold higher than in spermatids, 5.3-fold higher than in spermatogonia, and about 8.3-fold higher than in spermatozoa. Therefore, the increase in spermatogenic cell synthase before day 23 can be accounted for by the appearance of the pachytene spermatocytes. Enzymatic activity decreased remarkably after the differentiation of spermatids into spermatozoa. Synthase activity in enriched Sertoli cell preparations was 1.5-2.3-fold higher than in spermatogenic cell preparations between days 15 and 30. Therefore, both spermatogenic cells and Sertoli cells contribute to changes in the enzymatic activity in seminiferous tubules during development. These changes may be important in regulating the availability of dolichyl phosphate for glycoprotein synthesis during early stages of differentiation.

Age Factors↗
PubMed1989

Early soft tissue ingrowth into porous block hydroxyapatite.

A dog model was used to determine the rate of soft tissue infiltration into porous block hydroxyapatite (PBHA) in order to provide a scientific basis for treatment of exposed implants. Ten mongrel dogs underwent alveolar ridge augmentation with PBHA and were killed at various times up to 21 days. Significant soft tissue ingrowth had occurred by 14 days and was complete by day 21. Bone formation was also seen as early as 14 days.

Alveolar Ridge Augmentation↗
PubMed1989

Clinical, histologic and scanning electron microscopic study of the development of chronic candidiasis of the rat tongue.

In order to examine the development of the chronic candidal lesion of the dorsal rat tongue, 210 rats were given a single oral inoculum of Candida albicans on Day 0 and were sequentially killed over a 20-wk period. Dorsal tongue changes were evaluated using clinical photographs, histologic sections and scanning electron microscopy (SEM). Clinically evident lesions became apparent at 2 wk post-inoculation, and inflammatory changes of the underlying connective tissue were observed by 3 wk post-inoculation. SEM showed a gradient of destruction of the dorsal tongue papillae at the periphery of the candidal lesions. Hyphae were seen infrequently on the lesional surface by SEM, a finding which correlated with the light microscopy.

Animals↗
PubMed1989

Dentinal dysplasia type I: a report of four cases.

Dentinal dysplasia type I is a relatively uncommon condition and four cases are described. The radiographic features in these patients are somewhat different to those reported in other cases in that anterior teeth appeared to be less affected than posterior, and tooth loss was less prevalent. These findings support the proposal that the characteristics of dentinal dysplasia type I can be divided into two subgroups.

Adult↗
PubMed1989

Pyostomatitis vegetans. Report of a case and review of the literature.

This report describes a 39-year-old woman with pyostomatitis vegetans and ulcerative colitis. Pyostomatitis vegetans is a rare eruption of the oral cavity characterized by tiny yellow pustules coating the surface of the friable eroded mucosa. It is considered a marker for inflammatory bowel disease. In a review of the literature, 19 of 26 cases (73%) reported were associated with gastrointestinal disturbances, predominantly inflammatory bowel disease.

Adolescent↗