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Biomedical subjects

D Mock

Publications and source records attributed to D Mock.

At least 55 records · Page 3Linked to original sources
PubMed1991

Periodontitis as an early presentation of HIV infection.

OBJECTIVE: To determine whether the presence of rapidly progressive periodontitis (RPP) in people at high risk for acquired immunodeficiency syndrome (AIDS) may be the first symptom of previously unrecognized human immunodeficiency virus (HIV) infection. DESIGN: Case series. SETTING: Dental clinic. PATIENTS: Twenty patients who presented or were referred to the dental clinic over 6 months for the treatment of unexplained RPP and were at high risk for AIDS. OUTCOME MEASURES: Diagnosis of HIV infection: identification of candidal organisms in cytologic smears, determination of complete and differential blood counts and of ratio between T4 (helper) and T8 (suppressor) lymphocytes, and performance of HIV antibody assays. MAIN RESULTS: All of the patients were men, although sex was not an inclusion criterion. Sixteen (80%) of the 20 patients were found to have HIV infection. Four had been aware that they were HIV positive: two admitted it only when their T4:T8 ratio was known and the other two when the T4:T8 test was explained or requested. Fifteen of the patients were homosexual, three came from AIDS-endemic areas, and two had hemophilia. The RPP was responsible for alveolar bone loss in all of the patients. One patient lost bone in one site because of localized osteomyelitis. Only five patients had concurrent candidal overgrowth, and three had Kaposi's sarcoma. The mean T4:T8 ratio was 0.57 (standard deviation 0.52). CONCLUSIONS: These findings suggest that periodontal disease may be one of the first clinical presentations of previously undiagnosed HIV infection. Thus, patients at high risk for AIDS who present with aggressive periodontal disease should be investigated for possible HIV infection. However, further, prospective studies are required to confirm the contention that RPP is one of the first signs of HIV infection or AIDS.

Adult↗
PubMed1991

Temporal arteritis with normal erythrocyte sedimentation rates presenting as occipital neuralgia.

A retrospective review of 46 patients with biopsy-proven giant cell (temporal) arteritis revealed 8 (17%) whose initial presentation was occipital pain. The most likely etiology of occipital pain in these patients was occipital artery inflammation. A Westergren erythrocyte sedimentation rate less than 40 mm/hour was noted at presentation in 6 of these 8 patients. Giant cell arteritis should be considered in the differential diagnosis of elderly patients who present with occipital pain and demonstrate a normal erythrocyte sedimentation rate.

Aged↗
PubMed1991

In vitro study on the impact of fish sera on the survival and fine structure of the eel-pathogenic acanthocephalan Paratenuisentis ambiguus.

The effects of fish sera on the growth and fine structure of infective larvae of the eel-pathogenic acanthocephalan Paratenuisentis ambiguus (Eoacanthocephala: Tenuisentidae) were studied under in vitro conditions using sera from the final host Anguilla anguilla and from two accidental fish hosts as well as fetal calf serum. As controls larvae were also kept in medium in the absence of serum and in experimentally infected eels. Sera from the accidental fish hosts carp and rainbow trout exerted toxic effects on the acanthocephalans. Worms maintained in medium containing sera from these two fish were contracted and displayed inverted probosces. Moreover, the tegument exhibited vacuolization and the formation of necrotic areas, including lysis of the mitochondria. Due to these effects, the parasites died at 21 (rainbow trout) or 21-50 days (carp) post-incubation. Eel sera had no toxic effect on the infective larvae. The growth of the larvae in medium depended on the composition of the latter, but was reduced as compared with that in the natural final host. Based on these results, we conclude that components of the hosts' blood sera play a role in the determination of the host specificity of P. ambiguus.

Acanthocephala↗
PubMed1991

Alteration in glutathione level during carcinogenesis of hamster buccal pouch mucosa.

This study examined the level of glutathione (GSH)--a tripeptide that may have an important role in detoxification of carcinogens--in the hamster buccal pouch mucosa (HBPM) by a 12-week regimen of tri-weekly topical application of 7,12-dimethylbenz[a]anthracene (DMBA) in mineral oil. GSH was quantified periodically and shown to be doubled in carcinogen-treated vs. control pouch mucosa. In the tumors that developed, the level of GSH was three times that of the controls. Previous studies showed that gamma-glutamyl transpeptidase (GGT), one of the enzymes that may be responsible for the detoxification of carcinogens, was increased in the hamster mucosa pre-neoplastic foci, but decreased with the formation of overt neoplasia. GGT and GSH are intimately related, since GGT is the only enzyme that can cleave the intact GSH molecule. The increase in both GSH and GGT levels may be responsible for the increased resistance of the pre-neoplastic pouch epithelium to the toxic effects of the carcinogen.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1990

Chronic ethanol feeding and acute ethanol exposure in vitro: effect on intestinal transport of biotin.

This study examined the effects of chronic ethanol feeding and acute ethanol exposure in vitro on biotin transport in rat intestine. Transport studies were performed with intestinal everted sacs. Ethanol was fed to rats for 6-7 wk. Compared with pair-fed controls, ethanol feeding significantly decreased plasma biotin concentrations and transport at physiological concentrations (0.01, 0.1, and 0.3 mumol/L) but not at pharmacological concentration (100 mumol/L). When added to the incubation medium of everted jejunal sacs from dry-food-fed rats, ethanol (2% vol:vol) significantly inhibited the transport of biotin at a physiological concentration (0.1 mumol/L) but not at a pharmacological concentration (100 mumol/L). The inhibitory effect of ethanol on the transport of 0.1 mumol biotin/L increased with increasing concentration of ethanol in the incubation medium [0.5% to 5% (vol:vol)]. Acetaldehyde, the major ethanol metabolite, also significantly inhibited biotin transport at 0.2% (vol:vol). These data demonstrate that chronic ethanol feeding and acute ethanol exposure in vitro inhibit the intestinal transport of biotin by the carrier-mediated process. Chronic ethanol feeding is also associated with a significant decrease in plasma biotin concentrations. The ethanol-induced inhibition in intestinal transport of biotin may be a contributing factor in reducing plasma biotin concentrations.

Alcoholism↗
PubMed1990

Aggressive osteoblastoma of the temporal bone: a case report.

Osteoblastoma is a rare tumor of bone which is usually present in the long bones and vertebrae. Occasionally, they present in the head and neck, and only very rarely will they have a locally aggressive clinical course. We report a case of the aggressive subtype of benign osteoblastoma and its histologic and radiologic presentation.

Adult↗
PubMed1989

Cardiac and neurological abnormalities in v-fps transgenic mice.

Transgenic mice that widely express the v-fps protein-tyrosine kinase develop several independent pathological conditions, in addition to a high tumor incidence. v-fps expression and protein-tyrosine kinase activity in the heart were directly correlated with cardiac enlargement. This cardiomegaly was accompanied by severe myocardial and endocardial damage, which was concentrated in the left ventricular wall, and characterized by a progressive atrophy and necrosis of cardiac muscle fibers with concomitant fibrosis. This pathology was associated with congestive heart failure. Mice from five lines developed a marked trembling, correlated with expression of the v-fps transgene in the brain, and two lines showed a striking bilateral enlargement of the trigeminal nerves. Unlike tumor formation, these cardiac and neurological phenotypes were evident shortly after birth and showed 100% penetrance. The pleiotropic effects of the v-fps transgene suggest the involvement of protein-tyrosine kinases in mammalian neural development and cardiac function.

Animals↗
PubMed1989

Gamma-glutamyl transpeptidase activity in superficial exfoliated cells during hamster buccal pouch carcinogenesis.

The study of gamma-glutamyl transpeptidase (GGT) activity in transformed tissues has conventionally involved the killing of an animal or excision of the lesion, preventing longitudinal study. Oral exfoliative cytology allows longitudinal examination; however, it has been shown to be an unreliable criterion of malignancy. GGT activity has been demonstrated histochemically to involve the full thickness of the epithelium, including the keratin layer during carcinogenesis of hamster buccal pouch epithelium. This study correlates the GGT-stained foci in tissue sections and the proportion of GGT-positive cells in a superficial smear during a 13-week regime of tri-weekly topical application of 7,12-dimethylbenz[a]-anthracene (DMBA) in mineral oil. GGT-positive cells were detected in smears 3 weeks after application of the carcinogen, coincident with GGT-positive foci in tissue sections involving the keratin layer. The proportion of GGT-positive cells in each experimental period increased during the first 7 weeks of the experiment and plateaued thereafter. The number of GGT-positive foci in tissue sections in each experimental period also increased during the experiment. GGT activity was not detected in either smears or tissue sections of untreated or mineral oil treated mucosa. The correlation between the proportion of GGT-positive cells in smears and GGT-positive foci in tissue sections suggest the possibility of studying the GGT activity in an experimentally induced lesion without its elimination. Furthermore, oral exfoliative cytology using GGT staining may be useful in detecting precancerous lesions clinically.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1989

Lymphoid and mesenchymal tumors in transgenic mice expressing the v-fps protein-tyrosine kinase.

src, abl, and fps/fes are prototypes for a family of genes encoding nonreceptor protein-tyrosine kinases. The oncogenic potential of the v-fps protein-tyrosine kinase was investigated by introduction of the gag-fps coding sequence of Fujinami sarcoma virus into the mouse germ line. Transgenic mice with v-fps under the transcriptional control of a 5' human beta-globin promoter (GF) or with both 5' and 3' beta-globin regulatory sequences (GEF) were viable. Unexpectedly, both GF and GEF transgenes were expressed in a wide variety of tissues and induced a spectrum of benign and malignant tumors. These tumors, which included lymphomas, thymomas, fibrosarcomas, angiosarcomas, hemangiomas, and neurofibrosarcomas, developed with various frequencies after latent periods of 2 to 12 months. The majority of lymphoid neoplasms appeared to be of T-cell origin and were monoclonal, as judged by rearrangements of the T-cell receptor beta or immunoglobulin genes. Some tissues that expressed the v-fps oncogene, such as heart, brain, lung, and testes, developed no malignant tumors. The v-fps protein-tyrosine kinase therefore has a broad but not unrestricted range of oncogenic activity in cells of lymphoid and mesenchymal origin. The incomplete penetrance of the neoplastic phenotype and the monoclonality of lymphoid tumors suggest that tumor formation in v-fps mice requires genetic or epigenetic events in addition to expression of the P130gag-fps protein-tyrosine kinase.

Animals↗
PubMed1989

High incidence of lung, bone, and lymphoid tumors in transgenic mice overexpressing mutant alleles of the p53 oncogene.

We have investigated the role of the p53 gene in oncogenesis in vivo by generating transgenic mice carrying murine p53 genomic fragments isolated from a mouse Friend erythroleukemia cell line or BALB/c mouse liver DNA. Elevated levels of p53 mRNA were detected in several tissues of two transgenic lines tested. Increased levels of p53 protein were also detected in most of the tissues analyzed by Western blotting (immunoblotting). Because both transgenes encoded p53 proteins that were antigenically distinct from wild-type p53, it was possible to demonstrate that overexpression of the p53 protein was mostly, if not entirely, due to the expression of the transgenes. Neoplasms developed in 20% of the transgenic mice, with a high incidence of lung adenocarcinomas, osteosarcomas, and lymphomas. Tissues such as ovaries that expressed the transgene at high levels were not at higher risk of malignant transformation than tissues expressing p53 protein at much lower levels. The long latent period and low penetrance suggest that overexpression of p53 alone is not sufficient to induce malignancies and that additional events are required. These observations provide direct evidence that mutant alleles of the p53 oncogene have oncogenic potential in vivo and that different cell types show intrinsic differences in susceptibility to malignant transformation by p53. Since recent data suggest that p53 may be a recessive oncogene, it is possible that the elevated tumor incidence results from functional inactivation of endogenous p53 by overexpression of the mutant transgene. The high incidence of lung and bone tumors suggests that p53 transgenic mice may provide a useful model to investigate the molecular events that underlie these malignancies in humans.

Alleles↗
PubMed1989

[Proliferative kidney disease (PKD) of salmonids].

Proliferative Kidney Disease (PKD) of salmonids, pathology, occurrence and the causative agent are described according to recent literature. For diagnosis histology and/or impression smears of infected kidneys are recommended. Original coloured photos are added to serve this purpose.

Animals↗
PubMed1989

Pneumococcal colitis: report of a case with radiologic and endoscopic findings.

Gastrointestinal symptoms and signs have been reported in association with pneumococcal infection for many years. Only rarely has Streptococcus pneumoniae been reported as a bowel pathogen. We report the clinical, radiographic, colonoscopic, and pathologic features of a case of pneumococcal colitis in an otherwise healthy 3.5-year-old female.

Child, Preschool↗
PubMed1988

Bilateral mandibular hamartomas and familial natal teeth.

The case of a newborn girl with two mandibular incisor natal teeth and bilateral mandibular odontogenic harmartomas is presented. The hamartomas were evident as pedunculated masses on the posterior mandibular gum pads. The natal teeth were extracted at birth, and the hamartomas were excised at 5 months of age. Microscopic investigation of the hamartoma demonstrated the presence of all odontogenic tissues with the exception of an enamel organ. In addition, there was a strong family history of natal teeth, which may suggest a hereditary basis for the development of the odontogenic hamartoma.

Female↗
PubMed1987

Gamma-glutamyl transpeptidase activity in human oral squamous cell carcinoma.

Gamma-glutamyl transpeptidase (GGT) activity has been shown to increase in preneoplastic cells in various experimental carcinogenesis models and in some human tumors. This pilot study was undertaken to examine its potential use in detection of sites of human oral carcinogenesis. Samples were taken from 16 surgical specimens: 12 resection specimens for squamous carcinomas and 4 benign mucosal lesions. Twelve of the patients were tobacco users. Diffuse GGT activity was found in all tobacco users and heavy cellular activity in all carcinomas. In four of the carcinoma-resection specimens, occasional cells staining heavily for GGT activity were noted in epithelium distant from the tumor itself. These results are discussed in relation to the potential value of GGT activity as a marker from preneoplastic changes in oral epithelium.

Adult↗
PubMed1987

In vitro transformation of osteoblasts: putative formation of osteosarcoma in vitro.

The study of bone cancer has been difficult in part due to a lack of appropriate in vitro osteosarcoma model systems. The development of such systems is essential if a clearer understanding of the biology of and mechanisms behind the formation and progression of bone cancers is to be obtained. We report here the development of an in vitro model system which demonstrates important characteristics generally associated with osteosarcoma. The chick periosteal osteogenesis model was infected with the Fujinami Sarcoma Virus (FSV) containing the v-fps oncogene which encodes for a P140gag-fps protein-tyrosine kinase. Under the appropriate conditions FSV infected cultures developed bone and cartilaginous tissues which showed histopathological findings consistent with osteosarcoma. Biochemical data indicating massive increases in alkaline phosphatase activity, protein content, 3H-Thymidine incorporation as well as expression of active P140gag-fps confirm that transformation has occurred in FSV infected cultures. This novel in vitro model system should prove most useful in the study of bone cancer.

Animals↗
PubMed1987

Gamma-glutamyl transpeptidase activity during carcinogenesis of hamster buccal pouch epithelium.

Gamma-glutamyl transpeptidase (GGT) activity has been demonstrated histochemically in a number of experimentally induced neoplasms and has been suggested as a label for potential precursors for the development of squamous cell carcinomas. This study explores the kinetics of GGT-stained cell populations, their correlation with the hypothesized initiated cells and evidence of malignant transformation of epithelium in hamster buccal pouch by a 15-week regime of tri-weekly topical application of 7, 12-dimethylbenz[a]anthracene (DMBA) in mineral oil. GGT-positive foci were detected histochemically in tissue sections as early as 1 week after application of the carcinogen, when there was no morphological evidence of dysplasia. The average number of the GGT-positive foci in each experimental period was found to increase with time. Even though the majority of the foci were small, consisting of only a single cell or a small group of cells, a few larger GGT-positive lesions were noted, particularly in the later period of the experiment. A total of 66 grossly visible neoplasms were found. Thirty-seven of these were submitted for GGT staining. Thirty-two (86.5%) of these showed patchy GGT activity, primarily in the superficial epithelial cells and/or the keratin. In the non-neoplastic epithelium, the GGT staining could involve any or all layers of cells. GGT activity was not detected in untreated or mineral oil-treated mucosa. The results of this study support the hypothesis that GGT activity may label potential precursors for the development of squamous cell carcinomas.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1987

Biotin transport through the blood-brain barrier.

The unidirectional influx of biotin across cerebral capillaries, the anatomical locus of the blood-brain barrier, was measured with an in situ rat brain perfusion technique employing [3H]biotin. Biotin was transported across the blood-brain barrier by a saturable system with a one-half saturation concentration of approximately 100 microM. The permeability-surface area products were 10(-4) s-1 with a biotin concentration of 0.02 microM in the perfusate. Probenecid, pantothenic acid, and nonanoic acid but not biocytin or biotin methylester (all 250 microM) inhibited biotin transfer through the blood-brain barrier. The isolated rabbit choroid plexus was unable to concentrate [3H]biotin from medium containing 1 nM [3H]biotin. These observations provide evidence that: biotin is transported through the blood-brain barrier by a saturable transport system that depends on a free carboxylic acid group, and the choroid plexus is probably not involved in the transfer of biotin between blood and cerebrospinal fluid.

Animals↗