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Biomedical subjects

H Thompson

Publications and source records attributed to H Thompson.

At least 91 records · Page 5Linked to original sources

Distemper encephalitis in pups after vaccination of the dam.

A five-year-old labrador bitch which had whelped 10 pups three days previously was given booster vaccination against distemper, adenovirus, parvovirus, parainfluenzavirus and leptospirosis. Eighteen days later, signs of central nervous system disease developed in some of the pups, five of which were ultimately euthanased. The cause of the nervous disease was found to be canine distemper, and serological studies showed that the infection was limited to some members of the litter, suggesting that the vaccinal rather than a field virus was more likely to have been responsible.

Animals↗

Construction and characterisation of a yeast artificial chromosome library containing three haploid maize genome equivalents.

We have constructed a yeast artificial chromosome (YAC) library using high-molecular-weight DNA prepared from agarose-embedded leaf protoplasts of the maize inbred line UE95. This library contains 79,000 clones with an average insert size of 145 kb and should therefore represent approximately three haploid genome equivalents. The library is organised as an ordered array in duplicate microtitre plates. Forty-one pools of DNA from 1920 individual clones have been prepared for rapid screening of the library by the polymerase chain reaction (PCR). Using this approach, together with conventional colony hybridisation, we have been able to identify between one and eight positive clones for every probe used.

Chloroplasts↗

Clinical and pathological findings in feline immunodeficiency virus experimental infection.

A study is described of the clinical and pathological findings in 20 specific pathogen free cats infected when 1 year old with feline immunodeficiency virus and monitored over 12 months. Cats were divided into two groups (A and B). The clinical and clinicopathological features were studied in Group A. In Group B, at 1, 2, 4, 9 and 12 months post infection two cats were necropsied. Clinically all cats developed generalised lymphadenopathy, six cats were neutropenic and five cats lymphopenic. Three cats became febrile with conjunctivitis and anterior uveitis and one of these cats ultimately developed jaundice. Postmortem examinations confirmed a generalised lymphadenopathy involving peripheral and visceral lymph nodes with concurrent stimulation of splenic white matter and mucosal lymphoid tissue of the digestive tract and conjunctiva. Within the lymph nodes there was a reactive follicular hyperplasia accompanied by a paracortical hyperplasia with an increased paracortical vascularity. Unusual features were the presence of lymphoid follicles in the bone marrow, thymus and parathyroid tissue. In addition, aggregates of lymphoid cells were found within salivary glands, kidneys, sclera and choroid of the eye. One cat developed a lymphosarcoma affecting the liver and kidneys at 36 weeks post infection. The cat with jaundice had a cholangitis with marked biliary epithelial hyperplasia.

Animals↗

Histological and cytological diagnosis of carcinoma of the oesophagus.

Endoscopic examination of the oesophagus accompanied by histological examination of biopsies or cytological examination of smears enables a confident diagnosis of carcinoma to be established within a period of 24-48 h and in the case of cytology within 15-60 min. Squamous cell carcinoma and adenocarcinoma are easily identified in biopsies or smears taken directly from the lesion. The histopathologist should be alerted to the possible diagnosis of Barrett's adenocarcinoma provided adequate information is given regarding the level of the squamo-columnar junction and the level of the targeted lesion. Unusual tumours are encountered rarely and they include carcinosarcoma, mucoepidermoid carcinoma, adenocystic carcinoma, carcinoid, malignant melanoma, oat cell carcinoma, spindle cell sarcoma, malignant lymphoma, Kaposi's sarcoma, etc. Special stains and multiple levels from the biopsies will be required for accurate identification of these tumours. Dysplasia constitutes a difficult diagnostic problem with reference to its significance regarding surveillance and treatment. Low grade dysplasia represents a recommendation for surveillance provided that the patient is regarded as a good surgical risk if cancer should develop at a later stage. High grade dysplasia is associated with a high risk of invasive cancer and close surveillance is required for the detection and treatment of invasive cancer provided also that the patient is a good surgical risk.

Biopsy↗

Dietary calcium does not reduce experimental colorectal carcinogenesis after small bowel resection despite reducing cellular proliferation.

It has been proposed that colorectal carcinogenesis is accompanied by increased mucosal cell proliferation and that the converse may also apply. To examine this thesis, the crypt cell production rate (CCPR) was measured in eight groups of rats (n = 187) that had received 1,2 dimethylhydrazine, 70% small bowel resection, supplemental dietary calcium, or a combination of these. Analysis of variance showed the following: (1) the CCPR decreased between the ileum and distal colon; (2) the CCPR decreased between 16 and 32 weeks; (3) 1,2 dimethylhydrazine and small bowel resection increased the CCPR and calcium decreased the CCPR independently of one another; (4) the CCPR interacted with 1,2 dimethylhydrazine x small bowel resection, calcium x 1,2 dimethylhydrazine and interacted between the site of bowel and calcium, 1,2 dimethylhydrazine, small bowel resection, and 1,2 dimethylhydrazine x small bowel resection (p = 0.014 to p < 0.001). The tumour yield was reduced by calcium in 1,2 dimethylhydrazine treated animals (chi 2 = 14.1, df = 3, p < 0.01) but was unaffected by calcium in 1,2 dimethylhydrazine and small bowel resection treated animals despite significant differences in the CCPR. An increase of the CCPR both preceded and accompanied colorectal carcinogenesis but reduction of the CCPR was not invariably accompanied by reduced carcinogenes.

1,2-Dimethylhydrazine↗

Action potential response of the corneal nerves to irritants.

The cornea, in addition to its refractive function for the eye, and by way of its very dense sensory innervation, serves a very important protective function for the visual organ. The cornea receives mainly sensory innervation from the first division of the trigeminal ganglion and a sparse amount of sympathetic fibers. The sensory nerves carry out their protective function by responding to various types of stimuli in a way so that they are all perceived psychologically as painful. Neurophysiological data indicates that, despite the morphological similarity of free-nerve endings in the cornea, they are differentiated functionally. A concentration series, (0.005 to 10% solution in saline), of various potential irritants (phosphate detergent, baby shampoo, liquid chlorine bleach, herbal shampoo, onion juice, SDS, and sodium chloride) was applied directly to the cornea of the anesthetized rabbit. Neural activity was assessed from extra-cellular records of long ciliary nerve over a ten second application period, and for ten seconds following stimulus removal. Baby shampoo was non-stimulatory over the applied concentration range. Sodium chloride, on the other hand, exhibited linear response dynamics over the range of 0.01 to 5% (p < 0.001). SDS was highly stimulatory, but showed no predictable concentration or response relationship. All of the other irritants tested responded in a logarithmic fashion. This suggests that the application of neurophysiological techniques to assess the pain and potential inflammatory aspects of a substance for human use can be monitored in this fashion. Moreover, response profiles for various classes of compounds and homologous series, as well as pH and osmolality, can be established.

Action Potentials↗

Labor in the gravida with 10 or more years between pregnancies.

It has been suggested that women who have had a pregnancy interval of 10 or more years would have prolonged labor in pregnancies after the first, as do primigravidas. In a series of 94 multiparas with 10 or more years between pregnancies and 63 age-matched, multiparous controls, there was no significant difference in the length of the latent phase of labor or of the first, second and third stages of active labor in the two groups. The concept of a "physiologic primigravida" in these cases should be abandoned.

Adult↗

Induction of mast cell proliferation, maturation, and heparin synthesis by the rat c-kit ligand, stem cell factor.

We investigated the effects of a newly recognized multifunctional growth factor, the c-kit ligand stem cell factor (SCF), on mouse mast cell proliferation and phenotype. Recombinant rat SCF164 (rrSCF164) induced the development of large numbers of dermal mast cells in normal mice in vivo. Many of these mast cells had features of "connective tissue-type mast cells" (CTMC), in that they were reactive both with the heparin-binding fluorescent dye berberine sulfate and with safranin. In vitro, rrSCF164 induced the proliferation of cloned interleukin 3 (IL-3)-dependent mouse mast cells and primary populations of IL-3-dependent, bone marrow-derived cultured mast cells (BMCMC), which represent immature mast cells, and purified peritoneal mast cells, which represent a type of mature CTMC. BMCMC maintained in rrSCF164 not only proliferated but also matured. Prior to exposure to rrSCF164, the BMCMC were alcian blue positive, safranin negative, and berberine sulfate negative; had a histamine content of 0.08 +/- 0.02 pg per cell; and incorporated [35S]sulfate into chondroitin sulfates. After 4 wk in rrSCF164, the BMCMC were predominantly safranin positive and berberine sulfate positive, had a histamine content of 2.23 +/- 0.39 pg per cell, and synthesized 35S-labeled proteoglycans that included substantial amounts (41-70%) of [35S]heparin. These findings identify SCF as a single cytokine that can induce immature, IL-3-dependent mast cells to mature and to acquire multiple characteristics of CTMC. These findings also directly demonstrate that SCF can regulate the development of a cellular lineage expressing c-kit through effects on both proliferation and maturation.

Animals↗

c-Ki-ras gene mutations in dysplasia and carcinomas complicating ulcerative colitis.

One hundred and nine samples comprising carcinomas, adenomas, dysplastic, inflamed and normal mucosa from patients with sporadic colon cancer and ulcerative colitis (UC) were analysed for c-Ki-ras mutations. DNA was extracted from archival paraffin-embedded material, amplified using the polymerase chain reaction (PCR) and the PCR products analysed using restriction enzyme digestion. Forty-two per cent (14/33) of the sporadic carcinoma controls contained Ki-ras codon 12 mutations in contrast to 24% (8/33) of ulcerative colitis carcinomas. A significantly higher c-Ki-ras mutation rate was observed in rectal carcinomas (72%) in comparison to colonic carcinomas (28%) in control patients (P less than 0.04), while the opposite was observed in UC patients. The difference between the incidence of c-Ki-ras mutations in rectal carcinomas in UC (9%) and in sporadic rectal carcinomas (72%) was also significant (P less than 0.01). This lower prevalence rate and different site distribution of c-Ki-ras mutations in UC carcinomas compared to sporadic carcinomas suggests that specific genetic differences may underlie the causation of carcinomas arising in these situations.

Codon↗

Coeliac disease and malignancy of the duodenum: diagnosis by endoscopy, successful treatment of the malignancy, and response to a gluten free diet.

A patient presented with subtotal villous atrophy and a malignant duodenal tumour of uncertain histogenesis. He was successfully treated by resection and chemotherapy and the small bowel mucosa recovered on a gluten free diet. The tumour was diagnosed at upper gastrointestinal endoscopy when barium studies and abdominal computed tomography were normal, thus making this one of the earliest coeliac malignancies diagnosed.

Antineoplastic Combined Chemotherapy Protocols↗

Spontaneous perforation of the pharynx/esophagus.

Spontaneous perforation of the pharynx/esophagus is an unusual and probably under-diagnosed condition. This small series of patients demonstrating consistent clinical and radiological evidence of this condition suggests that it may be more common than has previously been supposed. It appears that in the majority of cases where the site of rupture occurs in the pharynx or upper esophagus that a self resolving clinical picture normally occurs.

Adult↗

Juvenile bovine angiomatosis: a syndrome of young cattle.

This report describes the clinical and pathological features associated with angiomatous lesions in two calves. In the first case, a single mass located in the atrioventricular ring of the heart was responsible for congestive cardiac failure. The mass was composed of numerous vascular cavities filled with blood and lined by a single layer of well differentiated endothelial cells. The second case had multiple blood-filled cutaneous masses which were confirmed as benign vascular tumours by histological examination of a biopsy specimen. The calf was later euthanased after profuse and uncontrollable haemorrhage from one of the lesions. At necropsy, additional tumours were found in the liver, spleen, kidneys, spinal canal and attached to the pleura, omentum and mesentery. It is proposed that these two cases are representatives of solitary and multiple forms of a syndrome which should be called juvenile bovine angiomatosis.

Angiomatosis↗

Characterization and expression of the gene for the human Fc receptor gamma subunit. Definition of a new gene family.

The high affinity IgE receptor, Fc epsilon RI, is one of the key molecules involved in allergic reactions. It is a tetrameric complex (alpha beta gamma 2). The gamma chains from Fc epsilon RI are also subunits of other Fc receptors. We have isolated, characterized, and sequenced the gene for the human gamma chain of Fc epsilon RI. It consists of five exons and spans 4 kilobases. The leader sequence is encoded by two exons, the second of which also contains the short extracellular domain, the hydrophobic transmembrane region, and the beginning of the cytoplasmic tail. Three short exons encode the remaining of the polypeptide and the 3'-untranslated flanking sequence. The transcription initiation sites have been mapped. Comparison between the gene structures of the gamma chain of the Fc receptor and of the zeta chain of the T-cell receptor indicates that these genes have evolved from a common ancestor by duplication and that they define a new gene family. In addition to being localized on the same chromosome, both genes show an analogous organization of their exons. A high level of homology is found in three of their respective exons, and the splice sites between them are identical. Furthermore, gamma and zeta chains are essential for surface expression of their respective receptors. Therefore, gamma chains of Fc receptors and zeta chains of T-cell receptors may also define a new family of functionally related polypeptides. Expression studies in COS cells show that the human gamma chain alone is sufficient to achieve expression of the human alpha chain on the cell surface, whereas both beta and gamma chains are required for the surface expression of the rodent alpha chain.

Amino Acid Sequence↗