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Biomedical subjects

H Thompson

Publications and source records attributed to H Thompson.

At least 163 records · Page 9Linked to original sources

A distinct class of vertebrate collagen genes encodes chicken type IX collagen polypeptides.

Type IX collagen is a disulfide-bonded protein first isolated from hyaline cartilage. The structure of this collagen is unusual in that the molecules contain three triple-helical domains interspersed with noncollagenous regions. The molecules are heterotrimers composed of three genetically distinct polypeptide chains. In our laboratory, cDNAs specific for two of these polypeptide chains have recently been isolated. Here we report on the isolation of genomic clones by use of these cDNAs as probes for screening a chicken genomic library. Nucleotide sequence analysis of these clones shows that the exon structure of type IX collagen genes is fundamentally different from the exon structure of the genes for the fibrillar collagen types I-III. Whereas the sizes of exons in fibrillar collagen genes are related to a basic 54-base-pair coding unit, the exons of type IX collagen genes show a large variation in size and do not appear to be related to a 54-base-pair unit. We propose, therefore, that type IX collagen genes belong to a class of vertebrate collagen genes distinct from that of fibrillar collagens.

Amino Acid Sequence↗

Epstein-Barr virus infections in homosexual men with chronic, persistent generalized lymphadenopathy.

The status of infection by the Epstein-Barr virus (EBV) in 20 patients with chronic, persistent generalized lymphadenopathy was evaluated with use of three parameters: antibodies to EBV, EBV excretion, and EB virocytemia. Results were compared with those obtained from two groups of control subjects: patients with infectious mononucleosis and healthy EBV-seropositive adults. Profiles of antibody to EBV and the prevalence of EBV excretion were essentially similar for study subjects and healthy control subjects, but the level of EB virocytemia was significantly higher in study subjects than in healthy control subjects.

Adult↗

Peroperative detection of patients with rectal cancer at high risk of local recurrence.

Identification at the time of surgery of patients with rectal carcinoma at high risk of local recurrence may allow a more rational decision to be made regarding the operative procedure to be performed. We have examined tumour bed biopsies and lymph nodes peroperatively using imprint cytology in 20 consecutive patients undergoing radical surgery for rectal carcinoma. The results were checked by subsequent paraffin section histology. We were unable to find lymph nodes in 6 cases (30%) peroperatively. Cytological and histological reporting of the tumour bed biopsies and lymph nodes concurred in 91% and 88% of specimens respectively. Peroperative cytology can differentiate between malignant and benign fixation of rectal tumours, can differentiate between hyperplastic and malignant lymph nodes and may be of value in identifying patients with rectal cancer at high risk of local recurrence.

Adult↗

Acorn poisoning.

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Animals↗

Canine parvovirus enteritis 3: Scanning electron microscopical features of experimental infection.

A group of 10-week-old puppies was orally inoculated with canine parvovirus of faecal origin. Scanning electron microscopy was used to study and compare the surface topography in both control and inoculated animals. In control dogs the villi were tall and finger-like in shape and numerous irregular transverse circumferential grooves were present on the surface. At higher magnification, the outlines of individual epithelial cells and depressions, interpreted as goblet cells, could be discerned. In the inoculated dogs, scanning electron microscopy changes were first seen at six days after inoculation. The small intestinal mucosa was covered by a thick layer of mucus. The underlying villi were stunted and had lost their surface features. In some instances there was loss of the luminal epithelium, exposing the lamina propria. In addition, there was dilation of the circumvillar basins and the crypt mouths. There appeared to be regenerative changes by day 7 after inoculation. The surface of the small intestinal mucosa was still covered by a thick layer of mucus. Where villi could be discerned, they were short and pointed and transverse grooves could be seen on their surface. There was some hypertrophy of the intervillus ridges. The changes in the surface topography of the small intestinal mucosa following canine parvovirus infection are compared to those seen in enteric infections in other species and the similarity of the lesion to that seen following sublethal irradiation is discussed.

Animals↗

Canine parvovirus enteritis 2: Pathogenesis.

Two groups of puppies, eight and 10 weeks of age, were inoculated orally with canine parvovirus of faecal origin. The patterns of faecal excretion of virus, antibody production and systemic viral localisation following inoculation were studied. Faecal excretion of virus was first apparent at day 3 after inoculation, was present most frequently and in greatest quantity at days 4 to 7 after inoculation and fell sharply thereafter. Serum antibody was first detected at day 5 after inoculation with high titres in all samples from day 7 onwards. Virus isolation from serum samples revealed a non-cell associated viraemia at days 3 and 4 after inoculation. Immunocytochemical examination, using both immunofluorescence and immunoperoxidase techniques, first revealed antigen in the thymic cortex at day 1 after inoculation and in the germinal centres of the lymph nodes and the splenic white pulp from days 2 and 3. Viral antigen was first detected in the intestines at day 4 in individual cells in the proliferative zone of the crypt epithelium. From day 5 onwards, the amount of antigen present in the lymphoid tissue decreased so that by days 7 and 8, only a trace was present. There was widespread specific staining in the small intestinal mucosa at day 6, but little antigen was present by day 7. Virus was present in the bone marrow of some dogs killed at days 5 and 6.

Animals↗

Canine parvovirus enteritis 1: Clinical, haematological and pathological features of experimental infection.

The effect of oral infection of puppies, eight and 10 weeks old, with canine parvovirus of faecal origin was studied. Clinical signs of enteric disease were first apparent at five days after inoculation and persisted during days 6 and 7 after inoculation. The severity of clinical signs varied from transient dullness and anorexia to emesis, dysentery and death. Changes in haematological parameters were first found at day 3 after inoculation when a relative lymphopenia was observed. A profound neutropenia developed in severely affected dogs after the appearance of clinical enteric disease. Post mortem examination revealed thymic atrophy in all dogs killed on day 4 after inoculation. Macroscopic changes in the small intestine were apparent only in animals examined during the phase of severe enteric disease and consisted of thickening, rigidity and congestion of the small intestines. Microscopically there was lymphocytolysis in the thymic cortex and the germinal centres of the lymph nodes from days 2 and 3 after inoculation respectively and this rapidly resulted in depletion of these tissues. There was repopulation of lymph nodes from day 7 after inoculation but significant thymic regeneration was not apparent during the course of this study. In the small intestine, necrosis of crypt epithelium, atrophy of villi and, in some areas, complete collapse of mucosal architecture were found but the extent of these changes varied along the length of the small intestine and between individuals. Regenerative intestinal changes were observed in those animals surviving the acute phase of enteric dysfunction. The variable severity of clinical and enteric lesions, together with the factors which may affect the expression of clinical disease, are discussed.

Animals↗

Incidence and prognosis of N4 node involvement in gastric cancer.

We have undertaken a prospective study of the frequency and prognosis associated with N4 node metastases in gastric cancer in 136 patients referred for surgical treatment between 1976 and 1983. N4 node metastases (pre-aortic or hepatic hilar nodes) were present in 20 of 31 patients who had a laparotomy without resection (64 per cent), in 2 of 8 patients who had a 'palliative' resection in the presence of distant metastases (25 per cent) and, in 19 of 85 patients who had a 'curative' resection (22 per cent). The median survival in patients having a 'curative' resection with N4 nodes was 4.5 months which was only marginally longer than in patients having a 'palliative' resection (median survival 3 months). In view of these findings and since immediate imprint cytology can be used to detect nodal metastases at operation, involvement of N4 nodes might be a contra-indication to extensive gastric resection in non-obstructing gastric cancer.

Humans↗

Immune responses to myelin antigens in Guillain-Barré syndrome.

Antibodies to nerve antigens were sought in the sera of 17 patients with acute Guillain-Barré syndrome (GBS), 11 with chronic relapsing demyelinating poly-radiculoneuropathy (CRP), 20 with other neuropathies (ON), 15 with other neurological diseases (OND) and 19 normal subjects. Complement-fixing antibodies to a suspension of human peripheral nerve tissue were identified in only 2 patients with GBS and 1 with chronic progressive neuropathy. Five GBS sera gave complement fixation reactions with rabbit sciatic nerve. The sera were also tested for galactocerebroside (Gal-C) binding activity using a solid phase assay. The range of values in all groups was the same, although the mean values for patients with GBS, ON and OND were higher than those of normal subjects. In a radioimmunoassay for antibodies to bovine P2 slightly more radiolabelled antigen was precipitated by the GBS group of sera than by sera from the other groups, but only one serum from the GBS and another from the CRP patients precipitated more than 10% of the label. Addition of bovine P2 to cultures of peripheral blood mononuclear cells from 11 patients with GBS did not cause significant stimulation. Immunoassay for antibody to myelin basic protein (MBP) showed an increased proportion of sera with low binding activity in the GBS and CRP groups. The results suggest that humoral immune responses to potentially neuritogenic antigens are found with marginally increased frequency in patients with GBS and CRP.

Adolescent↗

International migration, non-traded goods and economic welfare in the source country: a comment.

"Labor emigration redistributes income in a two factor, two good economy where one good is internationally non-traded. Labor's nominal wage rises as nominal capital payments fall. Recent research has shown that the prices of non-traded goods rise, causing society's welfare to decline. Here the induced change in the real income of each factor is considered separately. There is an ambiguity with regard to the real income of non-emigrating labor. If labor spends a relatively small fraction of income on the non-traded goods, its real income may rise, even though society suffers the loss of welfare."

Costs and Cost Analysis↗

A radioassay for angiotensin converting enzyme.

Current methods for measuring angiotensin converting enzyme activity (EC 3.4.15.1, ACE) are somewhat cumbersome and have limited the general availability of the test. We describe here a simple four-step radioassay for ACE which uses the substrate 14C-Hippurate-L-Histidyl-L-Leucine and measures the product, 14C-Hippurate. We found that incubation at pH 7.0 (Hepes buffer) increased the sensitivity of the test by 50 percent when compared to results obtained with the pH 8.0 buffer normally used for ACE assays. A split sample comparison study between the radioassay and the spectrophotometric method showed good correlation (n = 47; mean, spectrophotometric, 26.0 U/mL; mean, radioassay, 26.1 U/mL; m = 0.86; b = 3.9; r = 0.868). We found that there was no significant difference between the spectrophotometric, kinetic and radioassay (Newman-Keuls multiple range test), but the liquid chromatographic method gave results significantly different from the other methods. The assay for ACE described here combines enhanced technical ease with the sensitivity of a radioassay.

Carbon Radioisotopes↗

Carcinoembryonic antigen (CEA) expression and heterogeneity in primary and autologous metastatic gastric tumours demonstrated by a monoclonal antibody.

The expression of carcinoembryonic antigen (CEA) in gastric malignancies has been assessed using a monoclonal antibody in an immunoperoxidase technique. Of 119 primary tumours examined, 92% reacted with the antibody. Metastases were available for 81 of the patients and 83% were CEA positive. A noteworthy observation was the detection of malignant cells in the lymph nodes of two patients, as a result of the presence of CEA, who were originally reported to be free of metastases. Of those patients whose primary tumours expressed CEA, 86% had at least one CEA positive metastasis. Two or more metastases were available from 60 of the patients and in 20% the secondaries were a mixture of positive and negative for CEA. Consequently, the CEA status of a single lesion does not enable confident prediction of expression in other metastases. In addition to variation between multiple lesions removed from the same patient phenotypic diversity of expression was observed between tumour cells of a given mass. Such distribution of the CEA detected by this monoclonal antibody may impose certain restrictions on its application. However, the high frequency of expression by gastric cancers indicate that it is a potentially useful antigen as a target for radiolocalisation or therapeutic agents.

Antibodies, Monoclonal↗

Survival of patients with colorectal cancer complicating ulcerative colitis.

The crude five year survival of patients with colorectal cancer complicating ulcerative colitis in a large series of patients under long term review has, for the first time, been compared with the survival of patients with colorectal cancer in the general population (West Midlands region) from which the colitic patients were drawn. Thirty five cases of colorectal cancer were diagnosed in 676 patients with ulcerative colitis between 1944 and 1976. An actuarial five year survival curve was computed for the colitic and non-colitic patients with colorectal cancer. In ulcerative colitis patients with cancer the five year survival was 33.5% (range 16.9-50.1%) compared with 32.6% (28.2-37.0%) in the non-colitic cancer patients drawn from the relevant general population. Overall the prognosis is much better than earlier reports suggest. It is perhaps disappointing that in a closely monitored group the outcome is only as good as that in the general population. Surveillance programmes should improve the outcome in those patients with ulcerative colitis who accept the need for regular review.

Adult↗

A prospective randomized study of effect of proximal gastric vagotomy and vagotomy and antrectomy on bile reflux, endoscopic mucosal abnormalities and gastritis.

71 patients participated in a double-blind trial which compared proximal gastric vagotomy (PVG) with vagotomy and antrectomy (V & A). 82 percent of the patients subsequently volunteered for endoscopy 6 to 12 months after operation and 65 percent for measurement of fasting bile reflux (FBR) and peak acid output (PAO). The results of these follow-up assessments are given in this paper. None of the 36 patients who had undergone V & A had a recurrent ulcer; in contrast ulcers or fresh scars were found in 5 of 35 patients after PGV, even in 2 who had no symptoms. Erythema of the gastric mucosa was seen more commonly after V & A than PGV. Such erythema was associated with high levels of fasting bile reflux (an objective measure of reflux of bile into the stomach) and with symptoms of bile vomiting and mild epigastric pain. High levels of fasting bile reflux were not found after PGV. Histological gastritis of the proximal stomach was equally common after both operations in patients without a recurrent ulcer. Gastritis was not related to endoscopic mucosal erythema or fasting bile reflux, but did correlate with peak acid output. These results confirm that bile reflux is associated with mucosal erythema and symptoms after V & A but that significant bile reflux does not occur after PGV. However, bile reflux is not related to gastritis, which appears to be the result of an operation (either PGV or V & A) which successfully reduces peak acid output.

Adult↗

The place of fine needle aspiration cytology for the intraoperative diagnosis of pancreatic malignancy.

We report a 91% accuracy with fine needle aspiration cytology in 46 patients found to have a mass in the pancreas at laparotomy. Results were compared with conventional biopsy at operation which was accurate in only 56% of an earlier group of 48 patients with a localised mass compared with 97% in 33 patients with disseminated malignancy. Although we strongly advise a through attempt to establish a histological or cytological diagnosis before operation, there are many occasions when a surgeon is faced with an undiagnosed mass in the pancreas at laparotomy. Under these circumstances fine needle aspiration cytology of the pancreas should be advised in units with an experienced cytology service.

Biopsy↗

Gastric histology and its relationship to entero-gastric reflux after duodenal ulcer surgery.

Thirty-six volunteers, asymptomatic 7 to 22 years after various operations for duodenal ulcer, were screened for enterogastric reflux by external scanning following injection of 99mTc HIDA; they also had endoscopy for measurement of the fasting juice pH, and multiple biopsies. In patients with a pH above 4 there was an association between a positive bile reflux test and the presence of pre-malignant changes in the gastric mucosa. Carcinoembryonic antigen in the gastric mucosa was found in all patients and was not, therefore, a useful screening test for stump cancer. Blind examination of two sets of endoscopic biopsies obtained 6 weeks apart in symptomatic patients with post-operative reflux gastritis showed that histological assessment remained reproducible. Gastric biopsies obtained from 16 patients before, and a year after, Roux-en-Y gastro-jejunostomy demonstrated that foveolar hyperplasia tended to regress after bile diversion.

Biopsy↗

Immunity to canine adenovirus respiratory disease: effect of vaccination with an inactivated vaccine.

Nine puppies without maternal antibody to canine adenovirus (CAV) were divided into two groups. The first consisted of six puppies, each of which was given two doses of a commercial inactivated CAV-1 vaccine, 14 days apart. Eight days after administration of the second dose of vaccine, all six puppies, together with the second group, consisting of three unvaccinated controls, were challenged with an aerosol of virulent CAV-2. One dog from each group was killed on the third, fifth and 10th days after challenge and the three additional vaccinates killed at intervening times. All of the dogs developed respiratory signs, mainly coughing and tachypnoea, but the vaccinated dogs made a more rapid recovery. The lungs of both groups were consolidated, the areas affected being more extensive in the controls, and histological examination revealed the main lesion to be a severe necrotising bronchiolitis. Virus was isolated from the respiratory tissues and from throat swabs collected from both groups of dogs. The presence of neutralising antibody in the serum was not, of itself, sufficient to control viral replication and oblate the disease.

Adenoviridae↗