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Biomedical subjects

F D Lee

Publications and source records attributed to F D Lee.

At least 91 records · Page 5Linked to original sources

The endoscopic and histological features of peptic duodenitis.

This study attempts to compare the endoscopic features of duodenitis with the histological characteristics. During a 12 month period, 98 patients undergoing fibreoptic oesophago-gastro-duodenoscopy had the endoscopic appearances of the duodenum classified on a three point scale of increasing severity of duodenitis. Multiple duodenal biopsies were then taken and the histological features of the severity of duodenitis graded from 0 to 4 plus by an independent observer. The histological criteria included an assessment of neutrophil infiltration, villous bluting, gastric metaplasia and chronic inflammation. Routine endoscopic assessment alone was unsatisfactory for diagnosing and grading the severity of duodenitis and multiple target biopsies are required for histological examinations.

Duodenitis↗

Small-intestinal changes induced by an elemental diet (Vivonex) in normal rats.

1. Rats were fed with the elemental diet Vivonex for 1 or 3 months and their jejunal histology was compared with that of an equal number of rats fed on a normal diet. 2. After 1 month of Vivonex feeding a significant reduction in the ratio of crypt height: villus height (CH:VH) was found in the Vivonex-fed rats (n = 4) compared with the control rats (n = 4) (P less than 0.05). 3. After 3 months the CH:VH ratio was also reduced in the Vivonex-fed rats (n = 18) compared with control rats (n = 18) (P less than 0.002). Villus height was significantly increased (P less than 0.002) and crypt height decreased (P less than 0.05). 4. Jejunal protein content, alkaline phosphatase and disaccharidase activity were also determined in 12 control and 12 Vivonex-fed rats from the 3 months study. 5. Alkaline phosphatase activity was increased from a control value of 201 +/- 8 to 243 +/- 15 munits/cm in the Vivonex-fed rats (n = 12) (P less than 0.05) but no significant changes in lactase, sucrase or maltase activites were found. The observed decrease in the CH:VH ratio suggested an improved survival of the mature enterocyte population during elemental diet feeding.

Alkaline Phosphatase↗

Duodenitis.

Many questions regarding duodenitis remain unanswered. However, the evidence suggests that duodenitis is a clinical entity which can give rise to dyspepsia and, on rare occasions, gastrointestinal haemorrhage. Conventional and double contrast radiology has only a small part to play in the diagnosis of duodenitis but is important in helping to exclude other lesions such as duodenal ulcer. Provided care is taken during the fibre-optic visualization of the duodenal bulb, the endoscopic appearances of moderately severe duodenitis correlate well with the histological changes seen. A diagnosis of apparent duodenitis should be confirmed by the histological criteria described. Treatment at present is similar to that of peptic ulcer, with the withdrawal of any predisposing and precipitating factors such as aspirin, alcohol and smoking. Antacids may relieve the symptoms. It is not yet known what effect these measures may have on the duodenitis as opposed to the symptoms of dyspepsia. The H2-receptor antagonist, cimetidine, should be effective in treating duodenitis but double blind clinical and endoscopic studies are required to confirm this. The place of surgery is as yet undefined. With the data at present available, it appears that duodenitis is part of the pathophysiological spectrum of the duodenal ulcer diathesis rather than a separate disease. It may represent both the production and healing phases of duodenal ulceration. In some patients the duodenal mucosa may proceed from normal to duodenitis and then to normal again without the development of frank duodenal ulceration (Figure 4). Prospective studies are required which should include a long-term clinical follow-up of a large number of patients with duodenitis accurately and specifically diagnosed by endoscopy and histopathology.

Adolescent↗

Is duodenitis a dyspeptic myth?

In 502 fibreoptic oesophagogastroduodenoscopies performed over 30 months, 14 cases (2.8%) of symptomatic duodenitis without an associated duodenal ulcer were diagnosed. Follow up (1 to 3-5 years) including repeat endoscopy and double-contrast barium meal showed that duodenal ulcers later developed in 6 patients. All have undergone surgery. A further 2 patients continued to complain of dyspepsis, and repeat endoscopy showed duodenitis, confirmed by conventional light microscopy (haematoxylin and eosin). The remaining patients are symptom-free. Repeat endoscopy and histological examination were either normal or showed mild inflammation of the duodenal mucosa. These findings suggest that duodenitis can cause symptoms and may be part of the pathophysiological spectrum of duodenal ulceration rather than a separate disease. It may represent both the production and healing phases of duodenal ulceration.

Adolescent↗

Immunological abnormalities in splenic atrophy.

Multiple immunological abnormalities have been demonstrated in fourteen patients with evidence in the blood-film of hyposplenism due to splenic atrophy. Reduction in spleen size was confirmed radiologically, and impairment of phagocytosis by the spleen was demonstrated by studying the survival and fate of chemically damaged autologous red blood-cells. Eight of the patients had intestinal malabsorption, and there was a high frequency of autoimmune disease in the remainder. Although patients with splenic atrophy showed little evidence of impairment of normal immune responses, there was a high frequency of autoantibody formation. There is thus an association between widespread immunological disturbances, notably autoimmunity, and splenic atrophy.

Adult↗

An improved bacterial test system for the detection and classification of mutagens and carcinogens.

We previously described a set of four strains of Salmonella typhimurium designed for detecting the various types of mutagens, and showed their utility in detecting a wide variety of carcinogens as mutagens. The lipopolysaccharide that normally coats these bacteria is a barrier to penetration of mutagens to the cell membrane. The set of tester strains has been improved by adding a mutation (rfa: deep rough) that results in a deficient lipopolysaccharide. The techniques for using these strains for detecting mutagens are presented and the tests are shown to be extremely sensitive and convenient. The specificity of frameshift mutagenesis is clarified. As adjuncts to the test with the four strains, we describe a test that compares mutagenic killing in deep rough strains with and without DNA excision repair, and a test using forward mutagenesis in a deep rough strain lacking excision repair.

Acridines↗

Carcinogens are mutagens: a simple test system combining liver homogenates for activation and bacteria for detection.

18 Carcinogens, including aflatoxin B(1), benzo(a)pyrene, acetylaminofluorene, benzidine, and dimethylamino-trans-stilbene, are shown to be activated by liver homogenates to form potent frameshift mutagens. We believe that these carcinogens have in common a ring system sufficiently planar for a stacking interaction with DNA base pairs and a part of the molecule capable of being metabolized to a reactive group: these structural features are discussed in terms of the theory of frameshift mutagenesis. We propose that these carcinogens, and many others that are mutagens, cause cancer by somatic mutation. A simple, inexpensive, and extremely sensitive test for detection of carcinogens as mutagens is described. It consists of the use of a rat or human liver homogenate for carcinogen activation (thus supplying mammalian metabolism) and a set of Salmonella histidine mutants for mutagen detection. The homogenate, bacteria, and a TPNH-generating system are all incubated together on a petri plate. With the most active compounds, as little as a few nanograms can be detected.

Aflatoxins↗

Intestinal spirochaetosis.

An abnormal condition of the large intestine is described in which the surface epithelium is infested by short spirochaetes. Diagnosis can be made by light microscopy. A review of 14 cases diagnosed by rectal biopsy and 62 cases involving the appendix shows no consistent symptom complex. The possible significance is discussed.

Adult↗

A comparative study of Kaposi's sarcoma and granuloma pyogenicum in Uganda.

A comparison has been made between two vasoformative lesions, Kaposi's sarcoma and granuloma pyogenicum, as they are encountered in Uganda. Both are predominantly skin lesions arising in the distal extremities, may resemble each other clinically, and are widespread in their distribution in Ugandan communities. They bear a reciprocal relationship to each other as regards age and sex incidence, Kaposi's sarcoma being mainly a disease of adult males and granuloma pyogenicum a disease of immature males and females. Histologically there are many similarities between them, the essential difference being the presence of a spindle-cell sarcomatous element in Kaposi's sarcoma. The clinical behaviour reflects this difference in that granuloma pyogenicum develops quickly and appears to be self-limiting, while Kaposi's sarcoma is slowly progressive and shows much less tendency to regress. On the basis of these findings it is concluded that, although these two lesions may be completely unrelated, it is possible that both represent a response of the vasoformative elements in the skin to a similar form of initiating stimulus and that hormonal or sex-linked genetic factors determine which lesion will develop in response to this stimulus. The presence of intracytoplasmic inclusion in the tumour cells of Kaposi's sarcoma might be of significance in the histogenesis of this tumour, and of value in its histological differentiation from granuloma pyogenicum.

Adolescent↗