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Biomedical subjects

G M Forbes

Publications and source records attributed to G M Forbes.

At least 37 records · Page 2Linked to original sources
PubMed1996

Long-term follow-up of gastric histology after Helicobacter pylori eradication.

Helicobacter pylori causes chronic active gastritis and is thought to be associated with the development of gastric atrophy, intestinal metaplasia and carcinoma. As the effect of H. pylori eradication on this process is poorly understood, we sought to determine the long-term effects of H. pylori eradication on gastric histology. Fifty-four patients with duodenal ulceration associated with H. pylori infection received H. pylori eradication therapy in 1985/86 and either remained infected (n = 22) or had the infection eradicated (n = 32); patients were followed up by endoscopy with gastric antral biopsy for 7.1 years (mean). Histopathological analysis of gastric antral mucosa from patients rendered H. pylori-negative revealed a marked decrease in both inflammatory cells within the lamina propria and intraepithelial neutrophils and an increase in epithelial mucinogenesis. Gland atrophy remained unchanged in both H. pylori-positive and -negative patients. When examined for the presence and severity of intestinal metaplasia, there was neither a difference between the two patient groups nor a change with time. These data demonstrate that significant long-term improvements in gastric histology accompany H. pylori eradication when compared with histology in patients with persistent infection. Whether this confers a protective effect by reducing the risk of gastric carcinoma remains unknown.

Adult↗
PubMed1995

A prospective study of screening upper gastrointestinal (GI) endoscopy prior to and after bone marrow transplantation (BMT).

BACKGROUND: Upper gastrointestinal (GI) endoscopic abnormalities are common in symptomatic bone marrow transplant (BMT) recipients but the incidence of occult gastrointestinal disease in these patients is unknown. AIMS: To examine the role of screening upper GI endoscopy before and after BMT. METHODS: Endoscopy was performed routinely on allogeneic (n = 24) and autologous (n = 17) BMT patients before transplant and at 30 and 120 days after transplant. RESULTS: Twenty-one of 41 patients (51%) had an endoscopic abnormality on one or more occasions which necessitated a change in treatment. These abnormalities were present in ten of 41 (24%) pre-transplant endoscopies, ten of 32 (31%) endoscopies at day 30 after BMT, and in seven of 22 (32%) day 120 endoscopies. Abnormalities included mucosal erosions or ulcers n = 22 endoscopies), infections (n = 5) or previously undiagnosed GI graft-versus-host disease (n = 3). Mucosal erosions or ulcers were present in eight of 28 endoscopies despite regular anti ulcer drug therapy. CONCLUSIONS: Screening upper GI endoscopy before and after BMT is generally safe and detects a high yield of significant GI abnormalities. However, it remains to be demonstrated that treatment of these lesions will improve the clinical outcome in BMT recipients without GI symptoms.

Adult↗
PubMed1995

Immunohistochemical changes in sigmoid colon after allogeneic and autologous bone marrow transplantation.

AIM: To determine whether there are characteristic immunohistological changes in the colonic mucosa in acute graft versus host disease (GvHD). METHODS: Consecutive allogeneic (n = 11) and autologous (n = 11) bone marrow transplant recipients underwent endoscopic biopsy of sigmoid mucosa before transplant and on day 30 post-transplant. Immunohistochemical staining and quantitation of intraepithelial and lamina propria mononuclear cells were undertaken using a panel of monoclonal antibodies and a Streptavidin-biotin alkaline phosphatase staining technique. RESULTS: In the allogeneic group (nine of whom had clinical acute GvHD) there was a fivefold increase in lamina propria CD16+ mononuclear cells (3.1 +/- 4.3 to 17.0 +/- 12.2 per 100 lamina propria nucleated cells), compared with autologous transplant recipients in whom this rise was twofold (5.5 +/- 4.6 to 10.6 +/- 7.1 per 100 lamina propria nucleated cells). The CD16+ mononuclear cells had morphological appearances of tissue macrophages, but in neither the allogeneic nor autologous groups was there an increase in total macrophage numbers (CD14+). In patients with acute GvHD the lamina propria CD4+:CD8+ lymphocyte ratio fell (1.97 +/- 1.12 to 1.07 +/- 1.01), primarily because of a fall in the number of lamina propria CD4+ lymphocytes. In both allogeneic and autologous groups there was a fall in intraepithelial lymphocyte numbers, but there was no change in CD19+ (B cell), CD25+ (interleukin-2 receptor positive) or CD56+ (natural killer) cell numbers. CONCLUSION: Following bone marrow transplantation, there appears to be upregulation of lamina propria tissue macrophage CD16 (an Fc receptor for IgG), a change which is more noticeable after allogeneic transplantation and which may be related to the development of acute GvHD. In patients with acute GvHD there was a fall in the lamina propria CD4+:CD8+ lymphocyte ratio. If these changes are functionally important, they may have significant implications for understanding the pathogenesis of GvHD.

Acute Disease↗
PubMed1995

Prospective study of the quality of life in patients assessed for liver transplantation: outcome in transplanted and not transplanted groups.

The quality of life in adult patients with chronic liver disease who were considered for transplantation was assessed prospectively over a 2 year period, for both those who did and did not subsequently receive transplants. The main outcome measures were the Nottingham Health Profile and survival. Of the 109 patients who completed an entry profile, 27 were transplanted, 71 not transplanted during the study period, and 11 rejected for transplant. Quality of life and severity of liver disease at entry was worse for the transplant group, whose survival at 15 months from entry was 81% compared with 78% for those not transplanted. Among transplant survivors there were marked improvements in quality of life, whilst amongst those not receiving transplants there was little change. In conclusion, liver transplantation was effective in improving quality of life in patients with chronic liver disease, but comparison between transplant and non-transplant patients is difficult because of differences between the groups.

Activities of Daily Living↗
PubMed1995

Intestinal mucosal mononuclear cell chimaerism after sex-mismatched allogeneic bone marrow transplantation.

The contribution of haemopoietic cell chimaerism to the pathogenesis of GVHD after BMT is unclear. This report raises the possibility that donor lymphocyte-recipient macrophage chimaerism may occur shortly after allogeneic marrow engraftment and hence might contribute to the development of GVHD. Immunohistological studies of intestinal mucosa in an allogeneic BMT patient, who did not engraft, revealed an almost complete absence of lymphocytes 30 days after transplant, but preservation of mucosal macrophage numbers. Subsequently, combined immunohistology-Y chromosome in situ hybridization studies were performed in two female BMT recipients of male donor marrow. These studies revealed that between 25 and 40% of macrophages and between 25 and 40% of T lymphocytes were of donor origin during the first 6 months after transplant. In conclusion, whilst the immunohistological studies of intestinal mucosa from a patient who failed to engraft suggest that donor lymphocyte-recipient macrophage ('split') chimaerism may occur shortly after marrow engraftment, the subsequent in situ hybridization studies revealed 'mixed' chimaerism in the two sex-mismatched BMT recipients.

Adult↗
PubMed1994

Duodenal ulcer treated with Helicobacter pylori eradication: seven-year follow-up.

The long-term benefits of Helicobacter pylori-eradication treatment (HET) in H pylori-associated duodenal ulcer are unclear. We followed up patients with duodenal ulcers from a trial of H pylori eradication in 1985-86. 63 of 78 patients (81%) were reviewed clinically and had upper gastrointestinal endoscopy with gastric antral biopsy. Of 35 patients previously rendered H pylori negative, 32 (92%) remained H pylori negative after 7.1 years (mean). All patients initially H pylori positive remained infected, unless HET was given in the interim. Duodenal ulceration was found in 20% (5 out of 25) of patients remaining H pylori-positive, compared with 3% (1 of 38) of H pylori-negative patients (p < 0.05). The reduction of duodenal ulcer relapse obtained from H pylori eradication in H pylori-associated duodenal ulcer extends to at least 7 years after treatment, and is likely to be due to freedom from H pylori infection. However, duodenal ulcer may recur in patients rendered H pylori negative, due to factors other than reinfection with H pylori.

Adult↗
PubMed1992

Primary cerebral lymphoma: an association with craniopharyngioma or cadaveric growth hormone therapy?

OBJECTIVES: To present the first case of primary cerebral lymphoma associated with craniopharyngioma or previous cadaveric growth hormone therapy. CLINICAL FEATURES: A 22-year-old male shop assistant of European descent presented with unilateral uveitis and was found to have a high grade primary cerebral lymphoma. This occurred nine years after successful surgical resection of a craniopharyngioma without the administration of adjuvant radiotherapy. INTERVENTION AND OUTCOME: There was initial radiological resolution of cerebral lymphoma after cranial irradiation. Recurrence was noted 10 weeks later, resulting in the patient's death. CONCLUSION: The development of primary cerebral lymphoma following a craniopharyngioma is considered most likely a chance occurrence. Cadaveric growth hormone therapy may play a role in the genesis of lymphoma.

Adult↗
PubMed1992

Carbamazepine hepatotoxicity: another cause of the vanishing bile duct syndrome.

Serious carbamazepine hepatotoxicity is being recognized more frequently and is usually manifest as an acute granulomatous hepatitis that is self-limiting if the drug is withdrawn. The case of a 59-year-old man who developed the vanishing bile duct syndrome after 2 months of treatment with carbamazepine for glossopharyngeal neuralgia is reported. The characteristic histological features of this syndrome may also be seen in primary biliary cirrhosis, primary sclerosing cholangitis, graft-vs.-host disease after allogeneic bone marrow transplantation, chronic liver allograft rejection, and other drug reactions. The progress of this patient to date suggests that irreversible liver injury resulting in chronic liver disease is likely, in keeping with the clinical course of the vanishing bile duct syndrome in most cases.

Bile Ducts↗
PubMed1991

Nodular regenerative hyperplasia of the liver: the importance of combined macroscopic and microscopic findings.

A 40-year-old man with rheumatoid arthritis, splenomegaly and mild thrombocytopenia presented with gross ascites and a history of excess alcohol consumption. Oesophageal varices were documented endoscopically. Alcoholic cirrhosis was suspected and laparoscopy revealed a macronodular liver surface. Liver biopsy disclosed subtle microscopic structural variations which together with the laparoscopic findings were consistent with the diagnosis of nodular regenerative hyperplasia. The importance in diagnosis of macroscopic appearance combined with histological findings is emphasised. Clinically significant portal hypertension may be present at a histologically early stage of this condition.

Adult↗
PubMed1990

Nocardiosis in liver transplantation: variation in presentation, diagnosis and therapy.

Nocardiosis arose in seven of 191 liver transplant patients (3.7%) over a period of 3.5 years. Four patients had only pulmonary lesions while three had disseminated disease. Nocardia asteroides was isolated from three patients following bronchoscopy, percutaneous aspirate of a pulmonary lesion in one patients, and from the skin from the aspirates in three patients. Delay in diagnosis in two cases was due to negative microscopy; in one, the diagnosis was made only after repeated bronchoscopy. Of the seven patients, three (43%) died. In two of these, nocardiosis was considered to have directly contributed to death. Co-existent bacterial and viral infections were present in all patients who died. In vitro susceptibility of the organism to co-trimoxazole was variable and did not necessarily reflect clinical efficacy. In one patient, a good clinical response was achieved with co-trimoxazole despite apparently reduced in vitro susceptibility.

Adult↗
PubMed1989

Serum F protein estimation in liver allograft recipients with graft dysfunction.

Serum levels of F protein, a 44 kD cytoplasmic protein mainly found in hepatocytes, became elevated during episodes of graft dysfunction following orthotopic liver transplantation. In a study of 27 liver transplant recipients, the rise in F protein did not precede rises in the other conventional biochemical indices of hepatic dysfunction. Serum F protein concentration significantly correlated with serum levels of aspartate aminotransferase, gamma-glutamyltransferase, alkaline phosphatase, and bilirubin (all P less than 0.001) and also with the prothrombin time (P = 0.048). Despite its high concentration in liver cells, this marker does not provide any additional benefit in the diagnosis of graft dysfunction or in monitoring liver allograft function following transplantation.

Adolescent↗
PubMed1986

Intra- and extracellular modifications of apolipoproteins.

This chapter outlined the methods used to study intra- and extracellular modifications of apolipoproteins. These and other related studies have shown that several of the apolipoproteins undergo a series of intra- and extracellular modifications as follows: All apolipoproteins studied contain an 18-26 long signal peptide which is cleaved cotranslationally by the signal peptidase of the rough endoplasmic reticulum. ApoE is further modified intracellularly with carbohydrate chains containing sialic acid and is secreted in the modified form designated apoEs. The modified apoE is subsequently desialated in plasma. ApoA-I is secreted in a proapoA-I form, which consists of 249 amino acids. The N-terminal hexapeptide of proapoA-I is cleaved extracellularly by a proapoA-I to plasma apoA-I converting protease. This cleavage generates the plasma apoA-I form which consists of 243 amino acids. Other known apolipoprotein modifications include the modification of apoB, apoC-III, and apoD with carbohydrate chains that contain sialic acid and the proteolytic cleavage of the proapoA-II segment. At the present time we are able to distinguish several isoprotein forms for a particular apolipoprotein. In addition, we began to understand the biochemical changes which lead to a few of these isoproteins. Future research should be directed toward a better understanding not only of the structure but most importantly of the physiological significance of the different apolipoprotein forms.

Amino Acid Sequence↗
PubMed1982

Clonal interaction in tumours.

The development of cancer is contingent on the emergence of at least one clone of transformed cells. One method used to investigate whether human tumours are monoclonal depends on the mosaicism in the normal tissues of women heterozygous for the two forms of the enzyme glucose-6-phosphate dehydrogenase (G-6-PD). This mosaicism results from the inactivation of one X chromosome in all somatic cells and should not exist in a monoclonal population. Following the discovery in feral mice of an electrophoretic variant (A) of the X-coded enzyme phosphoglycerate kinase (PGK-1) which differs from the form (B) found in common laboratory mouse strains it was reported that fibrosarcomas induced chemically in hybrids of feral and laboratory-bred mice expressed both enzyme phenotypes, but the conclusion that both were expressed by neoplastic cells was based solely on morphological evidence. The development of histocompatible substrains of mice homozygous for one or other alloenzyme has made it possible to study the clonal composition of tumours under experimental conditions in which the neoplastic status of subpopulations of cells can be verified by transplantation. The experiments we now report, while confirming that murine fibrosarcomas are often pleoclonal, show that the clonal composition may change markedly during tissue culture and on transplantation to congenic hosts. These changes presumably reflect changes in the growth kinetics of differentiating subpopulations of the tumour. Cloned sublines are less readily transplantable than uncloned tumour cell populations, and some sublines are less readily transplantable than others; this suggests that sublines resistant to a host's attack are selected on transplantation or that some sublines require the cooperation of others to survive. We postulate that changes in clonal composition occur also during tumour development, metastasis and recurrence.

Animals↗