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Biomedical subjects

J Ma

Publications and source records attributed to J Ma.

At least 649 records · Page 36Linked to original sources
PubMed1982

Intestinal mucinous substances in gastric intestinal metaplasia and carcinoma studied by immunofluorescence.

Immunofluorescent studies using specific antisera against intestinal mucins revealed small intestinal mucin antigen (SIMA) and large intestinal mucin antigen (LIMA) in areas of intestinal metaplasia of the stomach. In 25 gastric carcinomas studied, both these antigens were detected in seven carcinomas, SIMA only was present in four and LIMA in only four cases; the antigens could not be detected in ten of the carcinomas. In 21 of the 25 gastric operation specimens, including the 15 carcinomas positive for intestinal mucin antigens, there was evidence of chronic gastritis and intestinal metaplasia. These immunohistologic observations confirm the results of recent histochemical studies that both small and large intestinal type mucins are present in intestinal metaplasia and gastric carcinomas. Our findings provide further evidence that at least a proportion of gastric carcinomas may supervene on intestinal metaplasia. The absence of one or both antigens in gastric carcinomas may indicate stages of dedifferentiation or alternatively differences in histogenesis.

Adenocarcinoma, Mucinous↗
PubMed1982

Inhibition by nonsteroidal antiinflammatory drugs of luminol-dependent human-granulocyte chemiluminescence and [3H]FMLP binding. Effect of sulindac sulfide, indomethacin metabolite, and optical enantiomers (+) and (-) MK830.

A system is described to evaluate for nonsteroidal antiinflammatory drugs by means of luminol-dependent human-granulocyte chemiluminescence (CL) is described. The CL is produced using either opsonized zymosan (yeast cells) or the soluble chemotactic peptide f-Met-Leu-Phe as the perturbant of the granulocyte membrane. Using either system, the following drug effects 2 x 10(-5) M were noted: only sulindac sulfide, and not sulindac sulfone or sulindac, displayed marked inhibition of chemiluminescence, following the in vivo data regarding inflammatory effects. The 5-OH indomethacin metabolite was likewise inactive as an inhibitor of CL mirroring in vivo effects. MK(+)410, MK(-)830 and MK835 all showed approximately 50% inhibition of CL, displaying deviation from in vivo data. MK(+)830 markedly stimulated CL, 4-6 times the control (without drug), which is clearly different from its enantiomer, MK(-)830. The reasons for this behavior are unclear. However, receptor binding studies with [3H]FMLP were accomplished in the presence and absence of the various drugs at 2 x 10(-5) M that were effective inhibitors of chemiluminescence (CL). Indomethacin, MK(-)830 and MK(+)410 had equivalent percent control binding and percent control CL. Sulindac sulfide and MK(+)835 both had higher percent control binding than percent control CL, with MK(+)835 displaying apparent increased numbers of available receptors relative to control. MK(+)830, which produces large increases in CL, produced a minor effect on percent control binding. A direct relationship between binding and CL does not exist with each drug. Chemiluminescence is dependent on ion movement and oxidative metabolism and is a secondary event to agonist-receptor occupation.

Anti-Inflammatory Agents↗
PubMed1982

The presence of oncofoetal antigens in large bowel carcinoma.

This paper is an immunohistological study of the occurrence of the oncofoetal antigens, (carcinoembryonic antigen (CEA), small intestine mucin antigen (SIMA), and normal large bowel mucin antigen (LIMA) in 60 surgically resected colons: 10 non-malignant specimens and 50 colorectal carcinomas. SIMA is a new oncofoetal antigen found in mucinous carcinoma of the large bowel. In the adult it is normally present only in the duodenum and jejunum. Of the 50 carcinoma specimens, 13 were mucinous, 17 non-mucinous and 20 mixed mucinous and non-mucinous. LIMA was the only antigen detected in the mucosa of non-malignant specimens. In mucinous carcinomas only SIMA was present, whilst in the non-mucinous specimens CEA was always found and to a lesser extent LIMA. The same relationship was observed in mixed tumours: SIMA in mucinous and CEA-LIMA in the non-mucinous parts. In the mucosa adjacent to the cancer in all 50 cases there was evidence of an increase or decrease in LIMA. In 42 cases (84%) both oncofoetal antigens (CEA and SIMA) could also be detected in this transitional or perineoplastic epithelium at varying distances from the tumour. These results provide evidence to suggest that the majority of large bowel carcinomas occur in areas of metaplastic change.

Adenocarcinoma↗
PubMed1982

Persistence of organ- and iso-antigens in vitro in a long-term culture cell line of colonic carcinoma.

Cells of colonic carcinoma line HT-29, cultured over more than 170 generations and extensively used in immunological studies of patients with colorectal tumours, still express several immunologically valuable characteristics presumably present since its inception. The cell line can induce a poorly differentiated adenocarcinoma in the nude mouse, it has human antigenic characteristics, it expresses blood group A antigen, and produces a colon-specific mucin and CEA, though not colon cancer-specific mucin (CCM). It remains useful as a target for in vitro testing of anti-tumour immunoreactivity in colorectal cancer patients.

Adenocarcinoma↗
PubMed1981

Inappropriate mucin production in gall bladder metaplasia and neoplasia--an immunohistological study.

This study demonstrates the presence of three antigens in glandular metaplasia occurring in patients with cholecystitis and cholelithiasis: specifically carcinoembryonic antigen (CEA), large intestinal mucin antigen (LIMA) and small intestinal mucin antigen (SIMA). These antigens could not be detected in normal gall bladder mucosa or in squamous metaplasia of the gall bladder. The occurrence of the three intestine-associated antigens in three carcinomas was irregular. In one mucinous carcinoma, only SIMA could be demonstrated. In one adenocarcinoma, SIMA was present in small areas of mucinous change, whilst CEA was present in the non-mucinous malignant tissue. In a mixed mucinous and non-mucinous adenocarcinoma with widespread dissemination, the three antigens were present both in the primary tumour and the metastases. These observations suggest that all forms of glandular metaplasia of the gall bladder are intestinal in nature and at least a proportion of gall bladder carcinomas are of an intestinal type. Finally they provide further immunological evidence that glandular metaplasia of the gall bladder should be considered a pre-malignant condition.

Adenocarcinoma↗
PubMed1981

Intestine-associated antigens in ovarian tumours: an immunohistological study.

The presence of 3 intestine-associated antigens, small intestine mucin antigen (SIMA), large intestine mucin antigen (LIMA) and carcinoembryonic antigen (CEA) was studied in the female genital tract and ovarian tumours by immunofluorescence. These antigens could not be detected in normal ovary, benign cysts of ovary, fallopian tube or endometrium, but both LIMA and CEA were present in endocervical glandular tissue. The antigenic cross-reactivity of endocervical and large bowel mucin may indicate a close embryological relationship between these organs during the cloacogenic stage. The 3 antigens could be demonstrated in mucinous tumours of the ovary but were absent in serous or mesonephroid tumours. In one of the 2 endometroid tumours CEA was the only detectable antigen. These observations confirm the presence of intestinal type of epithelium in cystic mucinous tumours of the ovary and explain the cross-reactivity of mucin of benign tumours of the ovary and mucin from colonic cancer, normal colonic mucosa and gastric mucosa as reported by earlier workers. In the process of malignant transformation the columnar epithelium of ovarian cystadenoma seems to behave in the same way as superficial gastric and gall bladder epithelium by forming inappropriate intestine-associated mucin substances. Our technique may provide a specific means for studies on the histogenesis of female genital tract tumours, particularly ovarian tumours. It can also be used in differentiating between benign and malignant variants of these tumours.

Antigens, Neoplasm↗
PubMed1980

The cardiovascular effect of vasopressin in relation to its plasma concentration in man and its relevance to high blood pressure.

The cardiovascular response and the changes of plasma arginine vasopressin (AVP) concentration following graded doses of AVP infused intravenously have been defined in six normal young men. The same measurements were also made during fluid deprivation in a patient with both nephrogenic diabetes insipidus and systemic hypertension. When, following AVP infusion, mean diastolic arterial pressure increased from 72 +/- 3 mmHg (SEM) to 78 +/- 2 mmHg (SEM) in the normal subject group, mean plasma AVP increased by 14.5 fmol/ml. When the patient was deprived of water, diastolic pressure increased, despite the fluid loss, from 90 to 105 mmHg, with a comparable increase of plasma AVP concentration of 15.3 fmol/ml. Further increases of plasma AVP concentration in either the normal subjects or in the patient were not associated with further increments of arterial pressure. We suggest that under pathophysiological circumstances in man plasma AVP concentrations may achieve levels which have a significant cardiovascular effect.

Adult↗
PubMedDate not supplied

Field strength and angle dependence of trabecular bone marrow transverse relaxation in the calcaneus.

The contribution from reversible dephasing, R2', to the effective transverse relaxation rate, R2*, in trabecular bone marrow, is governed by the magnetic field inhomogeneity induced by the difference in diamagnetic susceptibility between bone and bone marrow and should, therefore, scale linearly with field strength. Measurement of R2' in the calcaneus at 1.5 and 4 T by means of the GESFIDE (gradient-echo sampling of free induction decay and echo) pulse sequence showed R2' to increase by a factor of 2.73 at the higher field, which is close to the ratio of the field strengths (2.67). At both field strengths, R2' dominates R2*, contributing more than 90% to the total relaxation rate at 4 T. The data further indicate large regional variations within the calcaneus and a notable dependence of R2' on the angle of the foot relative to the direction of the static field. The findings have implications on the choice of the calcaneal site for assessment of trabecular density.

Adult↗
PubMedDate not supplied

A simple, rapid method for HPLC analysis of lycopene isomers.

A rapid method for the extraction, separation and quantification of the geometric isomers of lycopene and beta-carotene from tomato fruit is described. Carotenoids in tomato were separated and eluted using a reversed-phase HPLC with a C30 column and a mobile phase consisting of methyl-t-butyl ether, methanol and ethyl acetate. The system provided sharp resolution of cis- and trans-isomers of lycopene within approximately 23 min in contrast to the longer and more complex gradient procedures required by previously described methods. Experiments indicate that the stability of extracts of fresh tomato may be improved if stored at -20 degrees C, and that the presence of the antioxidant BHA has no apparent effect on stability.

Carotenoids↗
PubMedDate not supplied

Alzheimer A beta neurotoxicity: promotion by antichymotrypsin, ApoE4; inhibition by A beta-related peptides.

Two inflammation-associated proteins found in the Alzheimer amyloid deposits-alpha 1-antichymotrypsin (ACT) and apolipoprotein E4 (apoE4)-have been shown to be genetic risk factors for the development of Alzheimer's disease and to promote the polymerization of the A beta peptide into amyloid filaments in vitro. In the present study, we show that ACT and apoE4 increase the neurotoxicity of the A beta peptide in parallel with their promotion of filament formation. Preincubation of ACT or apoE4 with small A beta-related peptides, or of apoE4 with apoE2, abrogated their subsequent ability to promote both the formation and the neurotoxicity of A beta filaments. These results indicate that ACT and apoE4 may play a stimulatory role in the formation of neurotoxic amyloid in Alzheimer's disease, and that their amyloid promoting activity can be blocked by inhibitory peptides.

Alzheimer Disease↗