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Biomedical subjects

S Mehta

Publications and source records attributed to S Mehta.

At least 235 records · Page 13Linked to original sources
PubMed1992

Lymphokine-activated effector cells: modulation of activity by cytokines.

Interleukin 2 (IL-2) has been demonstrated to generate lymphokine-activated killer (LAK) cells from normal human peripheral blood lymphocytes (PBL). Such LAK cells have demonstrated lytic activities on certain tumor cell targets including melanoma, renal carcinoma, and other tumor targets. B lymphoblastoid cell lines such as Raji cells are routinely employed to assess functional LAK cell activity. In our studies we have assessed the effect of various cytokines that affect lymphocyte cell growth and differentiation, including rIL-2, interleukin 4 (rIL-4), interleukin 6 (rIL-6), interferon alpha and gamma (rIFN-alpha and -gamma) and tumor necrosis factors alpha and beta (rTNF-alpha, rTNF-beta), for their ability to generate functional LAK cell activity. Our data confirm that rIFN-alpha and -gamma singularly are capable of inducing LAK cell activity (55 +/- 21 and 40 +/- 10, respectively, in comparison to rIL-2 at 1000 units/ml) whereas rIL-4, rIL-6, BCGF, rTNF-alpha, or rTNF-beta failed to generate the functional LAK cell activity from human PBL. Interferon alpha, itself capable of generating LAK cell activity, was augmentative in its effect with rIL-2 for the generation of functional LAK cell activity. Conversely, rIL-4 inhibited LAK cell activity induced by either rIL-2 alone or the combination of rIL-2 and rIFN-alpha. Furthermore, the increased effects of rIFN-alpha with rIL-2 on LAK cell activity are partly abrogated by as much as 30 or 52% by delaying the addition of either rIL-2 or rIFN-alpha, respectively, for more than 24 h. These results suggest a regulatory role for certain cytokines on LAK cell functions.

Cell Line↗
PubMed1992

A prospective randomized study of the injurious effects of aspirin and naproxen on the gastroduodenal mucosa in patients with rheumatoid arthritis.

A prospective double-blind randomized placebo-controlled study was conducted to compare the injurious effects of aspirin and naproxen on the gastroduodenal mucosa. Patients with rheumatoid arthritis attending the immunology clinic of a tertiary care center were included in the study. Ninety consecutive patients were randomized to receive aspirin, naproxen, or placebo. Clinical evaluation was done every 2 wk. Upper gastrointestinal endoscopy, biopsies from the gastric antrum and duodenum for histological examination, and Helicobacter pylori studies were done at entry and after 2 months. The number of patients with dyspeptic symptoms was similar in the aspirin (12) and naproxen (9) groups. In both cases, however, it was higher (p less than 0.01) than in the placebo group (none). Naproxen was associated with a higher score of endoscopic abnormalities in the gastric body (0.6 +/- 1.3) than aspirin (0.2 +/- 0.6) or placebo (0.03 +/- 0.18). H. pylori was present in a similar proportion of patients in the three groups (33-43%). A greater fall in hemoglobin was observed with aspirin (0.35 +/- 0.48 g%) and naproxen (0.44 +/- 0.53 g%) than with placebo (0.09 +/- 0.4 g%). The present study suggests that aspirin and naproxen produce a similar degree of injury to the gastroduodenal mucosa.

Adult↗
PubMed1991

Diffuse embolization following percutaneous transluminal coronary angioplasty of occluded vein grafts: the blush phenomenon.

Percutaneous transluminal coronary angioplasty (PTCA) was performed on 146 saphenous vein grafts in 116 patients. In 29 patients, 31 grafts were totally occluded. Myocardial staining lasting over 5 minutes--"the blush phenomenon"--followed the opening of the occluded grafts in 9 of these patients. In 5 of these 9, enzyme release suggested infarction. A sixth patient died within a few hours of PTCA, with suspected infarction. Autopsy demonstrated diffuse and extensive distal coronary arterial embolization of grumous material, including cholesterol crystals, platelets, and fibrin. The blush phenomenon was not seen following PTCA in the remaining 20 patients with total occlusions, nor in any of the 87 patients with stenosed grafts. We have not observed the blush phenomenon following PTCA of more than 3300 coronary arteries. Of the 9 patients demonstrating the blush phenomenon, 6 had a recent history of myocardial infarction or unstable angina pectoris, compared with 4 of the remaining 20 patients with occluded grafts. We now approach occluded grafts with injection of intragraft thrombolytic agents or with atherectomy prior to PTCA. Future approaches may include atherectomy or laser angioplasty.

Adult↗
PubMed1991

Augmentation of the lymphokine-activated killer cell response in head and neck cancer patients by combination interleukin-2 and interferon-alpha.

The majority of patients with head and neck cancer present with advanced disease (stage III and IV), for which current chemotherapeutic regimens offer dismal results. Although known to have defects in their cell-mediated immunity, their poor performance status makes them unlikely candidates for aggressive immunotherapeutic protocols because of associated severe toxicities. This study evaluates the effect of subthreshold recombinant interferon-alpha (rIFN-alpha) and interleukin-2 (rIL-2) on the generation of lymphokine-activated killer (LAK) cells from the peripheral blood of patients with head and neck cancers. In vitro treatment of patients' lymphocytes consisted of incubation in 1,000 U/mL rIL-2, 100 U/mL rIL-2, 100 U/mL rIFN-alpha, and 100 U/mL rIFN-alpha plus 100 U/mL rIL-2 for 4 to 5 days. Cytotoxicity was measured using a standard 4-hour chromium-51 (51Cr)-release assay with Raji (B lymphoblastoid) tumor target cells. LAK activity was arbitrarily defined as greater than 20% cytolysis of Raji target cells. LAK activity was generated in a smaller percentage of the head and neck cancer patients by 1,000 U/mL rIL-2 compared with normal adult donors: 54% versus 100%, p less than 0.05; IFN-alpha (100 U/mL) induced LAK activity in approximately 50% of the cancer patients. The addition of rIFN-alpha (100 U/mL) to rIL-2 (100 U/mL) resulted in LAK generation in a higher percentage of patients (83% versus 54%), as well as increased levels of cytotoxicity, p = 0.05. This combination also resulted in cytotoxicity levels equivalent to high-dose (1,000 rIL-2 U/mL). These in vitro data support a clinical trial to assess the therapeutic efficacy of combined low-dose rIL-2 and rIFN-alpha in vivo in head and neck cancer patients.

Aged↗
PubMed1991

Enzyme-linked immunosorbent assay for copro-diagnosis of giardiasis and characterisation of a specific Giardia lamblia antigen in stools.

An enzyme-linked immunosorbent assay (ELISA) has been evaluated for copro-diagnosis of giardiasis with anti-trophozoite antibody to capture specific Giardia lamblia stool antigen (GLSA), which was then detected by specific antibody conjugated with horseradish peroxidase. GLSA was demonstrated in stool eluates from all the 24 confirmed cases of giardiasis. None of the stool eluates from apparently healthy subjects or from patients carrying intestinal parasites other than G. lamblia had GLSA. Of the 25 microscopy-negative clinically suspected cases of giardiasis, 17 (68%) patients had GLSA in their stool eluates; these patients responded to anti-giardial therapy. The specific antigen was isolated and affinity-purified by the use of specific antibody; it had a Mr of 66 Kda, and its immunoreactivity was lost after treatment with heat or trypsin but unaltered by metaperiodate. ELISA seems to be a sensitive and specific method for copro-diagnosis of giardiasis, especially in highly suspected cases.

Animals↗
PubMed1991

Intubation guide marks for correct tube placement. A clinical study.

The tracheas of 140 adult patients were intubated with either TFX or Portex tracheal tubes. Guide marks were printed at variable distances proximal to the tube cuffs, and during intubation the guide mark was positioned at the level of the vocal cords. The distance between the bevel end of the tube and the carina was determined with a fibreoptic bronchoscope. The mean distance between the tip of the tracheal tube and the carina varied between 3.7 and 4.1 cm with the head in the neutral position. The tip of the tracheal tube approaches the carina by a mean distance of 0.5 cm when the head is moved from the extended position to the neutral position. It is recommended that a guide mark be placed 2.5 cm from the proximal end of the cuff in tubes used for adult males and 2.25 cm in tubes used for adult females. The use of guide marks is a simple, safe and reliable method for correct tracheal tube placement.

Adult↗
PubMed1991

Altered diastolic function in asymptomatic infants of mothers with gestational diabetes.

Left and right ventricular filling was studied prospectively in 50 full-term (39.4 +/- 1.3 wk) asymptomatic newborns of mothers with gestational diabetes mellitus (GDM). Their data were compared with those of 80 asymptomatic full-term (39.8 +/- 1.2 wk) infants who served as control subjects. Infants were examined in the immediate newborn period (less than 48 h) and then again at 2-4 and 6-9 wk. Although mean weight, length, and gestational age did not differ, the mean +/- SD left ventricular dimensions during diastole (1.73 +/- 0.15 vs. 1.81 +/- 0.18 cm, P = 0.007) and systole (1.22 +/- 0.15 vs. 1.31 +/- 0.17 cm, P = 0.004) were significantly lower in infants of mothers with GDM compared with control infants. Diastolic measurements suggested a shift from the early diastolic filling of the ventricle to the later period of atrial systole in infants of mothers with GDM. A lower initial one-third area fraction and a higher peak flow velocity and velocity time integral during atrial systole were noted at the mitral valve in infants of mothers with GDM. These changes had resolved by 2-4 wk of age. The altered diastolic filling patterns in infants of mothers with GDM indicate poor myocardial relaxation and/or decreased passive compliance of the ventricular myocardium. These alterations were observed in asymptomatic infants in the absence of left ventricular or septal hypertrophy. If exposed to significant stress such as asphyxia or sepsis, the observed myocardial dysfunction could lead to higher morbidity in these infants.

Adult↗
PubMed1991

Diagnostic and therapeutic colonoscopy in children: experience from a pediatric gastroenterology centre in India.

Eighty colonoscopies were performed in 72 children suffering from various colonic disorders. The indications for colonoscopic examination were bleeding per rectum (83.3%), prolonged colitis (14.0%) and colonic obstruction (2.7%). Total bowel wash with normal saline was very good for colonic preparation in majority of the cases. Pediatric colonoscope (PCF-Olympus) was used and the procedure performed under sedation with intravenous diazepam and pentazocine. Juvenile polyps were the commonest lesions (69.4%). Diagnosis of idiopathic ulcerative colitis, acute colitis, tuberculous colitis, amebic colitis and allergic colitis was made in 5.5, 4.2, 2.7, 1.3 and 1.3% cases, respectively. Tuberculous hypertrophic lesion and tuberculous stricture was seen in one case each. The commonest site of juvenile polyps was rectosigmoid region. Ninety per cent of them were single, 8% had polyps ranging from 2-4 in number and one (2%) child had juvenile polyposis coli. Successful colonoscopic removal of polyps with polypectomy snare was possible in 96% cases. No complications were observed. Colonoscopy is a safe and useful mode of investigation of colonic disorders in expert hands. It has a great therapeutic value in childhood.

Adolescent↗
PubMed1991

Jejunal diaphragm.

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Child, Preschool↗