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Biomedical subjects

R K Chawla

Publications and source records attributed to R K Chawla.

At least 37 records · Page 2Linked to original sources
PubMed1985

The short child with subnormal plasma somatomedin C.

In 59 male and 59 female healthy children of average stature between 7 and 10 yr old, the normal range of plasma somatomedin C was investigated. The 95% tolerance limits narrowed progressively when the child's plasma somatomedin C status was described by the mean of one, two, three, or four determinations at 6-wk intervals. The 95% tolerance limits were therefore based on the mean of four determinations. In 97 children, age 7 to 10, below the 3.0 percentile in height, 44 had an average plasma somatomedin C below the 2.5 percentile. Among these hyposomatomedinemic short children, 19 were partially or totally deficient in growth hormone, 20 had normal immunoreactive growth hormone responses to dopa, glucagon, and sleep (nongrowth hormone deficient), and five had borderline provocative tests. Both growth hormone deficient and nongrowth hormone deficient children showed significant linear growth responses to 6-month courses of human growth hormone (0.16 to 0.70 unit/kg/wk). The responses of the latter group were 50 to 90% as great as those of the former.

Child↗
PubMed1985

Heterogeneity of growth hormone in the nocturnal serum of children.

The nocturnal serum of 13 nongrowth hormone deficient, hyposomatomedinemic short children and of 12 normal children of average height was analyzed by both polyclonal and biclonal radioimmunoassays. The biclonal/polyclonal ratio for immunochemical grade human growth hormone was 1.0, but for the nocturnal sera in both groups, this ratio was significantly less than 1.0 (range 0.5-1.2, average 0.7-0.8). The ratio did not differ significantly between the two groups of children.

Adolescent↗
PubMed1985

Characterization of autostimulatory and transforming growth factors from human melanoma cells.

Serum-free growth of the human malignant melanoma cell line Hs0294 is associated with production of transforming growth factor-alpha and an autostimulatory melanoma mitogen (melanoma growth-stimulatory activity, MGSA). The transforming activity is characterized by stimulation of anchorage-independent growth of normal rat kidney fibroblasts and competition with 125I-epidermal growth factor for binding to normal rat kidney cells. The second activity, MGSA, stimulates the anchorage-dependent growth of human melanoma cells in serum-free culture medium. When acetic acid extracts of Hs0294 conditioned medium are subjected to Bio-Gel P-30 chromatography followed by reverse-phase high-pressure liquid chromatography, the majority of the transforming growth factor-alpha elutes at 30 +/- 4% acetonitrile, while the major peak of MGSA elutes at 35 +/- 3% acetonitrile. These data indicate that the anchorage-dependent serum-free growth of the Hs0294 human melanoma cell line is apparently dependent upon the autostimulatory melanoma mitogen, MGSA, which is separable from the 125I-epidermal growth factor competing activity produced by these cells.

Chromatography, Gel↗
PubMed1984

Urinary cancer-related protein EDC1 and serum inter-alpha trypsin inhibitor in breast cancer.

In 1976 we isolated a novel glycoprotein labeled EDC1, Mr 27,500, which is immunologically related to the normal plasma protein inter-alpha trypsin inhibitor (IATI, Mr 160,000) and which is the major component of cancer-associated proteinuria. Urinary excretion of EDC1 (mg/g creatinine) may be classified in four ranges: i) low (less than 15); ii) light (15-30); iii) intermediate (31-45); and iv) heavy (greater than 45). Normal healthy women excrete 8.0 +/- 2.2 mg/g creatinine (average +/- SEM), whereas patients with metastatic breast cancer excrete 98.2 +/- 11.6 mg/g creatinine. Patients with a variety of non-malignant disorders excreted 14.6 +/- 4 mg EDC1/g creatinine, but patients with renal failure, rheumatoid arthritis, and infectious diseases averaged 130.3 +/- 60. Sixty-five to 95 percent of urinary immunoreactive EDC1 in the latter group was of higher molecular weight, perhaps reflecting increased renal clearance of plasma IATI. In patients undergoing excisional biopsy of breast lesions, preoperative EDC1 excretion was 21.5 +/- 3.4 in those whose lesions were benign and 43.1 +/- 7.6 in those whose lesions were malignant. Eight of these latter patients were heavy excretors; EDC1 excretion fell postoperatively in these patients. In normal serum the immunoreactive IATI (IR-IATI) exists in three molecular weight forms 160,000, 120,000 and 58,000. In patients who were heavy excretors of EDC1, the IR-IATI corresponding to Mr 58,000 was absent and total serum IR-IATI was about two-thirds of normal. There was also a negative correlation between serum levels of IATI and urinary EDC1 in these patients. These data suggest that urinary EDC1 may arise as a result of interaction between IATI and tumor-associated proteases.

Alpha-Globulins↗
PubMed1984

Plasma cysteine, cystine, and glutathione in cirrhosis.

Plasma contains three forms of cyst(e)ine: cysteine, cystine, and protein-bound cysteine. The former is a thiol and the latter two are disulfides. The levels of all three types of cyst(e)ine, as well as the cysteinyl tripeptide glutathione, were measured in the plasma of 14 normal and 10 cirrhotic individuals. All subjects ate mixed foods. Some cirrhotic patients were studied during nasogastric hyperalimentation with Vivonex (Norwich Eaton Pharmaceuticals, Norwich, N.Y.) as well as during total parenteral nutrition with FreAmine III (American McGaw, Irvine, Calif.); neither formula contains cyst(e)ine. Regardless of the nature of the diet, cirrhotic patients had significantly subnormal values for cysteine, glutathione, and albumin. In addition, the following significant changes were found to be diet-dependent: (a) elevated methionine during Vivonex, (b) subnormal taurine during mixed foods and total parenteral nutrition, (c) depressed protein-bound cysteine during total parenteral nutrition, (d) depressed cyst(e)ine thiol/disulfide ratio during mixed foods, and (e) depressed total thiol during Vivonex and total parenteral nutrition. The data indicate multiple abnormalities in sulfur metabolism in cirrhosis.

Adult↗
PubMed1984

Abnormal profile of serum proteinase inhibitors in cancer patients.

We reported previously that an antitryptic glycoprotein, EDC1 (Mr 27,500), which is immunologically related to the normal serum proteinase inhibitor, inter-alpha-trypsin inhibitor (IATI), is excreted in large quantities in the urine of metastatic cancer patients. We have now measured immunoreactive titers of urinary EDC1 and five serum proteinase inhibitors (including IATI) in 16 patients with hematological cancers, 9 patients with various solid tumors, and 32 healthy subjects. The mean urinary EDC1 levels were 22-fold greater in all cancer patients as compared to normals [187.0 +/- 136.6 (S.D.) versus 8.4 +/- 8.2 mg/g creatinine; p less than 0.001]. In the cancer group, serum levels of immunoreactive alpha 1-proteinase inhibitor (also called alpha 1-antitrypsin), alpha 1-antichymotrypsin, and C1 inactivator averaged 152, 237, and 165% of the normal values, respectively (p less than 0.01). Immunoreactive alpha 2-macroglobulin levels were unchanged, and immunoreactive IATI levels were depressed (75% of the normals; p less than 0.01). The lower levels of IATI and elevated levels of EDC1 are consistent with the latter being derived from the former. In spite of the increased immunoreactive alpha 1-proteinase inhibitor level, the serum antitryptic capacity of the cancer group averaged only 50% of the normal group (p less than 0.01; range, 5 to 110% of normal average). This suggests that about 70% of the serum alpha 1-proteinase inhibitor in the cancer group is functionally inert.

Adolescent↗
PubMed1983

Structural variants of human growth hormone: biochemical, genetic, and clinical aspects.

Human growth hormone (hGH) is a mixture of peptides in which the major physiologic component is a single chain polypeptide of 191 residues with a molecular weight of 22,000 ("22K" form). The minor components differ from the 22K form in terms of mass (e.g. the 20K form, a single-chain peptide synthesized by deletion of residues 32-46 of the 22K isomer, and the 45K variant formed by aggregation of the 22K molecule), or of charge (e.g. the more acidic two-chain forms alpha 2 and alpha 3 which are generated by proteolytic deletion of residues 135-140 and 135-146 from the 22K variant). The minor components also differ from the 22K molecule in (a) their metabolic effects; (b) their capacity to bind to antiserum raised against the 22K form in a radioimmunoassay (RIA); and (c) their ability to bind to membrane receptors for the 22K hGH in a radioreceptor assay (RRA). Two genes, N and V, involved in the biosynthesis of hGH, are located on human chromosome 17. Heritable alterations of the N gene may cause deficiency of immunoreactive hGH and growth failure. A pathologic variant of hGH has also been identified which is indistinguishable from the 22K form on RIA, but which has low reactivity on hGH-RRA and low somatomedogenic activity. Several mechanisms to account for this bioinactive variant are discussed.

Child↗
PubMed1983

Effects of opioid peptides and opiate alkaloids on insulin secretion in the rabbit.

In pentobarbital-anesthetized rabbits, iv injection of 9 nmol (31 micrograms) human beta-endorphin (beta h-endorphin)/kg BW caused a significant (P less than 0.05) increase in serum glucose and a significant decline in serum insulin during the subsequent 60 min. When 9 nmol/kg BW beta h-endorphin were injected simultaneously with 0.7 g glucose/kg BW, the clearance of serum glucose and the expected glucose-stimulated rise in serum insulin were both inhibited. The threshold dose for the insulinopenic effect of beta h-endorphin in the anesthetized, glucose-loaded rabbit was 0.09 nmol/kg BW. Threshold doses/kg BW were determined for six structurally related peptides found to possess insulinopenic activity: camel beta-endorphin, 0.09 nmol; N-arg-beta h-endorphin, 0.09 nmol; D-ala2-beta h-endorphin, 0.09 nmol; leu5-beta h-endorphin, 0.09 nmol; met-(O)5-beta h-endorphin, 0.9 nmol; and beta h-endorphin1-27, 0.9 nmol. Threshold dose/kg BW for somatostatin was 9 nmol. The following compounds were inactive at 9 nmol/kg BW: N-acetyl-beta h-endorphin; N-acetyl-arg-beta h-endorphin; beta h-endorphin2-31; beta h-endorphin6-31; beta h-endorphin(((1-5 + 6-31))); beta h-endorphin1-18 (gamma-endorphin); beta h-endorphin1-17 (alpha-endorphin); beta h-endorphin1-5 (met-enkephalin); leu5-beta h-endorphin (leu-enkephalin); met-NH2(5)-beta h-endorphin1-5 (met-enkephalinamide); D-ala2-leu5-beta h-endorphin1-5; D-ala2-N-me-phe4, met-(O)5-ol-beta h-endorphin1-5; and D-ala2-D-leu5-beta h-endorphin1-5. Ninety nmoles per kg BW of naloxone did not alter the insulinopenic effect of 0.9 nmol/kg BW beta h-endorphin. As little as 2.9 X 10(-10) molar beta h-endorphin inhibited glucose-stimulated release of insulin by rabbit pancreas slices in vitro. The capacities of the peptides and alkaloids to inhibit insulin secretion in vitro followed the same general order as the in vivo insulinopenic capacities. Naloxone at 2.9 X 10(-6) M did not reduce the antisecretagogue effect of 2.9 X 10(-8) M beta h-endorphin. These findings, when compared with previously described structure-activity relationships for opioid receptors, indicate the presence of a novel receptor for beta-endorphin in rabbit pancreas, the activation of which inhibits glucose-stimulated secretion of insulin.

Amino Acids↗
PubMed1983

Extraction of a melanoma growth-stimulatory activity from culture medium conditioned by the Hs0294 human melanoma cell line.

Extracts of conditioned medium (CM) from Hs0294 human malignant melanoma cells stimulate [3H]thymidine incorporation and an increase in cell number in serum-depleted Hs0294 cells. This activity is acid and heat stable, nonproteolytic, protease sensitive, contains disulfide bonds and elutes broadly from a Bio-Gel P-30 column with an approximate molecular weight range of 6,000 to 25,000. Hs0294 CM also stimulates [3H]thymidine incorporation in nonmalignant human nevus cells and normal rat kidney fibroblast cells but not in human fibroblasts. There was only limited competition with 125I-epidermal growth factor in binding assays. Hs0294 CM extracts stimulate anchorage-independent growth in normal rat kidney fibroblast cells in soft agar but not in Hs0294 cells, nevus cells, or human fibroblasts. This second activity elutes from the Bio-Gel P-30 column in two positions with apparent molecular weights of 27,000 and 11,000.

Agar↗
PubMed1982

In vitro growth promotion in human malignant melanoma cells by fibroblast growth factor.

Bovine pituitary fibroblast growth factor (FGF) stimulates the incorporation of [3H]thymidine into DNA in serum-depleted cultures of some but not other human melanoma cells. The melanotic malignant melanoma cell line MIRW exhibited a 40% increase in [3H]thymidine incorporation into DNA and a 48% increase in cell number in response to 3.73 x 10(-9) M FGF. This same concentration of FGF produced a 22% increase in [3H]thymidine incorporation in the melanotic melanoma cell line Hs0294. However, FGF had no effect on the amelanotic melanoma cell line Hs0675, early-passage cultures of a human amelanotic melanoma (W-1), or early-passage cultures of a congenital nevus (N-1).

Cell Division↗
PubMed1980

Decarboxylation of alpha-ketoisovaleric acid after oral administration in man.

The keto analogues of essential amino acids represent a promising therapeutic modality in hereditary and acquired disorders of nitrogen metabolism. The utilization of these substances in humans has been assayed primarily by nitrogen balance studies. A simple and accurate breath excretion test for 14CO2 enabled us to measure the decarboxylation of 1-14C-alpha-ketoisovaleric acid (KIV, the keto analogue of valine) in two normal and six diseased subjects. Normal volunteers as well as patients with gastrectomy, hepatic failure, renal failure, and myotonic dystrophy were tested in 5-g protein diets supplemented with essential amino acids and KIV (in place of valine). The normal volunteers and the gastrectomy patient were then restudied on 120 g protein/day. With low protein intake, 13 to 32% of ingeted KIV underwent rapid decarboxylation, and this proportion appeared to correlate inversely with damage to organ systems containing the branched-chain keto acid dehydrogenase. With high protein intake, the proportion decarboxylated rose to 44 to 53%. Thse results confirm that the decarboxylation of KIV in man varies under different conditions of dietary intake and metabolic disease. The 14CO2 brewth excretion test is applicable to other related analyses of carboxylic acid metabolism in human subjects.

Adult↗
PubMed1980

Abnormal polyamine metabolism in hereditary muscular dystrophies: effect of human growth hormone.

Previous studies showed hyperre-sponsiveness to human growth hormone (hGH) in men with myotonic or limb girdle dystrophies (MMD or LGD). Because polyamines may mediate some actions of hGH, we have now investigated polyamine metabolism in these and other dystrophies. Under metabolic balance study conditions, serum and urine levels of putrescine (Pu), spermidine (Sd), spermine (Sm), and cadaverine (Cd) were measured in six normal men (36-44 yr), four men with MMD (38-44 yr), and three men with LGD (30-36 yr), before and during treatment with 0.532 U/kg body wt ((3/4)/d) of hGH. Daily balances of N, P, and K were also monitored. In the normal subjects, hGH did not influence elemental balances or serum and urine polyamines. In MMD, hGH caused significant retention of N, P, and K (P < 0.005). Basal levels of Sm and Cd were significantly elevated above normal (P < 0.005), and Pu, Sm, and Cd increased two- to fourfold above basal during hGH treatment (P < 0.005). In LGD, hGH also caused retention of N, P, and K. Basal levels of nearly all the polyamines (not serum Pu) were significantly above normal in serum and urine (P < 0.05). During hGH treatment, all four polyamines rose significantly above basal (P < 0.005). Serum and urine polyamine levels in five boys with Duchenne muscular dystrophy, age 8-13, did not differ from those in five age-matched normal boys. Skeletal muscle polyamines were measured in five men (31-40 yr) without muscle disease and in three men with LGD (30-38 yr). Average concentrations of Pu, Sd, Sm, and Cd were 46, 306, 548, and 61 nmol/g wet wt in LGD and 1, 121, 245, and 14 in the normal subjects, respectively (P < 0.05 in each instance). Polyamines were determined in skeletal muscle, liver, kidney, and brain of male mice with hereditary muscular dystrophy and in age- and sex-matched normal controls. Pu, Sd, Sm, and Cd levels were two to three times higher than normal in muscle, but did not differ in liver, kidney, and brain. Similar findings were made in male hamsters with hereditary dystrophy and in their controls. The abnormality in hamster muscle polyamines appeared between 1 and 6 wk of age and persisted or intensified until 30 wk. These data reveal abnormalities of polyamine metabolism in men with MMD, in men with LGD, and in mice or hamsters with hereditary muscular dystrophy. The polyamine disorder could be related to dystrophic patients' hyperresponsiveness to hGH.

Adolescent↗
PubMed1980

Effects of melanotropic peptides on fetal adrenal gland.

Adrenal glands from early, mid, and late fetuses of rabbit, guinea pig, and rat, and from newborn animals of each species, were incubated for 1-4 h with and without 0.1 nM-1 microM ACTH, alpha- or beta-melanocyte-stimulating hormone (alpha MSH or beta MSH). The effects of the peptides were measured on production of glucocorticoids, and on incorporation of labeled thymidine or leucine into DNA or protein, respectively. The findings were similar in all three species. ACTH stimulated synthesis of glucocorticoids throughout fetal life. Potency increased progressively, as reflected by declining minimal effective dose and rising maximal response. In early and mid fetus alpha MSH and beta MSH caused a modest glucocorticoid steroidogenic effect. ACTH and alpha MSH stimulated DNA and protein synthesis in the early and mid fetal gland. alpha MSH was more potent than ACTH in these respects, minimal effective dose being generally 10 times less and maximal response 25-200% greater. The effects diminished or disappeared in the late fetal and newborn gland. These data indicate that alpha- and beta MSH possess steroidogenic or growth-promoting properties, or both, for the fetal adrenal gland.

Adrenal Glands↗
PubMed1980

Effect of plasma inter-alpha trypsin inhibitor and cancer-related glycoprotein EDC1 on phytohemagglutinin-induced thymidine uptake in lymphocytes.

EDC1, a glycoprotein with a molecular weight of 27,500, was purified from the urine of a leukemic patient, and a radioimmunoassay was developed to use as an immunodiagnostic tool for cancer. Previous studies showed that up to 60% of patients with disseminated neoplastic diseases excreted 100 to 500 mg of EDC1 per day. This protein was immunologically related to inter-alpha-trypsin inhibitor (IATI; M.W. 170,000), a glycoprotein normally present in plasma. EDC1, like IATI, inhibited trypsin and chymotrypsin. EDC1 and IATI have now been found to inhibit the incorporation of thymidine into DNA of normal lymphocytes transformed by phytohemagglutinin. In the presence of 1000 micrograms of EDC1 or 300 micrograms of IATI, incorporation of thymidine by cells was totally inhibited. These proteins were not cytotoxic, did not affect transport of thymidine across the membrane, formed no complex with phytohemagglutinin, and did not compete with phytohemagglutinin for its binding sites. It is proposed that EDC1 and IATI may exert this effect by inhibiting a protease required for blastogenesis.

Alpha-Globulins↗
PubMed1980

Elevated plasma and urinary guanosine 3':5'-monophosphate and increased production rate in patients with neoplastic diseases.

The plasma and 24-hr urinary levels of cyclic adenosine 3':5'-monophosphate and of cyclic guanosine 3':5'-monophosphate (cGMP) were determined for 19 healthy normal patients, 54 patients with six types of nonneoplastic diseases (cholelithiasis, peptic ulcer, coronary heart disease, hypertension, regional ileitis, and cirrhosis), and 54 patients with five types of neoplastic disease (cancers of the lung, colon, and breast, acute myelocyte leukemia, and Hodgkin's disease). The cyclic adenosine 3':5'-monophosphate levels of urine and plasma in normal subjects, in noncancer subjects, and in cancer subjects did not differ significantly. The cGMP levels in the noncancer group were similarly unchanged from those in the normal group. However, mean cGMP levels in the urine and plasma of patients with neoplastic diseases were, respectively, 2- and 3-fold greater than the normal values (p less than 0.005 for urine and p less than 0.05 for plasma). Pharmacokinetic studies with [3H]cGMP in nine healthy controls and 15 patients with neoplasia showed that the mean production rate of this nucleotide in patients with metastatic cancer was elevated when compared to normal patients, but many values fell within the normal range. In acute leukemia, the production rate was seven times normal, with four of five patients having values clearly outside the normal range. The plasma clearance rate in patients with neoplasia was not decreased when compared to that in normal patients. It is proposed that an increased production rate, rather than any change in plasma clearance, accounts for the increased levels of cGMP in the plasma and urine of some patients with neoplastic disease.

Cyclic AMP↗