Purification and state of activation of rat kidney phenylalanine hydroxylase

Phenylalanine hydroxylase, the enzyme that catalyzes the irreversible hydroxylation of phenylalanine to tyrosine, was purified from rat kidney with the use of phenyl-Sepharose, DEAE-Sephacel, and gel permeation high pressure liquid chromatography. Our most highly purified fractions had a specific activity in the presence of 6-methyltetrahydropterin, of 1.5 mumol of tyrosine formed/min/mg of protein, which is higher than has been reported hitherto. For the rat kidney enzyme, the ratio of specific activity in the presence of 6-methyltetrahydropterin to the specific activity in the presence of tetrahydrobiopterin (BH4) is 5. By contrast, this ratio for the unactivated rat liver hydroxylase is 80. These results indicate that the kidney enzyme is in a highly activated state. The rat kidney hydroxylase could not be further activated by any of the methods that stimulate the BH4-dependent activity of the rat liver enzyme. In addition, the kidney enzyme binds to phenyl-Sepharose without prior activation with phenylalanine. The phenylalanine saturation pattern with BH4 as a cofactor is hyperbolic with substrate inhibition at greater than 0.5 mM phenylalanine, a pattern that is characteristic of the activated liver hydroxylase. The molecular weight of the rat kidney enzyme as determined by gel permeation chromatography is 110,000, suggesting that the enzyme might be an activated dimer. We conclude, therefore, that phenylalanine hydroxylases from rat kidney and liver are in different states of activation and may be regulated in different ways.

Enhancement of antigonadotropin response to the beta-subunit of ovine luteinizing hormone by carrier conjugation and combination with the beta-subunit of human chorionic gonadotropin

Previous studies have demonstrated the control of fertility in monkeys on immunization with the beta subunit of ovine luteinizing hormone (beta-oLH) along with Freund's complete adjuvant (CFA). An eventual birth control vaccine would demand immunization without CFA. Beta-oLH linked to tetanus toxoid (TT) adsorbed on alum-induced antibody response in bonnet monkeys with detoxified sodium phthalyl derivative of Salmonella enteritidis lipopolysaccharide added only in the first injection. The antibodies reacted with both LH and human chorionic gonadotropin (hCG). A higher immune response was obtained with the use of a conjugate of beta-oLH and beta-hCG linked to a common carrier (TT) or with a mixture of beta-hCG/TT and beta-oLH/TT. In both cases, the antibodies were of high affinity with Ka ranging from 5 X 10(9) to 6 X 10(10) M-1. The antibodies were devoid of reactivity with human thyroid-stimulating hormone and human follicle-stimulating hormone. Monkeys with titers above 120 ng/ml hCG binding capacity (greater than 60 ng/ml in most cases) were protected from becoming pregnant during repeated mating with males of proven fertility in ovulatory cycles.

Adjuvant chemotherapy in Ewing's sarcoma

Adjuvant chemotherapy using vincristine, cyclophosphamide, and adriamycin was used in 28 patients with localized Ewing's sarcoma. Life-table analysis revealed 55% disease-free survival at 3 years. In contrast, our historical control showed less than 10% long-term survival. Adjuvant chemotherapy appears to control both micrometastasis as well as local residual disease. The present study demonstrates the improved survival with adjuvant chemotherapy including adriamycin, vincristine, and cyclophosphamide, in patients with localized Ewing's sarcoma.

Evidence for transcription and potential translation of the human 1.9 kb HindIII repetitive element

Recombinant cDNA clones corresponding to the human 1.9kb HindIII repetitive element have been isolated from a cDNA library of liver cytoplasmic polyadenylated RNA. These cDNAs share 95% homology with the reported genomic DNA sequence and a similar amount of homology at the amino acid level with putative coding sequences (see preceding article by Mottez et al). They were isolated as two of four false positives from a human cDNA library in lambda gt11 and were selected with an antibody to an unrelated enzyme. These results provide direct evidence that this repetitive element is transcribed to form poly(A)+ RNA which could be translatable. Also, these observations may add to our understanding of the sources of false positives which are frequently observed in screens of cDNA libraries with antibodies as probes.

Pediatric Hodgkin's disease in India

Twenty-one percent of all Hodgkin's disease in India was seen in the pediatric age groups at the Tata Memorial Hospital (Bombay, India). From 1975 to 1982, 151 cases of children were reviewed. The youngest presentation was at 3 years in three patients, with a marked male: female ratio of 5.5:1. Twenty-six patients were previously treated before referral while the remaining 125 cases were investigated and treated according to the prevalent protocols in 1975 to 1978 and 1979 to 1982. Clinical staging revealed 54% of patients in stages I and II with symptoms in 20%, and 46% of patients in stages III and IV with symptoms in 67%. Staging laparotomy was performed in 27 patients, with a total changes of staging in 17 children (63%). The mixed cell types (46%) and lymphocytic predominant types (31%) were the most common histologic presentations. Nine percent nodular sclerosis and 9% lymphocytic-depleted varieties were also observed. Five percent of all cases were not classifiable. Minimum adequate treatment was completed in 87 cases. Comparisons were made between the treatments administered to 40 patients during the initial period 1975 to 1978 when individualized treatment was administered, and the later 47 patients during the 1979 to 1982 period, when chemotherapy was the mainstay of treatment with involved field radiation.

Designing of a brain stimulator suitable for intracranial self-stimulation experiments for studying the brain-stimulation reward system

A circuit design has been developed and described for fabricating and using in the intracranial self-stimulation experiments on rat to study the brain-stimulation reward behaviour, and to explore into the underlying mechanisms of drives and motivated behaviours. The stimulator can be fabricated with parts available in India. It has been continuously used and tested during the last four years in different research studies.

T-cell acute lymphoblastic leukemia: a report of 60 patients from India

60 patients studied at the Tata Memorial Hospital from January 1976 to December 1982 were diagnosed as having T-cell acute lymphoblastic leukemia (ALL) by nonimmune rosette formation with sheep red blood cells. The analysis revealed a high incidence of mediastinal mass (50%) and extramedullary infiltration at presentation. The majority of patients (62%) presented with a high WBC count (greater than 50,000/mm3). Unipolar acid phosphatase activity was observed in 90% of patients. The remission rate with a combination treatment of adriamycin, vincristine and prednisolone was found to be 95%. Long-term survival was around 30%. More aggressive or innovative treatments will be needed to improve the results in T-cell ALL.

Acute lymphoblastic leukemia: end-result analysis of treatment and prognostic factors in Indian patients

Acute Lymphatic Leukemia (ALL) patients seen during the period 1974-1978 at the Tata Memorial Hospital. Bombay, are analyzed retrospectively to evaluate the clinical features at presentation, results of sequential therapy, and prognostic factors. A total of 301 patients were registered during the study period. There were 153 evaluable patients. Of these 73 patients received induction therapy with vincristine and prednisolone (VP) followed by cranial prophylaxis (cranial radiotherapy, 2,400 rads, and 10 weekly intrathecal injections of methotrexate 7.5 mg/m20 and continuous oral maintenance with daily 6-mercaptopurine and weekly methotrexate (group A). Another 39 patients (group B) received pulse therapy with vincristine and prednisolone during maintenance therapy. Finally 41 patients (group C) received L-asparaginase during induction and pulse therapy in addition to drugs as in group A. Of the 153 patients, 88 (58%) achieved complete response after induction treatment. Induction remission was 53% with vincristine and prednisolone (group A and group B), whereas it was 70% in group C. The difference in complete response rate in group C was statistically significant (P less than 0.05). The 3-year survival in our series was 22%, with median survival of 11 months. Group C patients receiving L-asparaginase along with vincristine and prednisolone showed 41% 3-year survival compared to 16% for group B. The 3-year survival in group A patients was only 7%, probably owing to lack of pulse therapy during maintenance treatment. The prognostic factors such as age, sex, WBC count, and mediastinal node were compared for induction remission and total survival. Possible factors relating to poor results in our series as compared to developed countries are discussed.

Purification and regulatory properties of mung bean (vigna radiata L.) serine hydroxymethyltransferase

Serine hydroxymethyltransferase, the first enzyme in the pathway for interconversion of C(1) fragments, was purified to homogeneity for the first time from any plant source. The enzyme from 72-h mung bean (Vigna radiata L.) seedlings was isolated using Blue Sepharose CL-6B and folate-AH-Sepharose-4B affinity matrices and had the highest specific activity (1.33 micromoles of HCHO formed per minute per milligram protein) reported hitherto.The enzyme preparation was extremely stable in the presence of folate or l-serine. Pyridoxal 5'-phosphate, ethylenediaminetetraacetate and 2-mercaptoethanol prevented the inactivation of the enzyme during purification. The enzyme functioned optimally at pH 8.5 and had two temperature maxima at 35 and 55 degrees C. The K(m) values for serine were 1.25 and 68 millimolar, corresponding to V(max) values of 1.8 and 5.4 micromoles of HCHO formed per minute per milligram protein, respectively. The K(0.5) value for l-tetrahydrofolate (H(4)folate) was 0.98 millimolar. Glycine, the product of the reaction and d-cycloserine, a structural analog of d-alanine, were linear competitive inhibitors with respect to l-serine with K(i) values of 2.30 and 2.02 millimolar, respectively. Dichloromethotrexate, a substrate analog of H(4)folate was a competitive inhibitor when H(4)folate was the varied substrate. Results presented in this paper suggested that pyridoxal 5'-phosphate may not be essential for catalysis.The sigmoid saturation pattern of H(4)folate (n(H) = 2.0), one of the substrates, the abolition of sigmoidicity by NADH, an allosteric positive effector (n(H) = 1.0) and the increase in sigmoidicity by NAD(+) and adenine nucleotides, negative allosteric effectors (n(H) = 2.4) clearly established that this key enzyme in the folate metabolism was an allosteric protein. Further support for this conclusion were the observations that (a) serine saturation exhibited an intermediary plateau region; (b) partial inhibition by methotrexate, aminopterin, O-phosphoserine, dl-alpha-methylserine and dl-O-methylserine; (c) subunit nature of the enzyme; and (d) decrease in the n(H) value from 2.0 for H(4)folate to 1.5 in presence of l-serine.These results highlight the regulatory nature of mung bean serine hydroxymethyltransferase and its possible involvement in the modulation of the interconversion of folate coenzymes.

kappa Chain joining segments and structural diversity of antibody combining sites

Immunoglobulin kappa light chains are coded for by at least three distinct gene segments designated variable, joining, and constant. The joining gene codes for the 13 amino acid segment linking the variable and constant regions. This peptide includes the last amino acid (96) in the third complementarity-determining region and thus could introduce structural diversity. We have determined the light chain variable region sequences from three myeloma proteins with beta(1,6)galactan-binding specificity, bringing to six the number of light chains sequenced from proteins demonstrating this specificity. Five of these have isoleucine at position 96 and the sixth tryptophan. This substitution appears to be accommodated with no significant change in association constant for a beta(1,6)galactan hapten. Additionally, as many as nine substitutions are found in both light and heavy chain complementarity-determining regions between members of this group although only minimal variations in hapten binding affinity are observed. The isoleucine found at position 96 in five of the kappa chains could not be coded for by any of the joining gene nucleotide sequences previously observed and would require a novel nucleotide sequence at the recombination site between variable and joining genes to produce the observed protein structure. Alternatively, there may exist joining gene segments not yet detected.

Excess volumes for binary liquid mixtures of 1-chlorobutane with normal alkanes

Excess volumes for binary mixtures of 1-chlorobutane with hexane, heptane, octane and nonane were measured dilatometrically at 303.15 K. Excess volumes are positive over the entire range of composition in the four mixtures. Further, it is observed that increase in chain length increases the magnitude of the excess function.

Structural evidence for independent joining region gene in immunoglobulin heavy chains from anti-galactan myeloma proteins and its potential role in generating diversity in complementarity-determining regions

We have determined the variable region sequences of four heavy chains from beta(1-6)D-galactan-binding myeloma proteins. Two of these proteins are identical to position 100 which is located in the third complementarity-determining region (CDR-3). The remaining two differ at a total of 8 positions over the first 100 amino acids, and all of the differences can be explained by single-base mutations at the DNA level. When an assessment is made of the protein segment following CDR-3, which has been termed "J segment" or "FR4," a completely different pattern of variation is observed. The J segments from the four proteins can be divided into two sets. Members of each set share a series of linked amino acids not found in members of the alternative set. The two proteins identical to position 100 have J segments from the two different sets, suggesting that recombination has occurred between V and J genes. An examination of the CDR-3 sequences from the four heavy chains reveals substitutions at positions 100 and 105. Gly is found at 100 in two of the proteins and His in the remaining two. In the two proteins with Gly-100, the following J sequence is limited to one of the two sets of J segments defined by linked amino acids. Similarly, the two heavy chains with His-100 have J segments from the second set. Thus, at the protein level an apparent association is seen between CDR-3 and J segment. If CDR-3 should be found linked to J segment at the DNA level, a new mechanism would be introduced for increasing antibody diversity by recombining various CDR-3 plus J genes with genes coding for the remainder of the variable region. Alternatively, if CDR-3 were coded for by the V gene, then the recombination of V with J may provide an opportunity to introduce mutations in CDR-3. In this case the linkage of amino acids in CDR-3 and the J segments would suggest that recognition signals are used such that certain V genes only pair with a given J gene.

k Chain variable regions from three galactan binding myeloma proteins

A series of seven BALB/c myeloma proteins has been identified with binding specificity for antigens containing beta(1 leads to 6)-D-galactopyranosyl moieties. We have determined the primary amino acid sequence of the first 108 residues from the light chains of three of these proteins. The framework portions of the variable regions of these three light chains are identical with residue 100 at which position three different amino acids are found in the three chains. An additional interchange was found at position 106 in one of the proteins. Based on recent DNA sequence studies suggesting that the variable region ends at residue 97, these substitutions indicate the possible existance of multiple genes coding for the region beginning at residue 98 and continuing toward the carboxy terminus. A single amino acid interchange was observed in complementarity determining regions occurring in L3. This substitution (Ile-Trp) would require changes in all three codon bases to produce the respective amino acids if one were derived from the other. Two of these chains are thus indistinguishable for their first 100 amino acids and are the first pair of k chains to exhibit complete identity over their variable regions.

Prognostic significance of the regional lymph nodes in osteosarcoma

This study was undertaken to find out if there are any factors of prognostic significance that can help the surgeon in the management of osteogenic sarcoma. One hundred and thirty-nine cases of osteogenic sacrocma were treated during a 30-year period and their survival figures have been analysed with respect to age, sex, extent of disease, previous treatment, and value of lymphadenectomy. We found that patients in whom the lymph nodes were preserved had a better survival as compared to patients in whom the lymph nodes were removed en bloc with the primary tumour. This further supports our contention that the regional lymph nodes have an important role to play in the immune response against osteosarcoma. The experimental work of the cytotoxic action of regional lymph node cells against osteosarcoma cell lines has been studied in our laboratory. The results of this study stimulated us to undertake this retrospective analysis.