Stjepan Gamulin - Academia.edu (original) (raw)
Papers by Stjepan Gamulin
Lijec̆nic̆ki vjesnik
The molecular mechanism of steroid hormone action is described and its clinical implications are ... more The molecular mechanism of steroid hormone action is described and its clinical implications are examined. Upon entering the cell of a target tissue the steroid hormone is bound to the specific receptor protein thus forming a steroid-receptor complex. The complex is transported to the nucleus where it is bound to chromatin and a sequence of biochemical effects is initiated. Any alterations in the receptor content or structure could be a pathogenic factor in various disorders involving steroid hormone actions. Specific estrogen and progesterone receptors and their release during the menstrual cycle are examined for clinical implications in phasal disorders and in carcinoma.(Authors modified)
Archiv für Toxikologie, 1981
Polyribosome sedimentation pattern and their in vitro protein synthetic ability were investigated... more Polyribosome sedimentation pattern and their in vitro protein synthetic ability were investigated in kidneys of mice treated with a single injection of HgCI2. Mercury bichloride, after 1 h, evokes polyribosome disaggregation, the extent of which is logarithmically correlated with the dose in the range of 2.5-20 ~tmoles/kg. With the dose of 2.5 ~tmoles/kg the effect occurs after 1 h, it is maximal between 1 h and 3 h. After 6 h polyribosomes are reaggregated. Cyclohehimide pretreatment does not prevent the HgC12 induced disaggregation of kidney polyribosomes. The cell-free system derived from kidneys of HgC12 treated mice (10 ~tmoles/kg, 1 h) has a decreased protein synthetic ability. Both, in livers of mice treated with 20 ~tmoles/kg HgC12 and in isolated rat's reticulocytes incubated with 20 ~tM HgC12 during 1 h there were no apparent changes in the polyribosome sedimentation patterns.
The Biochemical journal, 1973
1. To investigate the role of ribosome function in regulating protein synthesis, the activity, di... more 1. To investigate the role of ribosome function in regulating protein synthesis, the activity, distribution and functional states of ribosomal particles were investigated in livers of mice fed ad libitum or starved overnight. 2. The distribution of protein-synthesizing activity between polyribosomes of different sizes was analysed after incorporation of radioactive leucine, and the quantitative distribution of ribosomes as native subunits, monomers and polyribosomes was analysed after incorporation of orotic acid. Precursors labelled with (3)H or (14)C were given separately to fed and starved mice, so that livers from the two groups of animals were processed together. 3. The former experiments showed that starvation has little effect on the distribution of protein-synthesizing activity across polyribosome sedimentation patterns, though the latter experiments showed that the proportion of ribosomes existing as monomers increased from 9.5% to 15.2%, whereas the proportion existing as ...
Biochimica et biophysica acta, Jan 31, 1972
When the "postmitochondrial" fraction from fed mice was treated with aamylase, the polysomes prep... more When the "postmitochondrial" fraction from fed mice was treated with aamylase, the polysomes prepared subsequently were contaminated less by glycogen and had a decreased protein/RNA ratio and higher protein synthetic activity. The polysomes also had a higher proportion of heavy polysomal aggregates and higher protein synthetic activity than those obtained from fasted animals.
The Biochemical journal, 1972
Active ribosomes are found as 'polyribosomes' or as 'native subunits'. A third group of ribosomes... more Active ribosomes are found as 'polyribosomes' or as 'native subunits'. A third group of ribosomes, the unprogrammed 'single ribosomes', usually co-sediment with monoribosomes. In appropriate ionic conditions, however, single ribosomes are split into derived subunits that apparently co-sediment with native subunits. Since single ribosomes could be artifacts produced by association of subunits, we have investigated possible differences between the behaviour of derived and native subunits.
The Biochemical journal, 1975
1. A porphyrinogenic drug, 3,5-diethoxycarbonyl-1,4-dihydrocollidine, caused a decrease in the pr... more 1. A porphyrinogenic drug, 3,5-diethoxycarbonyl-1,4-dihydrocollidine, caused a decrease in the proportion of single ("run off") ribosomes, and an increase in the number of polyribosomes, in the livers of treated animals. 2. No change could be detected in the distribution of amino acid incorporation among hepatic polyribosomes.
Journal of Neurochemistry, 1985
Insulin-induced hypoglycemia provokes polyribosome disaggregation and accumulation of monomeric r... more Insulin-induced hypoglycemia provokes polyribosome disaggregation and accumulation of monomeric ribosomes in the brain of rats with hypoglycemic paresis and coma. The extent of brain polyribosome disaggregation depends on the decrease of blood glucose concentration, and in comatose animals on the duration of hypoglycemia. Cycloheximide prevents the disaggregation of brain polyribosomes induced by hypoglycemia, indicating that hypoglycemia affects brain protein synthesis, decreasing the rate of initiation relative to the rate of elongation of polypeptide chain synthesis.
ELECTROPHORESIS, 2008
Human DNA quantification by quantitative real-time PCR (QRT-PCR) has gained great importance in f... more Human DNA quantification by quantitative real-time PCR (QRT-PCR) has gained great importance in forensic DNA and ancient DNA studies. However, in such samples, DNA quantification is impaired by the frequently present humic acid (HA). We have previously shown that the addition of synthetic HA inhibits QRT-PCR. In this study we investigated the possible mechanisms of HA interaction with human DNA, and kinetics of QRT-PCR inhibition. In QRT-PCR with pure human DNA and no HA added, V MAX was 40. With DNA sample containing 4 mg/mL of HA, V MAX was 30.30 while the addition of extra Taq polymerase to the same sample changed V MAX into 38.91, amplifying between 80 and 90% of input DNA. The K M /V MAX ratio in all the samples remained constant, indicating that the mechanism of HA inhibition of QRT-PCR is uncompetitive by nature. Moreover, HA shifts the human DNA melting temperature point (T m ) from 75 to 877C and inhibits DNase Imediated DNA cleavage, most probably affecting the enzyme's activity.
Croatian medical journal, 2008
Annals of Nutrition and Metabolism, 1974
ABSTRACT The aminoacyl-tRNA and protein synthesizing activities of cell-free systems derived from... more ABSTRACT The aminoacyl-tRNA and protein synthesizing activities of cell-free systems derived from the livers of mice fed ad libitum and mice fasted overnight were measured. The ‘pH 5 fractions’ from both groups of mice have a similar ability to acylate tRNA. Cell-free systems derived from fasted mice had a reduced protein synthetic activity, but in heterogenous cell-free systems the activity of polysomes from these animals was significantly increased by cytosol fractions from fed mice. These results indicate that fasting affects a factor or factors in the cytosol which are required for incorporation of aminoacyl-tRNA into protein.Copyright © 1974 S. Karger AG, Basel
Tumori
Breast carcinoma is a heterogeneous disease, the prognosis of which correlates with various progn... more Breast carcinoma is a heterogeneous disease, the prognosis of which correlates with various prognostic factors. The aim of this study was to assess the prognostic significance of c-erbB-2 overexpression in breast carcinoma patients in association with other known prognostic factors. The relationship between immunohistochemical expression of the c-erbB-2 oncoprotein and various established prognostic factors such as tumor size, axillary node status, estrogen and progesterone receptor status, DNA ploidy, proliferation index, cathepsin D expression and histological grade in invasive ductal breast carcinoma is presented in this study. Of the 93 ductal invasive carcinomas 22 (23.7%) were grade I, 51 (54.8%) grade II, and 20 (21.5%) grade III, and the majority (78: 83.9%) were 2-5 cm in diameter. Tumor metastases were identified in one or more lymph nodes in 55 (59.1%) patients, the remaining 38 (40.9%) patients being lymph node negative. According to the DNA histograms 40 (43.0%) tumors ...
Cancer research, 1980
The qualitative and quantitative relationships between cytoplasmic estrogen receptors (ERC), tota... more The qualitative and quantitative relationships between cytoplasmic estrogen receptors (ERC), total nuclear estrogen receptors (ERN), and cytoplasmic progesterone receptors (PGR) in 74 primary and 23 metastatic human breast cancer tissues were studied. A positive correlation between the age of th patients and the receptor concentration was found only for ERC. Although ERN and PGR were more frequent in tumors with a higher level of ERC, there was no significant correlation between concentrations of either ERN or PGR and ERC. However, PGR were more frequent in ERN-positive than in ERN-negative tumors, irrespective of the presence of ERC. There was also a highly significant correlation between PGR and ERN concentrations. These findings support the assumption that induction of PGR by estrogen in human breast cancer is mediated by a mechanism involving nuclear receptors. Therefore, the ERN assay might increase the validity of steroid receptor determination for prediction of hormonal sensi...
Biomedicine & pharmacotherapy = Biomédecine & pharmacothérapie, 1985
In 60 breast cancer patients in stages I and II the blastogenic transformation of peripheral bloo... more In 60 breast cancer patients in stages I and II the blastogenic transformation of peripheral blood lymphocytes after phytohaemagglutinin (PHA) pokeweed mitogen (PWM) and concanavalin A (Con A) stimulation were assayed and estrogen (ER) and progesterone (PgR) receptor concentrations in tumor cytosol were measured. A negative correlation between lymphocyte reactivity to the mitogens and tumor steroid receptors concentration was found. The lymphocyte response to the mitogens in the patients with ER-PgR-tumors (R-) was significantly higher than in those with tumors either ER+PgR-or ER-PgR+ (R+) or ER+PgR+ (R++). There was also a negative correlation between lymphocyte response to PHA and either ER or PgR concentrations in the tumors. These results suggest that the presence of steroid receptors in tumor cells may be associated with the depression of immunological reactivity in breast cancer patients.
European Journal of Cancer and Clinical Oncology, 1991
The results of a single centre study on cytoplasmic oestrogen (ER) and progesterone (PR) receptor... more The results of a single centre study on cytoplasmic oestrogen (ER) and progesterone (PR) receptors and their combinations in primary breast cancer of 1957 patients from various parts of Croatia are presented. The frequency of ER+ tumours and tumour mean ER concentration were higher in patients over 50 years of age, while PR frequency and concentration were similar in patients over and under 50. The ER concentration was positively correlated with the age of patients, but the age-related increase in ER concentration appeared between 50 and 70 years of age. The pattern of receptor coexistence was age related. The frequency of ER+PR+ and ER+PRincreased and that of ER-PR+ and ER-PR-tumours decreased with the age of patients. The concentrations of ER and PR were higher in ER+PR+ than in ER+PR-or ER-PR+ turnouts, respectively. When the patients were divided into groups under and over 50 years of age these differences appeared only in the latter group, while in the former the concentrations of ER were similar in ER+PR+ and in ER+PR-tumours, and the concentration of PR was higher in ER+PR+ than in ER-PR+ tumours. These data suggest a biological difference between breast cancers with various receptor combinations, as well as a difference in pathogenesis of the receptor negative and positive breast cancer.
Biochemistry international
The binding properties of ochratoxin A to human and porcine plasma constituents were studied in v... more The binding properties of ochratoxin A to human and porcine plasma constituents were studied in vitro. Ochratoxin A was shown to bind to other plasma constituents with a considerably higher affinity than the earlier known nonspecific binding to plasma albumins. The association constant for the high affinity macromolecule (s) in human plasma was found to be 2.3 X 10(10) M-1 and for porcine plasma 0.59 X 10(10) M-1. The macromolecule (s) to which ochratoxin A binds more specifically than to albumins have not been identified, but their molecular weights were estimated by gel filtration to be 20 000.
Clinical and experimental rheumatology
The relationship between synovial Xuid (SF) cAMP level and IL-18 and PGE2 SF levels in rheumatoid... more The relationship between synovial Xuid (SF) cAMP level and IL-18 and PGE2 SF levels in rheumatoid arthritis (RA) and osteoarthritis (OA) patients, and between SF cAMP level and disease as well as inXammatory activity in RA were investigated in 17 RA and 19 OA patients. Erythrocyte sedimentation rate (ESR), serum (S) C-reactive protein (CRP) level and SF IL-18 level were higher in RA than in OA patients. SF PGE2 level was similar in both groups. SF cAMP level was higher in OA than in RA patients. In RA patients, SF cAMP level showed negative correlation with Disease Activity Score including a 28-joint count and S CRP, ESR and SF IL-18 level. The results suggest that cAMP promotes anti-inXammatory response in RA and OA patients, which is higher in the latter. Promotion of anti-inXammatory response by cAMP elevating agents might be useful in the treatment of RA.
Lijec̆nic̆ki vjesnik
The molecular mechanism of steroid hormone action is described and its clinical implications are ... more The molecular mechanism of steroid hormone action is described and its clinical implications are examined. Upon entering the cell of a target tissue the steroid hormone is bound to the specific receptor protein thus forming a steroid-receptor complex. The complex is transported to the nucleus where it is bound to chromatin and a sequence of biochemical effects is initiated. Any alterations in the receptor content or structure could be a pathogenic factor in various disorders involving steroid hormone actions. Specific estrogen and progesterone receptors and their release during the menstrual cycle are examined for clinical implications in phasal disorders and in carcinoma.(Authors modified)
Archiv für Toxikologie, 1981
Polyribosome sedimentation pattern and their in vitro protein synthetic ability were investigated... more Polyribosome sedimentation pattern and their in vitro protein synthetic ability were investigated in kidneys of mice treated with a single injection of HgCI2. Mercury bichloride, after 1 h, evokes polyribosome disaggregation, the extent of which is logarithmically correlated with the dose in the range of 2.5-20 ~tmoles/kg. With the dose of 2.5 ~tmoles/kg the effect occurs after 1 h, it is maximal between 1 h and 3 h. After 6 h polyribosomes are reaggregated. Cyclohehimide pretreatment does not prevent the HgC12 induced disaggregation of kidney polyribosomes. The cell-free system derived from kidneys of HgC12 treated mice (10 ~tmoles/kg, 1 h) has a decreased protein synthetic ability. Both, in livers of mice treated with 20 ~tmoles/kg HgC12 and in isolated rat's reticulocytes incubated with 20 ~tM HgC12 during 1 h there were no apparent changes in the polyribosome sedimentation patterns.
The Biochemical journal, 1973
1. To investigate the role of ribosome function in regulating protein synthesis, the activity, di... more 1. To investigate the role of ribosome function in regulating protein synthesis, the activity, distribution and functional states of ribosomal particles were investigated in livers of mice fed ad libitum or starved overnight. 2. The distribution of protein-synthesizing activity between polyribosomes of different sizes was analysed after incorporation of radioactive leucine, and the quantitative distribution of ribosomes as native subunits, monomers and polyribosomes was analysed after incorporation of orotic acid. Precursors labelled with (3)H or (14)C were given separately to fed and starved mice, so that livers from the two groups of animals were processed together. 3. The former experiments showed that starvation has little effect on the distribution of protein-synthesizing activity across polyribosome sedimentation patterns, though the latter experiments showed that the proportion of ribosomes existing as monomers increased from 9.5% to 15.2%, whereas the proportion existing as ...
Biochimica et biophysica acta, Jan 31, 1972
When the "postmitochondrial" fraction from fed mice was treated with aamylase, the polysomes prep... more When the "postmitochondrial" fraction from fed mice was treated with aamylase, the polysomes prepared subsequently were contaminated less by glycogen and had a decreased protein/RNA ratio and higher protein synthetic activity. The polysomes also had a higher proportion of heavy polysomal aggregates and higher protein synthetic activity than those obtained from fasted animals.
The Biochemical journal, 1972
Active ribosomes are found as 'polyribosomes' or as 'native subunits'. A third group of ribosomes... more Active ribosomes are found as 'polyribosomes' or as 'native subunits'. A third group of ribosomes, the unprogrammed 'single ribosomes', usually co-sediment with monoribosomes. In appropriate ionic conditions, however, single ribosomes are split into derived subunits that apparently co-sediment with native subunits. Since single ribosomes could be artifacts produced by association of subunits, we have investigated possible differences between the behaviour of derived and native subunits.
The Biochemical journal, 1975
1. A porphyrinogenic drug, 3,5-diethoxycarbonyl-1,4-dihydrocollidine, caused a decrease in the pr... more 1. A porphyrinogenic drug, 3,5-diethoxycarbonyl-1,4-dihydrocollidine, caused a decrease in the proportion of single ("run off") ribosomes, and an increase in the number of polyribosomes, in the livers of treated animals. 2. No change could be detected in the distribution of amino acid incorporation among hepatic polyribosomes.
Journal of Neurochemistry, 1985
Insulin-induced hypoglycemia provokes polyribosome disaggregation and accumulation of monomeric r... more Insulin-induced hypoglycemia provokes polyribosome disaggregation and accumulation of monomeric ribosomes in the brain of rats with hypoglycemic paresis and coma. The extent of brain polyribosome disaggregation depends on the decrease of blood glucose concentration, and in comatose animals on the duration of hypoglycemia. Cycloheximide prevents the disaggregation of brain polyribosomes induced by hypoglycemia, indicating that hypoglycemia affects brain protein synthesis, decreasing the rate of initiation relative to the rate of elongation of polypeptide chain synthesis.
ELECTROPHORESIS, 2008
Human DNA quantification by quantitative real-time PCR (QRT-PCR) has gained great importance in f... more Human DNA quantification by quantitative real-time PCR (QRT-PCR) has gained great importance in forensic DNA and ancient DNA studies. However, in such samples, DNA quantification is impaired by the frequently present humic acid (HA). We have previously shown that the addition of synthetic HA inhibits QRT-PCR. In this study we investigated the possible mechanisms of HA interaction with human DNA, and kinetics of QRT-PCR inhibition. In QRT-PCR with pure human DNA and no HA added, V MAX was 40. With DNA sample containing 4 mg/mL of HA, V MAX was 30.30 while the addition of extra Taq polymerase to the same sample changed V MAX into 38.91, amplifying between 80 and 90% of input DNA. The K M /V MAX ratio in all the samples remained constant, indicating that the mechanism of HA inhibition of QRT-PCR is uncompetitive by nature. Moreover, HA shifts the human DNA melting temperature point (T m ) from 75 to 877C and inhibits DNase Imediated DNA cleavage, most probably affecting the enzyme's activity.
Croatian medical journal, 2008
Annals of Nutrition and Metabolism, 1974
ABSTRACT The aminoacyl-tRNA and protein synthesizing activities of cell-free systems derived from... more ABSTRACT The aminoacyl-tRNA and protein synthesizing activities of cell-free systems derived from the livers of mice fed ad libitum and mice fasted overnight were measured. The ‘pH 5 fractions’ from both groups of mice have a similar ability to acylate tRNA. Cell-free systems derived from fasted mice had a reduced protein synthetic activity, but in heterogenous cell-free systems the activity of polysomes from these animals was significantly increased by cytosol fractions from fed mice. These results indicate that fasting affects a factor or factors in the cytosol which are required for incorporation of aminoacyl-tRNA into protein.Copyright © 1974 S. Karger AG, Basel
Tumori
Breast carcinoma is a heterogeneous disease, the prognosis of which correlates with various progn... more Breast carcinoma is a heterogeneous disease, the prognosis of which correlates with various prognostic factors. The aim of this study was to assess the prognostic significance of c-erbB-2 overexpression in breast carcinoma patients in association with other known prognostic factors. The relationship between immunohistochemical expression of the c-erbB-2 oncoprotein and various established prognostic factors such as tumor size, axillary node status, estrogen and progesterone receptor status, DNA ploidy, proliferation index, cathepsin D expression and histological grade in invasive ductal breast carcinoma is presented in this study. Of the 93 ductal invasive carcinomas 22 (23.7%) were grade I, 51 (54.8%) grade II, and 20 (21.5%) grade III, and the majority (78: 83.9%) were 2-5 cm in diameter. Tumor metastases were identified in one or more lymph nodes in 55 (59.1%) patients, the remaining 38 (40.9%) patients being lymph node negative. According to the DNA histograms 40 (43.0%) tumors ...
Cancer research, 1980
The qualitative and quantitative relationships between cytoplasmic estrogen receptors (ERC), tota... more The qualitative and quantitative relationships between cytoplasmic estrogen receptors (ERC), total nuclear estrogen receptors (ERN), and cytoplasmic progesterone receptors (PGR) in 74 primary and 23 metastatic human breast cancer tissues were studied. A positive correlation between the age of th patients and the receptor concentration was found only for ERC. Although ERN and PGR were more frequent in tumors with a higher level of ERC, there was no significant correlation between concentrations of either ERN or PGR and ERC. However, PGR were more frequent in ERN-positive than in ERN-negative tumors, irrespective of the presence of ERC. There was also a highly significant correlation between PGR and ERN concentrations. These findings support the assumption that induction of PGR by estrogen in human breast cancer is mediated by a mechanism involving nuclear receptors. Therefore, the ERN assay might increase the validity of steroid receptor determination for prediction of hormonal sensi...
Biomedicine & pharmacotherapy = Biomédecine & pharmacothérapie, 1985
In 60 breast cancer patients in stages I and II the blastogenic transformation of peripheral bloo... more In 60 breast cancer patients in stages I and II the blastogenic transformation of peripheral blood lymphocytes after phytohaemagglutinin (PHA) pokeweed mitogen (PWM) and concanavalin A (Con A) stimulation were assayed and estrogen (ER) and progesterone (PgR) receptor concentrations in tumor cytosol were measured. A negative correlation between lymphocyte reactivity to the mitogens and tumor steroid receptors concentration was found. The lymphocyte response to the mitogens in the patients with ER-PgR-tumors (R-) was significantly higher than in those with tumors either ER+PgR-or ER-PgR+ (R+) or ER+PgR+ (R++). There was also a negative correlation between lymphocyte response to PHA and either ER or PgR concentrations in the tumors. These results suggest that the presence of steroid receptors in tumor cells may be associated with the depression of immunological reactivity in breast cancer patients.
European Journal of Cancer and Clinical Oncology, 1991
The results of a single centre study on cytoplasmic oestrogen (ER) and progesterone (PR) receptor... more The results of a single centre study on cytoplasmic oestrogen (ER) and progesterone (PR) receptors and their combinations in primary breast cancer of 1957 patients from various parts of Croatia are presented. The frequency of ER+ tumours and tumour mean ER concentration were higher in patients over 50 years of age, while PR frequency and concentration were similar in patients over and under 50. The ER concentration was positively correlated with the age of patients, but the age-related increase in ER concentration appeared between 50 and 70 years of age. The pattern of receptor coexistence was age related. The frequency of ER+PR+ and ER+PRincreased and that of ER-PR+ and ER-PR-tumours decreased with the age of patients. The concentrations of ER and PR were higher in ER+PR+ than in ER+PR-or ER-PR+ turnouts, respectively. When the patients were divided into groups under and over 50 years of age these differences appeared only in the latter group, while in the former the concentrations of ER were similar in ER+PR+ and in ER+PR-tumours, and the concentration of PR was higher in ER+PR+ than in ER-PR+ tumours. These data suggest a biological difference between breast cancers with various receptor combinations, as well as a difference in pathogenesis of the receptor negative and positive breast cancer.
Biochemistry international
The binding properties of ochratoxin A to human and porcine plasma constituents were studied in v... more The binding properties of ochratoxin A to human and porcine plasma constituents were studied in vitro. Ochratoxin A was shown to bind to other plasma constituents with a considerably higher affinity than the earlier known nonspecific binding to plasma albumins. The association constant for the high affinity macromolecule (s) in human plasma was found to be 2.3 X 10(10) M-1 and for porcine plasma 0.59 X 10(10) M-1. The macromolecule (s) to which ochratoxin A binds more specifically than to albumins have not been identified, but their molecular weights were estimated by gel filtration to be 20 000.
Clinical and experimental rheumatology
The relationship between synovial Xuid (SF) cAMP level and IL-18 and PGE2 SF levels in rheumatoid... more The relationship between synovial Xuid (SF) cAMP level and IL-18 and PGE2 SF levels in rheumatoid arthritis (RA) and osteoarthritis (OA) patients, and between SF cAMP level and disease as well as inXammatory activity in RA were investigated in 17 RA and 19 OA patients. Erythrocyte sedimentation rate (ESR), serum (S) C-reactive protein (CRP) level and SF IL-18 level were higher in RA than in OA patients. SF PGE2 level was similar in both groups. SF cAMP level was higher in OA than in RA patients. In RA patients, SF cAMP level showed negative correlation with Disease Activity Score including a 28-joint count and S CRP, ESR and SF IL-18 level. The results suggest that cAMP promotes anti-inXammatory response in RA and OA patients, which is higher in the latter. Promotion of anti-inXammatory response by cAMP elevating agents might be useful in the treatment of RA.