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Biomedical subjects

G Ronquist

Publications and source records attributed to G Ronquist.

At least 37 records · Page 2Linked to original sources
PubMed1999

Distribution of prostasomes in neoplastic epithelial prostate cells.

BACKGROUND: Prostasomes are a secretory product from the prostate. We aimed to investigate whether the distribution and amount of prostasomes in normal prostate epithelium were influenced by the dedifferentiation occurring in adenocarcinomas of the human prostate gland. METHODS: Transurethrally resected material from 11 patients with prostatic carcinoma of various malignancy grades, material from two lymph node metastases, and benign tissue from 10 total prostatectomies were subjected to immunohistochemical staining, using a mouse monoclonal antibody against human prostasomes (mAb78). RESULTS: Immunostaining of low-grade carcinoma was similar to that of normal prostate gland which displayed a cytoplasmic granular staining of the apical (luminal) aspects of the secretory epithelial cells. In moderately well and poorly differentiated adenocarcinoma, the amount of stained components decreased, and the staining pattern became more heterogeneous. In multilayered glandular structures, the staining was concentrated at the lumen, leaving most other cells negative. The neoplastic cells of lymph node metastases of prostate carcinoma differed in amount and distribution of immunostained prostasomes. CONCLUSIONS: The antigen recognized in the prostasomes by mAb78 was expressed in benign prostate tissue, prostate cancer, and to a lesser degree in lymph node metastases. There was a tendency towards decreased expression with increasing tumor grade.

Adenocarcinoma↗
PubMed1999

Identification of dipeptidyl peptidase IV as the antigen of a monoclonal anti-prostasome antibody.

BACKGROUND: Our purpose was to elucidate the identity of an antigen of a monoclonal antibody against prostasomes, which are prostate-derived organelles occurring freely in human semen. METHODS: Monoclonal antibodies against prostasomes were generated by intrasplenic immunization to allow better characterization of the prostasomes. One third of the resulting antibodies bound to a 110-kDa prostasomal protein on Western blots. RESULTS: The antigen was purified from seminal prostasomes by anion exchange chromatography and gel electrophoresis. After in-gel digestion and amino-acid sequence analysis of selected peptides, it was identified as dipeptidyl peptidase IV (DPP IV), EC 3.4.14.5, also known as T-cell-activating antigen CD26. No DPP IV could be detected in the supernatant obtained after preparative ultracentrifugation of the prostasomes. CONCLUSIONS: DPP IV/CD26 is structurally bound to prostasomes rather than being free in seminal fluid. This enzyme may play a critical role in the promoting effect of prostasomes on forward motility of spermatozoa.

Amino Acid Sequence↗
PubMed1999

Metabolic fates in humans of linamarin in cassava flour ingested as stiff porridge.

Insufficiently processed products from cassava roots may contain residual amounts of cyanogenic glucosides, mainly linamarin. The fate of orally ingested linamarin was studied following a meal of cassava porridge prepared from cassava flour from southern Tanzania with 82 mg cyanide equivalents (3035 micromol) of linamarin per kg dry weight. Following ingestion of amounts of porridge containing 243-571 micromol linamarin by 15 healthy adults a mean (range) of 21% (1-47%) of the linamarin ingested was excreted in the urine within 24 hours and a mean of 1% in the next 24 hours. Serum thiocyanate, the main cyanide metabolite, increased in all subjects from a mean (+/-SD) of 34+/-26 to 78+/-28 micromol/litre (P < 0.001). In a second group of seven subjects we found that the ingestion of porridge with a mean (range) of 431 micromol (203-669%) of linamarin resulted in a mean linamarin excretion of 127 micromol/litre and an excess thiocyanate excretion of 118 micromol/litre and that 216 micromol was unaccounted for. We conclude that less than one-half of orally ingested linamarin is converted to cyanide and hence thiocyanate, about one-quarter is excreted unchanged and another quarter is metabolized into an as yet unknown compound.

Adult↗
PubMed1999

CD26 and adenosine deaminase interaction: its role in the fusion between horse membrane vesicles and spermatozoa.

Membrane vesicles of horse seminal plasma present at their surface a highly specific serine-type protease, dipeptidyl peptidase IV/CD26, a surface antigen known to characterize human prostasomes. Horse sperm cells expressed at their surface A(1) adenosine receptors (A(1)AR) and ecto-adenosine deaminase (ecto-ADA), both detected by immunoblot analysis, whereas CD26 was visualized at the equatorial segment by immunofluorescence microscopy. In addition to CD26, horse membrane vesicles showed ecto-ADA. The fusion process between horse sperm cells and vesicles was evidenced by confocal microscopy, which showed the localization of CD26 at the postacrosomal region and at the midpiece of the spermatozoa after incubation with vesicles. Moreover, a similar localization of CD26 and ecto-ADA on the spermatozoa was evidenced after fusion. Our results suggest that the interaction CD26/ecto-ADA might be responsible for fusion. Since A(1)ARs are said to be second receptors for ecto-ADA to form ecto-ADA/A(1)AR complexes, and since horse spermatozoa have A(1)ARs at their surface, the interaction CD26/ecto-ADA/A(1)AR during the fusion process cannot be ruled out.

Adenosine Deaminase↗
PubMed1999

The complexity of pregnancy anemia in Dar-es-Salaam.

OBJECTIVES: To investigate the main causes of anemia in pregnancy in Dar-es-Salaam and identify appropriate investigations at all levels of care. MATERIALS: All pregnant women booking for antenatal care at 2 clinics (n = 2,235) were screened for anemia. Investigations for etiology of anemia were done in all anemic women (Hb <10.5 g/dl) (n = 361). METHODS: Blood cell counts, microscopy of blood films, S-ferritin, C-reactive protein, HIV, stool parasite and bone marrow analysis were performed. RESULTS: Iron deficiency dominated in 86% and malaria in 1/3 of anemia cases. Since 42% had indication of ongoing inflammation, S-ferritin was less useful as indicator of iron deficiency but blood film microscopy identified most cases.

Acquired Immunodeficiency Syndrome↗
PubMed1999

Low myometrial glycogen content compared with rectus muscle in term pregnant women before labor.

Glycogen, glucose, some nucleosides and purine base derivatives were determined in biopsies from 10 term pregnant women undergoing elective cesarean sections before labor. The concentrations were compared in the biopsies which were cut from isthmus and fundus of the uterus and m. rectus abdominis. M. rectus biopsies had 1.5 and 2 times higher concentration of glycogen than the isthmic and fundal uterine biopsies, respectively. The glucose concentration in the striated muscle was on the other hand only half that in the myometrium. The uterus displayed regional differences in concentrations of glycogen (higher in isthmus). A relatively low glycogen content in term pregnant uterine smooth muscle compared with striated muscle signifies the restricted energy demands of pregnant myometrium.

Adenosine↗
PubMed1999

Expression of prostasome-like granules by the prostate cancer cell lines PC3, Du145 and LnCaP grown in monolayer.

Prostasomes are a granular type of secretory product in the human prostate gland cells. It is not known, whether in vitro grown cells derived from human prostate cancers also express prostate secretory components containing granules with properties similar to the prostasomes. Therefore, we carried out the present investigation and found that cytospins of in vitro grown PC3, DU145 and LNCaP cells generally expressed a granular secretion. DU145 demonstrated the highest ratio of cells with granules (about 90%), while cytospins of PC3 and LNCaP contained less stained cells (50-70%). Purified granules from PC3 cells were immunoreactive with a monoclonal antibody (mAb78) originally raised against human seminal prostasomes. The PC3 granules also shared the property with human seminal prostasomes having an elevated UV260/UV280 absorbance ratio. On the other hand we found a low aminopeptidase activity in PC3 granules contrary to that of human prostasomes. Prostasomes may form a heterogeneous group with different properties due to the source from which they are isolated and perhaps it is justified to recognize them as different members of a prostasome family.

Aminopeptidases↗
PubMed1998

[Prostasomes enhance sperm capacity. Prostatic components, or antibodies against them, may be used in in vitro fertilization, as contraceptive agents and for the diagnosis of cancer].

The article consists in a report of the prostasomes, which are secreted into the gland ducts of the human prostate. At ejaculation, these native prostasomes are expelled with prostate secretions and are to be found in the seminal plasma as seminal prostasomes which facilitate sperm function in various ways. The authors have designed methods for producing monoclonal anti-prostasome antibodies for use in immunohistochemistry, in sequencing analysis of the prostasomes, and in the immunostaining of prostate carcinoma metastases.

Antibodies↗
PubMed1998

Monoclonal antibodies against human prostasomes.

BACKGROUND: The prostasomes are secreted into the gland ducts of the human prostate. At ejaculation, these native prostasomes are expelled with the secretions of the prostate and appear in the seminal plasma as seminal prostasomes, where they facilitate sperm function in various ways. We have designed methods for producing monoclonal anti-prostasome antibodies to be used for immunohistochemistry and sequencing analyses of the prostasomes. METHODS: The immunogen applied was purified seminal prostasomes placed on small pieces of nitrocellulose membranes (prostasome blots) and deposited into the spleen of mice for immunization. For screening, both seminal and native prostasomes were used. RESULTS: We obtained antibodies which detected native prostasomes both in prostatic secretions and in paraffin sections of the prostate. The immunostaining demonstrated that all prostate epithelial cells contained prostasomes. They were located in the apical parts of the secretory cells and in the gland ducts, while the nuclei and the corpora amylacea were unstained. CONCLUSIONS: Using the methods described, monoclonal antibodies against native prostasomes were produced. In addition to their usefulness in structural and functional studies of prostasomes, specific monoclonal antibodies can be used to characterize prostasomes by sequencing analyses.

Animals↗
PubMed1998

Sudden infant death syndrome and nitrogen metabolism: further development of a hypothesis.

BACKGROUND: A hypothesis suggesting an inducible inability of the enteric bacteria to metabolize urea in infants, resulting in metabolic alkalosis and subsequent respiratory insufficiency, has been proposed as the cause of sudden infant death syndrome (SIDS). METHODS: Microbiological cultivation and determination of faecal urease activity and faecal urea content were carried out in 30 cases of unexpected infant deaths out of which 22 were considered to be due to SIDS and eight from other causes. The concentration of nitric oxide (NO) in sealed test tubes was determined after incubation of faeces in normal saline. RESULTS: The SIDS subjects differed significantly from the control cases in two respects: they had low or no sigmoid faecal urease activity and an unmetabolized sigmoid faecal urea content, whereas the control subjects had normal faecal urease activity and none, or very little, remaining faecal urea. The NO concentration in faeces was correlated with the faecal content of urea in the SIDS cases. CONCLUSION: The present findings lend support to the hypothesis of an insufficient metabolism of enteric urea in infants with SIDS.

Case-Control Studies↗
PubMed1998

Erythrocytic protein kinase C activity in primary hypertension.

OBJECTIVES: Increased protein kinase C activity has been reported in erythrocytes from patients with primary hypertension and also from hypertensive rats. In this phenomenological study, we investigated whether a possible increased activity was the result of an augmented amount of enzyme molecules or a more active enzyme. DESIGN: Collect blood samples, separate erythrocytes from other blood cells. After partial purification of protein kinase C in the erythrocyte lysate, assay the enzyme activity under optimal conditions using a specific peptide substrate. SETTING: Central Hospital in Eskilstuna and University Hospital in Uppsala, Sweden. SUBJECTS: Healthy individuals: 47 persons (20 women and 27 men). Ten patients with untreated primary hypertension. MAIN OUTCOME MEASURES: Erythrocytes were separated from leucocytes and platelets by passing through a cellulose column followed by repeated washings. Some proteins in the erythrocyte lysate interfering with protein kinase C assay were removed by chromatography on DEAE-cellulose. RESULTS: The mean protein kinase C activity in erythrocytes from healthy individuals was 0.18 +/- 0.02 pmol [32P]phosphate min(-1) x 10(6) cells, regardless of sex and age. The corresponding value for patients with primary hypertension was 0.16 +/- 0.04 pmol [32P]phosphate min(-1) x 10(6) cells. CONCLUSIONS: The amount of protein kinase C, measured as the activity at optimal assay conditions, in erythrocytes from patients with primary hypertension is not critical for the development of moderate hypertension.

Adult↗
PubMed1998

Occurrence of prostasome-like membrane vesicles in equine seminal plasma.

Equine seminal plasma was shown to contain membrane vesicles that are similar to the well characterized prostasomes in human seminal plasma. Determination of nucleoside and nucleotide concentrations of these particles have shown that ATP, ADP and adenosine are the main components of the nucleotidic pool. 5' nucleotidase, endopeptidase and dipeptidyl peptidase i.v. activities have been found on the surface of the particles. The interaction between these prostasome-like vesicles and spermatozoa was demonstrated by electron micrograph scans which revealed the steps of a fusion-like process leading to mixing of the membranes. In addition, endopeptidase activity, a marker enzyme of these seminal vesicles that is normally absent from equine spermatozoa, was shown to be acquired by these cells after interaction with the vesicles. The addition of these vesicles to equine spermatozoa resulted in the modification of adenylate catabolism. Therefore, a role in stabilizing the energy charge of the spermatozoa thus allowing longer viability is proposed for these organelles.

Adenosine↗
PubMed1998

Evidence of cerebral dysfunction associated with isoflurane- or propofol based anaesthesia for orthognathic surgery, as assessed by biochemical and neuropsychological methods.

A relationship has previously been described between individual mean isoflurane concentrations and the release of a marker of neuronal injury, adenylate kinase (AK), into the cerebrospinal fluid (CSF) after anaesthesia and orthognathic surgery. Likewise, reduced mental performance has been detected. Twenty-nine patients scheduled for orthognathic surgery were assigned to isoflurane- or propofol based anaesthesia, which was adjusted to a defined level with the aid of processed EEG and quantitative surface EMG. In the case of a mean arterial pressure (MAP) < 50 mmHg a phenylephrine infusion was started to keep the MAP above the minimal level, otherwise no regard was paid to the blood pressure, which never exceeded normal values. A lumbar puncture for CSF sampling was performed approximately 20 h postoperatively. The CSF sample was analysed for AK activity. Neuropsychological tests were performed the day prior to surgery and again in the period 4-8 weeks postoperatively. Five patients were re-examined by psychometry 12-30 months later. A release of AK into CSF was confirmed, equal in both groups. Correlation with the anaesthetic dose given was poor. Five patients from each group failed significantly in the postoperative neuropsychological tests. They differed in several demographic respects from the others. When five of the failed patients were re-examined 12-30 months later, three patients still performed poorly in the tests. Biochemical and neuropsychological disturbances were recorded in several patients objected to orthognathic surgery. The underlying mechanisms are unclear, including the role of the anaesthetic drugs or surgery itself.

Adenylate Kinase↗
PubMed1997

Postpolio muscular dysfunction: relationships between muscle energy metabolism, subjective symptoms, magnetic resonance imaging, electromyography, and muscle strength.

Eleven patients with previous polio were studied. The concentration of energy-related metabolites and energy charge was measured from the vastus lateralis muscle, as was isometric muscle strength of knee extension. Cross-sectional area of the quadriceps femoris muscle was calculated from magnetic resonance imaging. Reinnervation was studied using macroelectromyography. Muscle weakness, pain, and newly acquired muscle weakness in the legs was estimated by the patients. The findings in the legs in which the patients experienced new loss of muscle function were compared with the stable legs. There were no significant differences between these groups in any of the objectively measured variables. Only hip pain correlated with new loss of muscle function. Creatine phosphate was decreased in 5 patients. The symptoms and subjective muscle strength did not correlate with any of the objective measurements. There were no significant relationships between energy-related metabolites and postpolio symptoms.

Adult↗
PubMed1997

No further improvement of ischaemic myocardial metabolism by combining preconditioning with beta-blockade: an in vivo experimental study in the pig heart using a microdialysis technique.

Adenine nucleotides, lactate and pyruvate were monitored by microdialysis in pig hearts, comprising four experimental groups. Two preconditioned groups, one beta-blocked by metoprolol (0.3 mg kg-1 body wt; n = 6) and the other (n = 7) without beta-blockade. Two groups were not preconditioned, one beta-blocked (n = 6) and one without beta-blockade (n = 7). Probes were inserted into ischaemic and non-ischaemic myocardium. Preconditioning consisted of four consecutive 10 min periods of ischaemia each separated by 20 min of reperfusion. All animals were subjected to 40 min of index ischaemia followed by 25 min of reperfusion. Myocardial cAMP content was determined in biopsies after the final reperfusion and was found low in the beta-blocked groups. Lactate levels during index ischaemia exceeded the basal level 4-6 fold in dialysate. Adenosine concentration reached 12 mumol L-1 during the first preconditioning period while an attenuation was typical for the following three preconditioning periods. The sum of the concentrations of adenosine inosine and hypoxanthine was significantly lower during index ischaemia in the preconditioned groups displaying a peak value of 115 mumol L-1. The corresponding value for unpreconditioned hearts was 230 mumol L-1. The part of adenosine was 5% and less than 1%, respectively. Pyruvate concentration decreased during each brief ischaemic period of preconditioning rising to a higher level of reperfusion. The decrease in pyruvate was smaller in the controls during index ischaemia. The effects of beta-blockade and preconditioning on ischaemic metabolism were comparable and the results of the two treatments were not additive in this respect.

Adrenergic beta-Antagonists↗
PubMed1997

Response of myocardial cellular energy metabolism to variation of buffer composition during open-chest experimental cardiopulmonary resuscitation in the pig.

The aim of the present study was to investigate possible relationships in piglets between myocardial energy-related metabolites and intracellular electrolytes during open-chest cardiopulmonary resuscitation (OCCPR) supplemented by the administration of alkaline buffers with varying sodium content. Our hypothesis was that an increasing myocardial intracellular sodium content would decrease the intracellular energy stores. In addition to haemodynamics, acid-base and blood gas variables were analysed, and myocardial biopsies were collected before and during OCCPR as well as after the return of spontaneous circulation. After a period of 4 min of untreated ventricular fibrillation (VF). 25 piglets were randomly allocated to one of four groups: OCCPR with normal saline (n = 5); OCCPR with sodium bicarbonate (SB) (n = 7); OCCPR with Tris buffer mixture (TBM) (n = 7); and a totally untreated control group (n = 6). The results showed that 4 min of untreated VF almost eradicated creatine phosphate (CrP) and that the ATP/ADP ratio decreased to 1.5-2.0. During OCCPR with normal saline, the myocardial content of CrP increased, whereas lactate, ATP and ADP levelled off and AMP decreased, causing an increased ATP/ADP ratio. The adenosine and inosine contents increased, whereas inosine monophosphate was unchanged at a low level, the adenosine and inosine contents being inversely correlated with the total content of adenine nucleotides. In both buffered groups, the increase in most energy-related metabolites (CrP, ATP, ADP, AMP and the ATP/ADP quotient) was less and in lactate more pronounced than in the group not being buffered, with no difference between the groups receiving SB or TBM. Although the intracellular potassium content was unaltered, the sodium, chloride and calcium concentration increased, more so in the group receiving SB. The intracellular content of sodium was correlated with that of calcium. Thus, buffering increased the myocardial AMP degradation during OCCPR by increasing the flux via the 5'-nucleotidase reaction, and SB increased the intracellular contents of sodium and calcium to a greater extent than did TBM.

Adenosine Diphosphate↗