Fresh Human Urine Research Articles

Ion‐exchange softening of human urine to control precipitation

A major barrier to widespread implementation of urine source‐separation is the uncontrolled precipitation of magnesium (Mg) and calcium (Ca) minerals in waterless urinal plumbing, which results in clogging that increases maintenance requirements. The goal of this research was to investigate the use of ion‐exchange softening of undiluted, fresh human urine to control precipitation reactions in hydrolyzed urine. The working hypothesis was that selective removal of Ca and Mg from undiluted, fresh urine by cation exchange resin would decrease the precipitation of Ca and Mg minerals in hydrolyzed urine. Ion‐exchange experiments and precipitation experiments were used to investigate ion‐exchange reactions in synthetic urine. Cation exchange resin (Amberlite A200C) removed both Ca and Mg from undiluted, fresh urine with a greater affinity for Ca over Mg. Precipitation experiments showed that struvite, MgNH4PO4·6H2O, and hydroxyapatite, Ca5(PO4)3(OH), were the dominant minerals in untreated and ion‐exchange treated hydrolyzed urine. Overall, ion‐exchange softening decreased the mass of solids that would be deposited in the urinal plumbing and increased the phosphate available for nutrient recovery. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 564–571, 2014

A study on the migration and transformation law of nitrogen in urine in municipal wastewater transportation and treatment

Many studies suggest that the total nitrogen (TN) in urine is around 9,000 mg/L and about 80% of nitrogen in municipal wastewater comes from urine, because nitrogen mainly occurs in the form of urea in fresh human urine. Based on this fact, the study on the migration and transformation law of nitrogen in urine and its influencing factors was carried out. It can be seen from the experimental results that the transformation rate of urea in urine into ammonia nitrogen after standing for 20 days is only about 18.2%, but the urea in urine can be hydrolyzed into ammonia nitrogen rapidly after it is catalyzed directly with free urease or indirectly with microorganism. Adding respectively a certain amount of urease, activated sludge and septic-tank sludge to urine samples can make the maximum transformation rate achieve 85% after 1 day, 2 days and 6 days, respectively. In combination with some corresponding treatment methods, recycling of nitrogen in urine can be achieved. The results are of great significance in guiding denitrification in municipal wastewater treatment.

Long-Term Frozen Storage of Urine Samples: A Trouble to Get PCR Results in Schistosoma spp. DNA Detection?

BackgroundHuman schistosomiasis remains a serious worldwide public health problem. At present, a sensitive and specific assay for routine diagnosis of schistosome infection is not yet available. The potential for detecting schistosome-derived DNA by PCR-based methods in human clinical samples is currently being investigated as a diagnostic tool with potential application in routine schistosomiasis diagnosis. Collection of diagnostic samples such as stool or blood is usually difficult in some populations. However, urine is a biological sample that can be collected in a non-invasive method, easy to get from people of all ages and easy in management, but as a sample for PCR diagnosis is still not widely used. This could be due to the high variability in the reported efficiency of detection as a result of the high variation in urine samples’ storage or conditions for handling and DNA preservation and extraction methods.Methodology/Principal FindingsWe evaluate different commercial DNA extraction methods from a series of long-term frozen storage human urine samples from patients with parasitological confirmed schistosomiasis in order to assess the PCR effectiveness for Schistosoma spp. detection. Patientś urine samples were frozen for 18 months up to 7 years until use. Results were compared with those obtained in PCR assays using fresh healthy human urine artificially contaminated with Schistosoma mansoni DNA and urine samples from mice experimentally infected with S. mansoni cercariae stored frozen for at least 12 months before use. PCR results in fresh human artificial urine samples using different DNA based extraction methods were much more effective than those obtained when long-term frozen human urine samples were used as the source of DNA template.Conclusions/SignificanceLong-term frozen human urine samples are probably not a good source for DNA extraction for use as a template in PCR detection of Schistosoma spp., regardless of the DNA method of extraction used.

Power generation and contaminant removal in single chamber microbial fuel cells (SCMFCs) treating human urine

The potential of single chamber microbial fuel cells (SCMFC) to treat raw, fresh human urine was investigated. The power generation (55 μW) of the SCMFCs with platinum (Pt)-based cathode was higher than those with Pt-free cathodes (23 μW) at the beginning of the tests, but this difference decreased over time. Up to 75% of the chemical oxygen demand (COD) in urine was reduced after a 4-day treatment. During this time, the ammonium concentration increased significantly to 5 gNH4+-N/L in SCMFCs due to urea hydrolysis, while sulfate concentration decreased and transformed into H2S due to sulfate reduction reactions. Calcium and magnesium concentrations dropped due to precipitation at high pH, and phosphorous decreased 20–50% due to the formation of struvite that was found on the cathode surface and on the bottom of the anodic chamber. The advantages of power generation, COD removal, and nutrient recovery make SCMFCs treating human urine a cost-effective biotechnology.

Control charts in multi-element analysis of human urine

A plan for internal quality control (IQC) was designed to monitor the quality of analytical results obtained from the simultaneous determination by ICP-MS of nine trace elements (As, Cd, Mo, Ni, Pb, U, V, W and Zr) in 1350 samples of human urine collected as part of an epidemiological study. Analytical performances, assessed during the method validation, were as follows: limit of quantification ranging from 0.002 μg/L (U) to 0.9 μg/L (Ni); recovery rates varying between 82 % (As) and 110 % (W); intermediate precision as relative standard deviation ranging from 2.5 % (Mo) to 14.2 % (V). Only for Zr, a significantly higher relative standard deviation was obtained. Initially, two commercially certified reference materials (CRMs) based on freeze-dried human urine and containing the elements of interest at suitable levels of concentration were used as control materials. However, due to considerations of reliability, convenience and cost, a control material based on fresh human urine was prepared in-house, evaluated by comparison with the CRMs and implemented for the IQC. The IQC strategy was as follows: at least one control material was analysed in each analytical session and one more control material was analysed after every ten urine samples. The central lines of the control charts were based on the assigned concentration values; the warning and action limits were set on a statistical basis, as two-times and three-times the value of the uncertainty of certified values or the observed standard deviation. At the end of the study, the data collected for the in-house control material were re-evaluated and confirmed its suitability for the purpose. The use of an in-house control material had important advantages: it was more representative of the test samples; its preparation did not involve additional steps, therefore, reducing the risk of contamination; the cost of implementing the IQC was also reduced. Some issues concerning the control charts for As and Mo were addressed and will be discussed.

Use of human urine in phytoplankton production as a tool for ecological sanitation

Measurements of primary productivity of phytoplankton and enumeration of the counts of coliform and heterotrophic bacteria (HB) were made in the water of 12 experimental tanks used for 3 treatments and control in triplicate as follows: (a) fresh human urine (0.02%), (b) stored human urine (0.02%), (c) mixed urine of fresh and stored human urine (0.02%) and (d) control without input of urine. The gross primary productivity of phytoplankton was highest in the stored urine treated tanks (508 mg C m(-2) h(-1)) followed by fresh urine (353 mg C m(-2) h(-1)), mixed urine (303 mg C m(-2) h(-1)) and control (215 mg C m(-2) h(-1)). Similar was the response of net primary production of phytoplankton. The mean count of HB observed in stored urine fed tanks was significantly higher (59-184%) than the remaining urine fed treatments. The mean count of Escherichia coli did not differ from urine treated tanks to control implying the good quality of water. The concentration of dissolved oxygen of water (7.6 to 12.8 mg L(-1)) in these tanks remained satisfactory for aquaculture. The mean concentration of ammonium-N observed in fresh urine treated tanks was more than 10 times higher than the remaining treatments employed. In contrast, the level of phosphate and electrical conductivity in the stored urine treated tanks were significantly higher than the remaining treatments. It is proposed that stored urine with a significantly reduced load of E. coli might be an effective low cost liquid fertilizer for algal biomass production.

Comparative evaluation of the fertilizer value of human urine, cow manure and their mix for the production of carp fingerlings in small holding tanks

Advanced fry of Indian carps and post-larvae of freshwater prawn were reared for 120 days in 18 small holding tanks using each treatment in triplicate as: (a) non-aerated and (b) aerated fresh human urine (0.01%), (c) cow manure (1.8 kg tank−1), mixed treatment with cow manure and human urine under (d) iso-phosphorus and (e) iso-nitrogenous conditions and (f) control. Examination of water quality, primary productivity of phytoplankton, plankton and fish growth from different treatments revealed that the total fish yield was maximum in the cow manure treatment (621.5 g tank−1) followed by the mixed treatments under iso-nitrogenous (428 g tank−1) and iso-phosphorus (333 g tank−1) conditions. Fish yield in different treatments was the direct function of the gross and net primary productivity of phytoplankton which, in turn, were directly related to the concentrations of nitrate and phosphate levels of water as well as their ratios in different treatments employed.

Comparison of sampling tabanids (Diptera: Tabanidae) by four different potential attractants

AbstractSynthetic and natural attractants in traps are used in many parts of the world to attract female tabanids. Certain attractants in different geographic regions may be ineffective or effective under different environmental conditions for horseflies. One‐octen‐3‐ol, as a compound present in bovine emanations, has a behavioural effect on many horsefly species and together with other phenolic compounds makes very effective attractant for this group of insects. As the attractiveness of the mixture of three chemicals (1‐octen‐3‐ol, acetone and ammonia solution in the proportions 5 : 3 : 2), aged donkey urine, lactic acid and fresh human urine is not yet known, it was studied in Eastern Croatia. The combination of those three chemicals and efficiency of natural attractants offers promising results. Tabanus was the most represented genus with 83% of the total collected tabanids. The chi‐squared analyses of the trapping data for canopy traps revealed that each of the attractants (mixture of three chemicals, aged donkey urine, lactic acid and fresh human urine) significantly increased the number of collected horseflies in comparison to those collected in unbaited canopy traps. Some species differences in relative response to different attractants were noted. Significantly, more specimens of Haematopota pluvialis were collected from canopy traps baited with the mixture of three chemicals when compared with traps baited with other attractants. Canopy traps baited with aged donkey urine collected significantly more Atylotus loewianus females than did traps baited with the mixture. The F‐test analysis of the trapping data for the genus Tabanus showed that there is significant difference between average number of collected specimens between mixture of three chemicals and other used attractants (lactic acid and human urine) except aged donkey urine. Finally, traps baited with the mixture of three chemicals (1‐octen‐3‐ol, acetone and ammonia solution) collected 14.5 times more tabanids than unbaited traps, whereas aged donkey urine, lactic acid, and fresh human urine‐baited traps collected 12, 3.9 and 2.5 times as many tabanids, respectively, than did unbaited traps. The mixture of three chemicals (1‐octen‐3‐ol, acetone and ammonia solution) and aged donkey urine appear to be very effective attractants for tabanids.

Mud-puddling in the yellow-spined bamboo locust, Ceracris kiangsu (Oedipodidae: Orthoptera): Does it detect and prefer salts or nitrogenous compounds from human urine?

C. kiangsu adults were observed visiting human urine, especially on hot summer days. The main chemicals in fresh human urine include inorganic salts and CO(NH 2) 2. When human urine was incubated, NH 4HCO 3 became the richest nitrogenous compound. The phagostimulants, repellents and attractants in urine were identified here. On the filter papers treated with fresh or incubated urine samples, the 5th instar nymphs and the adults started and continued gnawing around the edges, in contrast to the 3rd and the 4th instar nymphs. The consumed areas were dramatically greater on the filters treated with the urine samples incubated for 3–6 days. The feedings of both male and female adults were also stimulated by several urine-borne components such as NaCl, NaH 2PO 4, Na 2SO 4, KCl, NH 4Cl and NH 4HCO 3 but not by CO(NH 2) 2. Among them NaCl was the most powerful phagostimulant. The repelling, or attractive/arresting effects of CO(NH 2) 2 and NH 4HCO 3 were also evaluated by a two-choice test. When exposed to water- and CO(NH 2) 2 solution-immersed filters simultaneously, the adults prefer to stay on water-immersed filter. In contrast, when provided water- and NH 4HCO 3 solution-treated filters, the adults prefer to stay on NH 4HCO 3 solution-treated filter. This demonstrated that CO(NH 2) 2 acted as a repellent and NH 4HCO 3 as an attractant/arrestant. In the bamboo forest, similar feeding behavior was also elicited by NaCl, NH 4HCO 3 but not by CO(NH 2) 2. Comparing to NaCl solution, a mixed solution of NaCl and CO(NH 2) 2 (1:1) significantly decreased the consumed area of the treated filters whereas a mixed solution of NaCl and NH 4HCO 3 (1:1) dramatically increased the consumed area. These results demonstrated that the phagostimulatory effect by NaCl was reduced by CO(NH 2) 2 in fresh urine and was enhanced by NH 4HCO 3 in incubated urine.

Highly sensitive spectrofluorimetric determination of cysteine by Cu2+-morin complex

A simple and sensitive fluorescence enhancement assay of trace cysteine (Cys) is presented. The method is based on the redox reaction between the Cu2+-morin complex and Cys. In Britton-Robinson buffer of pH 7.4, the addition of Cys to the Cu2+-morin system results in dramatic fluorescence intensity increase at 539 nm which is proportional to the concentration of Cys over the range of 6.52 × 10−7–2.20 × 10−5 mol L−1, with a limit of detection of 6.52 × 10−8 mol L−1. The method was applied to determine Cys in protein hydrolysate of fresh porcine blood and human urine, the recoveries being 91.3–94.1% and 95–98.6% respectively. The mechanism involved in the reaction was also studied.

A randomized clinical trial of Uroacitides combined with NP and NP regimen alone for advanced non-small cell lung cancer

Uroacitides is a group of cell differentiation inducers, which is purified from fresh human urine. Preclinical studies of Uroacitides have showed that cancer cells could be induced to differentiate, and the growth of cancer cells could be inhibited by Uroacitides. The aim of this study is to compare the efficacy and toxicity between Uroacitides combined with NP regimen and NP alone in treatment of advanced non-small cell lung cancer (NSCLC). Forty-two cases of advanced NSCLC were randomized into Uroacitides+NP and NP groups. NP group: NVB 25mg/m² on days 1 and 8, DDP 75mg/m² on day 1. Uroacitides combined with NP group: Uroacitides of 300mL was given through subclavian catheter daily for 7 days prior to the NP chemotherapy, then concurrently with NP regimen for 2 cycles, except the days of administration of chemotherapy. In the Uroacitides+NP group, the overall response rate was 44.4%, and 20.0% in the NP group (P > 0.05). The median survival time was 9 months in the Uroacitides+NP group and 6 months in the NP group (P=0.0287). The main toxicities were myelosuppression, gastrointestinal reaction and alopecia, and there was no significant difference in incidences of toxicities between the two groups (P > 0.05). Uroacitides combined with NP regimen shows a good curative effect and low toxicity, and may significantly prolong the median survival time for advanced NSCLC.

Abnormal Methylation Enzymes: A Selective Molecular Target for Differentiation Therapy of Cancer

A crucial difference between cancer cells and normal cells is the inability of cancer cells to undergo terminal differentiation. Alteration of methylation enzymes plays a pivotal role in the blockade of terminal differentiation of cancer cells. Elimination of abnormal methylation enzymes is, therefore, a logical approach of cancer therapy. Methylation enzymes play a central role in the regulation of cell replication, differentiation, and apoptosis. When these enzymes are activated, cells enter cell cycle replicating; and when these enzymes become inactive, replicating cells are then diverted into terminal differentiation or apoptosis. The activity of these enzymes in normal stem cells is strictly under the regulation of an exogenous growth factor. Cancer cells, on the other hand, produce a cancer specific endogenous protein factor to lock these enzymes in the active state. Thus, cancer cells keep on dividing. This cancer specific protein factor is an attractive molecular target for cancer therapy, which can be selectively antagonized by CDA-Ⅱ*. CDA-Ⅱ is a preparation derived from fresh human urine. Once abnormal methylation enzymes are corrected by CDA-Ⅱ to become normal enzymes, cancer cells are then induced to undergo terminal differentiation or apoptosis. The action of CDA-Ⅱ is selective on cancer cells, thus the therapy is free of adverse side effects. Better yet, many abnormal behaviors characteristic of cancer cells disappear naturally as a consequence of differentiation induced by CDA-Ⅱ, which include abnormal expression of oncogenes, silencing of suppressor genes, drug resistance, metastasis, telomerase, and tumor markers. CDA-Ⅱ has been approved by the State Drug Administration of China to undergo clinical trial, which is now in the final stage of phase Ⅲ. So far the clinical studies are encouraging. The best clinical result in the application of CDA-Ⅱ was, however, demonstrated by Sano of Japan, who has initiated a very effective protocol by combination therapy with vitamin C, restriction of protein intake, and other nontoxic remedies.

Experiments on the Feeding Behavior of the Hematophagous Candiru, Vandellia cf. Plazaii

Hematophagous candirus (family Trichomycteridae Vandellia cf. plazaii) did not respond to potential chemical attractants (ammonia amino acids fresh fish slime and human urine) added to their aquarium water. They seemed to respond visually to live goldfish Carassius auratus and Amazonian cichlids Cichlasoma amazonarum. One hypothesis tested is that the goldfish (an ostariophysan) might be preferred to the cichlid (a perciform fish). Goldfish were attacked first significantly more often when both prey species were present (one-sided difference in proportions test, N = 15, p = 0.02). However neither the elapsed time to the first attack nor the duration of the attacks differed significantly (Mann-Whitney's U-test N = 32 p = 0.27 and p = 0.92). These two species seemed incapable (goldfish) or weakly capable (cichlid) of avoiding or repelling candiru attacks

Calcium oxalate crystallization kinetics studied by oxalate-induced turbidity in fresh human urine and artificial urine

Calcium oxalate crystallization kinetics studied by oxalate-induced turbidity in fresh human urine and artificial urine

Calcium oxalate crystallization kinetics studied by oxalate-induced turbidity in fresh human urine and artificial urine

We have studied the kinetics of oxalate-induced turbidity in fresh human urine and artificial urine. Assays are performed in 96-well plates, which allows many oxalate concentrations to be studied, repeatedly, in a short time. The metastable limit is defined in terms of the lowest oxalate concentration that gives a rate of change of attenuance significantly greater than the control. Interpretation of rates above this limit is based on ln/ln plots of initial rates against added oxalate concentration. This approach has a good theoretical basis, is well supported by our results and gives a turbidity rate index that is related to the product of the growth rate constant and a factor relating to the number and characteristics of the heteronuclei responsible for initiation of crystallization. This interpretation is posited upon the assumptions that second-order crystallization kinetics occur in unseeded urine when supersaturation exceeds the metastable limit and that aggregation during the initial phase of crystallization does not significantly contribute to changes in turbidity. Metastable limits of urine from healthy volunteers corresponded to a calcium oxalate supersaturation ratio of approx. 10. The turbidity rate index was higher in human urine than in artificial urine. The metastable limit, based on either oxalate concentration or supersaturation, for induction of calcium oxalate crystallization in normal human urine is higher than is likely to be found in normal subjects in vivo. The shape of the relationship between the metastable limit (based on oxalate concentration) and calcium concentration emphasizes the benefit of achieving a low urine calcium concentration. Comparison of the turbidity rate indices for human and artificial urine suggests that the role of nucleation promoters is more dominant than that of growth inhibitors.

In vitro carboplatin-mesna interaction in aqueous solution, human plasma and urine.

The chemotherapeutic benefit of synergistic drug combinations and higher drug dosages has generated interest in the application of these regimens to cancer patients. A major obstacle in the application of these strategies to the treatment of cancer is the dose-limiting toxicities of drug combinations. Sodium 2-mercaptoethane-sulfonate (mesna), a chemoprotective drug, may reduce the nephrotoxicity of carboplatin [CBDCA, paraplatin, JM-8, cis-diammine (1,1-cyclobutane dicarboxylato) platinum II] when administered in combination chemotherapy. The purpose of this study was to evaluate, compare and contrast in vitro the interaction of mesna with carboplatin in aqueous solution, human plasma and urine. Carboplatin and mesna were incubated separately and together at clinically relevant concentrations in plasma and urine. The concentration of carboplatin was assayed by HPLC, and the decay of carboplatin alone and in combination with mesna was compared. The incubation of carboplatin with mesna in human plasma up to 8 days did not result in a statistically significant interaction: the half-life of carboplatin in plasma when it was combined with mesna was 1.62 +/- 0.08 (SE) days compared to 1.85+/- 0.04 (SE) days for carboplatin by itself. The incubation of drugs in fresh human urine up to 15 days gave a half-life of 3.43+/- 0.8 (SE) days for carboplatin alone and 2.78 +/- 0.7 (SE) days for carboplatin when it was combined with mesna. Our results show that carboplatin and mesna do not significantly interact in plasma. Although a statistically significant difference between the half-life of carboplatin and the half-life of the carboplatin/mesna combination is detected in urine, it is not likely to be clinically significant, as there is no significant interaction detected in the first 48 h). It is thus unlikely that mesna would substantially affect the pharmacokinetics of carboplatin when both are given together to patients as part of combination chemotherapy regimens.

Oxidative stress in clinical situations - fact or fiction?

Oxidative stress in clinical situations - fact or fiction?

Individualization of fresh and stored human urine samples by PGM 1- and Gc-subtyping

After 50- to 200-fold concentration by ultrafiltration, 56 fresh urine samples from healthy individuals (26 men, 30 women) and eight samples from corpses were subjected to isoelectrofocusing methods. All the urine samples tested could be correctly typed in both the phosphoglucomatase 1 (PGM 1) and Gc system when compared to reference blood samples. The activity of urinary PGM 1 revealed intraindividual and interindividual variations. To our knowledge this is the first report of PGM 1 detection in urine. A systematic storage experiment over a period of 6 months was carried out at different temperatures (−20°C, 4°C, 20°C); furthermore, aging of urine samples from 4 months to 4 years was investigated. The heterogeneous typing results were as follows. For Gc: after a storage period of 6 months positive results could be obtained in ∼40% of those samples that were stored frozen (−20°C) or in a refrigerator (4°C). Some samples, however, showed negative analyses already after a 1 month storage period. At room temperature positive results could be achieved up to 3 months. Additional bands can appear in pherograms of urine samples stored at room temperature or in a refrigerator; they may cause misinterpretation, dependent on the original Gc-type. The maximum storage time compatible with successful Gc-typing was 1 year. For PGM 1: this polymorphism could be regularly detected up to 1 week, and in some cases up to 1 month, in urine samples stored at 4°C. The PGM 1 activity gradually decreased; there were no additional or variant bands.

The specific binding activities of human urinary radioiodinated colony-stimulating factor-1 to various human tissue cells

1. 1. Colony-stimulating factor (CSF-1) was isolated from a large volume of fresh normal human urine by 5 steps of purification and enrichment. 2. 2. The purification factor is 100,000 fold and the purified compound exhibits a 2.16 × 10 7U/mg of protein sp. act. 3. 3. The isolated CSF-1 is a sialoglycoprotein with 41.5% of carbohydrate. The almost complete removal of this carbohydrate moiety (up to 91%) was achieved by incubation with trifluoromethane sulfoníc acid. 4. 4. The deglycosylated CSF-1 (DG-CSF-1) possesses an apparent M r 38,000 compared to native CSF-1 with an initial M r 57,000 (Goa et al., 1988). 5. 5. The features of the interaction of radio-iodinated [ 125I]CSF-1 with single cell suspensions from various human tissues (bone marrow, spleen, blood, peritoneal cavity, alveolar lavage, lymph node and thymus), were studied. 6. 6. The binding activity of peritoneal macrophages was the highest among the cells examined and erythrocytes, thymus and blood granulocytes showed no CSF-1 binding. 7. 7. On incubation with [ 125I]CSF-1 at 0°C, cellular binding of [ 125I]CSF-1 reached a stable maximum within 16 hr. This is in contrast to the association behaviour at higher temperature. 8. 8. At 37°C, cellular associated [ 125I]CSF-1 levels reached, within 90 min, an unstable maximum which was up to 10 times less than that occurring under the same conditions at 0°C. From the Scatchard plot analysis, we obtained the affinity constant and the number of receptor(s). 9. 9. The binding site is sensitive to trypsin. 10. 10. The receptor alone, (labelled by cross-linking to [ 125I]CSF-1 with di-succinylimidyl-suberate), is a polypeptide with an approx. M r, 110,000. 11. 11. Our results showed that the receptor of CSF-1 is a tyrosin-kinase.

Fibrin-Binding Urokinase (or Precursor Form of Urokinase) with a Molecular Weight of About 100,000 in Fresh Human Urine

Fresh human urine was found to contain at least three different molecular forms of fibrin-binding urokinase (UK) or its precursor, all of which were absorbed on a fibrin/Celite column at neutral pH, and could be eluted with 0.3-1.0 mol/l NaCl in phosphate buffer, followed by 0.2 mol/l, Arg, 2 mol/l KSCN, and 2 mol/l urea, respectively. The main molecular form isolated revealed a molecular weight (MW) of approximately 100,000 (UK-100), and the minor ones were estimated to have MW of 150,000-200,000 and 45,000. In contrast, commercially obtained UK preparations contained mostly active enzymes with MW of 53,000 and 32,000, respectively, and the remaining high molecular forms represented less than 2.0% of the total amount. Rabbit monospecific antibody (IgG) against UK subcomponent (active heavy chain; H-chain UK) reacted and inhibited the fibrinolytic activity of all the active UK molecules. The UK-100 isolated was relatively stable in solution at neutral pH and resistant to mild reduction, without molecular change. Although the preparation had a very low specific activity (ca. 300 IU/mg protein), both the pyro-Glu-Gly-Arg-pNA amidolytic and plasminogen activating activities could be partially enhanced by the addition of trace amounts of plasmin. In this process, the appearance of two additional active enzymes of MW 53,000 and 32,000 was also confirmed by zymography.