A comparative study on green synthesis and characterization of Mn doped ZnO nanocomposite for antibacterial and photocatalytic applications

Biological and green synthesis of nanomaterial is a superior choice over chemical and physical methods due to nanoscale attributes implanted in a green chemistry matrix, have sparked a lot of interest for their potential uses in a variety of sectors. This research investigates the growing relevance of nanocomposites manufactured using ecologically friendly, green technologies. The transition to green synthesis correlates with the worldwide drive for environmentally sound procedures, limiting the use of traditional harsh synthetic techniques. Herein, manganese was decorated on ZnO NPs via reducing agent of Withania-extract and confirmed by UV-spectrophotometry with highest peak at 1:2 ratio precursors, and having lower bandgap energy (3.3 eV). XRD showed the sharp peaks and confirms the formation of nanoparticles, having particle size in range of 11-14 nm. SEM confirmed amorphous tetragonal structure while EDX spectroscopy showed the presence of Zn and Mn in all composition. Green synthesized Mn-decorated ZnO-NPs screened against bacterial strains and exhibited excellent antimicrobial activities against gram-negative and gram-positive bacteria. To check further, applicability of synthesized Mn-decorated Zn nanocomposites, their photocatalytic activity against toxic water pollutants (methylene blue (MB) dye) were also investigated and results showed that 53.8% degradation of MB was done successfully. Furthermore, the installation of green chemistry in synthesizing nanocomposites by using plant extract matrix optimizes antibacterial characteristics, antioxidant and biodegradability, helping to build sustainable green Mn decorated ZnO nanomaterial. This work, explains how biologically friendly Mn-doped ZnO nanocomposites can help reduce the environmental impact of traditional packaging materials. Based on these findings, it was determined that nanocomposites derived from biological resources should be produced on a wide scale to eradicate environmental and water contaminants through degradation.

Designing a Silymarin Nanopercolating System Using CME@ZIF-8: An Approach to Hepatic Injuries

It is commonly known that silymarin, a phytoconstituent obtained from the Silybum marianum plant, has hepatoprotective and antioxidative properties. However, its low oral bioavailability and poor water solubility negatively impact its therapeutic efficacy. The goal of the present study was to determine the efficiency of the Cordia myxa extract-based synthesized zeolitic imidazole metal-organic framework (CME@ZIF-8 MOF) for increasing silymarin's bioavailability. A coprecipitation technique was used to synthesize the CME@ZIF-8 and polyethylene glycol-coated silymarin-loaded MOFs (PEG-Sily@CME@ZIF-8) and a complete factorial design was used to optimize them. The crystalline size of CME@ZIF-8 was 14.7 nm and the size of PEG-Sily@CME@ZIF-8 was 17.39 nm. The loading percentage of the silymarin drug in CME@ZIF-8 was 33.5%. The optimized formulations were then characterized by ultraviolet-visible (UV-vis) spectroscopy, X-ray diffraction, Fourier transform IR spectroscopy, surface morphology, gas chromatography-mass spectrometry, and drug release in an in vitro medium. Additionally, a rat model was used to investigate the optimized formulation's in vivo hepatoprotective effectiveness. The synthesized silymarin-loaded CME@ZIF-8 MOFs were distinct particles with a porous, spongelike shape and a diameter of (size) nm. Furthermore, the designed silymarin-loaded PEG-Sily@CME@ZIF-8 MOF formulation exhibited considerable silymarin release from the synthesized formula in dissolution investigations. The in vivo evaluation studies demonstrated that the prepared PEG-Sily@CME@ZIF-8 MOFs effectively exhibited a hepatoprotective effect in comparison with free silymarin in a CCl4-based induced-hepatotoxicity rat model via ameliorating the normal antioxidant enzyme levels and restoring the cellular abnormalities produced by CCl4 toxication. In combination, biologically produced CME@ZIF-8 may promise to be a viable biologically based nanocarrier that can enhance the loading and release of silymarin medication, which has low solubility in water.

Morpho-physiological growth performance and anti-oxidative capabilities of Acacia jacquemontii and Acacia nilotica upon exposure to Co3O4 Nbs in lead-contaminated soil

Immense crowd of heavy metal in cultivated land is evolving as a global concern as a result of boosted level of soil toxicity. Amongst various metals, Lead (Pb) contamination has become alarming for plant and human heath through ingesting of polluted soils and food crops. To counterfeit this, a nanotechnological neutralizer effective in form of soiling of cobalt oxide Co3O4 Nbs to Acacia jacquemontii and Acacia nilotica with various meditations as 25, 50, 75 and 100 ppm). A Substantial result was observed on growth of plants but premium results were got by applications of cobalt oxide Nbs at 75 ppm. By this means, enhanced root length (39%), fresh weight (32%), shoot length (58%), as well as dry weight (28%) in selected Acacia species compared to control. Chlrophy contents in A. jacquemontii were estimated to be 0.23, 2.73 and 3.19 mg/L with treated with different concentrations of cobalt Nbs while in A. nilotica, the contents were 0.51, 2.93 and 3.12 mg/L respectively on same concentration. The atomic absorption (AAS), antioxidant activity and defendable positive comeback by using Co3O4 Nbs. Hence, the greenly synthesized Co3O4 Nbs counter acts lead toxicity to override and preserving the growth of plant. Such nanotechnological kits can consequently enhance the alternative system to stunned toxicity for distinguish the yield demand end to end with the progress of agronomic management approaches.

Advancing Nanoscale Science: Synthesis and Bioprinting of Zeolitic Imidazole Framework-8 for Enhanced Anti-Infectious Therapeutic Efficacies

Bacterial infectious disorders are becoming a major health problem for public health. The zeolitic imidazole framework-8 with a novel Cordia myxa extract-based (CME@ZIF-8) nanocomposite showed variable functionality, high porosity, and bacteria-killing activity against Staphylococcus aureus, and Escherichia coli strains have been created by using a straightforward approach. The sizes of synthesized zeolitic imidazole framework-8 (ZIF-8) and CME@ZIF-8 were 11.38 nm and 12.44 nm, respectively. Prepared metal organic frameworks have been characterized by gas chromatography-mass spectroscopy, Fourier transform spectroscopy, UV-visible spectroscopy, X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. An antibacterial potential comparison between CME@ZIF-8 and zeolitic imidazole framework-8 has shown that CME@ZIF-8 was 31.3%, 28.57%, 46%, and 47% more efficient than ZIF-8 against Staphylococcus aureus and 43.7%, 42.8%, 35.7%, and 70% more efficient against Escherichia coli, while it was 31.25%, 33.3%, 46%, and 46% more efficient than the commercially available ciprofloxacin drug against Staphylococcus aureus and 43.7%, 42.8%, 35.7%, and 70% more efficient against Escherichia coli, respectively, for 750, 500, 250, and 125 μg mL-1. Minimum inhibitory concentration values of CME@ZIF-8 for Escherichia coli and Staphylococcus aureus were 15.6 and 31.25 μg/mL respectively, while the value of zeolitic imidazole framework-8 alone was 62.5 μg/mL for both Escherichia coli and Staphylococcus aureus. The reactive oxygen species generated by CME@ZIF-8 destroys the bacterial cell and its organelles. Consequently, the CME@ZIF-8 nanocomposites have endless potential applications for treating infectious diseases.

Rare serosal cystic gastric gastrointestinal stromal tumor with extensive intestinal metaplasia in an adherent gastric mucosa; a case report in a 65-year-old male

Gastrointestinal (GI) intestinal stromal tumors account for 60% of mesenchymal GI tract tumors commonly located in the stomach and small intestine, predominantly solid tumors that rarely undergo cystic degeneration. A 65-year-old patient with increasing upper abdominal swelling and a computed tomography scan abdomen showed a large unilocular 17 × 16 × 15 cm lesion. A colossal cystic swelling in the lesser omentum, anterior to the stomach, was found upon exploration. Histopathological examination showed a spindle cell tumor turned out to be CD117 positive and S100 negative on immunostains. The tumor was moderate risk gastric gastrointestinal intestinal stromal tumor (GIST) based on the site; Stomach, Size >10 cm; Mitosis <5/5 mm² according to risk assessment of GIST, 2006. GISTs are predominantly solid tumors and rarely undergo cystic transformation. The primary differential diagnoses of spindle cell neoplasm are GISTs, Leiomyoma, Leiomyosarcoma and Schwannoma. These spindle cell neoplasms are differentiated by applying a panel of Immunohistochemical stains, CD117, SMA and S100.

Bioinspired Cobalt Oxide Nanoball Synthesis, Characterization, and Their Potential as Metal Stress Absorbants

Massive accumulation of heavy metals in agricultural land as a result of enhanced levels of toxicity in the soil is an emerging global concern. Among various metals, zinc contamination has severe effects on plant and human health through the food chain. To remove such toxicity, a nanotechnological neutralizer, cobalt oxide nanoballs (Co₃O₄ Nbs) were synthesized by using the extract of Cordia myxa. The Co₃O₄ Nbs were well characterized via UV-vis spectrophotometry, scanning electron microscopy, and X-ray diffraction techniques. Green-synthesized Co₃O₄ Nbs were exposed over Acacia jacquemontii and Acacia nilotica at different concentrations (25, 50, 75, and 100 ppm). Highly significant results were observed for plant growth by the application of Co₃O₄ Nbs at 100 ppm, thereby increasing the root length (35%), shoot length (48%), fresh weight (44%), and dry weight (40%) of the Acacia species with respect to the control. Furthermore, physiological parameters including chlorophyll contents, relative water contents, and osmolyte contents like proline and sugar showed a prominent increase. The antioxidant activity and atomic absorption supported and justified the positive response to using Co₃O₄ Nbs that mitigated the heavy-metal zinc stress by improving the plant growth. Hence, the biocompatible Co₃O₄ Nbs counteract the zinc toxicity for governing and maintaining plant growth. Such nanotechnological tools can therefore step up the cropping system and overcome toxicity to meet the productivity demand along with the development of agricultural management strategies.

Casting Zinc Oxide Nanoparticles Using Fagonia Blend Microbial Arrest

Physical and chemical methods for production of nanoparticles (NPs) are not only harmful for environment but also toxic for living organism. The present study attempts to synthesize ZnO NPs using the natural plant extract of Fagonia cretica. The phytochemical screening of F. cretica water extract was performed to check the presence of biologically active compounds like alkaloids, tannins, carbohydrates, proteins, phenols, saponins, flavonoids, and steroids. Well-prepared ZnO NPs given sharp absorption peak at 362 were confirmed by UV-visible. XRD analysis showed the ZnO NPs having wurtzite hexagonal structure with crystalline form. TEM analysis endorses flower-shaped ZnO nanoparticles ~ 100-1000 nm. FTIR spectrum suggested the involvement of phenolic groups and amino acids and amide linkages in protein performs as the stabilizing agent in the synthesis of ZnO NPs. The ZnO NPs showed strong antibacterial behavior against two bacterial strains Gram-positive bacteria Staphylococcus aureus and Gram-negative bacteria Escherichia coli. In addition, ZnO NPs exhibited strong antioxidant activity of 79%:85.6%:89.9% at 5 μg/mL:10 μg/mL:5 μg/mL concentration of ZnO NPs respectively. This work indicates that Fagonia is considered to be appropriate and promising candidate for extending the innovative applications in the field of medicine and industry and also helpful and useful to the scientific communities.

Incubating Green Synthesized Iron Oxide Nanorods for Proteomics-Derived Motif Exploration: A Fusion to Deep Learning Oncogenesis

The nanotechnological arena has revolutionized the diagnostic efficacies by investigating the protein corona. This displays provoking proficiencies in determining biomarkers and diagnostic fingerprints for early detection and advanced therapeutics. The green synthesized iron oxide nanoparticles were prepared via Withania coagulans and were well characterized using UV-visible spectroscopy, X-ray diffraction analysis, Fourier transform infrared spectroscopy, and nano-LC mass spectrophotometry. Iron oxides were rod-shaped with an average size of 17.32 nm and have crystalline properties. The as-synthesized nanotool mediated firm nano biointeraction with the proteins in treatment with nine different cancers. The resultant of the proteome series was filtered oddly that highlighted the variant proteins within the differentially expressed proteins on behalf of nano-bioinformatics. Further magnification focused on S13_N, RS15, RAB, and 14_3_3 domains and few abundant motifs that aid scanning biomarkers. The entire set of variant proteins contracting to common proteins elucidates the underlining mechanical proteins that are marginally assessed using the robotic nanotechnology. Additionally, the iron rods indirectly possess a prognostic effect in manipulating expression of proteins through a smarter route. Thereby, such biologically designed nanotools provide a dual approach for medical studies.

Crest to Trough Cellular Drifting of Green-Synthesized Zinc Oxide and Silver Nanoparticles

Green nanotechnology facilitates the blooming of zinc oxide (ZnO) and silver (Ag) nanoparticles (NPs) with distinct flowerlike and spherical morphologies, respectively. The well-characterized NPs with an average size of 35 nm (ZnO) and 25 nm (Ag) were functionalized on the cresty plates for antibacterial inhibition against Staphylococcus aureus and Pseudomonas aeruginosa, with the flowerlike ZnONPs exhibiting 90.9% inhibition and AgNPs exhibiting 100% inhibition. Further, the in vivo underwater troughs for hematological, immunological, and serological analysis in Labeo rohita exhibited 102 > 575 > 104 and 206 > 109 > 81% at concentrations of 1, 2, and 3 mg/L with 4-day and 15-day treatment, respectively, over ZnONPs. However, AgNPs exhibited 257 > 408 > 124 and 86 > 202 > 43% with 4-day and 15-day treatment, respectively, at the same concentrations. The classical ZnNPs and AgNPs exhibited excellent inhibition potential and significant transfiguration of hematological, enzymological, and protein parameters as safe nanomedicine, but ZnONPs were found to be 58, 69, 29 and 34, 51, 70% more active than AgNPs with 4-day and 15-day treatment, respectively. Therefore, the onset of ROX and antioxidant arena favors beneficial cellular drifting of NPs.

Trident Nano-Indexing the Proteomics Table: Next-Version Clustering of Iron Carbide NPs and Protein Corona

Protein corona composition and precise physiological understanding of differentially expressed proteins are key for identifying disease biomarkers. In this report, we presented a distinctive quantitative proteomics table of molecular cell signaling differentially expressed proteins of corona that formed on iron carbide nanoparticles (NPs). High-performance liquid chromatography/electrospray ionization coupled with ion trap mass analyzer (HPLC/ESI-Orbitrap) and MASCOT helped quantify 142 differentially expressed proteins. Among these proteins, 104 proteins showed upregulated behavior and 38 proteins were downregulated with respect to the control, whereas 48, 32 and 24 proteins were upregulated and 8, 9 and 21 were downregulated CW (control with unmodified NPs), CY (control with modified NPs) and WY (modified and unmodified NPs), respectively. These proteins were further categorized on behalf of their regularity, locality, molecular functionality and molecular masses using gene ontology (GO). A STRING analysis was used to target the specific range of proteins involved in metabolic pathways and molecular processing in different kinds of binding functionalities, such as RNA, DNA, ATP, ADP, GTP, GDP and calcium ion bindings. Thus, this study will help develop efficient protocols for the identification of latent biomarkers in early disease detection using protein fingerprints.

Enhancing Cancer Immunotherapeutic Efficacy with Sonotheranostic Strategies

Immunotherapy has revolutionized the modality for establishing a firm immune response and immunological memory. However, intrinsic limitations of conventional low responsive poor T cell infiltration and immune related adverse effects urge the coupling of cancer nanomedicines with immunotherapy for boosting antitumor response under ultrasound (US) sensitization to mimic dose-limiting toxicities for safe and effective therapy against advanced cancer. US is composed of high-frequency sound waves that mediate targeted spatiotemporal control over release and internalization of the drug. The unconventional US triggered immunogenic nanoengineered arena assists the limited immunogenic dose, limiting toxicities and efficacies. In this Review, we discuss current prospects of enhanced immunotherapy using nanomedicine under US. We highlight how nanotechnology designs and incorporates nanomedicines for the reprogramming of systematic immunity in the tumor microenvironment. We also emphasize the mechanical and biological potential of US, encompassing sonosensitizer activation for enhanced immunotherapeutic efficacies. Finally, the smartly converging combinational platform of US stimulated cancer nanomedicines for amending immunotherapy is summarized. This Review will widen scientists' ability to explore and understand the limiting factors for combating cancer in a precisely customized way.

Fractionation of Biomolecules in Withania coagulans Extract for Bioreductive Nanoparticle Synthesis, Antifungal and Biofilm Activity

Withania coagulans contains a complex mixture of various bioactive compounds. In order to reduce the complexity of the plant extract to purify its phytochemical biomolecules, a novel fractionation strategy using different solvent combination ratios was applied to isolate twelve bioactive fractions. These fractions were tested for activity in the biogenic synthesis of cobalt oxide nanoparticles, biofilm and antifungal activities. The results revealed that plant extract with bioactive fractions in 30% ratio for all solvent combinations showed more potent bioreducing power, according to the observed color changes and the appearance of representative absorption peaks at 500-510 nm in the UV-visible spectra which confirm the synthesis of cobalt oxide nanoparticles (Co3O4 NPs). XRD diffraction was used to define the crystal structure, size and phase composition of the products. The fractions obtained using 90% methanol/hexane and 30% methanol/hexane showed more effectiveness against biofilm formation by Pseudomonas aeruginosa and Staphylococcus aureus so these fractions could potentially be used to treat bacterial infections. The 90% hexane/H2O fraction showed excellent antifungal activity against Aspergillus niger and Candida albicans, while the 70% methanol/hexane fraction showed good antifungal activity for C. albicans, so these fractions are potentially useful for the treatment of various fungal infections. On the whole it was concluded that fractionation based on effective combinations of methanol/hexane was useful to investigate and study bioactive compounds, and the active compounds from these fractions may be further purified and tested in various clinical trials.

Sodium-lithium countertransport activity as a determinant of deterioration of glomerular function in IgA nephropathy

We measured Na+/Li+ CT in 16 IgA nephropathy patients. Records were reviewed (mean observation period 5.5 years) for serial measurements of blood pressure (BP), urinary protein excretion, GFR (51Cr-EDTA) and plasma creatinine. Na+/Li+ CT correlated with the slope of the plot of GFR versus time (rs = -0.66, p = 0.005) systolic BP at diagnosis (rs = 0.62, p = 0.011) and both systolic and diastolic BP at the end of follow-up (rs = 0.69, p = 0.003, and rs = 0.56, p = 0.023). A diastolic blood pressure (DBP) > or = 95 mm Hg was associated with a faster rate of GFR decline (rate of change of GFR: -0.40 vs. -0.14 ml/min/month, p = 0.07; for DBP > or = 95 vs. < 95 mm Hg, respectively). In a multiple regression analysis with the rate of decline of GFR as dependent variable, Na+/Li+ CT emerged as a significant and independent determinant of the rate of fall of GFR (beta coefficient -1.56, SE beta 0.49, p = 0.006) and explained 52.7% of the variation in the GFR fall. Higher activities of Na+/Li+ CT are significantly associated with an increased rate of deterioration of renal function in IgA nephropathy; part of this effect could be mediated by higher blood pressure values.

Na+/H+ antiport activity and cell growth in cultured skin fibroblasts of IDDM patients with nephropathy

IDDM patients with incipient and overt nephropathy have been found to exhibit an overactivity of RBC sodium-lithium countertransport. To explore the physiological relevance of this finding, we measured the activity of Na+/H+ antiport in serially passaged cultured skin fibroblasts from IDDM patients with and without nephropathy and from normal, nondiabetic control subjects. Na+/H+ antiport activity (measured as the rate of amiloride-sensitive Na+ influx at pHi = 6.4, extracellular pH = 8.0, and [Na+] = 1 mM) was elevated significantly in IDDM patients with nephropathy compared with IDDM patients without nephropathy and nondiabetic control subjects (13.35 +/- 3.8 vs. 8.54 +/- 2.0 vs. 7.33 +/- 2.3 nmol Na+.mg protein-1.min-1; P less than 0.006 and P less than 0.001, respectively). A kinetic analysis of Na+/H+ antiport activity showed that the raised activity in IDDM patients with nephropathy was caused by an increased Vmax for extracellular Na+. Km values were similar in the three groups. pH-stimulated amiloride-sensitive Na+ influx also was higher under baseline conditions and after serum stimulation in cells from IDDM patients with nephropathy. pHi values were significantly higher, both during active proliferation and after 10-min exposure to serum, in cells from IDDM patients with nephropathy, compared with IDDM patients without nephropathy and nondiabetic control subjects. Serum-stimulated incorporation of [3H]thymidine into DNA was greater in IDDM patients with nephropathy than in the other two groups (35.7 +/- 18.9- vs. 17.4 +/- 7.5- vs. 11.9 +/- 8.7-fold stimulation above baseline; P less than 0.01 for both.(ABSTRACT TRUNCATED AT 250 WORDS)

Prevalence of raised sodium-lithium countertransport activity in type 1 diabetic patients

The prevalence of raised Na+/Li+ countertransport (CT) activity (greater than 0.41 mmol/liter RBC/hr) was assessed in 185 consecutive insulin-dependent diabetic patients attending an outpatient diabetic clinic. Normoalbuminuria was defined as an overnight albumin excretion rate (AER) of less than 20 micrograms/min (N = 121), microalbuminuria as AER between 20 and 150 micrograms/min (N = 35) and macroalbuminuria as AER greater than or equal to 150 micrograms/min (N = 29). The prevalence of elevated Na+/Li+CT (greater than 0.41 mmol/liter RBC/hr) was 21.5, 42.8 and 51.7% (P = 0.0005), in patients with normo-, micro- and macroalbuminuria, respectively. In the whole group, Na+/Li+CT was significantly related to mean blood pressure (MBP; rs = 0.37, P less than 0.001) and AER (rs = 0.38, P less than 0.001). In a multiple regression analysis the significant correlates of AER, as a continuous variable, or of proteinuria (micro + macroalbuminuria), as a categorical variable, were Na+/Li+CT, MBP, duration of diabetes and glycosylated hemoglobin (HbA1). The frequency of normoalbuminuric patients with high Na+/Li+CT activity fell with duration of diabetes. The risk of proteinuria was significantly greater in patients with raised Na+/Li+CT compared to those with Na+/Li+CT within the normal range (odds ratio 3.8, 95% CI, 1.9 and 7.8). A relative excess of patients with proteinuria (micro + macroalbuminuria) was found in the group with elevated Na+/Li+CT and HbA1 above the median value (8.05%) of the whole population (chi 2 = 9.7, P less than 0.002).(ABSTRACT TRUNCATED AT 250 WORDS)

Sodium-lithium countertransport activity in red cells of patients with insulin dependent diabetes and nephropathy and their parents

OBJECTIVE

To determine whether there are familial and genetic aspects of sodium-lithium countertransport activity in red cells in diabetic nephropathy.

DESIGN

Case-control study.

SETTING

Teaching hospital diabetic clinic.

SUBJECTS

40 Patients with insulin dependent diabetes, both of whose parents were alive: 20 with persistent proteinuria and 20 with normal albumin excretion matched for age, duration of diabetes, and body mass index. All 80 parents.

MAIN OUTCOME MEASURES

Sodium-lithium countertransport activity in red cells and arterial blood pressure.

RESULTS

Sodium-lithium countertransport activity in red cells was higher in the patients with proteinuria than in the patients with normoalbuminuria (mean (95% confidence interval) 0.47 (0.39 to 0.54) v 0.33 (0.28 to 0.38) mmol/l red cells/h respectively, p = 0.0036; mean difference 0.14 (0.04 to 0.22)). The mean countertransport activity for the two parents of each patient was calculated, and from this the mean value for each group of parents was calculated; the value was higher in the parents of the patients with proteinuria than in the parents of the patients with normoalbuminuria (0.40 (0.32 to 0.48) v 0.30 (0.26 to 0.33) mmol/l red cells/h respectively, p = 0.016; 0.10 (0.02 to 0.19)). Twenty-eight of the parents of the patients with proteinuria compared with 12 of the parents of the patients with normoalbuminuria had a countertransport activity that was above the median value in all 80 parents (p less than 0.001). Mean arterial blood pressure in the parents of the patients with proteinuria was related to that of their offspring (r = 0.46; p less than 0.01). There was a positive correlation between the sodium-lithium countertransport activity in red cells in the parents and their offspring when all parents and patients were considered (r = 0.37; p less than 0.001).

CONCLUSIONS

Increased sodium-lithium countertransport activity in red cells in the parents of diabetic patients with nephropathy provides further evidence that familial, and possibly genetic, factors related to a predisposition to arterial hypertension have a role in the susceptibility of diabetic renal disease.

Sodium-lithium countertransport in microalbuminuric insulin-dependent diabetic patients

A familial predisposition to arterial hypertension has recently been suggested as one important component of the susceptibility to diabetic kidney disease. Sodium-lithium countertransport activity, a marker of risk for essential hypertension, has been found to be increased in diabetic patients with overt nephropathy. We have measured red blood cell sodium-lithium counter-transport activity in 36 microalbuminuric insulin-dependent diabetic patients, a group at high risk of progression to clinical nephropathy and cardiovascular disease, and compared it with that of a matched group of 36 normoalbuminuric diabetic patients. Sodium-lithium countertransport was higher in the microalbuminuric (0.43 [95% confidence interval (CI) 0.38-0.47] mmol/l red blood cells [RBC]/hr) than in the normoalbuminuric diabetic patients (0.29 [0.25-0.33] mmol/l RBC/hr, mean difference 0.14 [0.08-0.20]; p less than 0.0001). Microalbuminuric patients had a higher frequency of parental hypertension than normoalbuminuric diabetic patients (56% vs. 28%, p less than 0.05). Sodium-lithium countertransport was related to mean arterial pressure in the microalbuminuric patients (r = 0.54, p less than 0.001) and to daily insulin requirements in both groups (microalbuminuric patients r = 0.39, p less than 0.05; normoalbuminuric patients r = 0.42, p less than 0.01). In a subset of patients in whom lipoproteins were measured, sodium-lithium countertransport activity was related to total and very low density lipoprotein triglycerides (r = 0.41, p less than 0.05 and r = 0.48, p less than 0.05) and to apolipoprotein B (r = 0.56, p less than 0.05), independently of body mass index, albumin excretion rate, glycemic control, and insulin dose.(ABSTRACT TRUNCATED AT 250 WORDS)