Karina S Litvinova

Imperial College London | Imperial · Department of Bioengineering

Conventional wet Ag/AgCl electrodes are widely used in electrocardiography, electromyography (EMG), and electroencephalography (EEG) and are considered the gold standard for biopotential measurements. However, these electrodes require substantial skin preparation, are single use, and cannot be used for continuous monitoring (>24 h). For these reaso...

The diagnosis and treatment of non-melanoma skin cancer remain urgent problems. Histological examination of biopsy material—the gold standard of diagnosis—is an invasive procedure that requires a certain amount of time to perform. The ability to detect abnormal cells using fluorescence spectroscopy (FS) has been shown in many studies. This techniqu...

An imbalance in angiogenic growth factors and poor utero-placental perfusion are strongly associated with preeclampsia. The reduced utero-placental perfusion (RUPP) model that mimics insufficient placental perfusion is used to study preeclampsia. The aim of this study was to develop a refined RUPP model in C57Bl/6 J mice to test the efficacy of MZe...

Background: The intra-operative real-time assessment of tissue viability can potentially improve therapy delivery and clinical outcome in cardiovascular therapies. Cardiac ablation therapy for the treatment of supraventricular or ventricular arrhythmia continues to be done without being able to assess if the intended lesion and lesion size have bee...

Wound healing and other surgical technologies traditionally solved by suturing and stapling have recently been enhanced by the application of laser tissue welding. The usage of high energy laser radiation to anastomose tissues eliminates a foreign body reaction, reduces scar formation, and allows for the creation of watertight closure. In the curre...

For over half a century, laser technology has undergone a technological revolution. These technologies, particularly semiconductor lasers, are employed in a myriad of fields. Optical medical diagnostics, one of the emerging areas of laser application, are on the forefront of application around the world. Optical methods of non- or minimally invasiv...

According to the International Diabetes Federation, the challenge of early stage diagnosis and treatment effectiveness monitoring in diabetes is currently one of the highest priorities in modern healthcare. The potential of combined measurements of skin fluorescence and blood perfusion by the laser Doppler flowmetry method in diagnostics of low lim...

The evaluation of the microcirculatory bed functional state and the identification of angiospastic disorders with related complications, when the pathological changes are reversible, have an important role in medical practice. The aim of this study was to evaluate the possibility of using optical noninvasive methods and the cold pressor test to sol...

The aim of this work was to study the possibilities of the laser Doppler flowmetry method for the joint study of microhaemo-and lymph circulation of human skin. Conducting a series of experimental studies allowed to trace the relationship of recorded signals of microcirculation of blood flow and lymph flow, as well as to study their oscillation nat...

Bladder cancer is among the most common cancers in the UK and conventional detection techniques suffer from low sensitivity, low specificity, or both. Recent attempts to address the disparity have led to progress in the field of autofluorescence as a means to diagnose the disease with high efficiency, however there is still a lot not known about au...

In recent years, there has been a growing interest in the development of compact and low-cost, versatile, broadly tunable CW and ultra-short pulse laser sources generating light across the near-infrared and visible spectral ranges. The progress in this area has brought to science and industry an enormous number of new applications. Such laser syste...

This study examines the effect of blood absorption on the endogenous fluorescence signal intensity of biological tissues. Experimental studies were conducted to identify these effects. To register the fluorescence intensity, the fluorescence spectroscopy method was employed. The intensity of the blood flow was measured by laser Doppler flowmetry. W...

Muscle invasive urinary bladder cancer is one of the most lethal cancers and its detection at the time of transurethral resection remains limited and diagnostic methods are urgently needed. We have developed a muscle invasive transitional cell carcinoma (TCC) model of the bladder using porcine bladder scaffold and the human bladder cancer cell line...

Skin blood microcirculation and the metabolism activity of tissue were examined on the patients with type 2 diabetes. Laser Doppler flowmetry (LDF) with 1064 nm laser light source and fluorescence spectroscopy (FS) with excitation light of 365 nm and 450 nm have been used to monitor the blood perfusion and the content of coenzymes NADH and FAD. Con...

Endothelial dysfunction is directly linked to preeclampsia, a maternal hypertensive condition that is life threating for both the mother and the baby. Epidemiological studies show that women with a history of pre-eclampsia have an elevated risk for cardiovascular disease. Here we report a new non-invasive diagnostic test for preeclampsia in mice th...

Urinary bladder diseases are a common problem throughout the world and often difficult to accurately diagnose. Furthermore, they pose a heavy financial burden on health services. Urinary bladder tissue from male pigs was spectrophotometrically measured and the resulting data used to calculate the absorption, transmission, and reflectance parameters...

An important field of application of lasers is biomedical optics. Here, they offer great utility for diagnosis, therapy and surgery. For the development of novel methods of laser-based biomedical diagnostics careful study of light propagation in biological tissues is necessary to enhance our understanding of the optical measurements undertaken, inc...

Fluorescence spectroscopy has recently become more common in clinical medicine. However, there are still many unresolved issues related to the methodology and implementation of instruments with this technology. In this study, we aimed to assess individual variability of fluorescence parameters of endogenous markers (NADH, FAD, etc.) measured by flu...

The optical redox ratio as a measure of cellular metabolism is determined by an altered ratio between endogenous fluorophores NADH and flavin adenine dinucleotide (FAD). Although reported for other cancer sites, differences in optical redox ratio between cancerous and normal urothelial cells have not previously been reported. Here, we report a meth...

Bladder cancer is among the most common cancers worldwide (4th in men). It is responsible for high patient morbidity and displays rapid recurrence and progression. Lack of sensitivity of gold standard techniques (white light cystoscopy, voided urine cytology) means many early treatable cases are missed. The result is a large number of advanced case...

Diseases of urinary bladder are a common healthcare problem world over. Diagnostic precision and predicting response to treatment are major issues. This study aims to create an optical cross-sectionional model of a bladder, capable of visually representing the passage of photons through the tissue layers. The absorption, transmission and reflectanc...

Fluorescent spectroscopy (FS) is becoming more widely used in chemistry, biology, in various fields of medical technology and medicine in general. Many purulent wounds, burns and other destructive inflammatory processes are accompanied by changes in the fluorescent activity of the tissues, which occurs due to a misbalance in accumulation of natural...

Collagen is an endogenous fluorophore that accounts for about 70% of all proteins of human skin, so it can be an optical marker for structural abnormalities in tissues registered by laser fluorescent diagnostics in vivo. Using the examples of such abnormalities as scars, scleroderma and basal cell carcinoma, this study shows the differences between...

New data were obtained by means of optical thermography and LDF method confirming the stimulating effect of LLLR in the matter. Thermal heating during LLLT is the dominant factor in the overall effect of LLLT.

This report, as a continuation of 8-years research on the problem of noninvasive clinical fluorescence diagnostics efficiency, discusses a hypothesis of influence of a chronic hypoxia state in soft alive tissues on the intensity of a laser-induced endogenous porphyrins' autofluorescence in a red region of optical spectra. Earlier this hypothesis wa...

The urgency of BCC study affecting maxillofacial area and neck is not only caused by high prevalence of this disease, but also insufficient efficiency of existing treatment methods which lead to full or partial recovery only in 60-80% of cases. We analyzed the results of 198 BCC cases cryosurgical treatment. 33 (16,6%) patients showed continued tum...

The phosphodiesterases inhibitor pentoxifylline gained attention for Duchenne muscular dystrophy therapy for its claimed anti-inflammatory, antioxidant, and antifibrotic action. A recent finding also showed that pentoxifylline counteracts the abnormal overactivity of a voltage-independent calcium channel in myofibers of dystrophic mdx mice. The pos...

The aim of this study was to elucidate the effects of 14- day hindlimb suspension (HS) and subsqquent reloading (3 or 7 days) on the m. soleus mass, muscle fiber cross-sectional area (CSA), soleus fiber properties and serum IGF-1 in rats. Rats were hindlimb suspended for 14 days or kept as controls (C, n = 7). Soleus muscles were isolated after HS...

The direct data concerning effects of unloading on dystrophic muscle were received in study of mdx mice, a model for Duchenne muscular dystrophy, muscles before and after hindlimb suspension. Experiments were performed on softer skinned soleus muscle fibers isolated from wild-type (C57black) as a control and mdx mice aged 2 weeks. Animals of two ex...

The effects of creatine oral supplementation combined with a 10-week resistive training of morphometric, contractile and molecular characteristics of human vast lateral muscle fibers were studied. 2 groups consisting of 9 young healthy men each were involved in resistive training of knee extensors for 10 weeks. Volunteers of the first group receive...

The effects of support withdrawal and support stimulation on the contractile characteristics of human soleus fibers and cellular factors which influence them were studied. The experimental model of the "dry" head-out water immersion was used in the study. In this model, the hydrostatic pressure on different sites of the body surface are equal so th...

Artificial support stimulation is known to attenuate or prevent many motor or skeletal muscle effects of actual or simulated microgravity. The present study was purposed to analyze the effects of artificial support on human soleus fibers after 7-day exposure to supportless environment. 8 healthy male volunteers were exposed to dry immersion in supi...

The present paper covers two series of the experiment studies performed in attempt to analyze the support-triggered cellular mechanisms, controlling the maintenance of tonic muscle fiber characteristics. Exposure to 7 day dry immersion induced significant decline of the human soleus single fiber peak isometric tension and the Ca(2+)-sensitivity of...

The contractile characteristics and muscle proteins of human soleus fibers were studied in subjects deprived of mechanical stimulation from support surfaces in a model called "dry immersion." In this model, a subject is immersed in water while lying on (and being almost enveloped in) a waterproof fabric; hydrostatic pressure is exerted equally on m...

Excessive intracellular calcium accumulation is believed to trigger the development of functional and structural changes in muscle fibers under microgravity conditions. The hypothesis was testified in the 14-day hindlimb suspension study with the application of a Ca2+-binding agent (10% EGTA). Twenty one rats were divided into 3 groups: cage contro...

Excessive intracellular calcium accumulation is believed to trigger the development of functional and structural changes in muscle fibers under microgravity conditions. The hypothesis was testified in the 14-day hindlimb suspension study with the application of a Ca(2+)-binding agent (10% EGTA). Twenty one rats were divided into 3 groups: cage cont...

To test the hypothesis that functional and structural changes of muscle fibers in microgravity are mediated by elevation in intracellular Ca 2+, a 14-day simulated microgravity study was made using a tail suspension rat model. The level of Ca2+ in muscle fibers was modulated by intraperitoneal injections of the Ca2+chelator EGTA given every other d...

It had been hypothesized and recently shown that the exposure to gravitational unloading brought out to sufficient accumulation of Ca2+ in the myoplasm of soleus muscle fibers. Some authors believe that this dramatic Ca2+ accumulation induces the muscle protein degradation (including cytoskeletal proteins) by means of Ca 2(+)-activated proteases. F...