Ontogenetic Characteristics of the Organization of Corticocortical Connections between the Primary Visual Cortex and the Lateral Suprasylvian Area of the Cat Brain

Studies on 10 cats aged five and 12 weeks included qualitative and quantitative analyses of the distribution in field 17 of initial neurons organizing corticocortical connections with the posteromedial lateral suprasylvian gyrus (PMLS) of the brain using retrograde labeling with horseradish peroxidase. The PMLS area is a higher center for processing information relating to the movement of visual stimuli. Ontogenetic characteristics of the formation of the ordered (clustered) organization of initial neurons in field 17 were identified. An age-related decrease in the density of initial neurons in field 17 was found, from 125.2 ± 69.8 cells/mm² in kittens aged five weeks to 34.7 ± 17.4 cells/mm² in 12-week-old kittens (p = 0.05). During the period between postnatal weeks 5 and 12, there was an increase in the size of the labeled area containing the majority of initial neurons. The morphofunctional aspects of the formation of the ordered structure of corticocortical connections between field 17 and the PMLS during postnatal ontogenesis and its possible relationship with the development of the function of the visual perception of moving objects are discussed.     

Structure of receptive fields of cat pulvinar neurons sensitive to photic stimulation

Receptive fields of 262 pulvinar neurons were studied. Receptive fields of 142 of these neurons were studied in detail with the aid of a stationary spot of light, flashing in different parts of the receptive field. Depending on responses to presentation of the stationary stimulus the neurons were divided into six groups. The first group included neurons with on-off responses to photic stimulation (44 of 142), the second group neurons with off responses only (42 of 142). In cells of the third group (19 of 142) an on response only was recorded in all structures of the receptive field tested. Neurons of the fourth group (eight of 142) had a receptive field of similar structure to that of the simple receptive fields of neurons in cortical area 17. The fifth group (10 of 142) included neurons with a receptive field of concentric structure, the sixth (19 of 142) consisted of neurons with receptive fields with multiple discharge centers. The structure of the receptive field of these neurons was mosaic, with an irregular distribution of exciting and silent zones. The mean response latency of the pulvinar neurons was 40–70 msec. Responses of neurons with shorter (20 msec) and longer (130–160 msec) latent periods also were recorded.Translated from Neirofiziologiya, Vol. 11, No. 1, pp. 3–10, January–February, 1979.     

Responses to Light of Sensorimotor and Visual Cortex Neurons in Rabbits with a Cryptic Focus of Excitation (a defensive dominant) in the CNS

In the sensorimotor cortex of rabbits with a formed cryptic (subthreshold) focus of excitation in the CNS, the spike frequencies of neurons responding to light stimulation were significantly lower (p = 0.01) than the spike frequencies of neurons not responding to light. Similar findings were obtained in the visual cortex of intact rabbits. In this case too, the spike frequencies of neurons responding to stimulation were significantly lower (p = 0.01) than the spike frequencies of neurons not responding to light stimulation. In both intact rabbits and rabbits with a cryptic focus of excitation formed in the CNS, 36 % of neurons in the sensorimotor cortex responded to light stimuli not specific to this area. In the sensorimotor cortex of rabbits with a cryptic focus of excitation formed in the CNS, as compared with intact rabbits, there were significantly more (p = 0.01) cells responding to light stimuli with latent periods of less than 100 msec and significantly fewer (p = 0.02) responding to light stimuli with latencies of 200–300 msec. In the visual cortex of rabbits with a formed cryptic focus of excitation in the CNS, as compared with intact rabbits, significantly fewer (p = 0.01) neurons responded to light stimuli with latent periods of 50–100 msec.     

Dynamics of the Formation of Rhythmic Activity of the Heart in Fetuses and Newborn Rats

The development of heart activity and its relationship with respiratory and motor activities were studied in rat fetuses with preserved placental circulation on gestation days 15-20 (E15-20) and in newborn rats (P0). During the studied period, the heart rate in fetuses increased from 175.93 ± 6.10 bpm (E15) to 271.82 ± 5.93 bpm (E20). After birth, the heart rate decreased to 220.94 ± 8.73 bpm. Heart rate variability in the decasecond and near-minute ranges was detected. At E16 stage it is presented by slow regular oscillations lasting for 20-35 sec with an amplitude of 10-45 msec. Comparison of functional activities of the cardiac and somatic motor systems showed that at E16, fl uctuations in heart rate are independent of the bouts of motor excitation. During growing, the degree of synchronization of heart rate variability with physical activity increased. E17-18 stage is characterized by short-term episodes of heart rate deceleration associated with motor activity; their duration and amplitude did not depend much on the force of movement. At E19-20, decelerations typical of early gestation terms were replaced by acceleration-type reactions typical for mature organism, which is related to maturation of coordination function of the nervous system. In the heart rhythm, respiratory arrhythmia appears during episodes of rhythmic breathing. Newborn rats demonstrated acceleration episodes; their parameters depend on the force of motor bouts; respiratory arrhythmia was not observed.     

Haematological and serum biochemical profile of the upside-down catfish, Synodontis membranacea Geoffroy Saint Hilaire from Jebba Lake, Nigeria

Haematological and serum biochemical studies of natural population of Synodontis membranacea from Jebba Lake, North Central Nigeria were investigated in order to establish their mean and reference values. Bi-monthly collection of 1,408 live fish samples was carried out between April 2002 and March 2004, using gill nets of various mesh sizes ranging from 5.08 to 10.16 cm. The mean baseline value established for species-specific haematological and serum biochemical parameters were red blood cell (RBC) 3.83 ± 1.49 × 10¹² l⁻¹, haemoglobin (HB) 8.38 ± 1.96 g dl⁻¹, and packed cell volume (PCV) 25.65 ± 5.89%; mean cell volume 78.25 ± 37.90 fl; mean cell haemoglobin (MCH) 33.04 ± 12.50 pg; mean cell haemoglobin concentration 26.53 ± 15.18 g dl⁻¹; white blood cell (WBC) 315.65 ± 95.37 × 10⁻⁹; agranulocytes (Agr) 82.07 ± 11.38%; monocytes (Mon) 6.37 ± 3.01%; lymphocytes (Lym) 76.49 ± 10.81%; granulocytes (Gran) 40.28 ± 17.48%; neutrophils (Neut) 24.42 ± 10.68%; eosinophils (Eos) 16.14 ± 8.25%; basophils 0.09 ± 0.04%; protein 40.19 ± 7.45 g l⁻¹; albumin 19.78 ± 5.67 g l⁻¹; creatinine 49.71 ± 16.15 μmol l⁻¹; urea 3.05 ± 0.67 nmol l⁻¹; uric acid 0.76 ± 0.33 nmol l⁻¹; glucose 4.24 ± 1.74 mmol l⁻¹; cholesterol 8.46 ± 2.27 mmol l⁻¹; calcium 2.35 ± 0.94 mmol l⁻¹; potassium 13.36 ± 4.45 mmol l⁻¹; sodium 139.39 ± 23.19 mmol l⁻¹; alanine aminotransferase (ALT) 11.79 ± 2.67 U l⁻¹; aspartate aminotransferase 16.80 ± 4.73 U l⁻¹; and alkaline phosphatase 63.01 ± 20.44 U l⁻¹. Only three of these parameters (i.e. neutrophil, glucose and potassium) differed significantly (P > 0.05) on gender basis. Pearson’s correlation coefficients indicated significant relationship of standard length and total weight with RBC, PCV, HB, WBC, Agr, Mon, Lym, Gran, Neut, Eos, sodium, and ALT only. The study has provided baseline haematological and biochemical data for use in health monitoring and productivity of S. membranacea, which would be of great value for future comparative surveys in this era of increased fish culture in Nigeria.     

Respiration Restitution in Rats Following Its Termination in Immersion Hypothermia

Rats were cooled in water until attaining profound hypothermia and respiratory arrest. After removal from water, 0.5% solution of Na₂EDTA was administered intravenously. This led to a drop of blood [Ca²⁺] by 20-30% from the baseline and promoted recovery of respiration following its arrest lasting 10.3 ± 1.4 min. By the 30th minute of Na₂EDTA administration, respiration rate increased to 32.3 ± 5.2 cycles per minute and respiration amplitude reached 68 ± 4% of the baseline level. This effect was observed without special warming of the rats. It was concluded that the period during which the organism maintains viability in respiration arrest and disturbances in respiratory center are still reversible is prolonged under conditions of profound hypothermia.     

Haematology and serum biochemistry of golden eagle (Aquila chrysaetos) in Iran

Haematological and serum biochemical values were estimated in blood samples collected from 21 apparently adult golden eagles (Aquila chrysaetos) of both sexes. The mean values of red blood cells, packed cell volume, haemoglobin, white blood cells, heterophils, lymphocytes, monocytes and eosinophils were 1.63 ± 0.11 × 10¹²/l, 0.47 ± 0.009 l/l, 91.73 ± 1.52 g/l, 24.31 ± 1.97 × 10⁹/l, 4.40 ± 0.22 × 10⁹/l, 16.81 ± 0.65 × 10⁹/l, 0.99 ± 0.19 × 10⁹/l and 2.10 ± 0.30 × 10⁹/l, respectively. The leucocytes had 69.14%, 4.09%, 18.12% and 8.65% lymphocytes, monocytes, heterophils and eosinophils, respectively. The results of serum biochemistry in the golden eagle indicated that the concentrations of glucose, total protein, albumin, total globulin, cholesterol, triglyceride, uric acid, blood urea nitrogen, creatinine, calcium, phosphorous, aspartate aminotransferase, alanine aminotransferase, creatine kinase, lactate dehydrogenase and alkaline phosphatase were 16.42 ± 0.73 mmol/l, 49.76 ± 1.35 g/l, 20.46 ± 0.79 g/l, 29.30 ± 1.47 g/l, 2.14 ± 0.09 mmol/l, 2.04 ± 0.08 mmol/l, 457.67 ± 97.46 μmol/l, 2.74 ± 0.17 mmol/l, 53.27 ± 3.87 μmol/l, 2.37 ± 0.24 mmol/l, 1.73 ± 0.08 mmol/l, 293.24 ± 18.96 IU/l, 28.21 ± 2.36 IU/l, 411.29 ± 58.37 IU/l, 1,209.89 ± 21.73 IU/l and 67.31 ± 5.29 IU/l, respectively. There were no significant differences between haematological and serum biochemical parameters of male and female golden eagles (P > 0.05).     

Exenatide enhances kaliuresis under conditions of hyperkalemia

Experiments on Wistar rats showed that exenatide (0.015–0.5 nmol per 100 g body weight) somewhat increased renal excretion of potassium from 7 ± 1 to 16 ± 1 μmol/h/100 g body weight (p < 0.05) in animals with normal serum concentration of glucose (4.6 ± 0.4 mM) and potassium (4.3 ± 0.1 mM). Exenatide dramatically enhanced excretion of potassium under conditions of hyperkalemia (11.4 ± 0.4 mM) produced by intraperitoneal injection of 1.25% KCl solution (5 ml per 100 g body weight). During the fi rst postinjection hour, potassium excretion increased 2-fold and attained 97 ± 11 μmol/h/100 g body weight in comparison with potassium load alone (47 ± 9 μmol/h/100 g body weight, p < 0.05). The data attest to a possible role of peptide regulators in normalization of potassium balance via renal mechanisms.     

Segmentation and Analysis of the Glomerular Basement Membrane in Renal Biopsy Samples Using Active Contours: A Pilot Study

Some renal diseases cause changes in the structure of the glomerular basement membranes (GBM). Measurement of the thickness of the GBM can be performed on transmission electron microscopy (TEM) images of renal biopsy samples. Increased thickness of the GBM is observed in patients with diabetic nephropathy. Abnormally thin GBMs are associated with hematuria. We propose image processing methods for the detection and measurement of the GBM. The methods include edge detection, morphological image processing, active contour modeling, skeletonization, and statistical analysis of the width of the GBM. In the present pilot study, the methods were tested with 34 TEM images of six patients. The estimated mean and standard deviation of the GBM width for a patient with normal GBM were 348 ± 135 nm; those for a patient with thin GBMs due to hematuria were 227 ± 94 nm; and those for a patient with diabetic nephropathy were 1,152 ± 411 nm. Comparison with manual measurements by an experienced renal pathologist indicated low error in the range of 36 ± 11 nm.     

The properties of the binocular receptive fields of lateral geniculate neurons

Summary The majority of cells in the dorsal nucleus of the lateral geniculate body (LGNd) in the cat have two receptive fields: one for each eye. Of the cells tested for binocularity (113), only 21 (18%) were purely monocular. The remainder had receptive fields for the non-dominant eye, the great majority of which (81 or 88%) were purely inhibitory and only 11 (12%) were excitatory. Cells with receptive fields for the non-dominant eye were found in all three laminae (A, A₁ and B) of the LGNd. The proportion of inhibitory receptive fields for the non-dominant eye was slightly greater when the dominant eye was ipsilateral (77%) than when it was contralateral (68%). The distribution of the binocular receptive field pairs about points of exact correspondence in the visual field had a standard deviation of about 0.9° in both horizontal and vertical directions.The properties of the inhibitory receptive fields were studied with moving slits of light and stationary flashing spots. Most of the fields were purely inhibitory and varied in size from 1.5° to 6° across. There were no specific stimulus requirements other than a change in contrast within the receptive field. The inhibitory effect was usually fairly weak, the spontaneous discharge of the neuron being inhibited much more readily than the driven discharge. The latency of the inhibition to a stationary flashing spot was about 50 msec, the inhibition was maximal about 20 msec after the onset and lasted up to about 400 msec.Binocular inhibition is not mediated by a corticogeniculate pathway from the visual areas since it survives removal of areas 17, 18 and 19 and the middle suprasylvian gyrus. It was concluded that the most likely mechanism was via interneurons whose axons cross the borders from one cell layer to another.     

Determination of some normal serum parameters in starry sturgeon (Acipenser stellatus Pallas, 1771) during spring season

Hematology can be a useful tool for monitoring health status, detecting illnesses, and following the progress of diseases and responses to therapy. Despite advances in fish medicine in recent years, interpretation of fish hematology is often hampered by lack of meaningful reference values and the bewildering diversity of fish species. Serum samples of 40 Acipenser stellatus fish were analyzed (20 male and 20 female) and their serum parameter values were measured in both sexes. Serum biochemical values were determined (mean ± SEM) for sodium (Na; 149.2 ± 1.917 mmol/l), potassium (K; 2.75 ± 0.097 mmol/l), calcium (Ca; 8.293 ± 0.282 mg/dl), phosphorus (P; 12.39 ± 0.267 mg/dl), glucose (Glc; 166.40 ± 8.264 mg/dl), triglyceride (trig; 699.6 ± 22.94 mg/dl), bilirubin (bilirubin; 0.616 ± 0.0234 mg/dl), total protein (TOP; 2.988 ± 0.0842 g/dl), albumin (Alb; 1.218 ± 0.0415 g/dl), cholesterol (CHO; 238.2 ± 11.24 mg/dl), creatinine (CREA; 0.1085 ± 0.0048 mg/dl), and blood urea nitrogen (BUN; 15.32 ± 0.5104 mg/dl). The serum values for bilirubin, Na, P, and CREA were significantly higher in females, whereas BUN and Alb were significantly higher in males. The correlations of coefficients between measured parameters were also determined.     

Development and characterization of a scalable microperforated device capable of long-term zero order drug release

A drug delivery system that consists of microperforated polyimide microtubes was developed and characterized. Two groups of polyimide tubes were used. One set consisted of microtubes (I.D. = 125 μm) with 32.9 ± 1.7 μm size holes. The second set consisted of larger tubes (I.D. = 1000 μm) with 362–542 μm holes. The number of holes was varied between 1 and 3. The small tubes were loaded with crystal violet (CV) and ethinyl estradiol (EE) and the drug release studies were performed in 0.01 M phosphate buffered saline (PBS) (pH 7.1–7.4) at 37.0 ± 1.0°C for upto 4 weeks. The large tubes were loaded with CV and the drug release was studied in vitro in PBS and also ex vivo in rabbit’s vitreous humor. Linear release rates with R² > 0.9900 were obtained for all groups with CV and EE. Release rates of 7.8 ± 2.5, 16.2 ± 5.5, and 22.5 ± 6.0 ng/day for CV and 30.1 ± 5.8 ng/day for EE were obtained for small tubes. For large tubes, a release rate of 10.8 ± 4.1, 15.8 ± 4.8 and 22.1 ± 6.7 μg/day was observed in vitro in PBS and a release rate of 5.8 ± 1.8 μg/day was observed ex vivo in vitreous humor.     

Ischemic postconditioning and size of myocardial infarction during inhibition of norepinephrine reuptake

We studied the effect of inhibition of norepinephrine reuptake during the reperfusion period on the size of infarction zone after focal myocardial ischemia and under conditions of ischemic postconditioning. In groups 1 and 2, 30-min occlusion of the left coronary artery followed by 120-min reperfusion was performed. In groups 3 and 4, ischemia was followed by ischemic postconditioning (six 10-sec occlusions alternating with 10-sec reperfusions). Ringer solution (1 ml, groups 1 and 3) and desipramine (0.8 mg/kg, groups 2 and 4) were injected intravenously at the beginning of reperfusion. The area of myocardial infarction in group 1 was 32.0 ± 3.1% of the area of the risk zone; in groups 2, 3, and 4 the corresponding value was 46.1 ± 3.4% (p = 0.006), 22.2 ± 2.6% (p = 0.028), and 50.3 ± 3.1% (p = 0.018), respectively. It was shown that inhibition of norepinephrine reuptake in the early reperfusion period after ischemia increased myocardial injury and abolished the protective effect of ischemic postconditioning.     

Six-stage cascade paramagnetic mode magnetophoretic separation system for human blood samples

This paper is focused on the development of a six-stage cascade paramagnetic mode magnetophoretic separation (PMMS) system for separating suspended cells in blood based on their native magnetic properties. The design and fabrication of a PMMS system are presented and the microfluidic separation system is characterized experimentally using human whole blood as the case study. The PMMS system can separate blood cells types continuously using the magnetophoretic force produced from a high magnetic field gradient without magnetic or fluorescent tagging. Experimental results demonstrated that red blood cell separation in the PMMS system at a volumetric flow rate of 28.8 μL / hr, resulting in a separation time of 10.4 min for a 5.0 μL blood sample with a separation efficiency of 89.5 ± 0.20%. The PMMS system was tested at higher volumetric flow rates of 50.4 μL / hr and 72.0 μL / hr. The measured separation efficiencies were 86.2 ± 1.60% and 59.9 ± 6.06% respectively.     

Myosin light-chain phosphorylation and potentiation of dynamic function in mouse fast muscle

The intent of this study was to determine if the stimulation-induced increase or “potentiation” of dynamic function of mouse extensor digitorum longus muscle (in vitro 25°C) during work cycles is graded to myosin regulatory light-chain (RLC) phosphorylation. To do this, concentric force and muscle work output during sinusoidal length changes were determined before (unpotentiated) and after (potentiated) the application of conditioning stimuli (CS) producing incremental elevations in RLC phosphorylation from rest. Sine wave excursion was from 1.09 to 0.91 of L _o with a period of 142 ms; stimulating muscles to twitch and generate force during these cycles produced plots of force × displacement termed work loops. Stimulation at 2.5-, 5.0-, and 100-Hz elevated RLC phosphorylation from 0.16 ± 0.02 (rest) to 0.29 ± 0.03, 0.45 ± 0.02 and 0.56 ± 0.02 mol phos per mole RLC, respectively (n = 6–7, P < 0.05). These CS potentiated mean concentric force (at all lengths) to 1.14 ± 0.02, 1.26 ± 0.04 and 1.41 ± 0.06 of pre-stimulus, control levels (all n = 5–7, P < 0.05) while work was increased to 1.07 ± 0.02, 1.17 ± 0.02 and 1.34±0.03 of controls, respectively. In a No CS condition that did not elevate RLC phosphorylation, neither mean concentric force nor work was altered. Thus, strong correlations between RLC phosphorylation and mean concentric force and work support the hypothesis that this molecular mechanism modulates muscle power output. No length-dependence for concentric force potentiation was observed in any condition, an outcome suggesting that interactions between instantaneous variations in muscle length and shortening velocity during work cycles modulates the potentiation response.     

Effect of praziquantel prolonged administration on granuloma formation around Schistosoma japonicum eggs in lung of sensitized mice

Schistosomiasis remains a major public health problem and it is an immune disease. The schistosome egg is the primary parasite factor responsible for the overt disease. The eggs release the soluble antigen, which induces intensive tissue reaction, a granulomatous reaction to the eggs. If granuloma formation could be suppressed, overt disease might not develop. Praziquantel is an effective antischistosomal drug especially for adult worms. However, whether praziquantel has a suppressing effect on granuloma formation around schistosome eggs directly remains unclear. The purpose of the present study was to investigate the effect of praziquantel, especially administered persistently, on granuloma formation around Schistosoma japonicum eggs in the lung of sensitized mice. Thirty-six mice were divided into three groups averagely. Group A was a control group. First, the mice were injected with schistosomal eggs hypodermically in abdomen, and 10 days later injected with schistosomal eggs intravenously via a tail vein. Group B was a praziquantel short administration group. In addition to the injections of schistosomal eggs as the same of Group A, the mice were administered with praziquantel in a daily dose of 300 mg/kg for 3 days, from 1 day before the intravenous injection of the eggs. Group C was a praziquantel prolonged administration group. In addition to the injections of schistosomal eggs as the same of Group A, the mice were administered with praziquantel in a daily dose of 150 mg/kg for 5 days weekly until the mice were sacrificed. Three mice of each group were sacrificed on days 7, 14, 28, and 56, respectively after the intravenous injection of the eggs, and the lung tissues were fixed with formalin and the slices were HE stained. The granulomas containing eggs in their centers were selected, and 25–30 granulomas from the animals of each group were measured at each time period. The mean areas of egg granulomas of each group were calculated, and the neutrophilic granulocytes, eosinocytes, lymphocytes, fibroblasts, and macrophages within the egg granulomas were counted. The mean numbers of them of each group were calculated. All the data of each group were analyzed and compared statistically. On day 56 after the intravenous injection of the eggs, the mean area of schistosomal egg granulomas in group B was (227.4 ± 728.0) × 10³ μm², less than that of [(297.9 ± 153.3) × 10³ μm²] in group A, and the suppression rate was 23.7% (P < 0.05). On days 7, 14, 28, and 56, the mean areas of schistosomal egg granulomas in group C were (575.8 ± 155.6) × 10³ μm², (310.5 ± 854.0) × 10³ μm², (267.7 ± 513.3) × 10³ μm², and (214.9 ± 446.4) × 10³ μm², respectively, significantly less than those of [(692.7 ± 232.6) × 10³ μm², (439.4 ± 165.0) × 10³ μm², (385.7 ± 129.3) × 10³ μm², and (297.9 ± 153.3) × 10³ μm²] in group A. The suppression rates were 16.9%, 29.3%, 30.6%, and 27.9%, respectively (P values <0.05). On day 56, the mean numbers of neutrophilic granulocytes were 11.4 ± 5.0 in group A and 5.2 ± 3.1 in group C, respectively, with the suppression rate of 54.4% in group C (P < 0.05). On day 56, the mean numbers of eosinocytes within the egg granulomas were 2.3 ± 2.0, 0.1 ± 0.3, and 0.3 ± 0.6 in groups A, B, and C, respectively, with the suppression rate of 95.7% in group B and 87.0% in group C (P values <0.05). On day 56, the mean numbers of macrophages within egg granulomas were 14.3 ± 6.9 in group C, compared with 18.6 ± 8.2 in group A, the suppression rate was 23.1% (P < 0.05). On day 56, the mean numbers of fibroblasts within the egg granulomas were 6.6 ± 4.4 and 5.8 ± 2.6 in groups B and C, respectively, and compared with 14.3 ± 7.8 in group A, the increasing extents decreased by 53.8% and 59.4%, respectively (P values <0.05). Therefore, the administration of praziquantel, especially the prolonged administration, can suppress the formation of schistosomal egg granulomas, including reduction in the areas of granulomas and suppression of the inflammatory cells and the hyperplasia of fibroblasts within granulomas.     

Effects of K-201 on the calcium pump and calcium release channel of rat skeletal muscle

The benzothiazepine derivative K-201 has been suggested as a potential therapeutic agent due to its antiarrhythmogenic action. To understand how the drug alters calcium release from the sarcoplasmic reticulum (SR), we investigated its effects on the SR calcium channel and calcium pump by single channel electrophysiology, whole-cell confocal microscopy, and ATPase activity measurements on control and post-myocardial infarcted (PMI) rat skeletal muscle. In bilayers, K-201 induced two subconductance states corresponding to ∼24% (S₁) and ∼13% (S₂) of the maximum conductance. Dependence of event frequency and of time spent in S₁ and S₂ on the drug concentration was biphasic both in control and in PMI rats, with a maximum at 50 μM. At this concentration, the channel spends 26 ± 4% and 24 ± 4%, respectively, of the total time in these subconductance states at positive potentials, while no subconductances are observed at negative potentials. K-201 altered the frequency of elementary calcium release events: spark frequency decreased from 0.039 ± 0.001 to 0.023 ± 0.001 s⁻¹ sarcomere⁻¹, while the frequency of embers increased from 0.011 ± 0.001 to 0.023 ± 0.001 s⁻¹ sarcomere⁻¹. Embers with different amplitude levels were observed after the addition of the drug. K-201 inhibited the Ca²⁺ ATPase characterized by IC_50,contr = 119 ± 21 μM and n _Hill,contr = 1.84 ± 0.48 for control and IC_50,PMI = 122 ± 18 μM and n _Hill,PMI = 1.97 ± 0.24 for PMI animals. These results suggest that although K-201 would increase the appearance of subconductance states, the overall calcium release is reduced by the drug. In addition, the effect of K-201 is identical on calcium release channels from control and PMI rats.     

Measurement of some haematological characteristics of the wild carp

The aim of the present study was to obtain a basic knowledge of the haematology and the influence of sex on some blood parameters of wild carp (Cyprinus carpio) spawners. Haematological indices [red blood cells (RBC), white blood cells, haemoglobin (Hb), packed cell volume (PCV), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC) and leucocyte differential count] were measured in one blood sample from 24 females (weight, 1.3 ± 0.1 kg; length, 47.4 ± 1.06 cm) and 27 males (weight, 1.265 ± 0.105 kg; length, 46.9 ± 0.8 cm). The highest haematocrit (PCV), haemoglobin concentration (Hb), RBC, MCH and MCHC were found for males. The highest leucocyte differential were also found for females. Statistical analysis revealed that differences in haematological parameters between males and females fish were not significant.     

Sensing magnetic flux density of artificial neurons with a MEMS device

We describe a simple procedure to characterize a magnetic field sensor based on microelectromechanical systems (MEMS) technology, which exploits the Lorentz force principle. This sensor is designed to detect, in future applications, the spiking activity of neurons or muscle cells. This procedure is based on the well-known capability that a magnetic MEMS device can be used to sense a small magnetic flux density. In this work, an electronic neuron (FitzHugh–Nagumo) is used to generate controlled spike-like magnetic fields. We show that the magnetic flux density generated by the hardware of this neuron can be detected with a new MEMS magnetic field sensor. This microdevice has a compact resonant structure (700 × 600 × 5 μm) integrated by an array of silicon beams and p-type piezoresistive sensing elements, which need an easy fabrication process. The proposed microsensor has a resolution of 80 nT, a sensitivity of 1.2 V⋅T⁻¹, a resonant frequency of 13.87 kHz, low power consumption (2.05 mW), quality factor of 93 at atmospheric pressure, and requires a simple signal processing circuit. The importance of our study is twofold. First, because the artificial neuron can generate well-controlled magnetic flux density, we suggest it could be used to analyze the resolution and performance of different magnetic field sensors intended for neurobiological applications. Second, the introduced MEMS magnetic field sensor may be used as a prototype to develop new high-resolution biomedical microdevices to sense magnetic fields from cardiac tissue, nerves, spinal cord, or the brain.     

Light microscopic study on Eimeria species infecting Japanese quails reared in Saudi Arabian farms

Japanese quails Coturnix coturnix japonica reared in economic farms were individually investigated for coccidian infections. The results indicated the absence of infections in birds younger than 1 month. An Eimeria infection rate of up to 80% was detected in birds 7–9 weeks old with a general infection rate of 29%. The infection rate decreased to 21.42% in birds older than 10 weeks. Morphometric characteristics of freshly shed, unsporulated oocysts were taken. These oocysts appeared pale yellow in color, were oval to subspherical in shape being limited by a bilayered oocyst wall of 1.2 μm. The unsporulated oocysts measured 17.73 ± 12.92 × 12.79 ± 1.69 μm (mean of 100) and possessed a polar granule, a micropyle and an oocyst residuum. The sporulation took 72 h and resulted in the formation of four elongated sporocysts containing two sporozoites, in addition to a stieda body and a sporocyst residuum. The life cycle of this Eimeria species was followed in experimentally infected quails. Three asexual generations (at 60, 78, and 96 h p.i.) were detected in the epithelium of the small intestine before the sexual cycle started at 84 h p.i. The prepatent period was 5 days, while the patent period covered 6–7 days. Besides this well-defined species, another Eimeria species occurred, the oocysts of which were excreted in low numbers and were characterized by the absence of a micropyle and an oocyst residuum. These oocysts measured 15.73 ± 2.22 × 14.18 ± 1.89 μm (mean of 100) and sporulated already within 60 h.