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Biomedical subjects

V Kumar

Publications and source records attributed to V Kumar.

At least 1,009 records · Page 56Linked to original sources
PubMedDate not supplied

The influence of light wavelength on reproductive photorefractoriness in migratory blackheaded bunting (Emberiza melanocephala).

There are two effects of long day length on reproductive responses in birds, one is the photoinduction of gonadal growth and maturation and the other is the induction of gonadal regression and photorefractoriness. Although it is likely that the same photoreceptors are involved in the photoinduction of gonadal growth and the onset and maintenance of photorefractoriness. and so the influence of wavelength should be similar, this has not been investigated. Therefore, we investigated the influence of light wavelength on reproductive photorefractoriness in the migratory male blackheaded bunting held under long photoperiods. In mid May, when photoperiod was approximately 14L:10D (14 hours light:10 hours darkness), eight groups of sexually mature birds were moved indoors on an artificial photoperiod of 14L:10D (L - 450 lux. D - 0 lux). Then after 3 weeks, for six groups, a 4-h light period in the morning (zt 0-4; zt 0 [zeitgeber time 0] refers to the beginning of lights-on period) or in the evening (zt 10-14) was substituted with green (428 nm), red (654 nm) or white light at 16 +/- 2 lux intensity. Of the remaining two groups, one was maintained on 14L: 10D and the other transferred to 10L:14D: these served as controls. At the end of 4 weeks, all birds were found to have undergone testicular regression, irrespective of LD cycle they were exposed to. When these gonadally regressed birds were subjected to 16L:8D for another 4 weeks, to test their responsiveness to the stimulatory effects of long day lengths, only those exposed to 10L:14D and 14L:10D with a 4-h green light period showed testicular regrowth. On the other hand, birds exposed to 14L:10D with a 4-h white or red light period remained fully regressed, similar to 14L:10D controls. Except for some individual difference, there was no difference in response between the groups that received a 4-h light period in the morning and that received it in the evening. These results suggest that the wavelengths of light influence induction of buntings from the photosensitive state into the photorefractory state. Whereas the short light wavelengths facilitated recovery from the photorefractoriness, the long light wavelengths were more effective in maintaining the photorefractoriness.

Animals↗
PubMedDate not supplied

Immunofluorescence and enzyme immunomicroscopy methods.

Immunohistochemistry is a very versatile immunopathological tool for the study of distribution and differentiation of antigens and of the presence of in vivo-bound immune complexes. In addition, these methods are invaluable for detection of circulating antibodies to the various antigens. Such methods may be the only ones of choice in certain situations. For the detection and quantitation of these antigens, it is very essential that the immunohistochemical methods for detecting them are properly standardized, with the inclusion of appropriate controls.

Animals↗
PubMedDate not supplied

A longitudinal study of growth in length and weight of Punjabi infants in Chandigarh, India.

One hundred and fifty-four Punjabi infants (86 male, 68 female) were followed longitudinally and their lengths and weights measured each month during the first year of life. Monthly distance and velocity means for their weight and crown-heel length with the respective standard deviations are presented. The general pattern of growth is characterized by a period of rapid initial increase followed by a period of slower increment during the second half of infancy. Length velocity decreased from birth onwards, but weight velocity shows a peak at around 1.5 months, followed by a decline.

Aging↗
PubMedDate not supplied

QRS detection using new wavelets.

This paper deals with a new wavelet (WVT) which has been developed and very effectively and efficiently used for the detection of QRS segments from the ECG signal. After carrying out the detection using five existing wavelets (two symmetric--WT1 and WT2--and three asymmetric--WT3, WT4 and WT5), two new wavelets (WT6 and WT7) were constructed and used for QRS detection. WT6 is a symmetric wavelet and has been constructed by a trial-and-error method. WT7 is an adaptive symmetric wavelet and adjusts its threshold as per the amplitude of the ECG signal. The accuracy of QRS detection obtained from WT6 is 99.8 % and from WT7 100%. The CSE DS-3 database has been used for tests. Both WT6 and WT7 have been proved to be superior in performance to the existing wavelets. Out of WT6 and WT7, WT7 holds high promise for error-free reliable QRS detection in computer-aided feature extraction and disease diagnostics.

Algorithms↗
PubMedDate not supplied

Telecardiology for effective healthcare services.

Continuous monitoring of the electrocardiogram (ECG) and other signals related to current heart activity are necessary for patients who are suffering from cardiac diseases. This paper deals with the work that has been carried out to transmit ECGs from remote sites. Software has been developed which enables the uploading of ECG data from a patient so that the physician can monitor the state of the patient from a distance and at the same time may consult other experts for a second opinion. Records can only be examined by the authorized physician after proper registration and diagnosis or prescription may be sent back to the referring site. Further consultation with the patient through a 'chat' facility is also possible. The suitability of the system over transport control protocol (TCP), internet protocol (IP), local area network (LAN), wide area network (WAN) and World Wide Web (WWW) has been assessed. The bandwidth, latency, availability, security and ubiquity have also been discussed. A study has also been undertaken in order to make the system compatible with available bandwidths and to find out which one out of a number of available techniques is most efficient for ECG data compression. The results indicate that the scheme is suitable for telecardiology and can form part of an overall telemedicine system in a health care network.

Computer Security↗
PubMedDate not supplied

The psuedo-Chediak-Higashi anomaly: an unusual staining pattern in an Indian child with acute myeloid leukemia.

The authors describe the psuedo-Chediak-Higashi anomaly in a 12-year-old boy with acute myeloid leukemia (AML-M2). There were large purple granules in the blasts, promyelocytes, and myelocytes. Instead of the previously described patterns, the authors observed a unique rim pattern staining of the granules in both the May-Grunwald-Giemsa and the myeloperoxidase stains. Moreover, many of the granules had central vacuoles with strong myeloperoxidase positivity at the periphery. The bone marrow had a much higher positivity for these mega-granules as compared to the peripheral blood. On remission, these granules were no longer seen. To the best of the authors' knowledge, this pattern of staining has not been previously reported in the literature.

Chediak-Higashi Syndrome↗
PubMedDate not supplied

High resolution shadowing of Mycobacterium leprae.

Metal shadow casting techniques for transmission electron microscopic examination was used to determine the morphological characteristics of Mycobacterium leprae in untreated and treated patients. This technique is used to visualize bacterial surface structures by thermal evaporation of platinum alloys under moderate vacuum. This method gives a high contrast image at relatively low resolution and is useful for correlating micro-morphology quantitatively to early therapeutic effects of anti-leprosy drugs. Using these techniques in untreated cases, the surface structures of M. leprae were uniformly filled with relatively homogenous protoplasm surrounded by a cell wall. Most of the bacilli had thick cell walls with prominent banded and fibrous structures on the surface of the cell body. The cell wall was not detached in any of the solid bacilli in untreated cases. The bacilli varied in size and some of them were swollen in their mid-portion. Some bacilli were very short and completely filled with cytoplasm; therefore, these short bacilli were counted as solid bacilli in electron microscopic morphological index (EM-MI) determination. During treatment, mainly the cytoplasms of the bacilli were affected, and degeneration was observed. Ultrastructurally, the cytoplasm was shrunken and detached from the cell wall indicating mild degeneration. After moderate degeneration, the cytoplasm appeared fragmented. In advanced degeneration, all structures except the cell walls collapsed completely and no fibrous or band structures were visible on the surfaces of the cell walls. Therefore, these bacilli were counted as non-solid bacilli for EM-MI determination. This study shows that transmission electron shadowing gives more accurate counts than standard light microscopy of intact M. leprae bacilli in patient specimens.

Humans↗
PubMedDate not supplied

Evaluation of traditional African medicine "Compound R" for the treatment of thermal burn wounds in fuzzy rats.

The efficacy of an oil-in-water emulsion of a traditional Kenyan medicine, Compound R, on thermal burn wounds in fuzzy rats is reported. The burn wounds were inflicted on the depilated skin of rats with a 2 cm diameter aluminum template heated at 65 degrees C. Mean +/- SD days to healing (complete closure) were 9.9 +/- 2.2 (range 7 to 14 days) and 13.3 +/- 2.4 (range 10 to 16 days) for the treated and control (untreated) wounds, respectively (paired Student's t test, t value -5.667, p = 0.0003). Preliminary microbiologic results showed no activity of Compound R against some of the commonly encountered pathogens in burn wounds. Compound R appears to decrease the days to burn wound healing in fuzzy rats. This study provides preliminary data for further investigations of Compound R in managing burn wounds.

Administration, Topical↗
PubMedDate not supplied

Comparative studies of different gliadin preparations in detecting antigliadin antibodies.

Antigliadin antibodies (AGA) have been used as indicators of celiac disease. The presence of these antibodies in other gastrointestinal and liver disorders and even in normal healthy controls casts a shadow on the diagnostic significance of AGA. We examined 91 normal controls of varying ages and 97 patients with various gastrointestinal and liver disorders. Forty-eight of 97 nonceliac patients were positive for AGA, and diagnosis-specific incidences ranged as high as 75% in patients with small bowel disease. In addition, the levels of AGA were dependent upon age as their presence increased from 12% in children with a mean age of 10, to 35-40% in normals within the 60-70 age group. The lack of celiac disease specificity of AGA was not due to either the source of gliadin nor to the sensitivities of the test methods. Both the enzyme-linked immunosorbent assay (ELISA) and the immunofluorescence methods gave comparable results. ELISA was more sensitive than immunofluorescence. These results thus strongly suggest that AGA are not markers of celiac disease and increase with age in normals.

Adult↗
PubMedDate not supplied

Disease specificity and dynamics of changes in IgA class anti-endomysial antibodies in celiac disease.

We evaluated the sensitivity and kinetics of serum IgA class anti-endomysial antibodies in the diagnosis of celiac disease (CD) as established by the criteria of the European Society for Pediatric Gastroenterology and Nutrition (ESPGAN). Eighty-four cases that satisfied the ESPGAN criteria for CD were evaluated for IgA-EmA titers during various phases of establishing the diagnosis. Thirty-three cases were infants and children less than 5 years of age undergoing intestinal biopsies for symptoms of CD and 51 were previously diagnosed adults. Of the 33 children, 11 were untreated and symptomatic and were IgA-EmA positive at initial presentation. Twenty-two children previously controlled on a gluten-free diet (GFD) exhibited IgA-EmA titers during gluten challenge. Furthermore, the antibody levels declined in all cases (usually to negative) when the patients were again placed on a GFD for 6-12 months. Changes in intestinal histopathology paralleled the changes in antibody titers in six cases undergoing serial biopsies. Of the 51 adult patients with proven CD who were prescribed a GFD for at least 12 months, IgA-EmA were detected in 10 cases who were noncompliant to their GFD, whereas the antibodies was found in only 1 of the remaining 41 patients strictly adhering to their diet. The sera of 140 aged-matched children with various intestinal problems, 87 healthy adults, and 67 patients with dermatological diseases served as controls and were also IgA-EmA negative. On the basis of these findings, we suggest a role for the IgA-EmA as a serological screening test for active CD. It further offers the potential for monitoring compliance to diet in established cases of CD and also indicates the proper timing for biopsy in patients undergoing evaluation of CD.

Adolescent↗
PubMedDate not supplied

Relationship of endomysial antibodies to jejunal mucosal pathology: specificity towards both symptomatic and asymptomatic celiacs.

Serum immunoglobulin A class antibodies reactive to the endomysial lining of the smooth muscle bundles of the gastrointestinal tract have recently been reported to be specific and sensitive indicators of celiac disease (CD). A total of 203 subjects were examined for serum endomysial antibodies (EmA) and in 103 small bowel biopsies were obtained. EmA were detected in 43 cases including 26 CD patients evaluated during the gluten challenge phase of diagnosis by European Society for Pediatric Gastroenterology and Nutrition criteria, 11 of 53 symptomatic patients, and 6 asymptomatic family members. All patients with detectable antibody at the time of biopsy exhibited grade III-IV villous atrophy. Disaccharidase activities performed in 19 cases revealed severe deficiencies. EmA were not detected in 160 subjects including 42 infants and children with chronic nonspecific diarrhea. Eighteen of these possessed grade II-III villous atrophy with moderate disaccharidase deficiency and 24 were found to have normal histology and enzymes. The EmA were also not detected in 3 CD patients who were well maintained on a gluten-free diet for greater than 1 year and 25 asymptomatic family members exhibiting normal histology and enzymes. An additional 90 infants and children with other gastrointestinal and liver diseases were also negative for the serum EmA. Fourteen of these patients underwent biopsies and were demonstrated to have normal histology.

Adolescent↗
PubMedDate not supplied

Diagnostic acceptability of FFT-based ECG data compression.

There are three signal domains in which ECG data compression can be performed, namely time domain, frequency domain and parameter extraction. The present paper deals with the frequency domain method of compression using fast Fourier transform. The algorithm has been tested on the third set of the CSE database library. A performance evaluation has been made using two important parameters, namely compression ratio and percent root-mean-square difference besides visual comparison. Further, in order to know the clinical acceptable quality of the reconstructed signal peak, boundary and interval measurements were made both on the reconstructed and the original signal of the same record for comparison. The visual examination reveals that most of the noise in the original signal had been filtered out during the compression. This amounts to reduction of electromyographic noise to a considerable extent. The experimental observations show that a compression ratio of 8 is feasible while ensuring clinical acceptability.

Algorithms↗
PubMedDate not supplied

ANN-based QRS-complex analysis of ECG.

Reliable detection the QRS complex in either a normal or an abnormal ECG and its analysis is the first and foremost task in almost every ECG signal analysis system aimed at the diagnostic interpretation of ECG. Conventionally, detection of the QRS complex is accomplished using a rule-based/algorithmic approach. This work, uses the learn and generalize approach of an artificial neural network (ANN) for the detection of QRS complexes in either a normal or an abnormal ECG. This is followed by the analysis of the QRS complex to designate and measure the morphological components within the QRS complex in all 12 standard leads. An ANN has been developed to detect the QRS complex in ECG and trained, with the help of back propagation algorithm, on more than a hundred ECGs selected from the CSE Data Set-3. The trained ANN was tested on all the recordings of the CSE Data Set-3 and the sensitivity has been found to be 99.11%. Subsequent to the identification of the QRS complex, an analysis of this complex and measurement of peak amplitudes of the component waves is done. The results are validated using the CSE multilead measurement results. Both the QRS detection and the QRS analysis software developed in C-language have been successfully implemented on a PC-AT. The results are found to be in agreement with visual measurements carried out by medical experts.

Electrocardiography↗
PubMedDate not supplied

Endomysial antibodies in the diagnosis of celiac disease and the effect of gluten on antibody titers.

Celiac disease, a common chronic gastrointestinal disorder, is gluten induced and is controlled with a gluten-free diet. While the management of CD with a gluten-free diet is quite effective, the diagnosis is rather difficult. The ESPGAN criteria for the diagnosis of CD seems to be tedious and time-consuming. Serological tests for IgA class endomysial antibodies, as detected by indirect immunofluorescence, on human and primate smooth muscles are specific and sensitive markers of celiac disease. Of all the specimens examined, endomysial antibodies were present in patients with gluten-sensitive enteropathy. These antibodies occurred in all active cases of celiac disease, in 90 percent suspected celiac patients where all the ESPGAN criteria has not been fulfilled. This contrasts to the presence of endomysial antibodies in 46 percent of confirmed and 17 percent of suspected celiac patients maintained on a gluten-free diet for various time intervals. Endomysial antibodies also occurred in all cases with chronic diarrhea and gut histology consistent with CD and 8% of asymptomatic family members of CD patients. None of the patients with other gastrointestinal and liver diseases had endomysial antibodies. These studies thus emphasize the specificity and sensitivity of endomysial antibodies for celiac disease.

Animals↗
PubMedDate not supplied

Anti-phospholipid antibody profiles of different specificities in syphilis and systemic lupus erythematosus.

Controversies exist as to the differences in the specificities of phospholipid antibodies in SLE and syphilis. We report an ELISA assay that could distinguish phospholipid antibodies associated with SLE and syphilis based on their differential reactions with phosphatidyl choline and VDRL antigens. Antibodies to phospholipid from patients with SLE reacted equally well when tested with these two antigens in the ELISA assay whereas phospholipid antibodies present in syphilis patients exhibited little or no binding to phosphatidyl choline. There were no differences in the binding of phospholipid antibodies to other phospholipids such as cardiolipin and phosphatidyl serine. In addition, there was no association of anti-phospholipid antibodies with the presence of either DNA or RPR antibodies suggesting their distinctness from each other.

Antibodies, Antinuclear↗
PubMedDate not supplied

An ultrastructural study of blood vessels in peripheral nerves of leprosy patients: blood vessels in peripheral nerves.

Ultrathin sections of nerves of tuberculoid and lepromatous leprosy were examined in an electron microscope for changes in endoneural blood vessels. In the tuberculoid nerves, hypertrophy of endothelial cells was the most prominent feature. This was to such an extent that the lumen of blood vessel was often closed. Endoneural blood vessels showed multilayers separated by collagen and ground substances. In contrast, in the lepromatous nerves, there was no hypertrophy of endothelial cells in the blood vessels and the lumen of the vessels was open. M. leprae were seen within the endothelial cells and these organisms were intact and probably viable. These observations suggest a possible involvement of endoneural blood vessels which may contribute to nerve damage in leprosy.

Endothelium, Vascular↗
PubMedDate not supplied

Ultrastructural characteristics of macrophages in dermal leprosy granulomas: macrophages in leprosy granulomas.

The characteristics of the cells of mononuclear phagocyte series (MPS) in the dermal granulomas of tuberculoid and lepromatous leprosy were studied by elereron microscopy. In the tuberculoid granulomas, majority of the cells of MPS (epithelioid cells) showed a distinct appearance. They were seen in close association with a large number of activated lymphocytes. The cells of MPS had a prominent nucleus. Their cytoplasm contained mainly rough endoplasmic reticulum, developed golgi and was free of M. leprae or its products. In contrast, the cells of MPS (macrophages) in lepromatous leprosy had a large nucleus. Their cytoplasm contained mainly whole M. leprae organisms/its phagocytosed products and rough endoplasmic reticulum. There was paucity of lymphocytes in these granulomas. These observations support the view that the cells of MPS in the tuberculoid granulomas may be secretory while those in the lepromatous granulomas were phagocytic.

Granuloma↗