Search PubMed⌕ Search

Biomedical subjects

K Rao

Publications and source records attributed to K Rao.

At least 91 records · Page 5Linked to original sources
PubMed1991

Normalization of force generated by canine airway smooth muscles.

A variety of normalizations have been employed to compare maximal isometric force (Po) produced by smooth muscles at different locations and stages of maturation. Because these procedures have not always been based on rigorous principles, confusion has resulted. To obtain a less ambiguous index of force production, we measured in vitro Po from mongrel canine tracheal (TSM) and bronchial (BSM) smooth muscle with an electromagnetic lever and normalized it to force per unit cross-sectional area of whole tissue (tissue stress), to force per unit cross-sectional area of muscle in the cross section of total tissue (muscle stress), and to force per fractional unit of myosin in the tissue cross section (myosin stress). Proportion of myosin in cross-sectional area of tissue was deduced from data obtained by sodium dodecyl sulfate gel electrophoresis of crude muscle extracts. For TSM, tissue stress was 1.499 X 10(5) N/m2 +/- 0.1 (SE), whereas it was only 0.351 X 10(5) N/m2 +/- 0.05 (SE) for BSM, representing a 4.27-fold difference (P less than 0.01). There was a 1.60-fold difference (P less than 0.05) in muscle stress, which was correlated to the morphometric finding that 79 +/- 1.4% (SE) of the tracheal strip cross section was muscle, whereas only 30 +/- 1.0% (SE) of bronchial tissue was occupied by muscle. Average myosin content was the same in smooth muscle cells of TSM and BSM, indicating that total amount of myosin in tissue cross sections was essentially a function of proportional area of muscle cells in total tissue cross sections.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Pulmonary vascular smooth muscle: biochemical and mechanical developmental changes.

To evaluate the developmental changes in pulmonary vascular smooth muscle contractile protein content, mechanical properties, and their contribution to the high resistance characteristic of the fetal and immediate neonatal period, we studied pulmonary vessels of fetal, newborn, and adult sheep, as well as newborn and adult pigs. Strips of the second- through fifth-generation vessels were dissected, and their content of tissue total smooth muscle cell protein, myosin, and actin-to-myosin ratio were measured; the mechanical properties of the second-generation vascular strips were also studied. For all ages the smooth muscle protein and myosin content of the second-generation vessels were significantly greater than for the lower pulmonary vascular orders (P less than 0.05). The myosin content in fetal sheep (0.77 +/- 0.03 micrograms/mg wet tissue) was similar to that of the newborn (0.79 +/- 0.04) and adult (0.86 +/- 0.05). However, the smooth muscle protein content (7.94 +/- 0.21 micrograms/mg wet tissue) and the actin-to-myosin ratio of the pulmonary vascular tissue of the fetus (1.00 +/- 0.04) were lower (P less than 0.01) in the fetal than in the newborn (9.16 +/- 0.26 and 1.60 +/- 0.12) and adult (9.38 +/- 0.3 and 1.60 +/- 0.11, respectively). No differences were observed for these parameters between the newborn and adult pig. Stress (16.5 +/- 1.7 mN/mm2) and the maximum shortening capacity (13.0 +/- 1.5% of optimal length) in the newborn pulmonary vascular strips were significantly greater than for the fetus (6.8 +/- 1.4 and 5.9 +/- 1.0, respectively) but similar to those of the adult sheep.(ABSTRACT TRUNCATED AT 250 WORDS)

Actins↗
PubMed1991

Primary amenorrhoea (analysis of 40 cases).

Forty cases of primary amenorrhoea attending gynaecological department of Kasturba Medical College Hospital, Manipal, in the year 1987-88, were analysed. Majority (50%) of cases were of muellerian dysgenesis. One case was a true hermaphrodite with bilateral ovotestis and one case of genital tuberculosis. Attempt has been made to establish value of laparoscopy in primary amenorrhoea. It is seen that laparoscopy gives much better information and obviates the need for costly tests like radio-immuno-assays in some cases of primary amenorrhoea.

Adolescent↗
PubMed1990

Differential expression of class I and class II major histocompatibility complex antigen in early postnatal rats.

Cells expressing major histocompatibility complex (MHC) antigens are rarely found in normal mature brains, but cells resembling microglia can be induced to express these antigens following the onset of neural degeneration. In young rats, these cells show spontaneous expression of class I MHC antigens, which is further enhanced in the superior colliculus by the degeneration resulting from eye removal. By contrast, class II MHC antigen expression does not occur spontaneously and can only be induced by eye removal when the lesion is performed after the first postnatal week, when the optic tract begins to myelinate. We suggest that different signals are responsible for induction of class I and of class II MHC antigen expression.

Animals↗
PubMed1990

Bcr/abl recombinant DNA analysis versus karyotype in the diagnosis and therapeutic monitoring of chronic myeloid leukemia.

Karyotype and bcr/abl recombinant DNA analyses are two means of detecting the chromosomal aberration in chronic myeloid leukemia. The authors compared these two methods in a retrospective study of 36 patients with CML in which they found the bcr/abl DNA recombinant event in 100% (29 of 29) of those patients who had the Philadelphia chromosome. To achieve this sensitivity, a battery of two bcr probes and three restriction enzymes is necessary. The authors propose a sequential algorithm for efficient use of these probes and enzymes. In 76% of the patients, bcr/abl rearrangement can be detected with a Bgl II digest and a 3' commercial probe. An additional 21% of patients can be detected by a second assay in which the same membrane is rehybridized to a 3' and 5' combination bcr probe. One patient (3%) required an additional restriction enzyme digest with BamH I to detect the recombinant event by the same 3' probe. Karyotype analysis is used to determine cytogenetic remission in patients with CML under therapy. The authors studied the use of DNA analysis by the Southern blot technique to detect a decrease in the relative number of leukemic cells. By dilution studies and densitometric scanning of autoradiographs, the authors were able to detect a 15% decrease in the relative number of cells having the bcr/abl recombinant event. The authors report the preliminary results of three patients in whom they compared the karyotype and recombinant DNA analysis at multiple time points in their clinical course. In conclusion, the bcr/abl recombinant DNA analysis is superior to karyotype for the diagnosis of CML and can be used for monitoring treated patients.

Adolescent↗
PubMed1990

Theoretical models and prediction of the changes in case mortality patterns in major Chinese cities.

"Through a comparison of different methods, this study is intended to set up more satisfactory theoretical models of case mortality patterns in major Chinese cities, to ascertain the manner of changes in the time sequence of various diseases, and to predict the trends of these changes. This study is based on the data of causes of death in the country's 14 cities having a population of over one million, where there are complete statistical registration systems and reliable data."

Cause of Death↗
PubMed1989

Degeneration of optic axons induces the expression of major histocompatibility antigens.

Eye removal from adult rats causes induction of major histocompatibility complex (MHC) antigen expression by cells within areas of optic terminal degeneration. Class I MHC antigen expression occurs through the degenerating optic terminal areas, while class II MHC antigen expression is found within areas of degenerating myelinated axons. This could be an important step in the process of immunological recognition and subsequent rejection of neural transplants that are located in the region of the degenerating fibers. It could also be a precipitating factor in certain neurodegenerative diseases of the central nervous system.

Animals↗
PubMed1989

Integrity of the blood-brain barrier in retinal xenografts is correlated with the immunological status of the host.

The purpose of this study was to determine the immunological correlates of blood-brain barrier breakdown in retinal xenografts in rats by utilizing skin grafting to initiate a timed immune response to the transplanted neural tissue. Embryonic day 13-14 CD-1 mouse retinae were grafted into the brainstem parenchyma of neonatal Sprague-Dawley rats. In one group of animals a 100 mm2 CD-1 skin graft was placed on the flank 21 days after the initial neural transplant in order to provoke an immune response to the neural graft. Control animals received no skin graft. Animals were injected with horseradish peroxidase (HRP) in the femoral vein 2-8 days after skin grafting. Brains were processed for Nissl, HRP-tetramethylbenzidine, and anti-M-6, -lymphocyte, -macrophage, and -astrocyte antibodies. Experimental and control animals injected 2-4 days after skin grafting showed no leakage of reaction product in the grafted tissue. A small percentage (one of eight) of 5-day animals showed isolated, patchy leakage, but no evidence of rejection of the neural graft. At 6 days all of the grafts showed evidence of leakage, and 71% of these grafts showed infiltration of lymphocytes. By 7-8 days extensive leakage of HRP and widespread infiltration of lymphocytes and macrophages were clearly evident. The present study demonstrates that blood-brain barrier breakdown is correlated closely with the sequence of immunological rejection of the graft. While these results confirm that a barrier exists in healthy neural transplants, they suggest that immunological factors should be considered in cases in which grafts are not protected by an intact barrier.

Animals↗
PubMed1989

An analysis of 300 EEG referrals.

Although the EEG suffers from limited diagnostic significance it is a useful adjuvant to diagnosis and demands for the examination are increasing. Three hundred consecutive referrals to one unit are analysed.

Adolescent↗
PubMed1989

Transplanted rat retinae do not project in a topographic fashion on the host tectum.

We report here that transplanted rat retinae do not project in a topographically organized fashion onto the host tectum. In fact, following the injection of two small non-overlapping regions of the host tectum, one with Fluorogold, the other with Rhodamine conjugated latex microspheres, groups of ganglion cells labelled with either dye are found interspersed throughout the ganglion cell layer of the retinal transplant. The absence of topography in the projections of transplanted retinae offers a new opportunity to examine the mechanisms which lead to topographically ordered projections in normal development.

Animals↗
PubMed1989

Leiomyoma of the female urethra--a clinical curiosity.

A case of leiomyoma of the female urethra is reported. The patient, a perimenopausal, multiparous woman presented with a gradually enlarging mass per vagina for the past 6 months. A provisional diagnosis of carcinoma of skene's duct or vaginal leiomyoma was entertained and an excisional biopsy performed. To our surprise, histopathological examination revealed an urethral cellular leiomyoma.

Female↗
PubMed1989

Epidemic iatrogenic Acinetobacter spp. meningitis following administration of intrathecal methotrexate.

We report the first outbreak of Acinetobacter species meningitis in a group of children with acute leukaemia following the administration of intrathecal chemotherapy. Eight of twenty patients receiving methotrexate injections on a single day developed signs and symptoms of meningitis within 18 h of treatment, and cases were clustered by time of administration. A cohort study comparing case and non-case patients did not identify any specific host factor associated with meningitis. Acinetobacter calcoaceticus var anitratus was isolated from the cerebrospinal fluid (CSF) of five patients; three patients died. Our investigation determined that the methotrexate was extrinsically contaminated by reused needles, used for reconstitution and administration, which had been inadequately sterilized. Acinetobacter calcoaceticus var anitratus was isolated from an autoclaved needle and a vial of methotrexate used for chemotherapy; these and the clinical isolates had similar antibiograms. After introduction of single-use disposable needles no subsequent cases occurred.

Acinetobacter Infections↗
PubMed1989

The role of MHC and non-MHC antigens in the rejection of intracerebral allogeneic neural grafts.

Embryonic DA retinal allografts that have survived for prolonged periods after having been transplanted into the brains of neonatal BN rats can be induced to reject following peripheral sensitization with a DA skin graft. The results show that histocompatibility antigens play the major role in the rejection of grafts placed in the CNS and that a disparity between the retinal and skin grafts for MHC antigens induces a more severe rejection response than does a non-MHC antigen disparity.

Animals↗
PubMed1989

Cervical myelopathy secondary to movement disorders: case report.

Involuntary cervical movements that result in cervical spondylosis and secondary myelopathy have not been adequately emphasized in the literature. We present two patients with cerebral palsy and long histories of involuntary movements who developed cervical myelopathy. We use these illustrative cases to emphasize that in the presence of underlying neurological symptoms and signs due to advanced cerebral palsy, any recent worsening should provoke a higher index of suspicion for myelopathy. The mechanics of neck movements and surgical treatment are discussed.

Cerebral Palsy↗
PubMed1989

A study of the pattern of deaths by diseases in major Chinese cities.

"In research in recent years, the co-authors of this article have discovered that changes in PDD [patterns of disease and death] in urban and rural areas [in China] follow to a large degree an identical pattern except for a difference in the timing of these changes (approximately 5 to 10 years). This study is based on statistics obtained in 14 cities with a population of more than one million, complete registration systems and higher data reliability. It is intended to ascertain how the pattern of deaths by diseases changes, and to predict the tendency of such changes through dynamic research on such patterns in those cities." The authors analyze changes in specific causes of death and their impact on life expectancy in China.

Asia↗