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Biomedical subjects

G Singh

Publications and source records attributed to G Singh.

At least 487 records · Page 27Linked to original sources
PubMed1991

Efficacy of the Hamilton Thorn Motility Analyzer (HTM-2030) for the evaluation of bovine semen.

Semen samples from four Holstein-Friesian bulls were evaluated by the Hamilton Thorn Motility Analyzer (HTM-2030) for sperm concentration, motility and other motion parameters. In the first trial, the extender preparation (P<0.005) and the program settings (P<0.001) of the motility analyzer significantly effected the accuracy of sperm concentration estimates. The student's t-test revealed that setting the variables on the HTM-2030 Analyzer according to the dimensions and brightness of bull spermatozoa and the background of the extender was better than using the settings for bull semen as recommended in the manufacturer's manual. In the second trial, different quantities of dead cells were added to semen samples to evaluate the accuracy of the HTM-2030 Analyzer for the estimation of percentage of motile cells and other motion characteristics. All motion parameter estimations except mean path velocity were similar for the settings studied. Addition of dead spermatozoa had a significant effect (P<0.0001) on all parameters of sperm movement. High correlation coefficients between the percentage of dead cells added and the decline in sperm motility verified the accuracy of this system. Use of the HTM-2030 system yielded simple, rapid and objective analysis of the studied spermatozoal parameters.

Journal Article↗
PubMed1991

Ultrasonography for detection of early pregnancy following embryo transfer in unknown breed of Bos indicus cows.

Real time, B mode ultrasound was used from Days 18 to 64 to detect and monitor the conceptus in 30 unknown breeds of Bos indicus recipients following embryo transfer. The embryonic vesicle was first visible within the uterus between Days 18 and 20 (mean +/- SD 18.5 +/- 0.7d) d). The embryo proper was detected at Day 19.5 +/- 0.7. The heartbeats were detected at Day 22.6 +/- 0.9. The average day of first detection of the allantois, the C - shaped embryo and the amnion was 23.1 +/- 0.8, 23.8 +/- 1.4 and 25.1 +/- 1.4 d, respectively. The fore limb, the limb buds, the spinal cord and the optic area were observed on Days 32.7 +/- 1.3, 32.9 +/- 1.3, 33.0 +/- 1.5 and 33.6 +/- 1.4, respectively. Fetal movements could be detected at Day 50.7 +/- 1.0. Ribs and vertebrae were detected on Day 60.9 +/- 1.7. The mean length of the embryo proper was 4.5 +/- 0.8 mm. on Day 19. At Day 60 it was 52.5 +/- 7.0 mm. The growth of the embryo proper increased steadily until Day 39, growing rapidly thereafter. Embryonic death was detected in one recipient on Day 32. The echogenic area started increasing and recipient appeared in estrus on Day 40. Sixteen recipients exhibited estrus on Days 22 to 24. An increase in intrauterine fluid was observed on Days 18 to 24.

Journal Article↗
PubMed1991

Dissipation of some organochlorine insecticides in cropped and uncropped soil.

Dissipation of four organochlorine insecticides, viz. aldrin, HCH, chlordane and heptachlor was studied in a sandy loam soil with and without crops during a period of 10 cropping seasons. Dissipation of all chemicals followed first-order kinetics (r(2)=0.537 - 0.976) with almost similar persistence in cropped and uncropped soils for all the insecticides. The average half-lives, (t(1/2) values) for total residues of aldrin, HCH, chlordane, and heptachlor in cropped treatments were 80.7, 58.8, 93.2, and 110 days. Their respective values in fallow plots were 78.4, 83.8, 154, and 116 days. None of the parent compounds or their isomers could be detected below the 20 cm depth at the termination of the experiment. Highest residue concentrations were observed in the surface 10 cm layer in fallow plots, but in the deeper (10-20 cm) layer in cropped plots. Analysis of plants and grains showed significant residues of all the chemicals. Degradation of these compounds in cropped and uncropped plots is discussed with regard to their volatilization, microbial degradation, leaching, and plant uptake.

Journal Article↗
PubMed1991

Thermostability of Japanese encephalitis vaccine produced in India.

Different batches of bulk vaccine, final bulk at in-process level, finished freeze-dried and reconstituted Japanese encephalitis vaccine were assayed for their stability at temperatures of 22, 37 and 40 degrees C. After ultrazonal purification of 50 times concentrated brain suspension, JE Bulk vaccine was found to be stable for up to 2 years at 4 degrees C, however, the percentage loss in potency (log 10 N antibody titre) after 2.5 years was 24%. Three-times concentrated final bulk showed rapid deterioration by the fourth week at 37 and 40 degrees C. Freeze-dried JE vaccine maintained at 22 degrees C for 28 weeks did not show perceptible deterioration. At 37 degrees C, the same vaccine started showing deterioration (14%) after 8 weeks whereas at 40 degrees C the loss of potency was 24% after 8 weeks. The freeze-dried vaccine was found to be stable for up to 2 weeks duration at 40 degrees C.

Drug Stability↗
PubMed1991

Case report: an oxidized cellulose granuloma--another hepatic pseudotumour?

We report a patient who presented with right upper abdominal pain and jaundice 4 months after an elective cholecystectomy. A clinical diagnosis of choledocholithiasis was supported by imaging. Ultrasound and computed tomography also led us to diagnose an incidental liver tumour which guided biopsy demonstrated as an oxidized cellulose ('Oxycell') granuloma.

Cellulose, Oxidized↗
PubMed1991

Depressed gut absorptive capacity early after trauma-hemorrhagic shock. Restoration with diltiazem treatment.

Although bacterial translocation occurs after trauma-hemorrhage, it is unknown whether gut absorptive capacity (GAC) is altered under those conditions. The aim of this study, therefore, was to determine this and also whether diltiazem (DZ) has any effect on GAC after hemorrhage. Rats (n = 12; 270 to 300 g) were lightly anesthetized with ether and a 6-cm midline laparotomy performed (i.e., trauma induced). A nasogastric tube was inserted, cannulation of a carotid and femoral artery and a jugular and the portal veins performed, and the animals allowed to recover from anesthesia. They were then bled to a mean blood pressure of 40 mm Hg within 10 minutes and maintained at this pressure by further bleeding or return of fluid (lactated Ringer's solution [LRS] ) until 40% of the shed blood volume (SBV) had been returned in the form of LRS (end of hemorrhage, EH; time from onset of hemorrhage to EH = 93.4 +/- 4.4 minutes). The rats then were resuscitated with LRS, 3 times the SBV over 45 minutes, followed by 2x over 60 minutes. One group received 400 micrograms/kg DZ, and another group received saline, with the 2x LRS. Sham animals were not hemorrhaged. Gut absorptive capacity was determined by the 1-hour D-xylose absorption test at 2 and 4 hours after EH. Results demonstrate that GAC is significantly depressed after hemorrhage and resuscitation. Administration of diltiazem restored GAC to normal levels. Thus DZ is a useful adjuvant to treatment after trauma-hemorrhagic shock, because it restores GAC to normal and allows for early enteral nutrition.

Animals↗
PubMed1991

legless insertional mutation: morphological, molecular, and genetic characterization.

Limb morphogenesis is an excellent model system to study pattern formation during vertebrate development. The legless (lgl) insertional mutation can serve as a tool to analyze specific events in limb development at the embryologic, genetic, and molecular levels. Hemizygous mice of this transgenic line are phenotypically normal, but homozygous mutants are inviable and exhibit limb, brain, and craniofacial malformations, as well as situs inversus. By morphological analysis of mutant hindlimb buds we show absence of a normal apical ectodermal ridge, a structure required for limb bud outgrowth, and an unusually high degree of mesenchymal and ectodermal cell death. Mutant embryos are extremely sensitive to retinoic acid, a known teratogen with a proposed role in limb development. The hindlimb malformations in legless mutants are less severe when bred into the BALB/c background, suggesting the involvement of other strain-specific genes. Molecular analysis of the disrupted region indicates two tightly linked insertion sites. Sequences flanking the transgene insertions have been cloned and mapped to chromosome 12, near the iv (situs inversus viscerum) locus. Consistent with this, complementation tests confirm allelism of lgl and iv and suggest that the transgene insertion may have disrupted more than one gene. Phylogenetically conserved sequences flanking the transgene insertions were identified and used to isolate candidate lgl and iv cDNAs.

Alleles↗
PubMed1991

Structure of 75Se.

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Journal Article↗
PubMed1991

Resistance to photodynamic therapy in radiation induced fibrosarcoma-1 and Chinese hamster ovary-multi-drug resistant. Cells in vitro.

A degree of resistance to photodynamic therapy (PDT) has been induced in radiation-induced fibrosarcoma-1 (RIF-1) tumor cells by repeated photodynamic treatment with Photofrin (4 or 18 h incubation) in vitro to the 0.1-1% survival level, followed by regrowth from single surviving colonies. The resistance is shown as increased cell survival in the strain designated RIF-8A, compared to the wild-type RIF-1 cells, when exposed to increasing Photofrin concentration for 18 h incubation and fixed light exposure. No difference was found between RIF-1 and RIF-8A in the uptake of Photofrin per unit cell volume at 18 h incubation. Resistance to PDT was also observed in Chinese hamster ovary-multi-drug resistant (CHO-MDR) cells compared to the wild-type CHO cells, possibly associated with decreased cellular concentration of Photofrin in the former. By contrast, the PDT-resistant RIF-8A cells did not show any cross-resistance to Adriamycin, nor was there any significant drug concentration difference between RIF-1 and RIF-8A. These findings suggest that different mechanisms are responsible for PDT-induced resistance and multi-drug resistance.

Animals↗
PubMed1991

Measurement of D-xylose gut absorptive capacity in conscious rats.

Recently, it has become evident that the gut plays a central role in the development of multiple organ failure in the critically ill patient after trauma-hemorrhage and sepsis. However, it remains unknown whether gut absorptive capacity (GAC) is altered under those conditions. The aim of this study, therefore, was to use a rat model for GAC measurements independent of the function of other organs and to determine whether GAC is altered after trauma. Rats (n = 79; 250-325 g) were lightly anesthetized with ether, and a 6-cm midline laparotomy was performed (i.e., trauma induced). A nasogastric tube was inserted and after cannulation of various blood vessels, the animals were allowed to recover from anesthesia. They were then divided into various groups for determinations of GAC over a period of 5 days. Control animals had GAC measurements without any surgery being performed on them. GAC was determined using the 1-h D-xylose absorption test and measuring D-xylose concentration in the portal blood. Results demonstrate that GAC 1) is significantly depressed for the first 48 h after trauma, 2) returns to normal 72 h after trauma, and 3) is further depressed by hemorrhage and resuscitation and by sepsis after trauma. Thus the model described here can be used to investigate the effects of trauma, trauma plus hemorrhage, trauma plus sepsis, hemorrhage alone, and sepsis alone on GAC, independent of the function of other organs.

Analysis of Variance↗
PubMed1991

Accident & Emergency Department's response to patients' inquiries by telephone.

A prospective survey of all telephone calls for medical advice to the Accident & Emergency Department of Leicester Royal Infirmary was undertaken. The objectives of the study were to quantitate the frequency and circumstances related to these inquiries. Over the study period of 10 days, details of 154 telephone calls were recorded. The results demonstrated the perception of the general public, that the A & E department was the most logical place to contact. Only 30% (46) attempted to seek advice from their general practitioner prior to calling the department.

Emergency Medical Services↗