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Biomedical subjects

H Singh

Publications and source records attributed to H Singh.

At least 775 records · Page 43Linked to original sources
PubMedDate not supplied

A nuclear factor that binds to a conserved sequence motif in transcriptional control elements of immunoglobulin genes.

Trans-acting factors that mediate B-cell specific transcription of immunoglobulin genes have been postulated based on an analysis of the expression of exogenously introduced immunoglobulin gene recombinants in lymphoid and non-lymphoid cells. Two B-cell-specific, cis-acting transcriptional regulatory elements have been identified. One element is located in the intron between the variable (V) and constant (C) regions of both heavy and kappa light-chain genes and acts as a transcriptional enhancer. The second element is found upstream of both heavy and kappa light-chain gene promoters. This element directs lymphoid-specific transcription even in the presence of viral enhancers. We have sought nuclear factors that might bind specifically to these two regulatory elements by application of a modified gel electrophoresis DNA binding assay. We report here the identification of a human B-cell nuclear factor (IgNF-A) that binds to DNA sequences in the upstream regions of both the mouse heavy and kappa light-chain gene promoters and also to the mouse heavy-chain gene enhancer. This sequence-specific binding is probably mediated by a highly conserved sequence motif, ATTTGCAT, present in all three transcriptional elements. Interestingly, a factor showing similar binding specificity to IgNF-A is also present in human HeLa cells.

B-Lymphocytes↗
PubMedDate not supplied

A lymphoid-specific protein binding to the octamer motif of immunoglobulin genes.

Immunoglobulin gene promoters are active only in lymphoid cells and this tissue-specific activity requires an octamer sequence, ATTTGCAT. Paradoxically, this same octamer motif seems to be a transcriptional control element in promoters which are active in all tissues. Using an electrophoretic mobility shift assay to identify DNA binding proteins, we have now detected two species of nuclear proteins which bind specifically to this octamer. One previously characterized form (NF-A1) was found in all cell lines tested while the other form (NF-A2) was restricted to lymphoid cell lines. NF-A2 was found in cell lines representing all stages of B-cell differentiation and in half of the T-lymphoma cell lines tested. The identification of a lymphoid-specific octamer binding protein may account for the lymphoid-specific activity of immunoglobulin promoters.

Animals↗
PubMedDate not supplied

The efficacy of continuous cryotherapy on the postoperative shoulder: a prospective, randomized investigation.

This prospective, randomized investigation evaluated the efficacy of cryotherapy on subjective responses after both open and arthroscopic procedures on the shoulder. Seventy patients were randomly assigned to one of two study groups: (1) continuous cryotherapy group and (2) age-matched control group. Visual analog scales were used to assess subjective responses on postoperative days 1, 7, 14, and 21. On day 1, patients receiving cryotherapy reported significantly less pain during sleep and significantly more comfort in bed and rated their sleep as more restful than the control subjects. During days 7 through 21, cryotherapy subjects reported a significant reduction in frequency and intensity of pain, as well as less pain during shoulder rehabilitation, than the control subjects. These results indicate that cryotherapy is an effective method for postoperative pain control because it decreases the severity and frequency of pain and allows a return to normal sleep patterns while increasing overall postoperative comfort and satisfaction.

Analysis of Variance↗
PubMedDate not supplied

Effects of thio-tepa and hydroxyurea on sperm production in Lakeview hamsters.

The spermatogenic cell sensitivity in the induction of sperm abnormalities by two antineoplastic agents, thio-TEPA and hydroxyurea in inbred Lakeview hamsters was studied and the results were compared with those of similar investigations with mice. Testis weights, epididymal sperm numbers, and body weights were also monitored up to 12 wk after treatment. Thio-TEPA administration increased sperm abnormalities and reduced testis weights as well as sperm numbers in a dose-dependent manner at wk 4 and 12 after treatment. Hydroxyurea administration was ineffective in inducing sperm abnormalities, but testis weights and sperm numbers were adversely affected dose-dependent changes in body weights after treatment with either agent were also recorded. The findings with thio-TEPA on sperm morphology agree with those reported for the mouse. However, unlike the results of the mouse studies, hydroxy-urea effects on sperm shape were not observed in the hamster.

Animals↗
PubMedDate not supplied

Antispermatogenic effects of ethyl methanesulfonate and benzo[a]pyrene in PD4 Lakeview hamsters.

Mammalian sperm seems to provide an excellent cell type for monitoring mutagenic and other toxicological damage to the germinal tissue. Studies with mice indicated that most agents known for their mutagenic activity in vivo produced marked elevations in sperm abnormalities. To determine whether this response is typical of other species, groups of inbred Lakeview hamsters were exposed to ethyl methane-sulfonate (EMS) and benzo[a]pyrene (BP) in five daily subacute ip doses ranging from 5 to 125 mg/kg and 2 to 50 mg/kg, respectively. Percentage of abnormal sperm, testis weight, and body weight were monitored at wk 1, 4, and 10 after treatment. EMS exposures increased the frequency of sperm abnormalities and reduced sperm numbers and testis weights. Body weights were also affected. BP exposures did not induce sperm abnormalities; however, there were marked reductions in sperm number and testis weight. These findings are in agreement with results of EMS studies in the mouse; however, BP exposure did induce sperm abnormalities in the mouse.

Animals↗
PubMedDate not supplied

Effect of topical applications of silver sulfadiazine on the natural killer cell activity in a rat model of thermal injury.

The effect of topical application of silver sulfadiazine cream on the natural killer (NK) cell cytotoxicity was studied in a rat model of thermal injury. The rats were given a 30% total body surface area scald injury and the NK cell cytotoxicity was studied in rats at different days postinjury with or without treatment with silver sulfadiazine. The NK cell activity was observed to be significantly (P less than .0025) suppressed at day 7 postinjury in nontreated burned rats compared with control sham burned animals. Interestingly, in rats treated with silver sulfadiazine twice daily, no suppression in NK cell activity was observed. The application of base cream (without silver sulfadiazine) did not have any significant effect on the NK cell activity in burned rats. The data show that the effect of silver sulfadiazine on NK cell activity may be due to the sulfadiazine component, since the serum levels of sulfadiazine (33.7 +/- 1.9 micrograms/dL) were observed to be maximal at day 7 postinjury.

Administration, Cutaneous↗
PubMedDate not supplied

Effects of rat interleukin-2 and rat interferon on the natural killer cell activity of rat spleen cells after thermal injury.

The natural killer cell activity of splenocytes from rats with scald injury was observed to be significantly suppressed at 7 days after injury compared with that of normal nonburned controls. Incubation of splenocytes from normal rats or rats with burn injury with either rat interleukin-2 or rat interferon (IFN-alpha and IFN-beta) significantly increased the natural killer cell activity. Addition of a rabbit anti-rat interferon antibody to spleen cells incubated with interleukin-2 did not produce any significant alteration in interleukin-2-related enhancement of natural killer cell activity. These results suggest that enhancement of natural killer cell activity after incubation of splenocytes with interleukin-2 is not due to interferon production but is an independent event. Preincubation of spleen cells with a mouse monoclonal antibody to rat interleukin-2 receptor was observed to abolish the interleukin-2-related enhancement of natural killer cell activity completely, whereas it partially blocked the interferon-related enhancement. These results were also confirmed by enhancement of natural killer cell activity of burned rats after in vivo administration of interleukin-2. Our studies thus indicate that after thermal injury, the observed decrease of natural killer cell activity can be enhanced by both interleukin-2 and interferon independently of each other. The decreased natural killer cell activity may be due to a decrease in interleukin-2 production or availability and not to an interleukin-2 receptor defect. These studies thus point toward a potential therapeutic significance of interleukin-2 in enhancing immune function after thermal injury.

Animals↗
PubMedDate not supplied

Some actions of chandonium iodide, a new short-acting muscle relaxant, in anaesthetized cats and on isolated muscle preparations.

1. The actions of the new skeletal muscle relaxant chandonium (HS310) on the cardiovascular, respiratory and skeletal muscle systems of the cat under chloralose anaesthesia and on chick and rat isolated skeletal muscle preparations have been described. 2. In the cat chandonium exhibited a potent, competitive, non-depolarizing neuromuscular blocking action that was rapid in onset and of short duration. It possessed a selective atropine-like action at the cardiac vagus neuro-effector junction but little or no ganglion blocking activity. Neither adrenergic neurone noralpha-adrenoceptor blocking properties were evident. 3. Unlike tubocurarine, chandonium was without effect on the airways system of the anaesthetized cat. 4. Chandonium possessed weak anticholinesterase action. It is conceivable that this effect may contribute to its short duration of action. 5. The results from these studies suggest that chandonium may have possible clinical applications as a short-acting muscle relaxant.

Acetylcholine↗
PubMedDate not supplied

Solitary nodular goiter. Review of cytomorphologic features in 441 cases.

OBJECTIVE: To study the cytomorphologic features of solitary nodular goiters (SNG). STUDY DESIGN: May-Grünwald-Giemsa-stained smears in 441 SNG diagnosed by ultrasonography and fine needle aspiration (FNA) and found to have optimum cellular material at review were subjected to detailed cytologic assessment. The age of the patients ranged from 11 to 75 years, with a median of 35. Male: female ratio was 69:372. The parameters for cytologic assessment included cellularity, colloid content, acinar formation, papillary formation, intranuclear cytoplasmic inclusions, nuclear grooves, marginal vacuoles, Hürthle cells and various inflammatory cells. Histopathology reports on thyroidectomy specimens were available in 27 cases from two Delhi hospitals. RESULTS: Hyperplastic nodules (68 cases) differed significantly from colloid goiters (269 cases) by having more cases with excessive cellularity, acinar formation and marginal vacuoles (P < .001). There was also a significant difference with respect to papillary formation and moderate-to-excessive colloid content (P < .001). As compared to hyperplastic nodules, neoplasms (60 cases) had a significantly higher number of cases with papillary formation, intranuclear inclusions and nuclear grooves but lower number of cases with marginal vacuoles (P < .01-.001). Among neoplasms, usual papillary carcinoma (19 cases) differed from follicular neoplasms (20 cases) with respect to acinar formation, papillary formation and nuclear grooves (P < .001). A significant difference was also observed with respect to colloid content and nuclear inclusions. Follicular variant of papillary carcinomas (FVPC) (10 cases) emerged as a distinct cytologic entity following review and differed from usual papillary carcinomas in having a higher number of cases with acinar formation, tubular formation and marginal vacuoles (P < .01-.001) and lower number of cases with nuclear grooves (P = .05). FVPC also differed from follicular neoplasms with respect to papillary formation, tubular formation, intranuclear inclusions and nuclear grooves (P < .01-.001). Overall cytohistologic agreement was achieved in 24 of 27 (88.9%) cases. CONCLUSION: Detailed cytologic assessment of FNA smears-in SNG was helpful in highlighting parameters that differentiate between various types of goiters.

Adolescent↗
PubMedDate not supplied

Valgus laxity of the ulnar collateral ligament of the elbow in collegiate athletes.

In this investigation, we determined the patterns of valgus laxity and acquired valgus laxity of the ulnar collateral ligament in the elbows of collegiate athletes involved in overhead and nonoverhead sports. Acquired valgus laxity of the elbow is defined as the differential amount of stress valgus opening between the dominant and nondominant elbows. Forty-eight asymptomatic male athletes involved in sports that require overhead arm movements (baseball, tennis, and swimming) and 88 asymptomatic male athletes involved in nonoverhead sports (track, lacrosse, fencing, and wrestling) underwent fluoroscan examination of both their elbows with (13 daN) and without (0 N) valgus stress. There were no statistically significant differences in the amount of valgus stress opening or in acquired valgus laxity between the two groups. In fact, 25% (34 of 136) of the athletes showed an acquired valgus laxity of more than 0.5 mm, and 51.5% (70 of 136) had an acquired valgus laxity that was actually negative. There was also no correlation between the number of years played and acquired valgus laxity. Our results show that acquired valgus laxity does not exist in asymptomatic athletes involved in overhead sports, and there is no threshold value of measurement indicative of acquired valgus laxity.

Analysis of Variance↗
PubMedDate not supplied

Determination of ventilatory minute volumes for normocapnic ventilation under anaesthesia in healthy adults.

BACKGROUND: Mechanical ventilation under anaesthesia needs to be controlled to maintain normal oxygen and carbon dioxide tensions in the blood and to economize on fresh gas flows. Various ventilation nomograms such as Radford's nomogram and Nunn's CO2 predictor are based on data from studies, some of which do not mimic the conditions which prevail under anaesthesia. We, therefore, planned a study to formulate nomograms for normocapnic ventilation for anaesthetized adult subjects. METHODS: Two hundred and fifty-three patients with normal pulmonary function tests, scheduled for elective non-thoracic surgery were studied. Subjects were ventilated with a Siemens Servo 900 B ventilator using CO2 analyser 930 (Siemens-Elema Sweden) to adjust the minute volume sufficient to maintain end-tidal carbon dioxide fraction (FE,CO2) at around 5.5 normocapnia (PaCO2 5.06-5.6 kPa). This was confirmed with arterial blood gas analysis. RESULTS: The mean (SD) ventilation required for male patients was 6.123 (0.91) L [105 (13.1) ml/kg]. This was significantly higher than the requirement for female patients [5.262 (0.82) L; 98.7 (13.3) ml/kg]. The minute volume requirements showed a significant correlation with weight (W), height (H), body surface area, body mass index and other combinations of weight and height such as W x H, W/H, W2, W3 and H/W1/3. Nomograms were constructed for different weights and heights of males and females using multiple regression analysis. These minute volumes were found to be significantly higher than those calculated according to Radford's nomogram as well as Nunn's CO2 predictor and significantly lower than the Adelaide ventilation guide. CONCLUSION: The differences obtained in our nomograms are probably because the earlier ones were based on minute carbon dioxide production and physiological dead space data obtained from widely differing studies, some of which did not resemble conditions prevailing under anaesthesia. None of these used strict inclusion criteria such as pulmonary function tests. These may also be due to a difference in body structure between the subjects studied. Therefore, minute volume requirements calculated based on available western nomograms should not be applied to Indian subjects for normocapnic ventilation under anaesthesia.

Adolescent↗
PubMedDate not supplied

Two stage reconstruction for the Shepherd's crook deformity in a case of polyostotic fibrous dysplasia.

Polyostotic fibrous dysplasia leads to progressive and disabling deformity involving the proximal femur. Conventional methods of treatment have been ineffective in controlling this problem. Two stage reconstruction was carried out in a case of polyostotic fibrous dysplasia with bilateral shepherd's crook deformity. Bilateral subtrochanteric osteotomies with intramedullary fixation in the first stage and intertrochanteric osteotomies in the second stage with nail plate fixation was done to provide definitive control of the deformity. Bone graft was not used.

Adult↗