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Biomedical subjects

K Ahmad

Publications and source records attributed to K Ahmad.

At least 163 records · Page 9Linked to original sources
PubMed1985

Plasmid characterization of Shigella spp. isolated from children with shigellosis and asymptomatic excretors.

Strains of Shigella dysenteriae type 1 and Sh. flexneri isolated during 1981-82 from children with shigellosis and also from asymptomatic excretors were examined for drug resistance and for the presence of plasmids. Shigella strains isolated from dysenteric children showed multiple plasmid bands. Thirty-eight percent of the strains transferred the drug resistance factor(s), either partially or fully to a recipient Escherichia coli K12 strain. Plasmids in the molecular weight range from between 44-76 Mdal were correlated with drug resistance. It was found that multi-resistant clinical isolates generally harbour a single large transmissible plasmid. Strains isolated from asymptomatic excretors demonstrated plasmid patterns different from those isolated from children with shigellosis although the bands were relatively homogeneous within each group. Both the groups showed the presence of a 140 Mdal plasmid band conferring invasiveness and such strains gave a positive Sereny test. This study thus shows that Shigella strains from asymptomatic excretors also retain invasiveness.

Carrier State↗
PubMed1985

Motility and fertility of frozen bull spermatozoa in tris-yolk and milk extenders containing amikacin sulfate.

Amikacin sulfate, an aminoglycoside antibiotic, effective against some streptomycin-resistant organisms, was tested in bull semen extended with whole milk and egg yolk-Tris extenders in a 6 X 5 X 2 factorial arrangement. Semen from six bulls was frozen in extenders containing 500, 1000, and 2500 microgram/ml of amikacin, a control containing 500 IU/ml of penicillin plus 1000 micrograms/ml of streptomycin plus 500 IU/ml of polymyxin, and control plus amikacin (1000 micrograms/ml). Semen was frozen in .5 ml polyvinyl chloride straws in liquid nitrogen vapor and stored in liquid nitrogen for 2 wk. Straws were thawed in a water bath at 35 degrees C for 30 s. Postthaw motility of spermatozoa in each treatment was assessed using two straws by two observers independently. At amikacin concentrations of 500, 1000, or 2500 micrograms/ml, the percentage of motile spermatozoa averaged 47, 45, and 36% in whole milk and 52, 46, and 46% in egg yolk-Tris. Control and control plus amikacin (1000 micrograms/ml) were 49 and 47% in whole milk and 48 and 52% in egg yolk-Tris. Only amikacin in milk at 2500 micrograms/ml, depressed sperm motility. A fertility trial was conducted to compare the control mixture of antibiotics in whole milk with whole milk also containing 500 micrograms/ml of amikacin. The nonreturn rate to 1182 first service inseminations with semen treated with amikacin (500 micrograms/ml) plus control antibiotics was 70.4% compared with 70.5% for 1494 first service inseminations with control semen. Amikacin can safely be added to whole milk and egg yolk-tris extenders to control streptomycin-resistant organisms.

Amikacin↗
PubMed1984

Apical lung carcinoma.

During the period 1955 to 1975, 63 consecutive cases of apical lung carcinoma were treated in the Radiation Therapy Division of the University of Michigan Medical Center (UMMC). Supervoltage external radiation alone or combination of radiation and surgery were the main modalities of treatment used in these patients. Our results show 27.9% and 20.9% 3 and 5 years actuarial survival, respectively, in patients who received 5000 to 6000 cGy (rad) of radiation alone. Survival was better in T2 lesions (24.9%) as compared with T3 lesions (7.9%) and in those patients who had no regional adenopathy (30.2% in T2, N0 lesions and 11.6% in T3, N0 lesions). Local osseous and nervous extensions also carried poor prognosis. The results with preoperative irradiation were no better than radiation therapy alone.

Adenocarcinoma↗
PubMed1984

High-dose radiation therapy in carcinoma of the pyriform sinus.

In a retrospective analysis of 61 patients with carcinoma of the pyriform sinus, treated primarily with high doses of radiation therapy with surgery reserved for persistent or recurrent tumor, survival rates of 56.5% and 12.4% were found in Stages III and IV, respectively. The two patients with Stage II disease were cured. There were no Stage I patients. The local control of T4 lesions and N2-3 lesions, as well as the survival of patients with Stage IV disease, is poor with radiation alone. This points out the necessity of combining irradiation with surgery and/or chemotherapy for Stage IV disease. The results in early stages with radiation alone are acceptable.

Adult↗
PubMed1984

Role of radiation therapy in carcinoma of the hypopharynx.

In a series of 199 patients with hypopharyngeal carcinoma treated with irradiation, the primary tumor was controlled in 63 per cent, 54 per cent, 44 per cent and 14 per cent of T1-T4 lesions, respectively. The five-year actuarial survival for stages I, II, III and IV patients was 60 per cent, 66 per cent, 49 per cent and 18 per cent. It was significantly better in patients with tumors located at the upper hypopharynx (p = 0.024). Early lesions yielded satisfactory results with irradiation alone. Advanced tumors had poor prognosis and other treatment modalities along with irradiation should be tried.

Actuarial Analysis↗
PubMed1984

Effect of thaw rates on survival of buffalo spermatozoa frozen straws.

Eighteen ejaculates from three buffalo bulls of Nili-Ravi breed were tested in a 3 X 6 X 3 factorial experiment. Semen was extended in lactose-fructose-egg yolk-glycerol extender containing penicillin (1000 IU/ml) and streptomycin (1000 micrograms/ml). Semen was frozen in .5-ml polyvinyl chloride straws in liquid nitrogen vapor and stored in liquid nitrogen for 24 h. Straws were thawed at water bath temperatures of 0, 37, or 75 degrees C for 2 min, 15 s, and 9 s, respectively. At thawing bath temperature of 0, 37, or 75 degrees C, percentage of motile spermatozoa averaged 30, 40, and 50%. Differences were significant between thaw rates for initial postthaw motility, postthaw sperm survival at 37 degrees C, and absolute index of survival of spermatozoa. Bulls were also different for initial postthaw motility, postthaw sperm survival at 37 degrees C, and absolute index of survival of spermatozoa. Thaw rate of 75 degrees C for 9 s was superior to other rates.

Animals↗
PubMed1984

Effect of ascorbic acid in the treatment of tetanus.

The effect of daily intravenous administration of 1000 mg ascorbic acid (AA) in tetanus patients aged 1-30 years was studied. In the age group of 1-12 years, 31 patients were treated with AA as additional to antitetanus serum, sedatives and antibiotics. It was found that none of the patients died who received AA along with the conventional antitetanus therapy. On the other hand, 74.2 per cent of the tetanus patients who received the conventional antitetanus therapy without AA (control group) were succumbed to the infection. In the other age group of 13-30 years, there were 27 and 38 patients in the treatment and control groups respectively. The mortality in the AA and control groups were 37 percent and 67.8 percent respectively. These results suggest that AA might play an important role in reducing the mortality of tetanus. This was supported by the fact that AA was found to mitigate the toxic effects of strychnine producing tetanus like condition in young chicks in the present study.

Adolescent↗
PubMed1983

Erythrocyte membrane stabilization by decamethonium and succinylcholine.

The effects of decamethonium and succinylcholine on hypotonic haemolysis of erythrocytes were studied. These drugs at concentrations of 5 X 10(-8) M to 10(-4) M caused a dose-dependent inhibition of haemolysis of erythrocytes in 0.45% NaCl but lysis occurred when the drug concentrations were increased to 10(-3) M. These results indicate that decamethonium and succinylcholine may have a membrane stabilization-lysis effect on erythrocytes.

Decamethonium Compounds↗
PubMed1981

Squamous cell carcinoma of the maxillary sinus.

A retrospective analysis of 59 cases of squamous cell carcinoma of the maxillary sinus, which were treated either with radiation alone or combined surgery and radiation, was performed. Fifty-six cases (95%) had T3 and T4 lesions. Our results show that six (66.6%) of nine of T3 and T4 lesions were controlled by combined therapy, while radiation alone controlled 15 (34%) of 44 of T3 and T4 lesions. Five-year actuarial survival of T3 and T4 patients treated with combined therapy was 75% and 33.3%, respectively, while survival of T3 and T4 patients treated with radiation alone was 38.4% and 33.2%, respectively. The five-year actuarial survival for the whole series was 39.3%. It is our opinion that better results could be obtained with surgery followed by radiation therapy in selected cases.

Adult↗
PubMed1981

Effect of carbon source on growth rate and phospholipid composition of Escherichia coli 15T- and an unsaturated fatty acid auxotroph.

Escherichia coli 15T- was grown with glucose, succinic acid, aspartic acid, oleic acid, and oleic plus aspartic acids as carbon sources, and a fatty acid auxotroph derived from 15T- was grown on oleic acid and oleic plus aspartic acids. The doubling time, phospholipid composition, phosphorus content, and the fatty acid composition of the phospholipids of cells in each of the media were determined. In all cases, phosphatidylethanolamine was the major phospholipid present; but with 15T- its concentration was inversely proportional to the doubling time in unsupplemented media. With the auxotroph the phosphatidylethanolamine concentration was essentially unchanged with growth. Total lipid phosphorus was inversely proportional to doubling time, an effect particularly evident with the auxotroph. Without oleic acid supplementation, the major effects of carbon source on fatty acid composition are decreases in the content of palmitoleic acid and increases in the content of cis-9, 10-methylene hexadecanoic acid as growth rate decreases. Oleic acid supplementation elevated 18:1 fatty acid content in both 15T- and the auxotroph.

Aspartic Acid↗
PubMed1981

Computer controlled hyperthermia unit for cancer therapy.

Hyperthermia is the artificial elevation of tissue temperature above 41 degrees C with therapeutic intent. Most of the currently used hyperthermia units lack feedback temperature control mechanisms, and, therefore, are not optimal for clinical trials. To solve this problem, we have developed a control system based on a microcomputer. The computer measures the tumor and normal tissue temperature using fine thermocouple sensors and regulates the output of the microwave generator to achieve and maintain the prescribed tumor temperature under specified conditions. Safety procedures are incorporated to avoid heating the tumor or normal tissue beyond predetermined limits.

Computers↗
PubMed1980

Cryopreservation of buffalo semen.

Twenty-one split semen samples from five bulls were diluted in five diluents. The diluents comprised lactose-egg yolk-glycerol, fructose-egg yolk-glycerol and three different combinations of lactose and fructose with equal proportions of egg yolk and glycerol. The straw-method of deep freezing was used. Frozen semen was evaluated on the basis of post thawing motility percentage, survival of spermatozoa at 37 degrees C and absolute index of survival. Statistical analysis of data revealed highly significant differences between diluents for the three characteristics tested. The diluent comprising 11 per cent lactose 56.25 ml + 6 per cent fructose 18.75 ml + egg yolk 20 ml + glycerol 5 ml achieved the best results.

Animals↗