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Biomedical subjects

K Ahmad

Publications and source records attributed to K Ahmad.

At least 145 records · Page 8Linked to original sources
PubMed1991

Antibodies to sperm surface antigens and the c-myc proto-oncogene product inhibit early embryonic development in mice.

The effects of antibodies against sperm antigens and the c-myc proto-oncogene product on early embryonic development were investigated in mice. Affinity-purified Fab' antibodies against lithium diiodosalicylate (LIS)-solubilized murine sperm extract and fertilization antigen (FA-1) reduced (p less than 0.01 to p less than 0.001) blastulation rates of in vitro cultured 2-cell murine embryos primarily because of an arrest of development at the morula stage. Similarly, the c-myc monoclonal antibody (mAb) affected early embryonic development in a dose-dependent manner. These effects were specific, since immunoabsorption, with its respective peptide, completely blocked the inhibitory effect of the c-myc mAb. Anti-LIS sperm Fab' identified four protein bands (approx. 36, 29, 24.6, and 17.6 kDa) on Western blots of extracts from unfertilized and fertilized ova, one band (approx. 68 kDa) each on 4-8-cell embryo and morula extracts, and one band (approx. 53 kDa) on blastocyst extracts. Anti-FA-1 Fab' did not react with unfertilized or fertilized ova, but specifically identified two protein bands (approx. 53 and 25.7 kDa) on blots of 2-cell-embryo extract, one band (approx. 25.7 kDa) on morula extract, and one band (approx. 53 kDa) on blastocyst extract. The c-myc mAb did not react with any band corresponding to the c-myc protein on blots of extracts from unfertilized or fertilized ova, 2-cell embryos, 4-8-cell embryos, morulae, or blastocysts. These results suggest that some of the cross-reacting sperm antigens that are expressed during early cleavages, and the product of the c-myc proto-oncogene may have a role in normal early embryonic development.

Animals↗
PubMed1991

Role of membrane phosphotyrosine proteins in human spermatozoal function.

The monoclonal anti-phosphotyrosine antibody (PTA) recognized proteins related to relative molecular mass regions of 94,000 +/- 3000 and 46,000 +/- 3000 Mr on Western blots of detergent-solubilized non-capacitated human sperm extract (HSE). The pattern of phosphorylation at tyrosine residues depended upon the physiological state of the sperm cells. At least six protein bands corresponding to four molecular regions of 94,000 +/- 3000, 46,000 +/- 3000, 25,000 +/- 7000 and 12,000 +/- 2000 Mr, respectively, were labeled with 32P when human sperm were capacitated in vitro; the proteins belonging to the former three regions were phosphotyrosine proteins as they were precipitable by PTA. In vitro kinase assay performed directly on HSE indicated autophosphorylation of proteins of the same four molecular regions, with the capacitated sperm preparations having 30% higher 32P incorporation into 94,000 +/- 3000 Mr proteins and 17% less incorporation into 12,000 +/- 2000 Mr proteins as compared to the non-capacitated sperm preparations. Both of these protein regions were also autophosphorylated at tyrosine residues when immunoprecipitated phosphotyrosine proteins were used for the kinase assay. Phosphorylation of tyrosine residues of 94,000 +/- 3000 Mr proteins was further stimulated by 1.38- to 1.46-fold in response to exposure to zona pellucida proteins, namely the porcine ZP3 and human zona proteins (HZP); the HZP induced the highest response. Immunofluorescence observations on fixed human sperm demonstrated that capacitation as well as exposure to zona proteins increased the degree of tyrosine-specific fluorescence per sperm cell as well as the number of sperm cells that showed fluorescence at the acrosomal region of the spermhead.(ABSTRACT TRUNCATED AT 250 WORDS)

Antigens↗
PubMed1990

Results of treatment in locally advanced carcinoma of the endometrium.

The impact of treatment on survival was analyzed in 106 patients with carcinoma of the endometrium stage II (n = 61) and stage III (n = 45). There was no significant difference in survival in patients with stage II who were treated with radiation therapy alone or with combination of surgery and radiation therapy. Their five-year actuarial survival was 74.5% and 71.3% respectively (p = greater than 0.05). However, combined treatment was associated with significantly superior survival in patients with stage III disease where the survival was 57.3% versus 17.5% in patients who received irradiation alone (p = 0.01). Diagnosis of stage III disease based upon clinical (CS III) or pathological (PS III) findings was responsible for this difference in survival. Patients with CS III whose tumor could not be resected because of its extent carried poorer prognosis. Patients with stage II had excellent tumor control in pelvis as compared to patients with stage III. Treatment-related complications were minimal. Overall survival of patients with stage III was poor (33.8%) due to a high rate of pelvic and/or extrapelvic recurrences.

Adenocarcinoma↗
PubMed1989

Radiation therapy in stage II carcinoma of the endometrium.

A retrospective analysis of 61 patients with Stage II carcinoma of the endometrium was carried out. Our results suggest that when given carefully and adequately, radiation therapy alone is as effective as a combination of surgery and irradiation and is well tolerated. Five-year actuarial survival was 74.5% in patients treated with radiation therapy alone (16 patients) as compared to those patients who received either preoperative radiation (35 patients) or postoperation radiation (ten patients) where the survival was 70.8% and 78.3%, respectively (P greater than or equal to 0.05). Tumor was controlled in the pelvis in 93.4% of patients. Complications of treatment were seen in 8.2%. With the exception of one patient with bowel obstruction requiring surgery, the rest of the complications were minor. From these results, it appears that a planned radiotherapy is a good alternative to combination of surgery and irradiation.

Combined Modality Therapy↗
PubMed1989

Assessment of the viability and fertilizing potential of cryopreserved bovine spermatozoa using dual fluorescent staining and two-flow cytometric systems.

A dual fluorescent staining system utilizing 5 (and-6)-carboxy-4',5'-dimethyl fluorescein diacetate (CDMFDA) and Hydroethidine (HED) was developed to provide quantifiable information reflective of spermatozoal viability and fertilizing potential. Cryopreserved spermatozoa from ten bulls on which there was fertilizing capacity information were incubated for 1.5, and 3 hr at 39 degrees C prior to fluorogenic staining. Spermatozoa were analyzed using both a FACS Analyzer and an EPICS V flow cytometer to determine if a particular fluorescence pattern was due to an instrumental artifact or cellular processes. Five fluorescent cellular populations were identified by the FACS Analyzer and three populations by the EPICS V. Spermatozoa were quantified after each incubation time for red (HED) and green (CDMFDA) fluorescence. Viable spermatozoa retained the greatest amount of both green and red fluorescence. Dead or moribund spermatozoa had a decrease in over-all fluorescence. The number of viable cells at 0 hr plus the number of dead or morbid cells at any time period were identified by the FACS Analyzer as important in estimating the potential fertility of a bull. The EPICS V identified the number of dead or moribund cells as being related to nonreturn rates. Incubation of samples decreased cellular viability, which resulted in reduced levels of both green and red fluorescence. Similarities between data obtained with both flow cytometers illustrated that cellular processes, not instrumental artifacts, were responsible for the decrease in over-all fluorescence when viability declined, the relationship between the number of cells with specific fluorescence levels and nonreturn rates, and the incubative-induced changes in fluorescence patterns.

Animals↗
PubMed1989

Stage III carcinoma of the endometrium. Results of treatment.

The impact of treatment on survival was analysed in 45 patients with stage III carcinoma of the endometrium. Our results indicate that patients treated with a combination of surgery and radiation therapy did significantly better than those treated with radiation alone. The five-years survival was 57.3% and 17.5%, respectively (p = 0.01). Patients with clinical stage III (CS III) whose tumor could not be resected surgically did poorly than patients with pathological stage III (PS III). This difference, however, was not statistically significant (p = greater than 0.05). Treatment related complications were minimal. Overall survival of patients of 33.8% was directly attributable to increased pelvic and/or extra pelvic recurrences.

Adult↗
PubMed1988

Carcinoma in situ and microinvasive squamous carcinoma of the laryngeal glottis.

Twenty-five patients with severe squamous intraepithelial neoplasia, grade 3 (SIN III) of the glottis were identified and followed up; three patients (12%) eventually developed invasive carcinoma and nine patients (36%) were noted to have coexisting microinvasive carcinoma. Two of the patients with microinvasive carcinoma were treated by hemilaryngectomy, three with stripping and radiation therapy, two with stripping alone, and two by radiation therapy. None of the patients developed recurrent disease after one to five years of follow-up. This observation supports the approach of treating "true" microinvasive carcinoma similar to carcinoma in situ. The 16 remaining patients were treated by stripping (ten patients), stripping and radiation therapy (four patients), and radiation therapy alone (two patients). Three patients progressed to invasive squamous carcinoma at 35, 39, and 84 months after the diagnosis of SIN III. Patients in this study displaying SIN III with or without microinvasive carcinoma were successfully treated by surgery or radiation therapy alone or by combined therapy. The finding of 12% progression to invasive carcinoma and coexisting microinvasive carcinoma in 36% confirms the preinvasive nature of SIN III of the laryngeal glottis.

Adult↗
PubMed1988

Chemo/radiation with and without surgery in the thoracic esophagus: the Wayne State experience.

Wayne State University was the site of one of the initial experiences with combination chemotherapy, radiation, and surgery for carcinoma of the thoracic esophagus. This review analyzes all the patients seen with thoracic esophageal carcinoma from 1980 to 1984 inclusive, plus an additional 22 patient pilot study. The great majority of patients seen were treated with combination radiation and chemotherapy, which may have a greater applicability than dose esophagectomy. Eighty-nine patients completed planned preoperative treatment consisting of (5-FU cisplatin and radiation therapy). Of these patients, 39 patients refused or were not offered surgery, and 4 patients are still alive and well several years from treatment initiation. Fifty patients underwent esophagectomy. Twelve of this patients were free of tumor at esophagectomy, and 4 of these are still alive and well several years from treatment. One patient with residual tumor in the esophagectomy specimen alone is still alive. Because of disappointing results and surgical mortality risk, 22 patients were entered on the pilot study, increasing the tumor dose of 5,000 cGy, and increasing chemotherapy to 4 courses. Six patients are still alive in this small series. Since the results of radiation and chemotherapy combination approximates that of best prior trials of radiation therapy alone, a randomized study has been initiated comparing these treatment plans to determine if the combination of radiation and chemotherapy is superior to radiation alone.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1987

Some acoustic and aerodynamic characteristics of pharyngeal consonants in Iraqi Arabic.

The articulation of pharyngeal consonants in Arabic is still not fully understood. The production of these sounds by a small group of speakers of an Iraqi dialect was analysed by means of acoustic and aerodynamic techniques. It was found that both [n] and could be said to be produced by a constriction in the pharynx (whereby the possibility of epiglottal involvement cannot be excluded), but that laryngeal tension may also play an important role. Vowels preceded or followed by pharyngeals have lowered and centralized allophones. High rates of airflow for [n] may be facilitated by lowering the velum. Both sounds could be regarded as approximants, formed in a region of the vocal tract where true fricatives are very difficult to produce.

Epiglottis↗
PubMed1987

Head and neck cancer. Reliability of American Joint Committee's staging system as prognostic indicator.

The present American Joint Committee (AJC) staging system for the head and neck cancer does not satisfy the criteria as a prognostic or therapeutic indicator when patients are treated initially with radiation therapy. There are certain groups of patients allocated to advanced AJC stages where the prognosis is more favorable and, thus, should not be grouped with the poor prognosis stages. Recognition of these groups is important for any treatment planning or reporting of the end results.

Carcinoma↗
PubMed1987

Antibiotics for bull semen frozen in milk and egg yolk extenders.

In six experiments, gentamicin, clindamycin, amikacin, minocin, tylosin, and Linco-Spectin were tested for their effect on motility and fertility of frozen bull spermatozoa and all but clindamycin were used in fertility trials. Antibiotics were added to raw (unextended) semen and nonglycerol portions of the three commonly used semen extenders, whole milk, egg yolk-Tris, and egg yolk-citrate. Semen was frozen in .5-ml straws, stored in liquid nitrogen, and thawed at 37 degrees C for 30 s. Postthaw percentage of motile spermatozoa in antibiotic-treated semen was different for individual bulls in each experiment. Percentage of motile sperm was slightly but significantly depressed at the higher concentrations of clindamycin and Linco-Spectin tested in whole milk and with minocin in the two egg yolk extenders. In general, nonspermicidal concentrations of each antibiotic were established. Of five antibiotics tested for fertility, only gentamicin reduced fertility on the basis of 59-d nonreturn rates.

Animals↗
PubMed1986

Combined modality therapy utilizing a cisplatin combination for effective chemotherapy in patients with previously untreated head and neck cancer.

In patients with locally advanced head and neck cancer, the results of standard definitive treatments of surgery, radiotherapy, or both were disappointing. The local and regional recurrence rates were high, despite adequate surgical resection with negative margins and postoperative radiotherapy to all known or possible disease areas. Combination cisplatin chemotherapy given initially before definitive treatments produced a high overall antitumor response and up to 50 percent clinical complete response. Before answering the question of value of chemotherapy as part of the multimodality treatment, it is important to identify the safest and most form of chemotherapy. The degre of chemotherapy effectiveness is defined by the incidence of clinical and, most important, histologic complete response. To assess this effectiveness, chemotherapy was given before definitive treatments to patients with measurable disease. From our 10 year experience we have concluded that continuing the development of induction chemotherapy, including investigating the timing of such effective treatment and assessing the value of such therapy, is of the utmost importance.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1986

Postthaw survival and fertility of frozen bull spermatozoa treated with antibiotics and detergent.

Five factorial experiments were conducted, each with 10 bulls, three extenders, and six antibiotic treatments to determine safe levels of new antibiotics to add to bull spermatozoa. Dicloxacillin, cephapirin, ceforanide, gentamicin, and minocin were added at five concentrations to whole milk, egg yolk-Tris, and egg yolk-Tris detergent (sodium triethanolamine lauryl sulfate) extenders with penicillin and streptomycin as a control. Semen was extended to 20 X 10(6) sperm/ml, packaged in .5-ml straws, frozen and stored in liquid nitrogen, and thawed at 35 degrees C for 30 s. Two people assessed postthaw percentage of motile spermatozoa from two straws per treatment. Bulls and extenders always affected sperm motility significantly. Percentage of intact acrosomes of spermatozoa was assessed in selected treatments but did not differ in any experiment. Sodium triethanolamine lauryl sulfate tended to improve cryopreservation of spermatozoa. Percentage of motile spermatozoa in milk declined when concentrations of dicloxacillin exceeded 200 micrograms/ml or when gentamicin, as Gentocin, exceeded 500 micrograms/ml. Minocin was toxic at all levels tested in egg yolk and was nontoxic to sperm in milk extender at concentrations less than or equal to 100 micrograms/ml. Cephapirin and ceforanide were innocuous at all concentrations tested (200 to 2000 micrograms/ml). Fertility with cephapirin (500 micrograms/ml) added to an extender containing control antibiotics resulted in a 56-d nonreturn rate of 75.5 versus 72.1% for the control.

Animals↗