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Biomedical subjects

A Weaver

Publications and source records attributed to A Weaver.

At least 73 records · Page 4Linked to original sources
PubMed1991

An automated method for DNA preparation from thousands of YAC clones.

We describe an automated method for the preparation of yeast genomic DNA capable of preparing thousands of DNAs in parallel from a YAC library. Briefly, the protocol involves four steps: (1) Yeast clones are grown in the wells of 96-well microtiter plates with filter (rather than plastic) well-bottoms, which are embedded in solid growth media; (2) These yeast cultures are resuspended and their concentrations determined by optical density measurement; (3) Equal numbers of cells from each well are embedded in low-melting temperature agarose blocks in fresh 96-well plates, again with filter bottoms; and (4) DNA is prepared in the agarose blocks by a protocol similar to that used for preparing DNA for pulsed-field gels, with the reagents being dialyzed through the (filter) bottoms of the microtiter plate. The DNA produced by this method is suitable for pulsed-field gel electrophoresis, for restriction enzyme digestion, and for the polymerase chain reaction (PCR). Using this protocol, we produced 3000 YAC strain DNAs in three weeks. This automated procedure should be extremely useful in many genomic mapping projects.

Blotting, Southern↗
PubMed1990

The differential effect of eicosapentaenoic acid and oleic acid on lipid synthesis and VLDL secretion in rabbit hepatocytes.

The suppression of plasma very low density lipoprotein (VLDL) triglyceride levels by dietary fish oils rich in polyunsaturated n-3 fatty acids has been attributed to decreased hepatic VLDL secretion. To investigate the effect of n-3 fatty acids on lipid metabolism and VLDL secretion in a tissue culture system, we incubated rabbit hepatocytes with oleic acid and eicosapentaenoic acid (EPA) and examined [3H]glycerol and [14C]fatty acid incorporation into hepatocyte triglyceride and phospholipid and into media VLDL. Glycerol incorporation studies showed that EPA failed to stimulate VLDL triglyceride secretion from hepatocytes as occurred with oleic acid (P less than 0.05). Oleic acid preferentially enhanced hepatocyte triglyceride synthesis while EPA stimulated significantly phospholipid synthesis (P less than 0.01). Varying the relative concentrations of oleic acid and EPA at a constant total fatty acid concentration corroborated preferential triglyceride synthesis from oleic acid. Synthesis shifted predominantly to phospholipids with increasing concentrations of EPA and lower levels of oleic acid. Incorporation of the [14C]fatty acids (800 microM) followed similar patterns: 87% of [14C]oleic acid was incorporated into hepatocyte triglyceride and 44% of [14C]EPA was assimilated in hepatocyte phospholipid (p less than 0.001). Fatty acids at trace concentrations (53 nM) showed a more divergent pattern of lipid incorporation: 60% of [14C]oleic acid was incorporated into triglyceride while 91% of [14C]EPA was incorporated into phospholipid (p less than 0.001). We conclude that in primary rabbit hepatocyte culture, which appears to be a useful model to study lipid metabolism and VLDL secretion, EPA is avidly incorporated into phospholipid while oleic acid predominantly becomes esterified in triglyceride.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Oocyte production and ovarian steroid concentrations of immature rats in response to some commercial gonadotrophin preparations.

Four commercial gonadotrophin preparations, namely Folligon, F.S.H.-P., Folltropin and Ovagen, were examined for their effects on oocyte production and ovarian steroid concentrations in immature rats. The ratios of the FSH to LH concentrations of the preparations, determined by radioreceptor assays, were Folligon 5, F.S.H.-P. 18, Folltropin 49 and Ovagen 1090. Forty-eight hours after administering each gonadotrophin preparation to immature rats, ovulation was induced by injection of chorionic gonadotrophin. Twenty-four hours later, oocytes were recovered from the oviducts and counted. Oocytes were produced after injection of chorionic gonadotrophin following a single injection of Folligon (10-50 i.u.). However, no oocytes were produced in response to the other gonadotrophin preparations unless they were administered by continuous infusion (30-1000 micrograms day-1). When given by injection (Folligon) or infusion (others), the gonadotrophin preparations all promoted a dose-dependent increase in mean oocyte production, except at the highest doses when mean oocyte numbers either remained unchanged or declined significantly in the cases of Folligon and F.S.H.-P. The highest mean numbers of oocytes produced in response to Folltropin (48 +/- 9 oocytes, mean +/- s.e.m.) and Ovagen (47 +/- 7) were greater than those attained with Folligon (21 +/- 6) or F.S.H.-P. (31 +/- 5). Mean ovarian weights also increased in a dose-dependent fashion in response to each of the gonadotrophin preparations. Measurements of ovarian steroid concentrations 48 h after the onset of gonadotrophin treatment (i.e. immediately prior to ovulation induction with chorionic gonadotrophin) showed that the gonadotrophin preparations markedly influenced the ratios of ovarian oestradiol-17 beta and androgen (androstenedione plus testosterone) concentrations. At low doses the gonadotrophin preparations increased the ratio of oestradiol-17 beta to androgens, but at the highest doses, with the exception of Ovagen, the ratio was reduced relative to peak values. Co-infusion of ovine LH (NIADDK-oLH-25; 10-20 micrograms day-1) with Ovagen (250 micrograms day-1) or ovine FSH (10 micrograms day-1, NIADDK-oFSH-17), both low in LH content, increased the mean number of oocytes produced and also the ovarian oestradiol-17 beta:androgen concentration ratio. However, with 40 micrograms LH day-1, the oestradiol-17 beta:androgen ratio fell due to a continued increase in mean ovarian androgen concentrations and a decrease in mean ovarian oestradiol-17 beta concentration. The mean number of oocytes produced also fell significantly.(ABSTRACT TRUNCATED AT 400 WORDS)

Androstenedione↗
PubMed1990

The effects of chemotherapy on murine wound healing and orocutaneous fistula closure.

The effects of cisplatin and 5-fluorouracil on wound breaking strength and the rate of closure of an orocutaneous fistula were studied in 80 male rodents. Treatment rats received a total of 4.6 mg/kg cisplatin and 62 mg/kg 5-fluorouracil in six doses/12 days; control rats received 0.9 per cent saline. After treatment, 30 treatment and 30 control rats received a dorsal skin incision which was closed primarily. Wound breaking strength were tested at one, three and five weeks in ten rats from each group. An 8-mm orocutaneous fistula was made in the remaining ten treatment and ten control rats; the rate of closure was noted weekly. Cisplatin and 5-fluorouracil did not significantly impair wound breaking strength at one, three, or five weeks. The rate of closure of the orocutaneous fistula was not effected by cisplatin/5-fluorouracil. The chemotherapy caused severe facial cellulitis and death in four orocutaneous fistula rats. Combined chemotherapy with cisplatin and 5-fluorouracil should not interfere with planned surgical care of head and neck tumors. Concomitant antibiotic coverage, however, is advocated.

Animals↗
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

An intensive, five course, alternating combination chemotherapy induction regimen used in patients with advanced, unresectable head and neck cancer.

Progress in the treatment of advanced squamous cell cancer (SCC) of the head and neck (H & N) has included the development of combination chemotherapeutic regimens that achieve impressive complete response (CR) rates using two to three courses therapy with minimal toxicity and good patient tolerance. Further improvements in these results will require intensification of induction regimens. Therefore, a five course, alternating combination chemotherapy induction trial was initiated in an attempt to test the feasibility and toxicity of a prolonged, intensive induction regimen in patients with advanced SCC of H & N. Courses 1, 3, and 5 consisted of fluorouracil as a 120-hour infusion (5FU-I) with cisplatin (CACP) as an intravenous (IV) bolus. Courses 2 and 4 consisted of 3 weekly doses of high-dose methotrexate (HDMTX) followed by 5FU (5FU-b) and leucovorin rescue (LR). Forty-six stage IV patients with SCC of H & N (85% T4 and 58% N3) were entered. Thirty-one patients completed the study and 15 did not. Twenty-one of the 46 patients (46%) achieved a CR. Twenty-five of the 46 patients had N3 neck disease, ten of these 25 achieved a CR (40%), and eight did not complete therapy. Of the 15 patients not completing this study, one patient achieved a CR and eight achieved a partial response (PR). Eight of 46 (17%) were removed from study for reasons of toxicity (6% to 13%) or tumor progression (2% to 4%). The remaining seven were removed due to intercurrent medical conditions (four uncomplicated pneumonias and one gun shot wound) or lost to follow-up (2). Myelosuppression, mucositis, and skin toxicity increased in frequency by the end of the trial but were acceptable and reversible. The activity of this five-course regimen is promising given the advanced disease status of patients treated. Consideration of concurrent medical conditions, patient compliance, intensity of medical, nutritional and social support, and levels of acceptable toxicity will be necessary in the design of future, intensive induction trials.

Adult↗
PubMed1987

Achievement of superior survival for histologically negative versus histologically positive clinically complete responders to cisplatin combination in patients with locally advanced head and neck cancer.

In a series of three consecutive pilot studies conducted between 1977 and 1982 at Wayne State University, Detroit, Michigan, 191 consecutive patients with previously untreated, locally advanced head and neck cancer were treated with cisplatin (CDDP), vincristine, and bleomycin or CDDP and 5-fluorouracil (5-FU) infusion before definite surgery or radiation. A 39% (75/191) rate of complete clinical responses was achieved. Thirty-two of the chemotherapy-induced complete responders underwent radical surgery. Thirteen had no histologic evidence of residual disease in the surgically resected specimen. The CDDP and 5-FU infusion combination achieved the highest histologic complete response rate. All histologically complete responders who had completed local radiation therapy are clinically free of disease at median follow-up of 36 months. Patients who achieved complete response both clinically and histologically had superior survival as compared to patients who achieved complete response clinically and were subsequently found to have residual tumor in their surgically resected specimen (P = 0.01). An analysis of the clinical and pathological pretreatment characteristics was performed to identify factors predictive of histologic complete response. Advanced nodal disease correlated inversely with the achievement of negative histology in the surgically resected specimen (P = 0.02). No other factors were significant in predicting response.

Adult↗
PubMed1987

Solid tumor preparation for clinical application of flow cytometry.

Intense interest in advanced squamous cell cancers of the head and neck (SCC of H&N) has resulted from the recent progress made in tumor responses with chemotherapy and radiotherapy. Unfortunately, the response patterns and clinical outcome of such patients are not adequately predicted on an individual patient basis using clinical parameters or conventional morphology. The study of flow cytometrically determined cellular parameters in such tumors is therefore of interest, but is hindered by inadequate tumor preparative technology. The previous article (10) in this journal describes the use of a murine SCC tumor, LC12, which was employed for comparative testing and determination of optimum techniques of preparation for this tumor. This report describes the application of these techniques to 144 specimens of human SCC of H&N. The mean total yield for these specimens is 7.4 X 10(7) cells/g of tissue. The mean viable enzymatic yield (3.3 X 10(7) cells/g) was higher than the mean viable mechanical yield (2.0 X 10(7) cells/g) except when lymph nodes were the source of the specimen (5.4 X 10(7) cells/g). The mean dye exclusion viability from enzymatically dissociated specimens were above 90%. Significant aneuploidal subpopulation losses were evident in mechanically dissociated and enucleated specimens. 65% of the enzymatically dissociated specimens were successfully cultured with a mean cloning efficiency of 2.1 X 10(-3). Preparative techniques derived from comparative testing with a murine standard tumor have been successfully applied to 144 specimens of SCC of H&N with resultant high yields and excellent viability. Technical problems detected during the preliminary testing with LC12 were confirmed in the human tumors.

Adult↗
PubMed1987

Mannitol-induced acute renal failure.

Mannitol is an osmotic diuretic widely used in the diagnosis and prevention of acute oliguric renal failure, acute cerebral edema and acute glaucoma. Mannitol, though ordinarily a benign substance, may accumulate in renal failure with potentially deleterious consequences. Mannitol intoxication is ordinarily characterized by confusion, lethargy, stupor, and if severe enough, coma. The use of mannitol in renal failure has rarely been associated with a worsening of the preexistent renal dysfunction. We report a case of acute oliguric renal failure solely attributable to mannitol administered in the course of therapy for acute glaucoma.

Acute Kidney Injury↗
PubMed1986

The impact of conventional morphologic analysis on response rates and survival in patients with advanced head and neck cancers treated initially with cisplatin-containing combination chemotherapy.

The response to initial treatment with cisplatin-containing combination chemotherapy as well as survival, were correlated with tumor differentiation (well, moderate or poorly differentiated) in 164 patients with advanced, untreated squamous cell carcinoma of the head and neck. Thirty-three percent of the tumors were graded as poorly differentiated, 59% moderately differentiated, and 8% were well differentiated. The overall clinical response rates were nearly equal for the three grades of differentiation: 79% for well differentiated, 86% for moderately differentiated, and 89% for poorly differentiated. The complete response rate was somewhat higher for poorly differentiated tumors: 46% as compared to 32% and 29% for moderately and well differentiated respectively, but the differences were not statistically significant. The median survival for each morphologic group was 22, 16, and 12 months for well differentiated, moderately differentiated and poorly differentiated tumor, respectively (P = 0.097). For patients achieving a complete clinical response to chemotherapy, there was a difference in survival when stratified according to degree of histologic differentiation. Patients who were complete responders and had well or moderately differentiated tumors attained 75% and 38% survival at 36 months, respectively, versus 19% for patients with complete response and poorly differentiated tumors (P = 0.064). The degree of differentiation of previously untreated squamous cell cancers of the head and neck does not conclusively predict tumor response to combination chemotherapy, but may reflect differences in natural history. Survival is improved in patients with differentiated tumors as compared to those with poorly differentiated tumors. Morphologic grading in patients achieving a complete response reveals a decrease in survival for patients with poorly differentiated tumors.

Adult↗
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

Prognostic significance of tumor growth during radiation therapy.

A retrospective review of 282 consecutive patients with squamous cell carcinoma of the head and neck that were seen in the Radiation Oncology Department from January 1, 1980, through December 31, 1983, was performed. From this population a subgroup of six patients was identified that experienced growth of tumor in the radiation field during treatment. All except one of these patients expired from progression of cancer within 16 months. At the time of writing, the one remaining patient has progressive cancer in spite of additional therapy. Growth of cancer in the radiation field during therapy is unusual. It appears to be associated with a very poor prognosis even with aggressive salvage therapy. This observation should be taken into consideration in the medical/surgical management of these patients.

Carcinoma, Squamous Cell↗
PubMed1985

A randomized trial of cisplatin (CACP) + 5-fluorouracil (5-FU) infusion and CACP + 5-FU bolus for recurrent and advanced squamous cell carcinoma of the head and neck.

One of the most active chemotherapeutic regimens for treatment of advanced and recurrent head and neck cancer is cisplatin (CACP) + 5-fluorouracil (5-FU) infusion with a response rate of 90% in advanced, previously untreated patients and 70% in patients with recurrent disease. Forty-four patients from two Wayne State University-affiliated hospitals were entered into a randomized trial of CACP (100 mg/m2) day 1 and 24-hour infusion of 5-FU (1000 mg/m2) days 1 through 4 versus CACP (100 mg/m2) day 1 and bolus 5-FU (600 mg/m2) day 1 and day 8. Thirty-eight patients were evaluable for three induction courses. Response for the infusion arm was 72% (4/18 complete response [CR] + 9/18 partial response [PR]). Response for the bolus arm was 20% (2/20 CR + 2/20 PR). The difference in response was statistically significant by chi-square analysis (P less than 0.01). Seventy percent of the patients on the bolus arm experienced leukopenia with several episodes of grades 3 and 4 leukopenia. In addition, 50% of the patients on the bolus arm experienced thrombocytopenia. Stomatitis was more frequent on the infusion arm but it was mild and reversible. The complete responders on either arm have a median survival of 120+ weeks; partial responders, 30 weeks. Cisplatin + 5-FU infusion produces a superior response as initial chemotherapy for three courses compared with CACP and 5-FU bolus.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1985

Improved complete response rate and survival in advanced head and neck cancer after three-course induction therapy with 120-hour 5-FU infusion and cisplatin.

In a series of three consecutive pilot studies carried out between 1977 and 1981 at Wayne State University, Detroit, Michigan, designed to test the feasibility of multimodality therapy in patients with previously untreated advanced squamous cell carcinoma of the head and neck, patients received three different induction chemotherapy regimens: cisplatin + Oncovin (vincristine) + bleomycin (COB) for two courses; 96-hour 5-fluorouracil (5-FU) infusion and cisplatin for two courses, or 120-hour 5-FU infusion + cisplatin for three courses. Over-all response rates (complete response + partial response) to each of the three induction chemotherapy regimens were high: 80%, 88%, and 93%, respectively. Superior complete response rate in the group receiving three courses of 120-hour 5-FU infusion + cisplatin was 54% versus 29% for COB and 19% for two-course 96-hour 5-FU infusion + cisplatin (P = 0.04). Significant survival advantage at 18 months minimum follow-up for the group receiving three courses of 120-hour 5-FU + cisplatin induction therapy was found. Actual T and N stage may influence the clinical complete response rate. Responders to initial chemotherapy have significantly better survival as compared to nonresponders regardless of subsequent surgery and/or radiotherapy. These studies show that a multimodality approach to management of advanced head and neck cancer is feasible. Superior complete response rate and survival in one of the treatment groups suggest that choice of induction chemotherapy regimens and/or number of courses is of prime importance in such multimodality treatment programs.

Adolescent↗
PubMed1985

Isolation of newt lung ciliated cell models: characterization of motility and coordination thresholds.

Demembranated ciliated cell models are useful for studying mechanisms responsible for the regulation of ciliary coordination and waveform. This paper describes procedures for isolating ciliated cells from the newt, Taricha granulosa, by trypsin dissociation, their subsequent demembranation by Triton X-100, and their reactivation with MgATP to produce highly motile, coordinated, ciliated cell models. Reactivation of cell models with a high degree of mechanochemical coupling depended on avoiding mechanical damage and maintaining optimal conditions during all stages of isolation and reactivation. Highly motile models were prepared from cells incubated in trypsin, treated briefly with EDTA, separated by gentle agitation, and concentrated by centrifugation at low gravitational forces. Optimal demembranation and reactivation conditions were similar to those described previously for isolated newt lung axonemes. Under these conditions, nearly 100% of the models were reactivated when provided with MgATP and 90-95% beat with coordinated waves. The ciliary tufts beat at frequencies within the range measured in living cells and their reactivated motility was stable for at least 30 min at constant MgATP. These highly coupled models were used to show (1) that development of coordination in the ciliary tuft occurs at a higher substrate concentration range (10-25 microM) than that required to initiate motility per se (2-10 microM; (2) that outer dynein arms may not contribute to beat frequency at substrate concentrations below 35 microM; and (3) that vanadate has effects both on beat frequency and coordination of the tufts.

Animals↗
PubMed1985

Newt lung ciliated cell models: effect of MgATP on beat frequency and waveforms.

Highly coupled newt lung ciliated cell models were used to study the effects of MgATP concentration on ciliary beat frequency and waveform. Models were prepared from ciliated lung cells of the newt Taricha granulosa by trypsin dissociation of the epithelium, demembranation with Triton X-100, and reactivation with MgATP, as described previously [Weaver and Hard, 1985]. Beat frequencies were measured stroboscopically. Ciliary waveforms of reactivated models and intact mucociliary epithelial sheets were determined by single frame analysis of high-speed movies. Waveform parameters calculated included the durations of the effective and recovery strokes, the angular swings and angular velocities of the ciliary base and tip, the position of the bend along the ciliary shaft during the recovery stroke, the velocity of recovery stroke bend propagation, and the ratio of the duration of recovery stroke bend propagation to the duration of the recovery stroke itself. We found that beat frequency varied biphasically in response to MgATP at 21 degrees C, as shown previously for isolated, individual, newt lung axonemes. Apparent Fmax (maximum beat frequency) and Km values of 25 Hz and 0.14 mM, and 35 Hz and 0.47 mM, respectively, were obtained for each linear segment of the biphasic double reciprocal plot. Demembranation did not alter either ciliary waveform or the pattern of coordination. In this system, metachrony is antilaeoplectic and ciliary waveform appears to be regulated independent of beat frequency.

Animals↗
PubMed1985

Ototoxicity from cis-platinum in patients with stages III and IV previously untreated squamous cell cancer of the head and neck.

Forty-four patients were evaluated for ototoxicity following treatment with the chemotherapeutic agent cis-platinum. Statistically significant hearing changes at 2,000 Hz (p less than 0.001); 4,000 Hz (p less than 0.05); and 8,000 Hz (p less than 0.001) were observed. Chi-square analysis demonstrated that at 8,000 Hz patients who had lower than average thresholds prior to chemotherapy were more likely to experience greater threshold shift than those patients whose pre-chemotherapy thresholds were higher than average. In this patient sample, there was no significant correlation shown between serum creatinine levels and ototoxicity.

Adult↗