Sub-pocket-focused designing of tacrine derivatives as potential acetylcholinesterase inhibitors

Human acetylcholinesterase (hAChE) has a potential role in the management of acetylcholine, one of the neurotransmitters that modulate the overall activity of cholinergic system, AChE inhibitors have a greater impact in the therapeutics. Though the atomic structure of hAChE has been extensively studied, the precise active site geometry upon binding to different ligands are yet to be explored. In the present study, an extensive structural analysis of our recently reported hAChE-tacrine complex has carried out and revealed the presence of two prominent sub-pockets located at the vicinity of the hAChE active site. Structural bioinformatics assisted studies designed 132 putative sub-pockets focused tacrine derivatives (SPFTDs), their molecular docking, free energy estimations revealed that they are stronger than tacrine in terms of binding affinity. Our in vitro studies also supported the in silico findings, all these SPFTDs are having better potencies than tacrine. Cytotoxic nature of these SPFTDs on HepG2 and Neuro-2a cell lines, diminishes the possibilities for future in vivo studies. However, the identification of these sub pockets and the SPFTDs paved a new way to the future drug discovery especially since AChE is one of the promising and approved drug targets in treatment of AD drug discovery.

Synthesis of trans N-Substituted Pyrrolidine Derivatives Bearing 1,2,4-triazole Ring

BACKGROUND

1,2,4-triazoles scaffolds display significant biological activities due to hydrogen bonding, solubility, dipole character, and rigidity.

OBJECTIVE

The core motif of 1,2,4-triazoles plays a vital role in clinical drugs such as Rizatriptan (anti-migraine), Ribavirin (antiviral), anastrozole (anticancer), etizolam (anxiolytic), estazolam (anticonvulsant), alprazolam (anti-hypnotic), letrozole (aromatase inhibitor), loreclezole (anticonvulsant), trazadone (antidepressant) etc. Method: Epoxide ring opening of tert-butyl 6-oxa-3-azabicyclo [3.1.0] hexane-3-carboxylate followed by methylation under basic conditions and de-protection gave the corresponding trans 1-(4-methoxypyrrolidin-3-yl)-1H-1,2,4-triazole hydrochloride salt as the precursor. This precursor on reaction with substituted benzoyl chlorides and benzyl bromides gave the desired amide and amine products.

RESULTS

A library of 14 N-substituted pyrrolidine derivatives i.e. trans3-methoxy-4-(1H-1,2,4-triazol-1-yl) pyrrolidin-1-yl) (phenyl)methanone and trans 1-benzyl-4-methoxypyrrolidin-3-yl)-1H-1,2,4-triazole were prepared.

CONCLUSION

Eight novel amides (6a-h) and six amines (8a-f) derivatives were synthesized using 1-(4-methoxypyrrolidin-3-yl)-1H-1,2,4-triazole 4 salt with substituted benzoyl chlorides and benzyl bromides.

Neuroprotective derivatives of tacrine that target NMDA receptor and acetyl cholinesterase - Design, synthesis and biological evaluation

The complex and multifactorial nature of neuropsychiatric diseases demands multi-target drugs that can intervene with various sub-pathologies underlying disease progression. Targeting the impairments in cholinergic and glutamatergic neurotransmissions with small molecules has been suggested as one of the potential disease-modifying approaches for Alzheimer’s disease (AD). Tacrine, a potent inhibitor of acetylcholinesterase (AChE) is the first FDA approved drug for the treatment of AD. Tacrine is also a low affinity antagonist of N-methyl-D-aspartate receptor (NMDAR). However, tacrine was withdrawn from its clinical use later due to its hepatotoxicity. With an aim to develop novel high affinity multi-target directed ligands (MTDLs) against AChE and NMDAR, with reduced hepatotoxicity, we performed in silico structure-based modifications on tacrine, chemical synthesis of the derivatives and in vitro validation of their activities. Nineteen such derivatives showed inhibition with IC₅₀ values in the range of 18.53 ± 2.09 – 184.09 ± 19.23 nM against AChE and 0.27 ± 0.05 – 38.84 ± 9.64 μM against NMDAR. Some of the selected compounds also protected rat primary cortical neurons from glutamate induced excitotoxicity. Two of the tacrine derived MTDLs, 201 and 208 exhibited in vivo efficacy in rats by protecting against behavioral impairment induced by administration of the excitotoxic agent, monosodium glutamate. Additionally, several of these synthesized compounds also exhibited promising inhibitory activitiy against butyrylcholinesterase. MTDL-201 was also devoid of hepatotoxicity in vivo. Given the therapeutic potential of MTDLs in disease-modifying therapy, our studies revealed several promising MTDLs among which 201 appears to be a potential candidate for immediate preclinical evaluations.

Drug Re-purposing Approach and Potential Therapeutic Strategies to Treat COVID-19

The current pandemic of COVID-19 caused by SARS-Cov-2 has posed a severe threat to the whole world with its highly infectious, progressive nature with up to 10% mortality rates. The severity of the situation faced by the whole world and the lack of efficient therapeutics to treat this viral disease have led the WHO to depend on the drug-repurposing approach to tackle this major global health problem. This review aims at highlighting the various synthetic approaches employed for the synthesis of these FDA approved drugs that have been presently used for COVID-19 treatment. Additionally, a brief overview of several therapeutic strategies is also presented. This review will encourage the scientific community across the globe to come up with better and efficient synthetic protocols and also novel chemical entities along with this core with more potent activity.

2-Aminoaryl-3,5-diaryl pyrazines: Synthesis, biological evaluation against Mycobacterium tuberculosis and docking studies

Rationally designed Mycobacterium tuberculosis (Mtb) inhibitors were synthesized under Buchwald conditions using Pd₂ (dba)₃ /xantphos and the compounds were investigated for their biological activity against the Mtb standard strain H37Rv and two other clinically isolated multidrug-resistant strains with different drug resistance patterns. Compounds 5e, 6e, 7e, and 8e exhibited excellent antituberculosis activity against H37Rv with a minimum inhibitory concentration (MIC) value of 15 μg/ml. Compounds 5a, 6c, 7b, 8a, 8b, and 8d also displayed their potency with a MIC value in the range of 15-25 μg/ml. In addition to the Mtb studies, compounds 4e, 5e, 7e, and 8e were tested for cytotoxicity on HEK-293 cells and compounds 7e and 8e were identified to have low toxicities of up to 200 and 300 μM, respectively. The synthesized compounds docked with the 2FUM protein of Mtb and the docking studies revealed that compounds 5e, 6e, 7e, and 8e can bind strongly in the active site of the enzyme and showed binding energies of -9.62, -10.7, -11.48, and -12.06 kcal/mol, respectively. Compound 7e forms four hydrogen bonds, whereas compound 8e forms five hydrogen bonds with amino acids, respectively. Based on these results, compounds 7e and 8e might be considered potential lead compounds with good anti-Mtb potency.

Functionalised dihydroazo pyrimidine derivatives from Morita–Baylis–Hillman acetates: synthesis and studies against acetylcholinesterase as its inhibitors

Dihydroazo pyrimidine derivatives were synthesized at room temperature using MBH acetates and aminoazole derivatives. The in vitro studies carried on a couple of derivatives exhibited much higher potency for Alzheimer's disease (AD).

Tympanoplasty with and without cortical mastoidectomy - a comparative study

Perfimttion of the tympanic membrane is nature's may of maintaining the middle far vntilation under the pressure of inflammatory process in the tempanomastoid cleft. An attempt at reconstruction with the possibility of infection lurking in and around the mastoid air cells may seem futile. Vow the quntinn arises as to whether a cortical Mastoidectomy is essential before an attempt at reconstruction is made. Our experience with one hundred and twenty patients is presented here. Our study shovn that conicul mastoidectomy does not signifieantly improve the results in well-selected ears.

Early-stage breast cancer: local control after conservative surgery and radiation therapy with immediate interstitial boost

Two hundred forty-five women (250 breasts) with early-stage breast cancer were treated between June 1982 and June 1990 with lumpectomy, immediate (boost) interstitial iridium-192 to 15-20 Gy, and external-beam irradiation to the entire breast to 45-50 Gy. There were 123 stage I cancers (T1N0M0), 123 stage II cancers (36 T1N1, 50 T2N0, 33 T2N1, four T3N0), and four stage III cancers (two T2N2, two T3N1). At a median follow-up of 69 months (range, 26-122 months), there were 14 recurrences in the treated breasts. Four were at the site of primary disease, eight were in other quadrants, and two were in both. With immediate interstitial boost, the 11-year actuarial recurrence rate in the breast is 7.7% and the recurrence rate at the site of primary disease is 3.2%.

Prostate cancer: results of external irradiation

From 1975 to 1982, 205 patients with local prostate cancer were treated at the radiation oncology department, the University of Kansas Medical Center, Kansas City, Kansas. Patients' median age was 73 years. All of the patients were staged according to American Urologic staging criteria. Twenty-eight patients had stage A2 cancer, 91 patients had stage B cancer, and 86 patients had stage C cancer. All patients were treated using megavoltage radiation (dosage range: 6000 cGy to 7100 cGy). The follow-up period ranged from a minimum of 8 years to a maximum of 15 years (median: 9.4 years). The clinical local control was 96% for stage A2, 94% for stage B, and 90% for stage C disease. The overall and disease-free survival rates were 71% and 60%, respectively. Fourteen patients developed moderate complications with one patient (0.5%) requiring surgical intervention. The local control and survival rates reported in this study are comparable with surgical results, suggesting that external beam irradiation in prostate cancer is safe and effective.

Management of advanced squamous cell carcinomas of the maxillary sinus

From 1970 to 1988, 41 cases of advanced maxillary sinus cancers were treated at the University of Kansas Medical Center. Local control for the 37 evaluable patients was achieved in 21 (57%). Local control by radiation therapy alone was achieved in ten of 19 (53%) patients compared with eight of 14 (57%) treated with a combination of surgery and radiation therapy. A dose greater than 6500 cGy correlated with better local control in patients treated with radiation therapy alone. Neck node failure occurred in three of 35 (8%) patients when not electively treated. Neck metastasis either at presentation or at a later stage reduced survival. The overall absolute survival for the entire group at 5 years was 35%. A combination of preoperative radiation therapy and surgery is recommended for patients with advanced-stage maxillary sinus cancer. Radiation therapy is an equally good alternative for those who are not surgical candidates or refuse surgery.

Testicular neoplasms: seminoma

From 1969 to 1984, 58 patients with a diagnosis of testicular seminoma were seen and treated at the University of Kansas Medical Center. The median age was 34 years (range of 20 to 62 years). The American Joint Committee on Cancer Staging System was followed: stage I (34 patients); stage II (6); stage III (8); and stage IV (10). Forty-two patients had typical seminoma, and 16 had anaplastic histology. Nine patients had elevated B subunit of human chorionic gonadotropin, and nine had a history of cryptorchidism. Fifty-six patients received radiation treatment, and seven received chemotherapy with or without radiation. The median follow-up was 7 years (range 3 to 16 years). The overall disease-free (absolute) survival according to stage was: stage I, 91% (100%); stage II, 66% (80%); stage III, 75% (85%); and stage IV, 50% (50%). There were no late complications. The survival for patients with anaplastic histology or with elevated B subunit of human chorionic gonadotropin was not significantly different from that of typical seminoma.

Dosimetric analysis in brachytherapy of carcinoma of the cervix

Brachytherapy plays an essential role in the definitive radiation treatment of cervical carcinoma. The dosimetry of intracavitary irradiation is complex in that the optimum doses that can be delivered are dictated not only by the volume and extent of tumor but also by the close vicinity of dose-limiting structures, such as the small and large intestines, rectum, and bladder. To facilitate understanding of the relationships between the various dosimetric parameters involved, a retrospective analysis of 50 randomly chosen intracavitary insertions with Cesium-137 in 41 patients performed at our institution between 1975 and 1985 was carried out. All 50 cases utilized Fletcher-Suit-Delcos applicators and only the insertions using three sources in the tandem and one in each of the ovoids were included in this analysis. Using the AP and lateral radiographs and the lymphatic trapezoid, the reference points were obtained and transferred digitally to the treatment planning computer, and computerized dosimetry performed. In addition to the specified reference points, points were added and modified to obtain more complete information. The doses at the specified points were normalized to the average dose at AT, a reference point 2 cm superior to external os and 2 cm lateral to the tandem, and expressed as a percentage. It was noted that the average dose at the closest bladder point was 103 +/- 41% of the dose at AT, the maximum rectal dose 77 +/- 29% of the dose at AT and the maximum small bowel dose 65 +/- 16% of that at AT. The analysis of percent contribution of various sources to different reference points revealed that the dose to point AT was equally contributed to by all sources; bladder and rectal doses were mainly contributed to by the lowermost uterine and ovoid sources. Our analysis may provide a model for optimizing brachytherapy in cervical carcinoma.

Treatment options in early breast cancer

Conservative management of early breast cancer with limited surgical excision and radiotherapy is now being accepted as a viable alternative to mutilating surgical procedures. In this paper, the major steps in the historical development of conservative management are traced, and the results of the current randomized trials are summarized. An innovative method used at the University of Kansas Medical Center delivers a "boost" dose to the tumor bed with interstitial Ir-192 immediately following resection of the primary tumor mass. The results obtained in terms of local control and cosmesis with this technique are presented, and the current state of the art is discussed.

Primary orbital lymphomas

Between 1950 and 1982, seventeen patients with primary orbital lymphoma were treated at the University of Kansas Medical Center. There were 10 males and 7 females with a median age of 61 years. Four patients had bilateral disease, seven patients had disease involving the conjunctiva, and in ten patients, the disease involved paraocular structures. Fourteen patients received radiation with a median dose of 3500 cGy (range 2250 cGy to 4250 cGy) given in about 3 1/2 to 5 weeks. Median follow-up was 10 years (range 5 to 31 years). Local control was 100% and 5-year survival was 76%. Three patients are living with no evidence of lymphoma; three patients died from progression of the disease, and others died from unrelated causes. Radiation treatment for localized primary orbital lymphomas appears to be the primary treatment of choice.

Cosmetic results in early breast cancer treated with lumpectomy, peri-operative interstitial irradiation, and external beam radiation

Patients with operable breast cancer were treated at the University of Kansas Medical Center with lumpectomy, peri-operative interstitial Iridium, and external beam radiotherapy, and concomitant adjuvant chemotherapy in a majority of node positive cases. Examination of the cosmetic results in 85 breasts followed for at least 2 years, at a median of 41 months revealed 20% to be excellent, 44% to be very good, 24% good, 9% fair, and 4% to have poor results. In this paper cosmesis is analyzed with reference to the size of the primary, its location, age of the patient, whether the patient received adjuvant chemotherapy, and whether the regional nodes were treated. In this group of patients, the size and the site of the primary, patient's age, and whether adjuvant chemotherapy was administered or not, did not adversely affect the aesthetic outcome. Treatment of the regional nodes gave a worse mean cosmetic score compared to the group in whom only the breast was treated (37.51 vs. 58.98 respectively, p less than 0.001). Among the 11 patients with fair/poor cosmesis, all had regional nodal treatment, 7/11 had inner quadrant lesions, and 7/11 had lesions greater than T1. Further follow-up and accrual would be needed to confirm our results and affirm if other factors would change.

Perioperative interstitial irradiation in the conservative management of early breast cancer

Conservation of the breast in early breast cancer with limited resection and radiation is proving to be as effective as modified radical mastectomy in survival and in loco-regional control. Management at the University of Kansas Medical Center consists of an interstitial implant at the time of lumpectomy to facilitate perioperative irradiation with Iridium-192 to the tumor bed. An axillary node dissection is also performed at that time. Two to 3 weeks later external beam irradiation is delivered to the entire breast. One hundred and twenty-three breasts in 120 patients have been treated between June 1982 and June 1986. There were 49 pathological Stage I, 63 Stage II, 8 Stage III carcinomas, and 3 carcinomas in situ, consisting of 72 T1, 43 T2, 5 T3, and 3 TIS lesions. Patients have been followed for a median of 30 months. One patient had a "true" recurrence in the breast. Another patient developed recurrence in a different quadrant. Ninety percent of the patients had good to excellent cosmetic results, 7% were considered fair, and 3% had poor results. Seven patients developed mild arm edema, 4 were found to have moderate edema, and 1 had severe arm edema. Our preliminary results indicate that interstitial irradiation immediately after excision results in excellent local control, with very satisfactory cosmesis and no morbidity due to the simultaneous excision and irradiation.

Breast conservation treatment with perioperative interstitial irradiation

Limited resection of the breast combined with radiation has proved to be as effective as more radical surgery in treating early breast cancer. At the University of Kansas Medical Center, the radiotherapy consists of an interstitial implant at the time of lumpectomy to deliver an interstitial boost dose to the tumor bed with iridium-192 immediately following the surgical procedure. An axillary node dissection is also performed at the time of lumpectomy. A dose of 2,000 cGy is delivered to the tumor bed between 40 and 60 h. Two to three weeks later, 4,500-5,000 cGy is delivered to the entire breast with external beam radiation over 5-5.5 weeks. One hundred breasts in 98 patients were so treated between June 1982 and February 1986, with 2 carcinomas in situ, 40 stage I, 51 stage II, and 7 stage III cancers, consisting of 2 TIS, 54 T1, 39 T2, and 5 T3 lesions. Locoregional control with a median follow-up of 31 months was 98%. One recurrence was in a different quadrant, and the other revealed predominantly the in situ component. Immediate implant did not compromise wound healing or cosmesis. The cosmetic result was graded as good to excellent in 88% of the breasts. Our preliminary results appear to suggest a better local control with immediate interstitial irradiation.

Intraoperative implantation radiation therapy plus lumpectomy for carcinoma of the breast

The preponderance of evidence indicates that lumpectomy plus radiation therapy produces the same survival as modified radical mastectomy in patients with early breast cancer and further suggests that the local failure rate may be lower in the patients who undergo irradiation. In this series, patients were treated with immediate implantation of the tumor bed with iridium Ir 192. There have been two recurrences in the breast from 110 breast cancers (44% had a clinical stage greater than T1, and 41% had axillary-node involvement) in 107 patients followed up for four to 52 months (25.8 +/- 13.3 months [mean +/- SD]). These preliminary data suggest that local treatment failure can be minimized by aggressive, immediate intraoperative implantation of the tumor bed with iridium Ir 192.

Local recurrence in adenocarcinoma of the rectosigmoid colon after curative surgical resection

Between January 1975 and January 1982, 157 patients with a diagnosis of adenocarcinoma of the rectosigmoid colon underwent curative surgical resection. The median follow-up was three years (range, 2.5 to 9 years). Two patients were excluded from the study for staging purposes because they received preoperative radiation. The remaining patients were categorized in the following stages: carcinoma in situ-3; A-14; B(1)-14; B(2)-41; B(3)-8; C(1)-1; C(2)-70; and C(3)-4. The overall local recurrence rate was 41 percent. The local recurrence according to stage was as follows: stage A-1/14 (7 percent); B(1)-2/14 (14 percent); B(2)-15/38 (39 percent); B(3)-3/8 (38 percent); C(1)-0/1; C(2)-31/56 (55 percent); and C(3)-4/4 (100 percent). Seventeen patients in stages B(2) and C(2) received postoperative irradiation. Only two patients (2/17, or 12 percent) recurred locally. In this study the local recurrence rate for patients undergoing curative surgical resection only was very high, especially in patients with advanced stage of disease (B(2) to C(3)). There is evidence that postoperative radiotherapy could minimize the local failure rate.

Comparison of single, fractionated and hyperfractionated irradiation on the development of normal tissue damage in rat lung

The effect of fractionated thoracic irradiation on the development of normal tissue damage in rats was compared to that produced by single doses. Animals received a single dose of 15 Gy, 30 Gy in 10 daily fractions of 3 Gy each (fractionation), or 30 Gy in 30 fractions of 1 Gy each 3 times a day (hyperfractionation). The treatments produced minimal lethality since a total of only 6 animals died between days 273 and 475 after the initiation of treatment, with no difference in survival observed between the control and any of the 3 treated groups. Despite the lack of lethality, evidence of lung damage was obtained by histological examination. At times less than 180 days after treatment, the lungs of animals receiving a single dose of 15 Gy displayed more severe changes than did animals from either fractionation group. At longer times after treatment (days 261 and 475), the histological appearances within each group were changed, collagen deposits and fibrosis being the most significant observations. Animals that had received either single doses or fractionated doses had more of the pulmonary parenchyma involved than did animals that had received hyperfractionated doses. We conclude that, in the rat lung model, a total radiation dose of 30 Gy fractionated over 14 days produces no more acute lethality nor damage to lung tissue than does 15 Gy delivered as a single dose. However, long-term effects as evidenced by deposits of collagen and development of fibrosis are significantly reduced by hyperfractionation when compared to single doses and daily fractionation.

Interaction of radiation, dihydroxyanthraquinone, and adriamycin on the induction of acute lethality in mice

The acute lethality induced by combinations of radiations, Dihydroxyanthraquinone (DHAQ), and Adriamycin (ADR) was investigated in mice. Whole-body irradiation produced acute lethality, with an LD-50/30 of approximately 6.5 Gy. ADR and DHAQ produced LD-50/30's of 14 and 4 mg/kg, respectively. When 10 mg/kg doses were fractionated into 5 X 2 mg/kg daily doses, both drugs were equally or more efficient at producing mortality, 90% by day 30. When 4 Gy radiation was combined with 5 mg/kg ADR or 5 mg/kg DHAQ, a response no greater than that produced by drug alone was obtained. However, when 5 mg/kg ADR was administered concomitantly with 5 mg/kg DHAQ, there was a less-than-additive induction of lethality, resulting in only 21% mortality by day 30. Since this response is similar to that seen after ADR only, it would appear that the DHAQ-induced toxicity was protected against. Less-than-additive effects were also observed for combinations of 5 mg/kg ADR with either 2.5 or 10 mg/kg DHAQ; and combinations of 10 mg/kg ADR with either 2.5 or 5 mg/kg DHAQ. If ADR and DHAQ (at doses of 5 mg/kg) were combined but with a 1 day interval between drugs, the protective effect was lost and animals died earlier than after either agent alone. At present, no definite explanation is available for this unusual protective effect of ADR against acute lethality induced by DHAQ.

Incidence of lymph node involvement in localized carcinoma of the prostate

Bilateral pelvic lymphadenectomy was performed in 100 patients as a staging procedure. Sixty-one patients received iodine 125 radioisotope implant and 39 patients received external radiation therapy. The overall incidence of lymph node metastases was 27 percent. The incidence of lymph node involvement was 14 percent with clinical stage A2 disease, 3 percent with stage B1, 44 percent with stage B2, and 40 percent with stage C disease. The grade of the tumor influenced the incidence of lymph node metastases. Only 6 percent of grade I tumors had lymph node metastases, whereas 26 percent of grade II tumors and 71 percent of grade III tumors showed lymph node metastases.

Effect of dihydroxyanthraquinone on the response of a rat solid tumor to radiation therapy

Dihydroxyanthraquinone (DHAQ, NSC 279836, a new cancer chemotherapeutic agent presently in clinical trials) was tested, alone and in combination with radiation, for therapeutic effectiveness in a rat solid tumor model. The Walker 256 fibrosarcoma was implanted subcutaneously in the leg via trochar so as to yield palpable tumors within 7-11 days. When tumor diameters reached 1 cm, the animals were treated as follows: as controls; with DHAQ (3.0 mg/kg, i.p.); with 300 KVP x-rays (15 Gy to the tumor-burdened leg); or with a combination of DHAQ and radiation. Tumor diameters were measured three times a week to monitor the response to therapy. DHAQ alone had no effect on tumor growth rate. Radiation alone produced a delay in tumor growth. The combination of DHAQ and radiation resulted in a consistently better therapeutic response than did radiation only, but at only a marginal level of statistical significance (0.05 less than p less than 0.10). However, there were 3/10 long-term survivors (greater than 80 days post treatment) without evidence of tumor in the combination therapy group; whereas all animals in the radiation group died or were sacrificed because of progressive tumor growth by day 71. These results suggest that even though DHAQ is only minimally effective against this rat solid tumor when used alone, there may still be some added therapeutic benefit derived from a combination of DHAQ and radiation therapy.

Radiation therapy for early glottic carcinomas

From 1973 to 1978, 30 cases of early glottic cancers (TINOMO) were treated in the Department of Radiation Therapy, University of Kansas Medical Center. All 30 patients have a minimal follow-up of three years with a mean of 50.2 months, and 26 (86.7%) are alive with no evidence of disease. Radiation therapy failed in three (10%), two of whom were salvaged by subsequent surgery. Thus the overall control rate was 29/30 (96.7%). We recommend primary radiation therapy for these early lesions, reserving operation for cases of unsuccessful radiotherapy.

External radiation therapy of localized prostatic cancer

From July 1975 to December 1980, 156 patients with localized carcinoma of the prostate received external radiation therapy at the University of Kansas Medical Center. Sixteen patients were lost to follow-up. The follow-up period for the remaining 140 patients ranged from 2 years to 7 years. Median follow-up period was 4.2 years. The overall survival according to stage was as follows: stage A2, 100 percent; stage B, 83 percent; and stage C, 53 percent. Corresponding disease-free survival was 91 percent, 70 percent, and 40 percent, respectively. Both stage and grade have great influence on survival. In stage B, about 44 percent of grade 3 tumors developed distant metastases compared with only 19 percent with grades 1 and 2 tumors. In stage C, 71 percent of grade 3 tumors showed progression of disease. A majority of patients with positive nodes showed progression of disease when compared with patients with negative nodes (75 percent vs 15 percent).

Chemodectoma of glomus jugulare

A retrospective review of 17 patients with a diagnosis of chemodectomas of glomus jugulare is presented. The patients' age ranged from 32 to 63 years, with a female to make ratio of 4:1, with 14 females and 3 males. In the majority of the patients (15/17), the primary treatment was surgery, with 10/15 (70%) incidents of recurrence. Radiation therapy was used in 11 patients, in 7 for recurrence, in 2 as postoperative and in 2 as a primary therapy. The radiation dose ranged from 2200 to 5600 rad. The follow-up period ranged from 2 to 22 years. Sixteen patients were living with disease controlled at the last follow-up.

Carcinoma of the uterine cervix: review of experience at University of Kansas Medical Center

A total of 211 patients with a diagnosis of carcinoma of uterine cervix, managed by radiotherapy at the University of Kansas Medical Center between 1969-1975 was reviewed. There were 90 patients in Stage I, 65 in Stage II, 43 in Stage III, and 13 with Stage IV disease. Squamous cell carcinoma was found to be the most common histologic type. Twenty-three patients had shown uterine extension of the disease; of these, eight had adenocarcinoma. The majority of the patients received external whole-pelvic telecobalt therapy followed by a variety of intracavitary radium applications. The combined dose to point A ranged from 5000-13,000 rad. There were 166 patients followed for five or more years. Overall five-year survival was 74% (124/166). Survival by stage: IA--92% (12/13); IB--88% (55/62); IIA2--74% (23/31); IIB--58% (14/24); IIIA&B--64% (18/28); and IV--25% (2/8). The overall three-year survival was 73% (155/211). Thirty-three patients (33/211 = 16%) developed local recurrence, and five of these patients were salvaged by surgery. Surgery for complications was required in nine patients. Rectovaginal and vesicovaginal fistulae occurred in three patients (1.5%). Local recurrence and complications vs. dose and system used were analyzed.

Results of radiation therapy in the treatment of epithelial carcinoma of the ovary

Between 1967 and 1976, 82 patients who had epithelial carcinoma of the ovary and were treated with surgery and postoperative radiation therapy, respectively, were studied. Of these patients, 35% had Stage I disease, 16% Stage II, 45% Stage III, and 4% Stage IV. Serous cystadenocarcinoma was the histologic cell type in 54% of the patients, and mucinous cystadenocarcinoma was involved in 24%. Of the tumors, 35% were Grade 1, 34% Grade 2, 18% Grade 3, and 13% were unspecified. Survival at five years was 96% for Stage I patients, 60% for Stage II, and 60% for Stage III. No stage IV patient survived past two years. Stage III patients with no palpable tumor prior to radiation therapy did well, with 80% alive at more than two years, while only 10% of Stage III patients with palpable tumors prior to radiation therapy are alive. Patients with Stage III disease treated by whole-abdominal irradiation with a pelvic boost did better than those who received 3,000 rad or less to the pelvis. Radiation therapy continues to be an important treatment modality in epithelial carcinoma of the ovary, particularly in patients with minimal tumor burden.

The search for new hypoxic cell radiosensitizers

A number of newly synthesized compounds whose chemical structure suggested possible or remotely possible ability to radiosensitize hypoxic mammalian cells were studied in an in-vitro system. Those compounds that were not excluded because of insolubility or extreme cytotoxicity were tested for radiosensitizing ability. The correlation between chemical structure and radiosensitizing ability will be used for the rational design of additional compounds with a high probability of being effective hypoxic cell radiosensitizers. It is hoped that this will contribute to attempts to improve the cure rate of patients with malignant tumors through the use of radiation therapy and hypoxic cell radiosensitizers.

Malignant salivary gland tumors: role of radiation therapy

Malignant salivary gland tumors are rare. They represent less than one percent of all head and neck tumors. Approximately three fourths of all salivary gland tumors occur in the major salivary glands.Traditionally, the treatment of choice for these tumors is surgery. The majority of these tumors reoccur after curative surgical procedures. Local recurrence rate following surgery varies with the histology, grade, and extent of the disease.In spite of high local recurrence rate following curative surgical treatment of these tumors, radiotherapy has seldom been used as an adjuvant to surgery. The value of elective postoperative radiation therapy for subclinical microscopic disease was not recognized. Review of the literature supports the improved local control rate with the use of immediate postoperative radiotherapy. Radiation therapy proved to be effective as an adjuvant to surgery. A local control rate of better than 40 percent can be achieved by radiation therapy as a sole modality in inoperable and locally advanced cases. Radiation therapy provides an excellent palliation for locally advanced tumors or symptomatic metastases.