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Biomedical subjects

M L Hicks

Publications and source records attributed to M L Hicks.

At least 37 records · Page 2Linked to original sources
PubMed1995

Some factors influencing comodulation masking release and across-channel masking.

The purpose of this study was to determine whether comodulation masking release (CMR) and across-channel masking (ACM) are by-products of a similar across-channel mechanism. This was addressed by examining how the two are affected by stimulus manipulations expected to influence their magnitude. Subjects were required to detect a 1000-Hz signal in the presence of a masker that consisted of a 1000-Hz (on-frequency) component alone or that component and up to six flanking components (500, 600, 700, 1300, 1400, and 1500 Hz). The on-frequency and flanking components typically were sinusoidally amplitude modulated at 10 Hz, although not necessarily in phase with one another. In experiment 1, the amount of CMR and ACM was highly influenced by whether the signal consisted of one or three 50-ms tone bursts; in fact, ACM was only observed when the signal was a train of three 50-ms tone bursts. In experiments 2 and 3, CMR tended to increase as the modulation depth or the number of flanking components increased, whereas ACM was relatively unaffected by these manipulations. In addition, ACM was observed under dichotic situations, whereas CMR was not. Taken together, the results suggest that ACM and CMR may be mediated by different mechanisms.

Adult↗
PubMed1995

Squamous cell carcinoma of the cervix metastatic to an ovarian Brenner tumor.

Metastatic tumors account for approximately 10 to 15% of surgically excised ovarian malignancies (Semin Diagn Pathol 8:250-276, 1991). Although the majority of tumors arise within the female genital tract, cervical cancer is a rare source of metastasis to the ovary. Cervical carcinomas with ovarian involvement are usually advanced lesions with lymph node involvement (Am J Obstet Gynecol 166:50-53, 1992; Cancer 71:407-418, 1993). We present a case of Stage IIB squamous cell carcinoma of cervix metastatic to an ovarian Brenner tumor. Our purpose in presenting this case is to report useful histologic features in the diagnosis of this rare combination of tumors. We are not aware of any other published reports of this entity.

Brenner Tumor↗
PubMed1995

Can you screen for ovarian cancer?

Screening for ovarian cancer has become an area of great interest because of the high mortality rate associated with advanced ovarian cancer. This article discusses the requirements for a test to be considered a screening modality, outlines the current methodology used in ovarian cancer screening, addresses the shortcomings as well as problems related to cost effectiveness with the current screening modalities, and identifies special circumstances in which ovarian cancer screening may be beneficial.

CA-125 Antigen↗
PubMed1994

Colonic anastomosis using the valtrac biofragmentable anastomosis ring: a new and useful surgical technique in gynecologic oncology.

Patients with a primary malignancy of the female genital tract may present with the majority of their disease confined to the pelvis. Not infrequently, infiltrating contiguous extension of disease may involve the rectosigmoid colon, resulting in symptoms of partial obstruction. This presentation in the patient with an epithelial ovarian malignancy may represent a patient that can be adequately cytoreduced if a segmental resection of the rectosigmoid colon is performed. Following resection, the continuity of the lower GI tract can be restored by anastomosis of the proximal and distal ends of the colon. In our institution three patients explored for large abdominal pelvic masses required segmental resection of the rectosigmoid colon. In each patient the colonic anastomosis was performed using the valtrac biofragmentable anastomosis ring (V-BAR). None of the patients experienced any intraoperative complications, and postoperatively there was no evidence of any anastomotic leaks. The average time of return of GI function was 6 days and there was no prolongation of their hospital stay. Currently, with 3 months of follow-up no patients have reported any symptoms suggestive of anastomotic stricture. Although our experience is limited, we found that this technique can be performed much faster than traditional hand-sewn or staple techniques. We submit that in the presence of uncompromised colon, the V-BAR is a safe and effective new alternative for colonic anastomosis in gynecologic oncological surgery.

Anastomosis, Surgical↗
PubMed1993

Survival in patients with paraaortic lymph node metastases from endometrial adenocarcinoma clinically limited to the uterus.

PURPOSE: The purpose of this study was (a) to evaluate the incidence of paraaortic lymph node metastasis from adenocarcinoma of the endometrium clinically limited to the uterus (1971 FIGO Stages I and II) and (b) to report the 5 year disease-free survival of patients with histologically documented paraaortic lymph node metastasis from endometrial adenocarcinoma clinically limited to the uterus treated on two separate protocols. METHODS AND MATERIALS: From June 1979 to June 1990, 109 patients underwent staging paraaortic lymphadenectomy or paraaortic lymph node biopsy at the time of total abdominal hysterectomy and bilateral salpingo-oophorectomy for adenocarcinoma of the endometrium clinically limited to the uterus. Patients with histologically documented paraaortic lymph node metastasis were treated on two protocols: (a) pelvic radiation (5,040 cGy) plus progestins or (b) pelvic radiation therapy (5,040 cGy) plus paraaortic radiation (4,500 cGy). RESULTS: Paraaortic lymph node metastases was primarily associated with grade 3 tumors (34.4%) and deep myometrial invasion (42%) and was present in 17.4% (19) of 109 patients. None of the women treated with pelvic radiation therapy and progestins survived five years disease-free. In contrast, the 5 year disease-free survival was 27% for patients treated by pelvic and paraaortic radiation. CONCLUSIONS: Since all patients with macroscopic metastases to the paraaortic lymph nodes developed recurrent cancer and only a small percentage of those with microscopic metastases to the paraaortic lymph nodes survived disease-free at 5 years, improved survival for patients with paraaortic lymph node metastases will necessitate the addition of effective cytotoxic chemotherapy to pelvic and paraaortic radiation.

Adenocarcinoma↗
PubMed1993

Predictive value of serum CA125 following optimal cytoreductive surgery during weekly cisplatin induction therapy for advanced ovarian cancer.

One hundred seventy-one patients with epithelial ovarian cancer were treated on a prospective protocol of weekly cisplatin induction (1 mg/kg weekly for four courses) followed by monthly cisplatin (50 mg/m2), Adriamycin (50 mg/m2), and cyclophosphamide (750 mg/m2). Seventy-five patients with FIGO stage III or IV disease who underwent optimal cytoreductive surgery (<2 cm residual disease) were treated on this protocol and had weekly as well as monthly serum CA125 levels measured. A retrospective analysis was performed in order to determine if a > or = 50% fall in elevated serum CA125 levels during weekly cisplatin induction therapy would be predictive of findings at second look operation, normalization of serum CA125 levels (< 35 u/ml) immediately prior to the third course of multiagent chemotherapy, and to determine the impact of such a decline on median progression-free interval. Positive predictive values for this parameter with respect to findings at second look operation ranged between 38% and 50% (P > 0.05). Positive predictive values for this parameter with respect to normalization of serum CA125 levels immediately prior to the third course of multiagent chemotherapy ranged between 64.2% and 89.6% (P > 0.05). Logistic regression analysis demonstrated that a > or = 50% fall observed in CA125 levels during four weekly courses of chemotherapy served as an independent predictor of normalization of serum CA125 levels (<35 u/ml) following two courses of multiagent chemotherapy (P = 0.009) and improved median progression-free interval (P = 0.04). Eighteen patients demonstrated a rise in serum CA125 levels during weekly induction cisplatin chemotherapy. Only one of these patients (5.5%) demonstrated a surgical complete response at the end of standard therapy.

Adult↗
PubMed1993

Vulvar carcinoma with 0.5 mm of invasion and associated inguinal lymph node metastasis.

A case of vulvar carcinoma with 0.5 mm of invasion treated by radical wide local excision only, which later developed ipsilateral inguinal lymph node recurrence, is presented. This represents the least amount of invasion reported resulting in inguinal lymph node metastasis. Review of the literature of stage I vulvar carcinoma with less than 1 mm of invasion indicates that this phenomenon occurs in only 1.6% of all patients who have undergone inguinal lymphadenectomy. Although this represents the second report of ipsilateral inguinal nodal metastasis associated with less than 1 mm of invasion, we continue to perform radical wide local excision without ipsilateral inguinal lymphadenectomy until more cases demonstrate a higher incidence of lymph node involvement.

Aged↗
PubMed1993

Intraoperative orthovoltage radiation therapy in the treatment of recurrent gynecologic malignancies.

A Phase I/II study was initiated to evaluate complications of orthovoltage intraoperative radiation therapy utilized in the treatment of patients with incompletely resected recurrent gynecologic malignancies. There were no osseous, vascular, neurologic, or ureteral complications. Of the 23 treated patients, 2 patients (8.7%) had complications outside the treated area. Survival of patients treated with intraoperative radiation therapy was highest among patients treated to a field of < or = 3 cm in greatest diameter and a tumor thickness of < or = 1 mm. A subgroup of patients (5) with microscopically positive margins following total pelvic exenteration demonstrated an absence of recurrence in the treated field. The role of intraoperative radiation therapy (IORT) in the treatment of recurrent and incompletely resectable gynecologic malignancies remains investigational.

Brachytherapy↗
PubMed1992

Factors influencing temporal effects with notched-noise maskers.

Temporal effects in simulataneous masking were studied by measuring the reduction in the amount of masking produced by a gated masker when that masker was preceded by a 400-ms noise (the precursor) that was usually spectrally identical to the masker. The signal frequency (fs) was 1.0 or 4.0 kHz. Experiment 1 revealed a temporal effect only when there was a spectral notch (centered at fs) in the masker and precursor. For a relative notchwidth of 0.4 fs, the temporal effect was larger at 4.0 than at 1.0 kHz. In experiment 2. where the masker and precursor both consisted of two bands of noise separated by a spectral notch of 0.4 fs, the size of the temporal effect remained essentially constant as the bandwidth of these noise bands increased from 0.2-0.8 kHz. The results from experiment 3 indicated that the temporal effect was largest when the level fo the precursor was equal to the level of the masker. Finally, the results from experiment 4 suggested that the temporal effect may depend upon the frequency region below as well as above fs, but that the frequency region above fs is probably more important.

Acoustic Stimulation↗
PubMed1992

Conservative surgery plus adjuvant therapy for vulvovaginal rhabdomyosarcoma, diethylstilbestrol clear cell adenocarcinoma of the vagina, and unilateral germ cell tumors of the ovary.

Significant progress has been made in the 1980s in early-stage vulvovaginal rhabdomyosarcoma, diethylstilbestrol (DES) clear cell adenocarcinoma of the vagina, and unilateral germ cell tumors of the ovary. In an early state of vulvovaginal rhabdomyosarcoma, systemic vincristine, dactinomycin, and cyclophosphamide (VAC) chemotherapy followed by local excision or local radiation results in a high cure rate with retention of future fertility. Similarly, early-stage DES-related adenocarcinoma of the vagina treated by wide local excision and localized vaginal radiation also results in retention of fertility and a high cure rate. Finally, significant progress has been made in unilateral germ cell tumors of the ovary in which surgical treatment by unilateral salpingo-oophorectomy followed by cisplatin, etoposide, and bleomycin results in not only high cure rates and retention of fertility but will probably be standard therapy for all germ cell tumors of the ovary, including dysgerminoma, a disease most frequently treated in the past by radiation therapy with loss of subsequent fertility.

Adenocarcinoma↗
PubMed1991

Effectiveness of halothane used with ultrasonic or hand instrumentation to remove gutta-percha from the root canal.

This study compared halothane and chloroform used with hand or ultrasonic instrumentation to remove gutta-percha and sealer from root canals. Apically extruded debris, residual debris, time for filling removal, and amount of solvent used were determined. The differences in extruded apical debris and radiographically visible residual debris were not significant (p greater than 0.05). Ultrasonic instrumentation required significantly less time to remove the root canal filling than did hand instrumentation (p = 0.02). The only significant difference in the amount of solvent used occurred when the ultrasonic-chloroform group was compared with the hand instrumentation-chloroform group (p = 0.05). Halothane was found to be an acceptable alternative to chloroform for removing gutta-percha and sealer from the obturated root canal.

Analysis of Variance↗
PubMed1991

The effect of pure-tone forward masking on overshoot.

The overshoot effect can be reduced by temporary hearing loss induced by aspirin or exposure to intense sound. The present study simulated a hearing loss at 4.0 kHz via pure-tone forward masking and examined the effect of the simulation on threshold for a 10-ms, 4.0-kHz signal presented 1 ms after the onset of a 400-ms, broadband noise masker whose spectrum level was 20 dB SPL. Masker frequency was 3.6, 4.0, or 4.2 kHz, and masker level was 80 dB SPL. Subject-dependent delays were determined such that 10 or 20 dB of masking at 4.0 kHz was produced. In general, the pure-tone forward masker did not reduce the simultaneous-masked threshold, suggesting that elevating threshold with a pure-tone forward masker does not sufficiently simulate the effect of a temporary hearing loss on overshoot.

Adolescent↗
PubMed1990

Alternative solvents to chloroform for gutta-percha removal.

The purpose of this study was to evaluate new or previously identified solvents for effectiveness in dissolving gutta-percha. The solubility of a standardized weight of gutta-percha was tested in 5-ml quantities of 32 solvents. Ten samples of 30 solvents were tested at both 22 and 37 degrees C for 15 min. If the gutta-percha samples dissolved within 15 min, the times were recorded and statistically analyzed. There was no significant difference (p greater than 0.05, one-way analysis of variance and Scheffe's test) between dissolving times of chloroform and trichloroethylene at 22 and 37 degrees C. At 22 degrees C, three solvents dissolved the gutta-percha sample, whereas at 37 degrees C, nine solvents dissolved the gutta-percha. At 37 degrees C, halothane (Fluothane) was twice as effective as cineole and demonstrated many favorable working qualities. An important finding from the experimentation with halothane was the discovery of a potential obturating material, which was termed "halopercha".

Chloroform↗
PubMed1990

Management of advanced endodermal sinus tumor of the ovary with preservation of reproductive function.

Endodermal sinus tumor of the ovary occurs primarily in children and young adults. This tumor is classified as a germ cell tumor which comprises approximately 5% of all ovarian tumors. In the past, patients with this highly malignant tumor had low survival. However, with the evolution of effective adjunctive chemotherapeutic regimens, specifically vincristine, actinomycin D, and cyclophosphamide, survival rates have improved. In an attempt to continuously improve survival rates, other combination chemotherapeutic regimens are currently under investigation. Unlike epithelial ovarian malignancies, endodermal sinus tumor can be monitored by a specific tumor marker, alpha-fetoprotein (AFP). Serum levels of AFP can be followed from the preoperative period through the course of chemotherapy. When elevated, AFP has excellent predictability that persistent disease is present. Because this disease presents primarily in young females, preservation of reproductive function is of utmost importance. We report a case of advanced endodermal sinus tumor which was managed with conservative surgery only, followed by radical combination chemotherapy, resulting in preservation of normal reproductive function and total resolution of disease documented by second-look laparotomy.

Adolescent↗
PubMed1990

Acquired immunodeficiency syndrome and Pneumocystis carinii infection in a pregnant woman.

Human immunodeficiency virus (HIV) infections are being seen with greater regularity by the obstetrician-gynecologist. Acquired immunodeficiency syndrome (AIDS), the extreme of the spectrum of HIV infections, is associated with Pneumocystis carinii infection in more than half of newly diagnosed cases. Four cases of AIDS and P carinii pneumonia complicating pregnancy have been reported in the literature, and all have caused maternal death. We report a case in which the mother survived. Treatment was similar to that used in the other reported cases except that steroids were added. A limited number of patients with AIDS and P carinii infection have been treated with trimethopterim-sulfamethoxazole and steroids, with good results. Steroids should be considered for cases in which other efforts are failing.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Bacteriological comparison of ultrasonic and hand instrumentation of root canals in dogs.

This study compared the effectiveness of hand and ultrasonic instrumentation for removing a standardized inoculum of pigmented Serratia marcescens from the root canal system of premolars in dogs. Forty-four premolars from nine beagle dogs were divided into two experimental groups of 20 and 24 teeth, respectively. The experimental teeth were inoculated with approximately 10 colony-forming units of S. marcescens. After the bacterial were allowed to colonize for 1 wk, the experimental teeth were instrumented with either hand instruments or the Cavi-Endo device. The teeth were extracted, crushed, and assayed for recoverable colony-forming units of S. marcescens. Statistical comparisons of the ratio of inoculated to recovered colony-forming untis were made. The results indicated that the difference between the positive controls and the experimental groups was significant. There was no significant difference between the two instrumentation groups.

Animals↗