Actin and myosin inhibitors block elongation of kinetochore fibre stubs in metaphase crane-fly spermatocytes.

We used an ultraviolet microbeam to cut individual kinetochore spindle fibres in metaphase crane-fly spermatocytes. We then followed the growth of the "kinetochore stubs", the remnants of kinetochore fibres that remain attached to kinetochores. Kinetochore stubs elongate with constant velocity by adding tubulin subunits at the kinetochore, and thus elongation is related to tubulin flux in the kinetochore microtubules. Stub elongation was blocked by cytochalasin D and latrunculin A, actin inhibitors, and by butanedione monoxime, a myosin inhibitor. We conclude that actin and myosin are involved in generating elongation and thus in producing tubulin flux in kinetochore microtubules. We suggest that actin and myosin act in concert with a spindle matrix to propel kinetochore fibres poleward, thereby causing stub elongation and generating anaphase chromosome movement in nonirradiated cells.

Phallacidin stains the kinetochore region in the mitotic spindle of the green algae Oedogonium spp.

We found previously that in living cells of Oedogonium cardiacum and O. donnellii, mitosis is blocked by the drug cytochalasin D (CD). We now report on the staining observed in these spindles with fluorescently actin-labeling reagents, particularly Bodipy FL phallacidin. Normal mitotic cells exhibited spots of staining associated with chromosomes; frequently the spots appeared in pairs during prometaphase-metaphase. During later anaphase and telophase, the staining was confined to the region between chromosomes and poles. The texture of the staining appeared to be somewhat dispersed by CD treatment but it was still present, particularly after shorter (< 2 h) exposure. Electron microscopy of CD-treated cells revealed numerous spindle microtubules (MTs); many kinetochores had MTs associated with them, often laterally and some even terminating in the kinetochore as normal, but the usual bundle of kinetochore MTs was never present. As treatment with CD became prolonged, the kinetochores became shrunken and sunk into the chromosomes. These results support the possibility that actin is present in the kinetochore of Oedogonium spp. The previous observations on living cells suggest that it is a functional component of the kinetochore-MT complex involved in the correct attachment of chromosomes to the spindle.

Pac-Man does not resolve the enduring problem of anaphase chromosome movement.

The Pac-Man hypothesis suggests that poleward movement of chromosomes during anaphase A is brought about by: disassembly of kinetochore microtubules (MTs) at the kinetochore; generation of the poleward force exclusively at or very close to the kinetochore; and the required energy coming from coupled disassembly of these MTs. This model has become widely accepted and cited as the sole or major mechanism of anaphase A. Rarely acknowledged are several significant phenomena that refute some or all of these postulates. We summarise these anomalies as follows: poleward movement of chromosomes occurring without insertion of any MTs at the kinetochore; "anaphase" shortening of kinetochore fibres in spindles entirely devoid of chromosomes and, presumably, kinetochores; continued movement of chromosomes while their severed kinetochore stub elongated poleward after treatment with UV microbeams; and fluxing of tubulin subunits through kinetochore MTs during anaphase A, indicating that during anaphase, kinetochore MTs disassemble partly or solely at the poles.

The cytoplast concept in dividing plant cells: cytoplasmic domains and the evolution of spatially organized cell.

The unique cytokinetic apparatus of higher plant cells comprises two cytoskeletal systems: a predictive preprophase band of microtubules (MTs), which defines the future division site, and the phragmoplast, which mediates crosswall formation after mitosis. We review features of plant cell division in an evolutionary context and from the viewpoint that the cell is a domain of cytoplasm (cytoplast) organized around the nucleus by a cytoskeleton consisting of a single "tensegral" unit. The term "tensegrity" is a contraction of "tensional integrity" and the concept proposes that the whole cell is organized by an integrated cytoskeleton of tension elements (e.g., actin fibers) extended over compression-resistant elements (e.g., MTs).During cell division, a primary role of the spindle is seen as generating two cytoplasts from one with separation of chromosomes a later, derived function. The telophase spindle separates the newly forming cytoplasts and the overlap between half spindles (the shared edge of two new domains) dictates the position at which cytokinesis occurs. Wall MTs of higher plant cells, like the MT cytoskeleton in animal and protistan cells, spatially define the interphase cytoplast. Redeployment of actin and MTs into the preprophase band (PPB) is the overt signal that the boundary between two nascent cytoplasts has been delineated. The "actin-depleted zone" that marks the site of the PPB throughout mitosis may be a more persistent manifestation of this delineation of two domains of cortical actin. The growth of the phragmoplast is controlled by these domains, not just by the spindle. These domains play a major role in controlling the path of phragmoplast expansion. Primitive land plants show different morphological changes that reveal that the plane of division, with or without the PPB, has been determined well in advance of mitosis.The green alga Spirogyra suggests how the phragmoplast system might have evolved: cytokinesis starts with cleavage and then actin-related determinants stimulate and positionally control cell-plate formation in a phragmoplast arising from interzonal MTs from the spindle. Actin in the PPB of higher plants may be assembling into a potential furrow, imprinting a cleavage site whose persistent determinants (perhaps actin) align the outgrowing edge of the phragmoplast, as in Spirogyra. Cytochalasin spatially disrupts polarized mitosis and positioning of the phragmoplast. Thus, the tensegral interaction of actin with MTs (at the spindle pole and in the phragmoplast) is critical to morphogenesis, just as they seem to be during division of animal cells. In advanced green plants, intercalary expansion driven by turgor is controlled by MTs, which in conjunction with actin, may act as stress detectors, thereby affecting the plane of division (a response clearly evident after wounding of tissue). The PPB might be one manifestation of this strain detection apparatus.

Cytochalasin D and latrunculin affect chromosome behaviour during meiosis in crane-fly spermatocytes.

Living crane-fly spermatocytes were treated with 10-20 microg/ml cytochalasin D (CD) or 0.3 microg/ml latrunculin (LAT) at various stages of meiosis I. The drugs had the same effects on chromosome behaviour, but CD effects were reversible and LAT effects generally were not. When applied in mid-prometaphase to metaphase, both drugs altered subsequent anaphase poleward movements: half-bivalents either moved more slowly than normal, or moved more slowly after a brief period of movement at normal rate or stalled for 10 min or more immediately after disjunction. CD effects were reversible: within 1 min after washing out the CD, stopped chromosomes started moving and slowed chromosomes sped up. When applied in anaphase, both drugs stopped or slowed poleward chromosome movements, usually reversibly. When applied near the end of prophase, both drugs often prevented one or more bivalents in the cell from attaching to the spindle. Attached bivalents behaved as in cells treated with drugs at later stages, as described above. Unattached bivalents in the same cells moved to poles or cytoplasm in early prometaphase, where they remained motionless; at anaphase they sometimes did not disjoin, but when they did disjoin the half-bivalents did not move, either in the continued presence of the drug or when CD was washed out, confirming that they were not atttached. When CD or LAT prevented all bivalents in the cell from attaching, spindles kept in the drug were invaded by granules at about the time of normal anaphase. Conversely, when CD was washed out during late prometaphase, chromosomes often attached to spindle fibres and later entered anaphase. As CD and LAT are different antiactin drugs, but have the same effect on chromosome behaviour, the results implicate actin in early interactions of chromosomes with spindle fibres and in anaphase chromosome movements.

Ultraviolet microbeam irradiations of epithelial and spermatocyte spindles suggest that forces act on the kinetochore fibre and are not generated by its disassembly.

Ultraviolet (UV) microbeam irradiations of crane-fly spermatocyte and newt epithelial spindles severed kinetochore fibres (KT-fibres), creating areas of reduced birefringence (ARBs): the remnant KT-fibre consists of two "stubs," a pole-stub attached to the pole and a KT-stub attached to the kinetochore. KT-stubs remained visible but pole-stubs soon became undetectable [Forer et al., 1996]. At metaphase, in both cell types the KT-stub often changed orientation immediately after irradiation and its tip steadily moved poleward. In spermatocytes, the chromosome attached to the KT-stub remained at the equator as the KT-stub elongated. In epithelial cells, the KT-stub sometimes elongated as the associated chromosome remained at the equator; other times the associated chromosome moved poleward together with the KT-stub, albeit only a short distance toward the pole. When an ARB was generated at anaphase, chromosome(s) with a KT-stub often continued to move poleward. In spermatocytes, this movement was accompanied by steady elongation of the KT-stub. In epithelial cells, chromosomes accelerated polewards after irradiation until the KT-stubs reached the pole, after which chromosome movement returned to normal speeds. In some epithelial cells fine birefringent fibres by chance were present along one edge of ARBs; these remnant fibres buckled and broke as the KT-stub and chromosome moved polewards. Similarly, KT-stubs that moved into pole stubs (or astral fibres) caused the pole stubs (or astral fibres) to bend sharply from the point of impact. Our results contradict models of chromosome movement that postulate that force is generated by the kinetochore disassembling the KT-fibre. Instead, these results suggest that poleward directed forces act on the KT-fibre and the KT-stub and suggest that continuity of microtubules between kinetochore and pole is not obligatory for achieving anaphase motion to the pole.

Traction fibre: toward a "tensegral" model of the spindle.

Most current hypotheses of mitotic mechanisms are based on the "PAC-MAN" paradigm in which chromosome movement is generated and powered by disassembly of kinetochore microtubules (k-MTs) by the kinetochore. Recent experiments demonstrate that this model cannot explain force generation for anaphase chromosome movement [Pickett-Heaps et al., 1996: Protoplasma 192:1-10]. Another such experiment is described here: a UV-microbeam cut several kinetochore fibres (k-fibres) in newt epithelial cells at metaphase and the half-spindle immediately shortened: in several cells, the remaining intact spindle fibres bowed outwards as they came under increased compression. Thus, severing of k-MTs can lead to increased tension between chromosomes and poles. This observation cannot be explained by models in which force is produced by motor molecules at the kinetochore actively disassembling k-MTs. Rather, we argue that tensile forces act along the whole k-fibre, which, therefore, can be considered as a classic "traction fibre." We suggest that anaphase polewards force is generated by MTs interacting with the spindle matrix and when k-MTs are severed, polewards force continues to act on the remaining kMT-stub; spindle MTs act as rigid struts concurrently resisting and being controlled by these forces. We suggest that the principles of "cellular tensegrity" [Ingber, 1993: J. Cell Sci. 104:613-627] derived from the behaviour and organization of the interphase cell apply to the spindle. In an evolutionary context, this argument further suggests that the spindle might originally have evolved as the mechanism by which a single tensegral unit (cytoplast) is divided into two cytoplasts; use of the spindle for segregating chromosomes might represent a secondary, more recent development of this primary function. If valid, this concept has implications for the way the spindle functions and for the spindle's relationship to cytokinesis.

The amyloid precursor protein of Alzheimer's disease is found on the surface of static but not activity motile portions of neurites.

We have previously found that the amyloid precursor protein (APP) of Alzheimer's disease is present on the surface of rat cortical neurons in culture, in a segmental pattern which first becomes evident after 24 hours and is fully developed by five days. As APP has previously been reported to have a short half-life in neuronal cell lines, and has been shown to contain binding sites for various extracellular matrix components within its extracellular domain, we hypothesized that APP would be associated with portions of neurites undergoing rapid structural change, such as growth cones. To test this hypothesis, we observed selected neurons by video time-lapse differential interference microscopy on 24-hour-old primary rat neuronal cultures for up to 45 minutes, followed by fixation and immunocytochemistry to ascertain surface APP distribution on those same neurons. In contrast to our predictions, surface APP was not found on active portions of neurites, even if the activity produced no net translational movement. This result indicates that surface APP is actually associated with stable portions of neurites, a conclusion that tallies with other recent results showing that neuronal surface APP has a longer half-life than general cellular APP, and is associated with markers of adhesion patches, which themselves are relatively stable structures.

Postirradiation sarcoma of the gynecologic tract. A report of 13 cases and a discussion of the risk of radiation-induced gynecologic malignancies.

With improvement in survival after cancer treatment, it is becoming increasingly important to examine treatment-related morbidity and mortality. Sarcomas can develop within the irradiated field after radiation therapy (RT) for gynecologic malignancies. We undertook a study to assess the outcome after treatment of postirradiation sarcoma (PIS) of the gynecologic tract. In reviewing our data and the literature, we compare the absolute risk of PIS and other radiation-associated second malignant neoplasms (SMNs) with the mortality risk of surgery and general anesthesia. Between 1955 and 1987, 114 patients with uterine sarcomas were seen at the University of California, Los Angeles (UCLA), Medical Center. Thirteen had a prior history of RT. Conditions for which these patients received RT included choriocarcinoma (one), menorraghia (four), cervical cancer (six), and ovarian cancer (two). RT doses were known in six cases and ranged from 4,000 to 8,000 cGy. Latency time from RT to the development of PIS ranged from 3 to 30 years, with a median of 17 years. Twelve patients were treated with surgery or additional RT. Two patients remain alive 5 months and 57 months, respectively, following salvage therapy. Five-year disease-specific survival for all patients is 17%. From our data and a review of the literature, we estimate that the absolute risk of PIS with long-term follow-up ranges from 0.03 to 0.8%. Postirradiation sarcoma of the gynecologic tract is a relatively rate event associated with a poor prognosis. Mortality risks of radiation-associated SMN are similar to mortality risks of surgery and general anesthesia. Given the large number of patients with gynecologic malignancies who can be cured or palliated with RT, concern regarding radiation sarcomagenesis should not be a major factor influencing treatment decisions.

The effects of diazepam on mitosis and the microtubule cytoskeleton. I. Observations on the diatoms Hantzschia amphioxys and Surirella robusta.

The effects of diazepam (DZP) on mitosis and the microtubule (MT) cytoskeleton in the live diatoms Hantzschia amphioxys and Surirella robusta were followed using time-lapse video microscopy. Similarly treated cells were fixed and later examined for immunoflouresence staining of MTs or for transmission electron microscopy. DZP treatment (250 microM) had no effect on interphase cells but affected mitosis, resulting in the majority of prometaphase and metaphase chromosomes releasing from one or both spindle poles and collecting irregularly along the central spindle. Chromosomes remaining attached to one pole continued to display slight prometaphase oscillations; however, this activity was never observed in metaphase spindles. Following removal of DZP, some chromosomes still bipolarly attached, immediately released elastically from one pole. Within the first 2 minutes of recovery, all chromosomes recommenced spindle attachment, exhibiting normal prometaphase oscillations and proceeded through mitosis. DZP treatment during anaphase had no detectable effect on chromosome motion or cell cleavage. These results suggest that DZP acts as an anti-MT agent, selectively affecting polar MTs at prophase, prometaphase and metaphase, and thereby weakening kinetochore connection to the poles. From these and other results (unpublished), its mode of action is different to that of most anti-MT agents.

A phase I trial of a rhenium 186-labeled monoclonal antibody administered intraperitoneally in ovarian carcinoma: toxicity and clinical response.

OBJECTIVES: To determine the maximum tolerated dose, spectrum of toxicity, and response of persistent and recurrent ovarian carcinoma to intraperitoneal injection of a conjugate of rhenium 186 (186Re) and a monoclonal antibody; to measure the radiation distribution to normal structures; and to establish the fate of the infused isotope. METHODS: Rhenium 186 was conjugated to murine monoclonal antibody NR-LU-10, which binds to a cell surface antigen present on ovarian carcinoma. In a dose-escalating phase I trial, a single dose of 25 mg/m2 of antibody complexed with 25-150 mCi/m2 of 186Re was administered intraperitoneally to 17 women with ovarian carcinoma that was recurrent or persistent after platinum-based chemotherapy. RESULTS: Severe myelosuppression was observed at 150 mCi/m2 of 186Re in two evaluable patients. Other clinically significant toxicities included low-grade fever and transient skin rash. Hepatic enzyme elevation was seen in 12 of 17 patients, but was not clinically significant. No chronic enteric toxicity was observed. Decreased tumor size was demonstrated by repeat operation in four of seven patients with disease measuring less than 1 cm at the time of treatment (four of 17 total). All four responders had serum CA 125 levels of 35 U/mL or less at the time of treatment and had received only one regimen of chemotherapy. CONCLUSION: This immunoconjugate can be administered intraperitoneally with acceptable toxicity and produces objective responses after a single dose in patients with minimal objective disease.

An extended corona attached to metaphase kinetochores of the green alga Oedogonium.

Mitotic cells of the green alga Oedogonium were treated with the anti-microtubule agent oryzalin (1.0-0.1 microM) for 5 to 10 min. Within 5 min treatment of living cells, metaphase spindles became spherical with disorganized chromosomes, and anaphase spindles collapsed. At lower concentrations, the effects were slower, and partial recovery was observed about 10 to 20 min after the drug was washed out. Following breakdown of the spindle, considerable disorganized activity detected by time-lapse continued within the nucleus, isolated from the cytoplasm by its intact nuclear membrane. Under the electron microscope, spindle microtubules (MTs) were absent in oryzalin-treated cells. Paired metaphase kinetochores displayed an array of fine filamentous material extended, usually straight, about 3 microns into the nucleoplasm. In cells recovering from oryzalin treatment, MTs became associated with kinetochores in the usual manner. However, this filamentous array, the "extended corona" (EC), was almost undetectable, even when the MTs were short and poorly organized. The EC is appreciably larger by metaphase than the corona of prophase chromosomes and so it may assemble during early mitosis. Fine filaments interspersed with kinetochore MTs have been described in carefully fixed cells of this alga (M.J. Schibler, J.D. Pickett-Heaps, Eur. J. Cell Biol. 22, 687-698 (1980)). The EC apparently represents a less organized form of this material remaining after its scaffold of MTs has been removed. These fibers appear involved in MT capture upon spindle recovery from anti-MT drugs. They could function during prometaphase and even anaphase movement along spindle MTs.

Concurrent cisplatin and 5-fluorouracil chemotherapy and radiation therapy for advanced-stage squamous carcinoma of the vulva.

A phase II trial of concurrent cisplatin and 5-fluorouracil (5-FU) chemotherapy and radiation therapy (CT + RT) was conducted for the primary treatment of 12 patients with retrospective surgical FIGO stages III-IV squamous carcinoma of the vulva. Eight patients were stage III and four were stage IV. Chemotherapy was used as a radiation sensitizer and it was administered in two 5-day cycles 28 days apart. Cisplatin, 50 mg/m2/day iv on Days 1 and 2 or 100 mg/m2 on Day 1 or 2, plus continuous-infusion 5-FU, 1000 mg/m2/day for 4-5 days commencing on Days 1 and 28 of external-beam radiation therapy, are given. The pelvic radiation to a dose of 4400-5400 cGy is administered AP and PA to treat the primary tumor, the groin nodes, and the iliac vessels to the level below the common iliac nodes. Complete tumor responses were seen in 8 of 12 (67%) patients. Responses were observed in 6 of 8 (75%) stage III patients and 2 of 4 (50%) stage IV patients. Partial response were observed in 3 patients, and 1 patient had persistent disease. At the completion of concurrent chemoradiation therapy, radical vulvectomy or excision was used in 3 patients and posterior exenteration in 1. With a median follow-up of 37 months (range, 7-60 months), 10 patients are alive and free of disease, and 2 patients died at 12 and 15 months. There were no treatment-related deaths and no grade 4 toxicity. The morbidity included moist desquamation of the vulva in all patients, with grade 2 toxicity in 10 and grade 3 in 2. One patient had a deep venous thrombosis that responded to anticoagulation therapy. These data support the use of concurrent cisplatin and 5-FU chemotherapy and radiation therapy as an alternative to primary radical surgery to treat advanced-stage squamous carcinoma of the vulva.

UV-microbeam irradiations of the mitotic spindle: spindle forces and structural analysis of lesions.

Mitotic PtK1 spindles were UV irradiated (285 nm) during metaphase and anaphase between the chromosomes and the pole. The irradiation, a rectangle measuring 1.4 x 5 microns parallel to the metaphase plate, severed between 90 and 100% of spindle microtubules (MTs) in the irradiated region. Changes in organization of MTs in the irradiated region were analyzed by EM serial section analysis coupled with 3-D computer reconstruction. Metaphase cells irradiated 2 to 4 microns below the spindle pole (imaged by polarization optics) lost birefringence in the irradiated region. Peripheral spindle fibers, previously curved to focus on the pole, immediately splayed outwards when severed. We demonstrate via serial section analysis that following irradiation the lesion was devoid of MTs. Within 30 s to 1 min, recovery in live cells commenced as the severed spindle pole moved toward the metaphase plate closing the lesion. This movement was concomitant with the recovery of spindle birefringence and some of the severed fibers becoming refocused at the pole. Ultrastructurally we confirmed that this movement coincided with bridging of the lesion by MTs presumably growing from the pole. The non-irradiated half spindle also lost some birefringence and shortened until it resembled the recovered half spindle. Anaphase cells similarly irradiated did not show recovery of birefringence, and the pole remained disconnected from the remaining mitotic apparatus. Reconstructions of spindle structure confirmed that there were no MTs in the lesion which bridged the severed spindle pole with the remaining mitotic apparatus. These results suggest the existence of chromosome-to-pole spindle forces are dependent upon the existence of a MT continuum, and to a lesser extent to the loss of MT initiation capacity of the centrosome at the metaphase/anaphase transition.

Adnexal torsion. An unusual cause of abdominal pain in postmenopausal women.

Adnexal torsion is a rare cause of abdominal pain in older women. Because the presenting symptoms and signs are vague, the diagnosis is not often considered. Lower abdominal pain with nausea and vomiting are usual in patients with torsion. Ultrasonography or computed tomography are useful diagnostic tests. Two case reports of older patients with adnexal torsion are presented to emphasize the diagnostic features of this entity, including lower abdominal pain, nausea and vomiting, and abdominal mass. Although the condition is uncommon, adnexal torsion should be considered in the differential diagnosis of acute abdominal pain.

Fine-needle aspiration cytology accuracy with palpable gynecologic neoplasms.

From 1984 to 1988, 62 fine-needle aspirations (FNA) were performed on palpable lesions in 59 gynecologic oncology patients at the UCLA Medical Center. Sites of aspiration included abdomen, cervix, vagina, superficial lymph nodes, and pelvic masses. Confirmatory open biopsy (41) or adequate clinical follow-up (17) was obtained in 55 patients (58 aspirates). FNA correctly established the diagnosis of malignancy in 19 of 26 (73%) biopsied patients. The predictive value for a positive test was 100%, and the predictive value for a negative test was 82%. Initial surgical biopsy had been incorrectly benign in 4 of these patients who were shown subsequently to have malignant tumors by FNA and clinical findings. In 7 patients, FNA failed to diagnose the malignancy found by open biopsy. Two of the false-negative FNAs were insufficient and five were in masses where palpation was inadequate. In 17 patients who were followed clinically without open biopsy, FNA correctly predicted the subsequent clinical course in 15 (88%). There were no false-positive FNA diagnoses obtained when cytologic results were correlated with both clinical outcome and surgical biopsy. Aspiration cytology has a specificity of 100% and a sensitivity of 65%. A negative FNA obtained from a clinically suspicious lesion should be followed by a repeat aspiration or surgical biopsy.

Surgical staging of cervical cancer.

Noninvasive radiologic methods to detect paraaortic lymph node metastases are reliable when combined with FNA of enlarged lymph nodes. However, the sensitivity is low, and undetected microscopic metastases leads to treatment failure. These patients with paraaortic lymph node metastasis are not treated with extended-field radiation, and they all die within 3 years. The CT scanning is probably the best diagnostic method to evaluate cervical cancer, because it can assess the primary tumor, the urinary tract, gastrointestinal tract, liver parenchyma, and retroperitoneum. It also permits the guidance of FNA and the arrangement of radiation ports. Surgical staging provides the direct assessment of the peritoneal cavity and the retroperitoneal spaces. Metastatic tumor, including enlarged lymph nodes, can be resected, but this is of dubious benefit. The operative morbidity is acceptable, with fewer intestinal complications when the extraperitoneal approach is used, and long-term morbidity is minimal when appropriate paraaortic radiation doses are employed (less than 5,000 cGy). Surgical staging has provided data on the frequency of paraaortic lymph node metastasis by stage of cervical cancer, and thus, treatment strategies can be better developed. Extended-field radiation results in 5-year survival rates of 20-25% in patients with microscopic paraaortic lymph node metastasis, patients who would not survive without the treatment. However, surgical staging has produced only a modest boost in survival rates, because of the high rate of pelvic and systemic failure. When extended-field radiation is used prophylactically or in patients with probable lymph node metastasis seen on radiographic studies, survival rates are similar to patients irradiated after surgical staging finds paraaortic lymph node disease. As our ability to predict, and detect nonsurgically, positive paraaortic node disease improves, extended radiation (or other adjuvant therapy) could be used more frequently without operation in patients who are at high risk for metastatic disease. In a study by Haie et al, prophylactic paraaortic radiation was given to patients at high risk for paraaortic metastasis. In patients with a high probability of local disease control, paraaortic radiation significantly reduced the incidence of paraaortic and distant metastases. Patients with known paraaortic lymph node metastases frequently have occult systemic metastases. In these same patients, pelvic failure is also common. Thus, until effective systemic therapies emerge, a marked improvement in survival is unlikely in patients who have paraaortic lymph node metastasis.(ABSTRACT TRUNCATED AT 400 WORDS)

Use of the inferior vena cava clip in patients at high risk for pulmonary embolism.

Sixteen gynecologic oncology patients at high risk of developing a postoperative pulmonary embolism underwent prophylactic clipping of the inferior vena cava during laparotomy for tumor resection. All patients had a prior history of deep venous thrombosis or pulmonary embolism or had an active deep venous thrombosis at the time of their surgery. Additionally, this group of 16 patients was characterized as being at high risk for recurrent thrombosis in the postoperative period based on traditional risk factors that are representative of most gynecologic oncology patients. The Adams-DeWeese or Moretz clip was used in this series. There were no pulmonary emboli in our 16 patients in the postoperative period or during follow-up. There were no signs of venous stasis attributable to clip placement. The procedure was quick, simple, and complication free and the external clip has the advantage of maintaining effectiveness throughout the patient's lifetime. Prophylactic clipping of the inferior vena cava at the time of laparotomy in patients at an increased risk of thrombosis deserves further study.

UV microbeam irradiations of the mitotic spindle. II. Spindle fiber dynamics and force production.

Metaphase and anaphase spindles in cultured newt and PtK1 cells were irradiated with a UV microbeam (285 nM), creating areas of reduced birefringence (ARBs) in 3 s that selectively either severed a few fibers or cut across the half spindle. In either case, the birefringence at the polewards edge of the ARB rapidly faded polewards, while it remained fairly constant at the other, kinetochore edge. Shorter astral fibers, however, remained present in the enlarged ARB; presumably these had not been cut by the irradiation. After this enlargement of the ARB, metaphase spindles recovered rapidly as the detached pole moved back towards the chromosomes, reestablishing spindle fibers as the ARB closed; this happened when the ARB cut a few fibers or across the entire half spindle. We never detected elongation of the cut kinetochore fibers. Rather, astral fibers growing from the pole appeared to bridge and then close the ARB, just before the movement of the pole toward the chromosomes. When a second irradiation was directed into the closing ARB, the polewards movement again stopped before it restarted. In all metaphase cells, once the pole had reestablished connection with the chromosomes, the unirradiated half spindle then also shortened to create a smaller symmetrical spindle capable of normal anaphase later. Anaphase cells did not recover this way; the severed pole remained detached but the chromosomes continued a modified form of movement, clumping into a telophase-like group. The results are discussed in terms of controls operating on spindle microtubule stability and mechanisms of mitotic force generation.

Surgical-pathologic variables predictive of local recurrence in squamous cell carcinoma of the vulva.

One hundred and thirty-five patients with squamous carcinoma of the vulva were treated at UCLA and City of Hope Medical Centers between 1957 and 1985. Sixty-two cases were stage I, 48 stage II, 18 stage III, and 7 stage IV. Twenty-one patients developed a local vulvar recurrence after primary radical resection. Ninety-one patients had a surgical tumor-free margin greater than or equal to 8 mm on tissue section and none had a local vulvar recurrence. Forty-four patients had a margin less than 8 mm; 21 had a local recurrence and 23 did not (P less than 0.0001). Of the 23 patients with a margin less than 8 mm who did not recur locally, 14 remained free of disease, and 9 had either advanced disease, declining health, or short follow-up. Depth of invasion is associated with local recurrence, with a 9.1-mm reference value correctly predicting outcome in 81.5% of cases. Increasing tumor thickness is associated with local recurrence, with a 10-mm reference value predictive of 90% non-recurrence and 33% recurrences. A pushing border pattern is less likely to recur than an infiltrative growth pattern. Lymph-vascular space invasion has a combined predictive accuracy of 81.5%. Increasing keratin and greater than 10 mitoses per 10 high-power fields correlate with local recurrence. Neither clinical tumor size nor coexisting benign vulvar pathology correlates with local recurrence. Fourteen of twenty-one patients with vulvar recurrence died of metastatic disease, four died of intercurrent disease, and three were alive at 32, 68, and 157 months, with 16 recurring in less than 1 year. Surgical margin is the most powerful predictor of local vulvar recurrence. Combining factors in a stepwise logistical regression does not significantly improve this predictive value. Accounting for specimen preparation and fixation, a 1-cm tumor-free surgical margin on the vulva results in a high rate of local control, whereas a margin less than 8 mm is associated with a 50% chance of recurrence.