Abstract PD8-12: Safety and efficacy of palbociclib and radiotherapy in metastatic breast cancer patients: Initial results of a novel combination

Purpose: Palbociclib is a selective CDK4/6 inhibitor approved for the treatment of metastatic ER+/HER2- breast cancer. Inhibition of CDK4/6 prevents cell cycle progression from G1 to the more radioresistant S phase, raising the possibility of an enhanced therapeutic effect if combined with radiotherapy (RT). Despite this potential benefit, clinicians seldom use this combination due to fear that RT may exacerbate palbociclib toxicity, particularly leukopenia. Our aim is to report the preliminary results of patients with metastatic breast cancer who received RT while receiving palbociclib.

Methods: We retrospectively reviewed records of all patients who were treated with palbociclib at our institution from 2015-2018. Patients who received RT for symptomatic metastases concurrently or within 14 days of last drug administration were included in our analysis. Local treatment effect was assessed by clinical exam and subsequent CT or MRI imaging, if applicable. Toxicity was graded based on CTCAE v5.0.

Results: A total of 16 females received palliative RT in association with palbociclib. The median age of the treated patients was 59.6 (range 33.3-91.0) years. The median time of closest palbociclib use to RT administration was 5 (range 0-14) days.

The following sites were treated in order of frequency: bone (10-axial skeleton [8-vertebra]; 1-ilium), brain (4: 3-WBRT & 1-SRS), and mediastinum (1). RT dose/fractionation for bone was 30 Gy/10 fxn (7), 35 Gy/14 fxn (2), 37.5 Gy/15 fxn (1), and 18 Gy/1 fxn (1). WBRT dose/fractionation was 30 Gy/10 fxn for all patients. SRS brain dose was 25 Gy/5 fxn. The patient treated to the mediastinum received 36 Gy/18 fxn.

At most recent follow-up, 12 patients are still living. The median time from RT to last known follow-up or death is 10.3 (range 1.7-29.6) months. Pain relief was achieved in 15 of 16 (93.8%) patients. No radiographic local failure was noted in the 13 patients with evaluable follow-up imaging.

The combination of RT and palbociclib was well-tolerated. Grade 1 fatigue, dermatitis, and nausea was noted in 5, 3, and 1 patient, respectively. One patient with WBRT developed Grade 1 headache. Six of 16 patients were leukopenic prior to RT initiation. Following RT, 7 patients were observed to have a drop in WBC count, of which 2 dropped into the leukopenic range. Only a total of 5 patients were leukopenic following RT, of which 3 were leukopenic before receiving RT. No acute or late Grade 2 or higher cutaneous, neurological, gastrointestinal, or hematologic toxicities were noted.

Conclusions: The use of RT in patients receiving palbociclib resulted in minimal Grade 1 and no Grade 2+ toxicities, including leukopenia. This treatment can be used safely in symptomatic patients without discontinuation of systemic therapy. Further larger prospective studies with longer follow-up are needed to confirm these results.

Citation Format: Chowdhary M, Sen N, Chowdhary A, Usha L, Cobleigh M, Patel KR, Wang D, Barry PN, Rao RD. Safety and efficacy of palbociclib and radiotherapy in metastatic breast cancer patients: Initial results of a novel combination [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr PD8-12.

Predictive factors for oligometastatic versus non-oligometastatic involvement of the central nervous system by brain metastases from breast cancer

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Background: To assess rates of oligometastatic (1-3 metastases) versus non-oligometastatic (4 or more) involvement of the central nervous system (CNS) from breast cancer and determine whether rates vary for different breast cancer subtypes.

Methods: We reviewed records of 65 patients with brain metastases from breast cancer. Fisher’s Exact Test compared incidence of oligometastatic versus nonoligometastatic CNS involvement and presence of visceral metastatic disease between groups. Paired Student's t test compared mean age and interval from initial diagnosis to development of brain metastases.

Results: 25 patients (38.5%) developed oligometastatic and 40 (61.5%) developed non-oligometastatic CNS disease. Subtypes predictive of oligometastatic disease included ER+ (p .04) and PR+ (p .008). Subtypes predictive of non-oligometastatic disease included HER2+ (p .05). HER2+ patients trended toward a lower incidence of visceral metastases compared to ER+ or PR+ patients (p .07). Non-oligometastatic and HER2+ patients developed brain metastases sooner after initial diagnosis (p .046 and .03, respectively).

Conclusions: ER+ breast cancer patients are more likely to develop oligometastatic CNS involvement and may be excellent candidates for stereotactic radiosurgery (SRS) alone. HER+ patients are likely to develop non-oligometastatic CNS involvement and may be better treated initially with whole brain radiotherapy (WBRT) even with apparent initial oligometastatic CNS involvement.

A phase II open-label trial to evaluate the efficacy and toxicity of erlotinib in women with metastatic, hormone receptor-negative, and HER2-negative breast cancer

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Background: There is limited success with current therapies for triple negative (TN) breast cancer. Epidermal growth factor receptor (EGFR) is a therapeutic target in solid tumors. Overexpression of EGFR has been linked to an aggressive breast tumor phenotype with a poor prognosis. Previous work at RUSH showed that 64% of 66 TN tumors were EGFR positive (Siziopikou SABCS 2004). To date, the use of EGFR tyrosine kinase inhibitors (TKIs) in metastatic breast cancer (MBC) has been disappointing. These trials enrolled refractory patients and did not select for EGFR expression. We hypothesized that if selected for EGFR expression, there may be a cohort of TN MBC patients who benefit from an EGFR TKI. This is a phase II study of erlotinib in TN-EGFR-positive MBC.

Methods: Eligible patients had TN-EGFR-positive MBC. EGFR positivity was defined as staining in >10% of tumor cells by IHC (Dako). Patients required measurable disease, prior treatment with anthracycline and taxane (adjuvant or metastatic setting) and ≤1 prior chemotherapy for MBC. Patients received erlotinib 150mg daily. Primary endpoint was progression-free survival (PFS). Initially, 18 patients were to be accrued. If ≥ 3 patients were progression-free at 4 months, accrual would continue to 43.

Results: The study was terminated prematurely due to poor accrual. In total, 11 patients enrolled, 10 were treated. Mean age 56.7y, 18% African-American. Four patients had prior chemotherapy for MBC. Most patients progressed rapidly, median PFS was 29 days (95% CI 25.90 – 32.10). However, 2 patients had stable disease for 225 and 476 days. Treatment was well-tolerated. Toxicities in the 2 patients with stable disease included grade 2 rash, grade 1 diarrhea, grade 1 nausea, grade 2 weight loss and grade 1 diarrhea.

Conclusions: Although most patients progressed rapidly, 2/10 patients had prolonged stable disease. This suggests there may be a subset of TN, EGFR positive MBC for whom EGFR-directed therapy may be suitable or that the natural history of their disease was indolent. Future studies to determine molecular and clinical profiles of patients likely to benefit from EGFR-TKI therapy in this population are warranted.

Defining the pathophysiology of the paclitaxel-acute pain syndrome

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Background: Paclitaxel therapy often results in a unique sub-acute pain syndrome, whose pathophysiology is unknown. While this syndrome is often termed as a ‘myalgia’ or ‘arthralgia’, it has not been demonstrated to be associated with any structural injury of muscles or joints. Identifying the pathophysiology mechanisms that result in the paclitaxel-acute pain syndrome might be a positive step in the development of effective prevention and/or treatment strategies. With the hypothesis that the paclitaxel-acute pain syndrome occurs as a result of nerve injury, an observational study to clarify the clinical characteristics of this syndrome was initiated. Methods: Oncology patients who were treated with at least one dose of paclitaxel and reported developing sub-acute pain were questioned using a detailed structured interview. Various aspects of the pain, including the time of onset, duration, location, severity, and exacerbating factors were evaluated. Data were tabulated descriptively. Results: Eighteen patients were interviewed. The onset of pain typically occurred 1–2 days after therapy and lasted for a median of 4–5 days. Pain was most commonly located in the back, hips, shoulders, thighs, legs and feet, with the most common descriptors used being ‘aching’ or ‘deep pain’. Commonly used adjectives to describe the pain were: ‘radiating’, ‘shooting’, ‘aching’, ‘stabbing’ and ‘pulsating’. Some patients described increased pain with weight bearing or walking. Fifteen of 18 patients specifically denied localization of pain to either joints or muscles. Conclusions: The nature of the pain, i.e. , generalized, deep aching pain, the notation of increased sensitivity with weight bearing (mechanical hyperalgesia) and the lack of localization to joints or muscles, support the hypothesis that the paclitaxel-acute pain syndrome results from a hyperalgesic dysfunction of nociceptive receptors, their fibers, or the spinothalamic system. These clinical conclusions are supported by the recent findings that markers of cellular injury can be identified in peripheral nerve tissues shortly following paclitaxel administration in an animal model (Peters CM, et al., Exp Neurol. 2007 Jan;203(1):42- 54).

No significant financial relationships to disclose.

N0377: Results of NCCTG phase II trial of the mTOR inhibitor RAD-001 in metastatic melanoma

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Background: RAD-001 (Everolimus) is an oral inhibitor of mammalian target of rapamycin (mTOR). Interim analysis results from a phase II study of RAD-001 in patients with metastatic melanoma (MM) were presented at ASCO 2005. This study was re-opened using a higher dose based on an improvement in the 16 week progression free survival (PFS) rate and good tolerability. Methods: A two- stage, phase II multi-institutional trial was conducted in patients with MM to assess that 16 weeks PFS rate was at least 50%. Inclusion criteria: measurable disease, ECOG performance score of 0–2. Exclusion criteria: presence of intracranial metastases, concurrent use of inducers of cytochrome 3A4 and abnormal organ function. The dose of RAD-001 in the second cohort was increased to 10 mg daily (increased from 30 mg weekly) based on evidence of safety of the higher dose. Results: Twenty-nine patients were enrolled; baseline information is available on 27. Median age was 63 yrs; 15 (56%) had >2 sites of metastatic disease. Most (48%) had stage M1c disease. PS was 0, 1 and 2 in 58%, 38% and 4%. All but 4 (15%) had received prior therapy. Grade 3 adverse events included stomatitis and fatigue (2 each), leukopenia, neutropenia, diarrhea, anorexia, dehydration, dyspnea, hyperglycemia, and hypersensitivity (1 each). Planned interim analysis was done after 20 patients were enrolled. 14 (70%) had progressed 16 weeks, failing to meet the decision rule needed (PFS >30%) to restart accrual. The median PFS for all 29 patients was 56 days. The median overall survival (OS) has not been reached. For the entire cohort of 53 pts treated on this study (at both dose levels), the median PFS, median OS were 59 and 286 days respectively. Conclusion: Interim analysis after enrollment of 20 patients at a higher dose of RAD-001 demonstrated significantly more toxicity and no added clinical efficacy. The 16 week PFS rate target was not reached, and accrual was suspended.

No significant financial relationships to disclose.

Phase II trial of the mTOR inhibitor everolimus (RAD-001) in metastatic melanoma

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Background: Mammalian target of rapamycin (mTOR) is a serine-threonine kinase that regulates the production vascular endothelial growth factor (VEGF) and cell growth and proliferation. Inhibitors of mTOR have anti-mitotic and anti-angiogenic effects in various cancers (including melanoma). Everolimus (RAD-001), an orally administered inhibitor of mTOR, is well tolerated at a dose of 30 mg/week. We conducted a phase II study to evaluate the role of RAD-001 in treating patients with metastatic melanoma (MM). Methods: A 2 stage, phase II multi-institutional trial was conducted in patients with MM to assess progression free survival (PFS) rate at 16 weeks was at least 50% against the alternative it was at most 30%. Data about expected baseline PFS were derived from historical controls. Each cycle was 8 weeks in duration. Inclusion criteria: measurable disease, ECOG performance score (PS) of 0–2. Exclusion criteria: presence of intracranial metastases, concurrent use of inducers of cytochrome 3A4 and abnormal hepatic, renal or bone marrow function. Correlative studies included changes pharmacodynamic endpoints to evaluate effect of therapy on signaling pathways. Results: 24 patients with MM were enrolled. Median age was 56 years (33–79), 21 (88%) had at 2 or more sites of metastatic disease. Most (75%) had stage M1c, with 13% each having 1a and 1b disease. PS was 0, 1 and 2 in 58, 38% and 4%, resp. All but 9 had received previous therapy for MM. Planned interim analysis was done after 20 patients were enrolled. Of these, 7 (i.e., 35%) were PF at 16 weeks, which exceeded the decision rule for restarting accrual. No patient had an objective response; all 7 had stable disease. There were no grade 3 toxicities. Grade 2 toxic events (at least possibly related to therapy) were: fatigue (17%), diarrhea (8%) and anemia (8%). Patients had a clinically relevant benefit, with the median PFS for all 24 patients of 3 months. Median overall survival was not reached. Three patients continue on therapy. RAD-001 treatment resulted in changes in serum VEGF levels. Conclusion: Interim analysis after enrollment of 20 patients suggests that RAD-001 is well tolerated and has sufficient anti-tumor activity in MM to warrant the opening of enrollment to the second stage of this trial. Further accrual is planned.

No significant financial relationships to disclose.

The efficacy of lamotrigine in the management of chemotherapy-induced peripheral neuropathy: A phase III randomized, double blind, placebo-controlled NCCTG trial, N01C3

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Background: Chemotherapy-induced peripheral neuropathy (CIPN) is a common dose limiting complication of chemotherapy. Lamotrigine (an anti-convulsant drug) appears to have some benefit when used to treat pain from neuropathy due to various etiologies. Based on these data, we conducted a phase III randomized placebo controlled study to determine the efficacy of lamotrigine in treating symptoms from CIPN. Methods: Patients with CIPN for 1 month or more were randomly assigned to lamotrigine (target dose 300 mg/day, increased by 50 mg/2 weeks) or placebo for 10 weeks. The co-primary endpoints were differences in average CIPN symptoms assessed by pro-rated area under the curve (AUC) of a numerical pain rating scale (NRS) and the Eastern Cooperative Oncology Group sensory neuropathy (ESN) scale. Accrual of 60 patients per group provided t-tests with 80% power to detect a difference of 0.57 standard deviation for each co-primary endpoint (moderate effect size) with a type I error of 0.025. Results: 131patients were enrolled, with complete data available for analysis in 93 (72%). Analyses were limited to this cohort but will be updated. Chemotherapy drugs considered to be causative of the CIPN were vinca alkaloids (30%), taxanes (25%), platinum-agents (7%), combinations (34%), and others (3%). Patients were equally matched with regards to baseline characteristics. Patients who enrolled had severe symptoms, with a baseline median ESN at enrollment of 3 (out of 3) in both groups. Toxicities were similar in both groups, however, more patients discontinued lamotrigine due to toxicities/refusals than those on placebo (32% vs 13% resp; p=0.04) and were therefore less likely to complete the 10 weeks therapy (60% vs. 78% resp, p=0.08). Average AUC of NRS score for patients on lamotrigine and placebo was 30.5 and 33.7 resp (p=0.48). The corresponding average AUC of the ESN scores were 12.4 and 14.5 (p=0.23). The proportions of patients with a 10 point (of 100) improvement in worst pain score (39% vs 36%) and a 1 point change in ESN (25% vs 27%) were similar between the lamotrigine and placebo arms, resp. Conclusions: These results suggest that lamotrigine is not effective for managing pain and symptoms due to CIPN.

No significant financial relationships to disclose.

Changes in galactose and lactic acid content of sweet whey during storage

Whey is often stored or transported for a period of time prior to processing. During this time period, galactose and lactic acid concentrations may accumulate, reducing the quality of spray-dried whey powders in regard to stickiness and agglomeration. This study surveyed industry samples of Cheddar and mozzarella cheese whey streams to determine how galactose and lactic acid concentrations changed with storage at appropriate (4 degrees C) and abuse (37.8 degrees C) temperatures. Samples stored at 4 degrees C did not exhibit significant increases in levels of lactic acid or galactose. Mozzarella whey accumulated the greatest amount of galactose and lactic acid with storage at 37.8 degrees C. Whey samples derived from cheese made from single strains of starter culture were also evaluated to determine each culture's contribution to galactose and lactic acid production. Starter cultures evaluated included Streptococcus salivarius ssp. thermophilus. Lactobacillus helveticus, Lactobacillus delbrueckii ssp. bulgaricus, Lactococcus lactis ssp. cremoris, and Lactococcus lactis ssp. lactis. Whey derived from L. helveticus accumulated a significantly greater amount of lactic acid upon storage at 37.8 degrees C as compared with the other cultures. Galactose accumulation was significantly decreased in whey from L. lactis ssp. lactis stored at 37.8 degrees C in comparison with the other cultures. Results from this study indicate that proper storage conditions (4 degrees C) for whey prevent accumulation of galactose and lactic acid while the extent of accumulation during storage at 37.8 degrees C varies depending on the culture(s) used in cheese production.

Aerosol therapy for malignancy involving the lungs

The lungs are common sites of involvement by primary and metastatic malignant disease. Patients with malignancies in the lung have limited treatment options and are usually not curable. Numerous investigators have studied the potential of delivering various therapeutic agents directly to the lungs and pulmonary lymphatics by nebulization. Most of the research involves the use of immunomodulatory strategies; a few aerosol studies of chemotherapy and gene therapy have also been conducted. Most of these studies have been conducted in animal models. A few human trials have also been completed. Results suggest that aerosol therapies have the potential to shrink pulmonary metastases of selected histologies, and that survival in selected patients with metastatic renal cell cancer may be prolonged. The approach to therapy of cancer in the lungs holds promise as a means to avoid systemic toxicity and obtain an improved therapeutic effect. Research is currently underway to address issues of local versus systemic toxicity, optimal drug delivery and selection of optimal drugs and schedules including outpatient aerosol therapy. Future issues in design of aerosol cancer treatment include identifying effective combinations of agents, schedules, and use of aerosol therapy at home as adjuvant therapy.

Late recurrence of a primitive neuro-ectodermal tumor

Late recurrences after therapy are rare in primitive neuro-ectodermal tumor (PNET). Most recurrences occur within the first 2 years after therapy, although a small number of recurrences may occur up to 5 years after therapy. We present a rare case of a recurrence of PNET in a 31-year-old woman 17 years after her initial presentation. The potential biological implications of this late recurrence as well as responses to subsequent therapy, including temozolomide, are discussed.

Whiplash injury determination with conventional spine imaging and cryomicrotomy

STUDY DESIGN

Soft tissue-related injuries to the cervical spine structures were produced by use of intact entire human cadavers undergoing rear-end impacts. Radiography, computed tomography, and cryomicrotomy techniques were used to evaluate the injury.

OBJECTIVES

To replicate soft tissue injuries resulting from single input of whiplash acceleration to whole human cadavers simulating vehicular rear impacts, and to assess the ability of different modes of imaging to visualize soft tissue cervical lesions.

SUMMARY OF BACKGROUND DATA

Whiplash-associated disorders such as headache and neck pain are implicated with soft tissue abnormalities to structures of the cervical spine. To the authors' best knowledge, no previous studies have been conducted to determine whether single cycle whiplash acceleration input to intact entire human cadavers can result in these soft tissue alterations. There is also a scarcity of data on the efficacy of radiography and computed tomography in assessing these injuries.

METHODS

Four intact entire human cadavers underwent single whiplash acceleration (3.3 g or 4.5 g) loading by use of a whole-body sled. Pretest and posttest radiographs, computed tomography images, and sequential anatomic sections using a cryomicrotome were obtained to determine the extent of trauma to the cervical spine structures.

RESULTS

Routine radiography identified the least number of lesions (one lesion in two specimens). Although computed tomography was more effective (three lesions in two specimens), trauma was not readily apparent to all soft tissues of the cervical spine. Cryomicrotome sections identified structural alterations in all four specimens to lower cervical spine components that included stretch and tear of the ligamentum flavum, anulus disruption, anterior longitudinal ligament rupture, and zygopophysial joint compromise with tear of the capsular ligaments.

CONCLUSIONS

These results clearly indicate that a single application of whiplash acceleration pulse can induce soft tissue-related and ligament-related alterations to cervical spine structures. The pathologic changes identified in this study support previous observations from human volunteers observations with regard to the location of whiplash injury and may assist in the explanation of pain arising from this injury. Although computed tomography is a better imaging modality than radiography, subtle but clinically relevant injuries may be left undiagnosed with this technique. The cryomicrotome technique offers a unique procedure to understand and compare soft tissue-related injuries to the cervical anatomy caused by whiplash loading. Recognition of these injuries may advance the general knowledge of the whiplash disorder.

Interleukin-6 and nerve growth factor levels in peripheral nerve and brainstem after trigeminal nerve injury in the rat

Earlier studies have demonstrated that inflammation plays a role in the development of evoked pain following partial nerve injury. In this report, we demonstrate bilateral changes in interleukin-6 (IL-6) and nerve growth factor (nerve growth factor) levels following unilateral infraorbital nerve (infraorbital nerve) constriction. infraorbital nerve constriction resulted in an initial period of decreased mechanical sensitivity (1 and 3 days), followed by recovery (7 days) and then a marked bilateral mechanical hypersensitivity (10 and 28 days). nerve growth factor levels in the injured infraorbital nerve were elevated on all days, but peak concentrations of nerve growth factor were observed on day 3. A smaller increase was also observed on days 1, 3, and 7 in the uninjured nerve. A bilateral elevation of IL-6 was also seen on days 3 and 10 in the infraorbital nerve, and in the brainstem on days 3, 7 and 10 after constriction. No changes in mechanical sensitivity were found after a sham-injury, but there was a small increase in brainstem IL-6 ipsilaterally at 7 days. We conclude from these data that increases in IL-6 and nerve growth factor may contribute to the development of mechanical allodynia after trigeminal nerve injury, but they are not specifically correlated with the onset or duration of pain behaviors.

Sequence information, distinction and quantitation of C-terminal leucine and isoleucine in ternary complexes of tripeptides with Cu(II) and 2,2'-bipyridine

Tripeptides form ternary complexes with Cu(2+) and 2,2'-bipyridine (bpy) that self-assemble upon mixing the components in aqueous methanol solution. Electrospray ionization (ESI) of the complex solutions provides abundant singly charged [Cu(peptide -- H)bpy](+) and doubly charged [Cu(peptide)bpy](2+) ions. Collision-induced dissociation (CID) at low ion kinetic energies of several tripeptides, AGG, GGA, LGG, GGL, GGI, FGG, GGF, LGF, GLF, GFL, GYA and GAY, showed fragments that were indicative of the amino acid sequence in the peptide. In addition, CID of single and doubly charged complexes of isomeric tripeptides GGL and GGI provided unambiguous distinction of the isomeric leucine and isoleucine residues. Leucine peptides eliminated C(3)H(7) radicals from the amino acid side-chain whereas isoleucine eliminated C(2)H(5) radicals. CID of gas-phase doubly charged peptide complexes in a quadrupole ion trap produced a series of singly charged sequence fragments that following isolation and further CID furnished distinct fragments that allowed quantitation of leucine and isoleucine-containing peptides in mixtures.

Non-Hodgkin's tumor and Pancoast's syndrome

A 60-year old man presented with Horner's syndrome, and acute right hand and lower extremity weakness. Chest X-ray and MRI revealed a right apical lung tumor (presumed to be a primary lung cancer), with brachial plexus infiltration and spinal cord compression. Emergent radiotherapy was initiated for spinal cord compression and a biopsy was obtained 24 h later. A careful review of pathology demonstrated a non-Hodgkin's lymphoma. The patient subsequently received chemotherapy, and is now in remission. This case illustrates the importance of a tissue diagnosis before initiating therapy for a Pancoast's tumor.

Holmium:YAG percutaneous nephrolithotomy: the laser incident angle matters

PURPOSE

Laser physics dictate that maximal radiant exposure occurs when the laser strikes the target at a normal incidence. Since the renal collecting system often limits nephroscope movements during percutaneous nephrolithotomy, the laser-calculus incidence angle may vary. We have observed during holmium:YAG percutaneous nephrolithotomy that the side firing fiber more easily approaches a normal incidence compared to the end firing fiber. We test the hypothesis that holmium:YAG percutaneous nephrolithotomy is faster with a side firing fiber compared to an end firing fiber.

MATERIALS AND METHODS

Consecutive holmium:YAG percutaneous nephrolithotomy cases were studied retrospectively. The calculus size and composition, surgical time, fragmentation speed (size/time) and stone-free rates were compared between 11 patients treated with end and 8 treated with side firing fibers.

RESULTS

When the end and side firing groups were compared, calculus sizes (mean plus or minus standard deviation) were 22 +/- 13 versus 48 +/- 17 mm. (p = 0.004), calcium oxalate monohydrate incidence was 55 versus 75% (p = 0.3), surgical times were 168 +/- 87 versus 124 +/- 51 minutes, computed fragmentation speeds were 0.15 +/- 0.09 versus 0.43 +/- 0.15 mm. per minute (p = 0.0009) and stone-free rates were 73 versus 88% (p = 0.4), respectively.

CONCLUSIONS

The side firing fiber is faster than the end firing fiber for holmium:YAG percutaneous nephrolithotomy. These results are consistent with principles of laser physics.

Ureteroscopic management of ureteral calculi: electrohydraulic versus holmium:YAG lithotripsy

PURPOSE

This study compared electrohydraulic and holmium:YAG lithotripsy for ureteral calculi.

MATERIALS AND METHODS

Two cohorts of consecutive patients with ureteral calculi treated with ureteroscopic electrohydraulic or holmium:YAG lithotripsy were retrospectively compared. Electrohydraulic lithotripsy was done using a 1.9F fiber at energy settings between 50 and 100 v. Holmium:YAG lithotripsy was done using a 365 microm. fiber at energy settings of 0.6 to 1.5 J.

RESULTS

A total of 23 and 47 consecutive patients underwent electrohydraulic and holmium:YAG lithotripsy, respectively. For preoperative calculi less than 15 mm. mean stone size plus or minus standard deviation was 9 +/- 3 versus 9 +/- 3 mm. (p = 0.5), mean operative time was 72 +/- 21 versus 102 +/- 38 minutes (p = 0.004), stone-free rate at the end of ureteroscopy was 65 versus 97 (p < 0.01) and 3-month stone-free rate was 94 versus 97% (p = 0.4) for electrohydraulic versus holmium:YAG lithotripsy. For preoperative calculi 15 mm. or greater stone size was 19 +/- 5 versus 19 +/- 4 mm. (p = 0.9), operative time was 159 +/- 61 versus 108 +/- 27 minutes (p = 0.01), stone-free rate at the end of ureteroscopy was 33 versus 87% (p = 0.001) and 3-month stone-free rate was 67 versus 100% (p = 0.02). Complications were not significantly different in either comparison.

CONCLUSIONS

The overall likelihood that a patient would be rendered stone-free at ureteroscopy and 3 months after ureteroscopy favored holmium:YAG over electrohydraulic lithotripsy. For ureteral calculi less than 15 mm. electrohydraulic lithotripsy was more rapid than the holmium:YAG procedure but for ureteral calculi 15 mm. or greater the holmium:YAG technique was more rapid than electrohydraulic lithotripsy. The outcomes differences may have resulted from the different mechanisms of electrohydraulic and holmium:YAG lithotripsy.

Carboxylate and amine terminus directed fragmentations in gaseous dipeptide complexes with copper (II) and diimine ligands formed by electrospray

Singly and doubly charged peptide complexes with copper(II) and 2,2'-bipyridyl (bpy) are formed in the gas phase by electrospraying water-methanol solutions containing the components. Collisionally activated dissociations at low kinetic energies of singly charged complexes of the [CuII(peptide-H)(bpy)].+ type provide information about the amino acid sequence for L-Phe-Leu, L-Leu-Phe, L-Phe-Pro, L-Pro-Phe, L-Phe-Met, L-Met-Phe, L-Ser-Phe, L-Asp-Phe, and L-His-Phe. Dissociations of doubly charged complexes of the [CuII(peptide)(bpy).2+ type also allow identification of the N- and C-terminal amino acid residues. Leucine and isoleucine residues are readily distinguished in L-Ala-Leu and L-Ala-Ile through dissociations of their Cu complexes. Ion dissociation mechanisms, as elucidated by deuterium labeling, are discussed.

Quantitative differences in the histology of the attachment zones of the meniscal horns in the knee joint of man

The attachment zones of the meniscal horns of 7 dissecting room cadavers were examined by routine histology. All the knees were devoid of gross pathological change and no discoid menisci were included. Significant differences are reported in the thickness of the zones of uncalcified fibrocartilage and cortical calcified tissue (calcified fibrocartilage and underlying lamellar bone) and in the percentage of bone:bone marrow. There was a thicker zone of uncalcified fibrocartilage and a greater quantity of calcified tissue at the horns of the lateral than the medial meniscus. The differences in uncalcified fibrocartilage were largely attributable to the posterior horns, but the variations in calcified tissue mainly reflected differences between the anterior horns. It is suggested that the greater mobility of the lateral meniscus and the blending of its anterior horn with the anterior cruciate ligament are important factors accounting for the quantitative differences in the meniscal attachment zones.