Intrahepatic cholangiocarcinoma initially diagnosed as adenocarcinoma of unknown primary with hepatoduodenal ligament lymph node metastases: A case report

Intrahepatic cholangiocarcinoma (iCCA) with regional lymph node metastases, which lacks a well-delineated liver mass, may be misdiagnosed as a carcinoma of unknown primary (CUP) origin. The present study reports the case of a 69-year-old man initially diagnosed with CUP, who was incidentally found to have abdominal lymphadenopathy during ultrasonography (US). The clinical course from the time of lymphadenectomy and CUP diagnosis to iCCA detection after long-term follow-up is reported. A patient with a history of hypertensive renal disease presented with an incidental finding of enlarged abdominal lymph nodes in the perihepatic region on US. Abdominal contrast-enhanced computed tomography (CT) scan and magnetic resonance imaging (MRI) revealed two enlarged lymph nodes in the hepatoduodenal ligament. Exploratory laparotomy and lymphadenectomy were performed for diagnostic and therapeutic purposes, respectively. Poorly differentiated metastatic adenocarcinoma positive for cytokeratin 7 and negative for cytokeratin 20 was identified in two of the 22 lymph nodes. Postoperatively, a positron emission tomography/CT (PET/CT) scan was performed, which failed to locate the primary site. The diagnosis of CUP was confirmed based on clinical, radiological and histopathological characteristics. A sequential abdominal CT scan 48 months after lymphadenectomy revealed a faintly enhancing, intraductal polypoid mass with localized ductal dilatation in liver segment 3. MRI and PET/CT confirmed a mass in the left lobe of the liver. US-guided percutaneous needle biopsy confirmed the presence of moderately differentiated adenocarcinoma. The patient refused surgical treatment because of general weakness caused by Coronavirus disease 2019 infection. The patient received radical radiotherapy and underwent left hepatectomy after recovery of their performance status. Histopathological examination of the surgical specimen demonstrated prevailing fibrosis and mucin accumulation, with scattered cancer cells observed focally in the resected liver specimen owing to the effect of the radiotherapy. Consequently, a definitive diagnosis of primary adenocarcinoma of the intrahepatic bile duct was confirmed. The present report may improve understanding of the pathophysiology and clinical progression of iCCA, with a specific focus on the intraductal growth subtype.

Real-World Outcomes of Nivolumab, Pembrolizumab, and Atezolizumab Treatment Efficacy in Korean Veterans with Stage IV Non-Small-Cell Lung Cancer

PURPOSE

To provide a comprehensive analysis of ICI usage and treatment outcomes in elderly Korean veterans with stage IV NSCLC.

METHODS

Patients diagnosed with stage IV NSCLC between 2016 and 2021 were included, and three cohorts were derived according to the type of ICI received. Thereafter, the clinical characteristics and survival outcomes were compared.

RESULTS

Of the 180 patients with NSCLC (median age, 76 years) included in this study, 49 (27.7%), 61 (33.9%), and 70 (38.9%) received pembrolizumab, nivolumab, and atezolizumab, respectively, and 19.4%, 36.1%, and 34.4% had PD-L1 expressions < 1%, 1-49%, and ≥50%, respectively. The pembrolizumab, nivolumab, and atezolizumab groups, the objective response rates (ORR), and the disease control rates (DCR) were 22.4%, 8.2%, and 4.3% (p = 0.004), and 59.2, 55.7%, and 30.0% (p = 0.001), respectively. However, no difference in the overall survival (OS) rate was noted among the groups (12.6 months vs. 8.4 months vs. 7.7 months, p = 0.334). Similarly, there was no treatment specific OS benefit with respect to the tumor PD-L1 expression status. Interestingly, multivariate analysis identified bone metastasis as a significant poor prognostic factor for OS (HR = 2.75 [95% CI, 1.31-5.76], p = 0.007).

CONCLUSION

Pembrolizumab and nivolumab showed stronger associations with increases in ORR and DCR than atezolizumab, but no statistically significant differences were observed with respect to OS.

New-onset type 1 diabetes mellitus as a delayed immune-related event after discontinuation of nivolumab: A case report

RATIONALE

Immune checkpoint inhibitors (ICIs) have revolutionized cancer treatment. However, they may cause immune-related adverse events. Although there have been a few reports of new-onset type 1 diabetes mellitus (T1DM) during ICI treatment, T1DM as a delayed immune-related event after discontinuing immunotherapy is extremely rare. Herein, we report the case of an elderly veteran who presented with diabetic ketoacidosis 4 months after the discontinuation of treatment with nivolumab.

PATIENT CONCERNS

A 74-year-old veteran was treated with second-line nivolumab for advanced non-small cell lung cancer. After 9 treatment cycles, the administration was discontinued due to fatigue. Four months later, he was admitted to the emergency department in a stuporous mental state and hyperglycemia, with high glycosylated hemoglobin levels (10.6%). C-peptide levels were significantly decreased, with negative islet autoantibodies.

DIAGNOSES

We diagnosed nivolumab-induced T1DM. There were no laboratory results indicating a new thyroid dysfunction or adrenal insufficiency, which are typical endocrine adverse reactions.

INTERVENTIONS

Since the hypothalamic and pituitary functions were preserved and only the pancreatic endocrine capacity was impaired, we administered continuous intravenous insulin injections, with fluid and electrolyte replacement.

OUTCOMES

His serum glucose levels decreased, and symptoms improved; hence, on the 8 day of hospitalization, we switched to multiple daily insulin injections.

LESSONS

The present case indicates that regular glucose monitoring and patient education are needed for diabetic ketoacidosis after the discontinuation of ICI therapy.

β‑catenin blockers enhance the effect of CDK4/6 inhibitors on stemness and proliferation suppression in endocrine‑resistant breast cancer cells

Wnt/β‑catenin signaling is involved in endocrine resistance and stem cell‑like properties of hormone receptor‑positive breast cancer cells. Palbociclib is a well‑known inhibitor of cyclin‑dependent kinase 4 and 6 (CDK4/6 inhibitor) that downregulates the activation of retinoblastoma protein, thereby inhibiting the cell cycle in breast cancer cells. The inhibitory effects of a combination of palbociclib and ICG‑001, a β‑catenin small‑molecule inhibitor, were investigated in tamoxifen‑resistant breast cancer cell lines. Tamoxifen‑resistant MCF‑7 (TamR) cells were established by continuously exposing MCF‑7 cells to tamoxifen. The characteristics associated with the stem cell‑like property of cancer were assessed using western blotting, cell cycle analysis, and the mammosphere assay. The effects of the combination of palbociclib and ICG‑001 were evaluated in control MCF‑7 and TamR cell lines. Compared with control cells, TamR cells exhibited elevated levels of Nanog, Sox2, ALDH1, and p‑STAT3, indicating stem cell‑like characteristics, and elevated β‑catenin activity. TamR cells also showed significantly higher mammosphere‑forming efficiency. Several markers of stem cell‑like nature of TamR cells showed reduced levels upon treatment of cells with the drug combination; there was a greater reduction in the levels of these markers when the cells were treated with the combination than in the case where cells were treated with one of the drugs individually (combination index value for 25 µM palbociclib and 50 µM ICG‑001 was 1.1±0.02). TamR cells treated with the palbociclib and ICG‑001 combination demonstrated significantly reduced cell proliferation and mammosphere‑forming efficiency compared with the cells treated with one of these drugs. The combination of the drugs could additively inhibit proliferation and suppress stem cell‑like characteristics. These results suggest that β‑catenin plays a role in endocrine‑resistant breast cancer; the inhibition of β‑catenin and CDK4/6 together can overcome endocrine resistance in breast cancer cells.

Role of Preoperative Chemoradiotherapy in Clinical Stage II/III Rectal Cancer Patients Undergoing Total Mesorectal Excision: A Retrospective Propensity Score Analysis

Background

Although the current standard preoperative chemoradiotherapy (PCRT) for stage II/III rectal cancer decreases the risk of local recurrence, it does not improve survival and increases the likelihood of preoperative overtreatment, especially in patients without circumferential resection margin (CRM) involvement.

Methods

Stage II/III rectal cancer without CRM involvement and lateral lymph node metastasis was radiologically defined by preoperative magnetic resonance imaging (MRI). Patients who received PCRT followed by total mesorectal excision (TME) (PCRT group) and upfront surgery (US) with TME (US group) between 2010 and 2016 were analyzed. We derived cohorts of PCRT group versus US group using propensity-score matching for stage, age, and distance from the anal verge. Three-year relapse-free survival rate, disease-free survival (DFS), and overall survival (OS) were compared between the two groups.

Results

A total of 202 patients were analyzed after propensity score matching. There were no differences in baseline characteristics. The median follow-up duration was 62 months (interquartile range, 46–87). There was no difference in the 3-year disease-free survival rate between the PCRT and US groups (83 vs. 88%, respectively; p=0.326). Likewise, there was no significant difference in the 3-year OS (89 vs. 91%, respectively; p=0.466). The 3-year locoregional recurrence rates (3 vs. 2% with US, p=0.667) and distant metastasis rates (16 vs. 11%, p=0.428) were not significantly different between the two groups. Time to completion of curative treatment was significantly shorter in the US group (132 days) than in the PCRT group (225 days) (p<0.001).

Conclusion

Using MRI-guided selection for better risk stratification, US without neoadjuvant therapy can be considered in early stage patients with good prognosis. PCRT may not be required for all stage II/III rectal cancer patients, especially for the MRI-proven intermediate-risk group (cT1-2/N1, cT3N0) without CRM involvement and lateral lymph node metastasis. Further prospective studies are warranted.

Correction to: Palbociclib use with grade 3 neutropenia in hormone receptor-positive metastatic breast cancer

In the original publication of the article, under the Results section, subheading "Patient survival", the second sentence that reads as "The 6-month PFS was 92.4%, 81.8%, and 93.3% and the one-year PFS was 72.0%, 88.9%, and 78.9% in Groups 1-3, respectively." should read as "The 6-month PFS was 82.8%, 75.0%, and 68.0% and the one-year PFS was 77.0%, 62.0%, and 63.8% in Groups 1-3, respectively.".

Palbociclib use with grade 3 neutropenia in hormone receptor-positive metastatic breast cancer

PURPOSE

Neutropenia is the most common toxicity of CDK4/6 inhibitors, causing frequent dose interruptions. However, CDK4/6 inhibitor-induced neutropenia shows a benign clinical course in contrast to that caused by chemotherapy. Here, we investigated the safety of a new dose scheme for palbociclib, which avoids dose delays or reductions due to afebrile grade 3 neutropenia.

METHODS

A consecutive cohort of ER( +)/HER2( -) advanced breast cancer patients who received palbociclib between 2017 and 2018 was analyzed. The patients were classified into Group 1 (patients who maintained palbociclib dose with afebrile grade 3 neutropenia), Group 2 (patients who experienced any dose modification with afebrile grade 3 neutropenia), and Group 3 (patients without afebrile grade 3 neutropenia). The primary endpoint was febrile neutropenia incidence; other toxicities were compared with those of the PALOMA-2 trial.

RESULTS

Among the 107 patients, 54.2%, 22.4%, and 23.4% were classified into Groups 1, 2, and 3, respectively. There was no febrile neutropenia in Groups 1 and 2 during palbociclib treatment. Group 1 showed higher incidence of thrombocytopenia (all-grade, 32.8%; grade 3-4, 8.6%) than Group 2 and the PALOMA-2 data, but there was no bleeding related to thrombocytopenia. Group 1 showed higher incidence of all-grade non-hematologic adverse events than Group 2; only one grade 3 non-hematologic toxicity was observed in Group 1. There were no treatment-related hospitalizations or deaths in Group 1.

CONCLUSIONS

Thus, omitting palbociclib dose modification with afebrile grade 3 neutropenia is safe and tolerable without febrile neutropenia events. This scheme could be useful to avoid unnecessary reductions in palbociclib doses in future practice.

Recurrent meningococcal meningitis with complement 6 (C6) deficiency: A case report

RATIONALE

Late complement deficiency increases susceptibility to meningococcal disease and recurrent infections. In Korea, 5 case reports have described meningococcal disease with complement deficiency. However, C6 deficiency has not been described previously.

PATIENT CONCERNS

A 21-year-old police trainee presented with recurrent meningococcal meningitis. He was housed in communal living quarters until 20 days before the initial symptom onset.

DIAGNOSIS

He was diagnosed with meningococcal meningitis with C6 deficiency.

INTERVENTIONS

He was treated with intravenous ceftriaxone. An additional dose of quadrivalent meningococcal conjugate vaccine was administered after discharge.

OUTCOMES

He was discharged without complications.

LESSONS

Screening for complement deficiency is necessary in patients with a history of recurrent meningococcal infections to provide appropriate care and prevent recurrent infections.

Vaginal deployment and tenofovir delivery by microbicide gels

Gels are one of the soft material platforms being evaluated to deliver topically acting anti-HIV drugs (microbicides) to the vaginal environment. For each drug, its loaded concentration, gel properties and applied volume, and frequency of dosing can be designed to optimize PK and, thence, PD. These factors also impact user sensory perceptions and acceptability. Deterministic compartmental modeling of vaginal deployment and drug delivery achieved by test gels can help delineate how multiple parameters characterizing drug, vehicle, vaginal environment, and dosing govern details of PK and PD and also gel leakage from the canal. Such microbicide delivery is a transport process combining convection, e.g., from gel spreading along the vaginal canal, with drug diffusion in multiple compartments, including gel, mucosal epithelium, and stroma. The present work builds upon prior models of gel coating flows and drug diffusion (without convection) in the vaginal environment. It combines and extends these initial approaches in several key ways, including: (1) linking convective drug transport due to gel spreading with drug diffusion and (2) accounting for natural variations in dimensions of the canal and the site of gel placement therein. Results are obtained for a leading microbicide drug, tenofovir, delivered by three prototype microbicide gels, with a range of rheological properties. The model includes phosphorylation of tenofovir to tenofovir diphosphate (which manifests reverse transcriptase activity in host cells), the stromal concentration distributions of which are related to reference prophylactic values against HIV. This yields a computed summary measure related to gel protection ("percent protected"). Analyses illustrate tradeoffs amongst gel properties, drug loading, volume and site of placement, and vaginal dimensions, in the time and space history of gel distribution and tenofovir transport to sites of its anti-HIV action and concentrations and potential prophylactic actions of tenofovir diphosphate therein.

Functional characterization of genetic variations in the MDR3 promoter

Multidrug resistance 3 (MDR3) is present on the canalicular membrane of the hepatocyte and plays an important role in protecting the liver from bile acids. In this study, we characterized the transcriptional effects of four common haplotypes and four polymorphic variants in the promoter region of MDR3 that were identified in 126 DNA samples from Koreans. We measured the luciferase activities of the four MDR3 promoter haplotypes using in vitro reporter assays. Among them, two haplotypes showed a significant decrease in reporter activity compared to the reference. One of the mechanisms by which these haplotypes might decrease MDR3 transcriptional activity was determined: one of the polymorphisms that are present in haplotype 3, was associated with a significant reduction in the promoter activity of MDR3, and the transcription factor NF-Y was predicted to bind to the promoter in the region of g.-1584C>T. Electrophoretic mobility shift assays showed that the g.-1584C allele exhibited greater binding to NF-Y than did the g.-1584T allele. Through the measurement of promoter activity after the overexpression of NF-Y, we found that NF-Y can act as a transcriptional activator of MDR3. These data suggest that the reduced transcriptional activity of g.-1584C>T results from a reduction in the binding affinity of the activator NF-Y to the MDR3 promoter region. Our study suggests that two common haplotypes of MDR3 can regulate the transcriptional rate of MDR3 and that NF-Y may be one of the transcriptional factors involved in this regulation.

P1-07-19: Analysis of HER2−Status in Breast Cancer by Mass Spectrometry in Archival, Formalin-Fixed Tissues

HER2 (ERBB2) is overexpressed in about 25% of breast cancers and predicts clinical benefit from trastuzumab, as well as response to anthracycline-based chemotherapy. Fluorescence in situ hybridization (FISH) to detect HER2 gene copy number and immunohistochemistry (IHC) to detect HER2 protein levels are approved by the FDA to identify HER2−positive (H2) tumors. However, the 2007 ASCO/CAP report concluded that approximately 20% of HER2 testing may be inaccurate. Further, the available data did not clearly demonstrate clear superiority of either IHC or FISH as a predictor of benefit from anti-HER2 therapy. Discordance between these methods is as high as 5%. Thus, novel complementary quantitative methods for interrogating HER2 expression in tumors are needed.

Targeted protein analysis by multiple reaction monitoring mass spectrometry (MRM-MS) offers a powerful approach to configure assays for specific proteins without using antibodies. Our studies using this platform have demonstrated applicability to formalin-fixed, paraffin-embedded (FFPE) specimens. In the current studies, we used this approach to measure signals from two tryptic peptides specific to HER2, one each from the extracellular and intracellular domains, selected from among 28 candidates based on their signal intensity and sharpness of their chromatographic profiles. Preliminary studies with a HER2−overexpressing BT474 xenograft in mice demonstrated quantitation and detected previously reported HER2 ectodomain shedding. Subsequent analysis of FFPE tissue from five H2 and five triple-negative (TN) tumors yielded measurement of at least 1 femptomole of receptor for H2 tumors and less than 0.2 femptomole of receptor for TN tumors per microgram of digest analyzed. If we assume 200 picograms of protein per cell, the results suggest 110,00 to 468,000 receptors per cell in the H2 tumors and only 2,000 to 14,000 receptors per cell in the TN tumors. Despite significant biological variability in receptor levels measured among the specimens of each type, a clear separation of the H2 and TN tumors was achieved based on the peptide quantitation. This preliminary study demonstrates the potential of MRM-MS in FFPE tissue to provide an alternate approach to IHC-based protein analysis. MRM-MS offers the potential for more, accurate and robust HER2 quantification in clinical breast cancer tissues. The next phase of this work will encompass a larger sample set, including tumors with equivocal and negative FISH and/or IHC test results. Correlation with response to anti-Her2 therapy will be performed in samples with available follow-up data.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-07-19.

Total Anthelmintic Failure to Control Nematode Parasites of Small Ruminants on Government Breeding Farms in Sabah, East Malaysia

Government-owned small-ruminant breeding farms in Malaysia provide the source of sheep and goats to smallholder farmers in the country. In the eastern Malaysian state of Sabah, high-level stock losses have been recorded on these farms for several years, frequently accompanied by clinical signs indicating pathogenic levels of infections with the nematode parasite Haemonchus contortus. This suggests that their dependence on chemotherapy to control parasite infections had failed. Accordingly, tests for anthelmintic efficacy using the faecal egg count reduction test (FECRT) on the range of drugs used to control nematode parasites were carried out on the five government small-ruminant breeding farms in Sabah. These tests showed a total failure of the benzimidazole, imidothiazole, macrocyclic lactone and salicylanilide groups of anthelmintics to control H. contortus infections of sheep and goats on all farms. Drastic changes in animal management need to be made in an attempt to deal with this situation, for which suggestions are made.

Design and initial evaluation of a low-cost 3-Tesla research system for combined optical and functional MR imaging with interventional capability

A 3-Tesla research system has been developed for functional and interventional magnetic resonance imaging (MRI) procedures on animal models based on a low field niche spectrometer. Use of two stages of fourth harmonic frequency multiplication has allowed us to produce a high-frequency spectrometer with good frequency stability based on a low-frequency direct digital synthesizer. The system has been designed with the ability to introduce interventional tools such as biopsy needles, radiofrequency (RF) electrodes, and fiber optics for optical spectroscopy and thermal ablation as well as drug infusions to allow function to be studied in the presence of external challenges. Full MR-compatible physiologic support capability allows animals to be maintained in a stable condition over extended periods of study. Functional MR images have been acquired by using gradient echoes (TR/TE = 40/12 msec) from the rat whisker barrel cortex using electrical stimulation (5-V, 1.5-mA, 1-msec pulses at 5 Hz via two needle electrodes inserted into the rat whisker pad). Initial results using respiratory gas challenges of 100% N(2), 100% O(2), and 10% CO(2) have shown excellent agreement between single wavelength (633 nm) optical and functional MR time series with subsecond time resolution. The 1-mm copper electrodes for interventional radiofrequency ablation procedures were easily visualized in the superior colliculus by using gradient echo sequences. This novel, low-cost, high field system appears to be a useful research tool for functional and interventional studies of rat brain and allows concurrent optical spectroscopy. J. Magn. Reson. Imaging 2001;13:87-92.

Formation and repair of DNA adducts in vinyl chloride- and vinyl fluoride-induced carcinogenesis

Vinyl chloride is a known human and animal carcinogen that induces angiosarcomas of the liver. We review here studies on the formation and repair of DNA adducts associated with vinyl chloride and vinyl fluoride in exposed and control rodents and unexposed humans. These vinyl halides induce etheno (epsilon) adducts that are identical to those formed after lipid peroxidation. Of these adducts, N2,3-ethenoguanine (epsilon G) is present in greatest amounts in tissues of exposed animals. After exposure to vinyl chloride for four weeks, epsilon G levels attain steady-state concentrations, such that the amount of newly formed adducts equals the number of adducts that are lost each day. We report the first dosimetry of epsilon G in rats exposed to 0, 10, 100 or 1100 ppm vinyl chloride for five days or four weeks. The number of adducts increased in a supralinear manner. Exposure to 10 ppm vinyl chloride for five days caused a two- to threefold increase in epsilon G over that of the controls, while four weeks' exposure resulted in a fivefold increase. This was confirmed with [13C2]vinyl chloride and by measuring exogenous and endogenous adducts in the same animals. Exposure to 100 ppm vinyl chloride for four weeks caused a 25-fold increase in epsilon G levels over that found in control rats, while exposure to 1100 ppm resulted in a 42-fold increase. The amount of endogenous epsilon G was similar in liver DNA from rats and humans. A comparable response to exposure was seen in rats and mice exposed to 0, 25, 250 or 2500 ppm vinyl fluoride for 12 months. There was a very high correlation between epsilon G levels in rat and mouse liver at 12 months and the incidence of haemangiosarcoma at two years. We were able to demonstrate that the target cell population for angiosarcoma, the nonparenchymal cells, contained more epsilon G than hepatocytes, even though nonparenchymal cells are exposed by diffusion of vinyl halide metabolites formed in hepatocytes. The expression of N-methylpurine-DNA glycosylase mRNA was induced in rat liver after exposure to either 25 or 2500 ppm vinyl fluoride. When this induction was investigated in hepatocytes and nonparenchymal cells, it was found that the latter had only 20% of the N-methylpurine-DNA glycosylase mRNA of hepatocytes, and that only the hepatocytes had induction of this expression after exposure to vinyl fluoride. Thus, the target cells for vinyl halide carcinogenesis have much lower expression of this DNA repair enzyme, which has been associated with etheno adduct repair.

DNA adducts: effects of low exposure to ethylene oxide, vinyl chloride and butadiene

Dose-response relationships of genotoxic agents differ greatly depending on the agent and the endpoint being evaluated. Simple conclusions that genotoxic effects are linear cannot be applied universally. The shape of the molecular dose of DNA adducts varies from linear, to supralinear, to sublinear depending on metabolic activation and detoxication, and repair of individual types of DNA adducts. For mutagenesis and other genotoxicity endpoints, the dose-response reflects the molecular dose of each type of DNA adduct, cell proliferation, as well as endogenous factors that lead to mutagenesis such as the formation and repair of endogenous DNA adducts. These same factors are important when interpreting the shape of dose-response data for carcinogenesis of genotoxic agents, however, tumor background variability adds additional complexity. Endogenously formed DNA adducts may be identical to those formed by chemicals, as in the case of vinyl chloride and ethylene oxide, or they may be those associated with oxidative stress. Data presented in this paper demonstrate that the exogenous number of adducts induced by 5 days of exposure to 10 ppm vinyl chloride is only 2. 2-fold greater than that present as a steady-state amount in unexposed control rats. Similar data are shown for ethylene oxide. Extremely sensitive methods have been developed for measuring the molecular dose of genotoxins. These methods can detect DNA adducts as low as 1 per 10(9) to 10(10). However, in view of the high number of endogenous DNA adducts that are present in all cells, it is unlikely that causal relationships can be attributed to very low numbers of such DNA adducts. Effects of both exogenous and endogenous DNA adducts need to be factored into the interpretation of chemical exposures.

A large-scale program in laparoscopic intrauterine insemination with frozen-thawed semen in Australian Merino sheep in Argentine Patagonia

This report shows the results of a large-scale laparoscopic intrauterine insemination program on a flock of Australian Merino sheep in Argentine Patagonia. The study was carried out on a total of 1824 ewes (3-to-7-yr-old) and 480 ewe hoggets (19-20 months old) on 2 farms in the southeastern region of Santa Cruz Province, in April and May 1996. The animals, divided into 15 groups, were synchronized with vaginal sponges containing 60 mg medroxyprogesterone acetate for 14 d and injected with 200 IU PMSG upon sponge removal. Estrus was screened every 12 h by means of vasectomized marker rams. The animals were inseminated laparoscopically by the intrauterine route using 2 schemes: 1) at a fixed time (12 h) after estrus detection, or 2) at a fixed time (60 h) after sponge removal irrespective of estrus. Pregnancy was determined at 30 d by transrectal ultrasound imaging. The results showed that 1) the onset of estrus occurs most often between 24 and 48 h after sponge removal, 2) ewe hoggets undergo estrus significantly earlier than sexually mature ewes, 3) in those animals showing estrus, there appears to be no relationship between fertility (as assessed by pregnancy outcome) and time of estrus, 4) there is a significant association between the percentage of estrus occurrence and pregnancy rate, 5) fertility is significantly higher in ewes than in hoggets, 6) for practical purposes insemination at a fixed time after the onset of estrus has no advantage over that of to insemination at a fixed time after sponge removal. It is concluded that large-scale laparoscopic intrauterine insemination can be successfully applied in Australian Merino ewes and ewe hoggets in low-productivity areas such as that of Argentine Patagonia and that estrus detection is unnecessary when insemination is performed at 60 h after sponge removal.

Effects of fluid shear stress on bone cells

Neonatal rat calvarial cells (osteoblast-enriched) were cultured in monolayer on glass slides and subjected to a step increase in shear stress ranging from 3 to 60 dyne/cm2 in a laminar flow chamber. The level of intracellular free calcium ion concentration was monitored using Fura-2 fluorescence during the application of stress. Application of a step increase in stress resulted in a transient increase in calcium starting about 10-20 s after turning on the pump, reaching a peak in about 35 s and declining thereafter, despite the continued shear stress, and reaching near baseline values in about 100 s. No change in cytoplasmic calcium was observed with a step increase in shear stress of 3 dyne/cm2. Between 6 dyne/cm2 and 60 dyne/cm2, the magnitude of the calcium response increased with the applied shear stress.

The influence of inter- and intra-speaker tempo on fundamental frequency and palatalization

A study was conducted to examine the influence of speaking rate and emphatic stress on patterns of fundamental frequency (F0) and palatalization across word boundaries. Two groups of speakers, exhibiting characteristically fast versus slow speech, uttered preselected sentences at normal, fast, and slow rates. Acoustic analysis of F0 showed somewhat higher F0 peaks for characteristically fast speakers and for fast rates of speech. Emphatic stress was accompanied by a typical heightening of F0 on the emphasized word and by a lowering of F0 on a neighboring word. Palatalization across word boundaries was more frequent among characteristically fast speakers and at fast rates of speech. In addition, palatalization was more frequent in the absence of emphatic stress at the key site. The results for F0 were discussed in terms of the influence of vocal fold tension, while the results for palatalization were discussed in terms of the incompatibility of phonological processes of lengthening versus shortening as well as possible look-ahead restrictions.