Cellular Uptake and Efflux of Palbociclib In Vitro in Single Cell and Spheroid Models.

Adequate drug distribution through tumors is essential for treatment to be effective. Palbociclib is a cyclin-dependent kinase 4/6 inhibitor approved for use in patients with hormone receptor positive, human epidermal growth factor receptor 2 negative metastatic breast cancer. It has unusual physicochemical properties, which may significantly influence its distribution in tumor tissue. We studied the penetration and distribution of palbociclib in vitro, including the use of multicellular three-dimensional models and mathematical modeling. MCF-7 and DLD-1 cell lines were grown as single cell suspensions (SCS) and spheroids; palbociclib uptake and efflux were studied using liquid chromatography-tandem mass spectrometry. Intracellular concentrations of palbociclib for MCF-7 SCS (C max 3.22 µM) and spheroids (C max 2.91 µM) were 32- and 29-fold higher and in DLD-1, 13- and 7-fold higher, respectively, than the media concentration (0.1 µM). Total palbociclib uptake was lower in DLD-1 cells than MCF-7 cells in both SCS and spheroids. Both uptake and efflux of palbociclib were slower in spheroids than SCS. These data were used to develop a mathematical model of palbociclib transport that quantifies key parameters determining drug penetration and distribution. The model reproduced qualitatively most features of the experimental data and distinguished between SCS and spheroids, providing additional support for hypotheses derived from the experimental data. Mathematical modeling has the potential for translating in vitro data into clinically relevant estimates of tumor drug concentrations. SIGNIFICANCE STATEMENT: This study explores palbociclib uptake and efflux in single cell suspension and spheroid models of cancer. Large intracellular concentrations of palbociclib are found after drug exposure. The data from this study may aid understanding of the intratumoural pharmacokinetics of palbociclib, which is useful in understanding how drug distributes within tumor tissue and optimizing drug efficacy. Biomathematical modelling has the potential to derive intratumoural drug concentrations from plasma pharmacokinetics in patients.

Symptom management and self-care for peripheral neuropathy in HIV/AIDS.

Peripheral neuropathy is the most common neurological complication in HIV and is often associated with antiretroviral therapy. As part of a larger study on self-care for symptoms in HIV disease, this study analyzed the prevalence and characteristics of peripheral neuropathy in HIV disease, sociodemographic and disease-related correlates and self-care strategies. A convenience sample of 1,217 respondents was recruited from data collection sites in several US cities, Puerto Rico, Colombia and Taiwan. Results of the study indicated that respondents with peripheral neuropathy (n=450) identified 20 self-care behaviors including complementary therapies, use of medications, exercise and rest and/or elevation of extremities. Ratings of frequency and effectiveness were also included. An activities checklist summarized into five categories of self-care behaviors including activities/thoughts, exercise, medications, complementary therapies and substance was used to determine self-care behaviors. Taking a hot bath was the most frequent strategy used by those with peripheral neuropathy (n=292) and received the highest overall rating of effectiveness of any self-management strategies included in this study at 8.1 (scale 1-10). Other self-care strategies to manage this symptom included: staying off the feet (n=258), rubbing the feet with cream (n=177), elevating the feet (n=236), walking (n=262), prescribed anti-epileptic agent (n=80), prescribed analgesics (n=84), over-the-counter medications (n=123), vitamin B (n=122), calcium supplements (n=72), magnesium (n=48), massage (n=156), acupuncture (n=43), reflexology (n=23) and meditation (n=80). Several behaviors that are often deemed unhealthy were included among the strategies reported to alleviate peripheral neuropathy including use of marijuana (n=67), cigarette smoking (n=139), drinking alcohol (n=81) and street drugs (n=30).

Leishmania mexicana and Leishmania major: attenuation of wild-type parasites and vaccination with the attenuated lines.

A method for attenuation of Leishmania species by culturing in vitro under gentamicin pressure has been used successfully with Leishmania mexicana, L. major, L. infantum, and L. donovani. The attenuated lines invaded but were unable to survive within bone marrow-derived macrophages in vitro, whereas wild-type parasites survived and multiplied. The attenuated lines of L. mexicana and L. major both failed to induce cutaneous lesions in the majority of BALB/c mice over a minimum 12-week observation period after subcutaneous injection of stationary phase parasites. The attenuated line of L. mexicana retained its properties in gentamicin-free medium over 40 subcultures. The attenuated lines of L. mexicana and L. major both induced significant protection in mice against challenge with wild-type parasites.

Leishmania mexicana H-line attenuated under pressure of gentamicin, potentiates a Th1 response and control of cutaneous leishmaniasis in BALB/c mice.

An attenuated line of Leishmania mexicana (the L. mexicana H-line) has been established by culturing in vitro under gentamicin pressure. BALB/c mice infected with the L. mexicana H-line developed a CD4(+)Th1-like response, indicated by the cytokine profile of their splenocytes stimulated by L. mexicana wild-type (WT) promastigotes. This profile is sustained after these mice are challenged with L. mexicana WT. Control mice infected with L. mexicana WT alone developed a CD4(+)Th2-like cytokine profile. In mice immunized with L. mexicana H-line and then challenged with WT-line, were eliminated when immunizing H-line parasites persisted in the skin and draining popliteal lymph nodes (PLNs). In experiments in which mice were inoculated with attenuated and WT parasites at the same time, either at the same site or on separate sides of the mouse, growth of the WT parasites was significantly contained and controlled, indicating a possible therapeutic role for the attenuated parasites.

Hyperglycemia during childhood diarrhea.

OBJECTIVE: To determine the cause of hyperglycemia in childhood diarrhea. METHODS: During an 8-month period, patients admitted to a diarrhea treatment center in Bangladesh had their blood glucose concentrations determined. Sixteen patients aged 2 to 10 years with hyperglycemia (blood glucose concentration >10.0 mmol/L) and 20 patients in the same age group with a normal blood glucose concentration (3.3 to 9.0 mmol/L) had blood samples obtained on admission and 4 and 24 hours later for determination of glucoregulatory hormones and gluconeogenic substrates. RESULTS: Prevalence of hyperglycemia among patients aged 2 to 10 years was 9.4%. Compared with the normoglycemic patients, hyperglycemic patients more often had severe dehydration (100% versus 10%, p <0.001), infection with Vibrio cholerae 0 1 or toxigenic Escherichia coli (94% vs 25%, p <0.001), and had similar duration of fasting (16 vs 14 hours, p = 0.677). Concentrations of epinephrine (7.15 vs 2.00 micromol/L), norepinephrine (10.35 vs 3.50 micromol/L), cortisol (1.38 vs 0.82 micromol/L), glucagon (36 vs 14 pmol/L), and C-peptide (1.22 vs 0.35 nmol/L) were all significantly (p < or = 0.014) higher in patients with hyperglycemia than in normoglycemic patients. CONCLUSIONS: The development of hyperglycemia in diarrhea is caused by a stress response to hypovolemia.

Partial splenic embolization in children with hypersplenism.

As an alternative to surgical splenectomy, partial splenic embolization was performed in seven children for hypersplenism manifested by splenomegaly, thrombocytopenia, leukopenia, and erythrocyte hemolysis. Within a few days, platelet and leukocyte counts rose significantly in all patients and were maintained in six of seven patients during a follow-up period of 9 to 69 months. Spleen size and abdominal distention also decreased significantly in all children. There were no infectious complications.

Experiência inicial com o dispositivo de anastomose intestinal por compressäo AKA-2 e AKA-4 em cirurgia colorretal / Initial experience with the AKA-2 and AKA-4 sutureless anastomotic gun in colorectal surgery

Os autores apresentam resultados iniciais de estudo clínico prospectivo sobre a realizaçäo de anastomose colorretal sem sutura, utilizando-se mecanismo de anastomose por compressäo desenvolvido pelos russos e designado como pistola AKA. Esta técnica foi empregada em dez pacientes submetidos a ressecçäo colorretal, dos quais cinco portadores de câncer do retossigmóide, três portadores de adenomatose familiar dos colos e dois portadores de procidência retal. Näo houve mortalidade, em um paciente houve o aparecimento de fístula próxima à anastomose colorretal, o qual, submetido à colostomia proximal desfuncionalizante, apresentou boa evoluçäo pós-operatória. Os parâmetros clínicos, radiológicos e endoscópicos analisados mostraram-se dentro da normalidade. Säo realizados comentários comparativos sobre as técnicas de anastomoses sem sutura e as convencionais. Consideram seus resultados como encorajadores, propondo-se prosseguir na avaliaçäo do método

[Initial experience with the AKA-2 and AKA-4 device for intestinal compression anastomosis in colorectal surgery]. / Experiência inicial com o dispositivo de anastomose intestinal por compressão AKA-2 e AKA-4 em cirurgia colorretal.

A prospective study was undertaken to analyse the results of sutureless colorectal anastomosis, by using an anastomotic compression device designed by Russians, the AKA gun. Ten patients were submitted do colorectal resection, 5 for retrosigmoid cancer, 3 for familial adenomatous polyposis and 2 for rectal procidentia. No mortality. Anastomotic leakage occurred in 1 patient which was treated by a defunctioning colostomy and had a good recovery. Clinical, radiologic and endoscopic postoperative controls were within normality. Comparisons are made between the sutureless anastomosis technique and the traditional ones. Initial results are regarded, by the authors, as encouraging and so they intend to go on the study.

Physicians' views of periodic abstinence methods: a study in four countries.

A study of the knowledge, perceptions, and behavioral intentions of physicians regarding periodic abstinence (PA) methods was undertaken in Mauritius, Peru, the Philippines, and Sri Lanka. Most respondents considered PA to be useful, although even the PA providers prescribed mainly non-PA methods. Detailed knowledge of PA methods was not evident, but most physicians were willing to initiate general discussion about PA with patients. Physicians favored methods perceived as "scientific" and "modern," which primarily prevent pregnancy and secondarily avoid other health risks. When carefully presented as "scientific" and "modern," methods presented to medical audiences may find acceptance and be more likely to result in referral.

PIP: This study attempts to assess the level of knowledge about periodic abstinence methods and willingness to communicate that knowledge to patients among a sample of 375 physicians from 4 developing countries: Mauritius, Peru, the Philippines, and Sri Lanka. For purposes of this study, periodic abstinence includes the calendar method (rhythm), the Billings method (ovulation method), the temperature method (basal body temperature), and the sympto-thermal method (temperature and cervical mucus observation). 54% of the doctors interviewed did not provide periodic abstinence services. 67% were male, 60% were over 40, 92% were not strongly Catholic, and 42% were general practitioners. Older doctors, female doctors, and strongly Catholic doctors were most likely to provide periodic abstinence services. 54% of providers were general practitioners, 46% were gynecologists, and 36% were clinicians. Both providers and nonproviders were most likely to recommend the pill or the IUD as a contraceptive method. The calendar method was the most commonly provided abstinence method. Providers, in general, had more knowledge about abstinence methods than did nonproviders, but even providers were deficient in knowledge about methods that they did not supply. Of the 3 main abstinence methods, the calendar method was perceived as most traditional, the Billings method as most modern. The sympto-thermal method was perceived as modern but also as "artificial." On a scale of 1 to 7 from bad/nonscientific to good/scientific, the pill scored highest (6.4), while the temperature, Billings, and calendar methods scored 5.2 or 5.1. 47% of all the physicians surveyed said that they would not recommend periodic abstinence to their patients. The majority said that they would respond to inquiries about these methods but would not initiate discussions about them. Among nonproviders, 12% said they would seek future training, but 17% said they had no future plans for either training or service.

The Yucatan miniature pig: characterization and utilization in biomedical research.

Yucatan miniature swine have a variety of applications in biomedical research. Sublines developed from the primary population at Colorado State University have been characterized genetically with special attributes. This report describes this unique laboratory animal, genetic selection programs, and its utilization in biomedical research.

Chemotherapy in giardiasis: clinical responses and in vitro drug sensitivity of human isolates in axenic culture.

To investigate drug sensitivities of human Giardia isolates, we developed a reproducible in vitro 3H-thymidine uptake assay to compare drug potencies. Among 13 Giardia intestinalis stocks obtained from the culture of trophozoites isolated from duodenal juice, considerable variation in susceptibility to a range of currently used drugs was found. The population doubling time of these stocks also varied widely. Clinical features in patients ranged in severity from mild chronic diarrhea to a celiac-like syndrome, with a similar variation in the degree of histologic change in the mucosa. Brush-border enzyme activities were universally reduced in children younger than 5 years of age. The two isolates with the highest ID50 values for furazolidone in vitro were from patients who had persistent symptoms after treatment with this drug; these patients subsequently responded to treatment with a nitroimidazole with greater in vitro potency. These studies suggest that biologic variants of G. intestinalis exist in humans and may in part account for the variable clinical manifestations and for some treatment failures.