Prograf five milligrams versus Tacrolimus medis in healthy volunteers: a bioequivalence study

For FDA approval, bioequivalence of a generic version of Tacrolimus must be demonstrated in a randomized, two-treatments, two-periods, two-sequences, single-dose crossover study in healthy adult volunteers. Currently there are at least 3 differents generic equivalent for Tacrolimus, that are approved by the EMA and the FDA, with a USA market share of nearly 50%. However, the market share of generic immunosuppressive drugs in the Middle East region is still very low due to the reluctance of the physician to accept Tacrolimus generics, considered to be a narrow therapeutic window drug, that are approved using the standard bioequivalence criteria of 80% to 125%. Herein we present a bioequivalence study of a new Tacrolimus generic, Tacrolimus Medis 5 mg developed by Medis Tunisia batch number 12G3003 compared with Prograf® 5 mg batch number 7202 manufactured by Astellas Toyama Co., Ltd. Japan and HIKMA Pharmaceuticals, Amman-Jordan in healthy adult volunteers using the 90%-111% criteria recommended for drugs with narrow therapeutic window. The study was, balanced, randomized, two-treatments, two-periods, two-sequences, single dose, crossover, comparative oral bioavailability study in healthy adult human volunteers. The study was carried out in accordance with the Basic Principles defined in the U.S. 21 CFR Part 312.20, the principles enunciated in the Declaration of Helsinki (World Medical Association Declaration of Helsinki). Thirty six non-smoking healthy, as determined by medical history, volunteers, 18 years and older, were included. Following randomization using a computer software (pharma solution) the volunteers were given a single oral dose of 5 milligrams following a 12 hour fast with a wash out period of 7 days. Pharmacokinetics profile with blood levels at: 0, 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, 8, 10, 12, and 24 hours were performed following each dose. Tacrolimus plasma level was determined using an HPLC validated method (Transmedical For Life S.A.R.L. Beirut Lebanon), for accuracy, suitability, reproducibility, precision , long-term stability and robustness. Physical examinations, hematology, urine analysis and serum chemistry tests were performed at screening and before dosing in each period and at end of the study. Volunteers were monitored for safety and adverse events throughout the study. Both products were bioequivalent at the entire pharmacokinetic parameters tested. The LSM were 95.31%-101.21% for AUC, 94.65%-101.11% for AUC0-inf, 97.15%-100.02% for Cmax and 91.54%-103.75% for Half-life. Respectively all of which are within the EU and FDA approval limits (90-111%) indicating that the 2 products are equivalent and switchable.

[Impressions techniques--Part 2]

A dental impression is a positive replica of the teeth, the surrounding gingiva and the border between them; the purpose of which is to create an accurate master model. Two major techniques for impressions exist today: The conventional and the digital impressions. The current article describes both techniques. In the conventional impressions, it is important to choose a proper tray, stock or custom, and to mix the material properly. The commonly used impression techniques for making a conventional impression are described with a review on the effect of the technique on its accuracy. The effect of the wash bulk on the accuracy of the stone dies and/or the restoration is discussed, as well. The digital impressions with their advantages and disadvantages are described in comparison to the conventional impressions. Although, digital impressions eliminate some of the negative characteristics of conventional impressions, proper soft-tissue management and isolation of tooth preparation margins is still mandatory.

[Tissue displacement and impression techniques--part 1]

In order to create an accurate model of the soft and hard tissues of the mouth, a complete control of the gingiva around the prepared teeth is needed. This gingiva must be displaced and bleeding must be avoided. This article describes the three techniques for tissue displacement: mechanical, chemicomechanical and surgical. Mechanical displacing the gingiva can be done by either the use of copper bands or with plain retraction cord. By combining chemical action with packing of a retraction cord a chemicomechanical displacement of the tissue can take place. The surgical retraction is possible by Laser, Electro surgery or Rotatory curettage. The advantages, disadvantages, and limitations of each of the different techniques are discussed. In addition, the different hemostatic agents are described with their mechanism of action, indications and contra-indications of each one of them.

An assay for the determination of sirolimus levels in the lymphocyte of transplant patients

Both tacrolimus (TAC) and sirolimus (SRL) bind to the same immunophilin FKBP12; however, their mechanisms of action are distinct. SRL inhibits mammalian target of rapamycin (TOR), which is an enzyme critical to the immune function. TOR inhibition blocks the signal that mediates T-cell proliferation by preventing cell-cycle progression from G1 to S phase. Moreover, TOR inhibition results in a decrease in antibody production by blocking B-cell proliferation and maturation into antibody producing cells. The use of SRL has resulted in a decrease in the number of rejection episodes. As with other immunosuppressive agents, SRL can cause dose-related side effects, the most notable of which are hypercholesterolemia, hyperlipidemia, anemia, and thrombocytopenia. Thus, therapeutic drug monitoring to assess efficacy and toxicity has became a necessity. SRL blood levels do not correlate with its bioactivity and are affected by the concomitant use of other immunosuppressive drugs. To determine the bioactivity of SRL we have developed an assay to determine the level of Sirolimus per lymphocyte of transplant patients. The levels were correlated with lymphocyte count.

METHODS

Whole blood samples from patients on SRL were collected in Ethylene Diamine Tetra-acetic acid (EDTA) vacutainer tubes. Immediately the lymphocytes from 2 mL of blood were separated using 1.5 mL of Ficoll gradient, by centrifugation for 30 minutes at 2500 RPM. The lymphocytes were washed three times with phosphate-bufferd saline and the pellet suspended in 150 microL of Middle East research institute (MERI) drug extraction solution (Beirut, Lebanon), which was then added to 300 microL of IMx solublizing reagent. The cytoplasmic SRL concentrations in lymphocytes were measured using kits supplied from Abbott diagnostics or by high-performance liquid tomography. A corresponding whole blood sample from each patient was used to measure blood levels. To determine the level per lymphocyte, the value obtained was divided by the number of lymphocytes and expressed as Pg/cell. A pharmacokinetic profile for both blood and lymphocytes was constructed for each patient using data corresponding to predose C(0), 1 hour (C(1)) and 2 hours (C(2)) after the dose. The lymphocyte enumeration for C(0), C(1), and C(2) was performed using the FACS Calibur Flow Cytometer from Becton Dickinson. The average dose was 2.86 +/- 1.27 mg/d with a C(0) = 8.05 +/- 4.24, C(1) = 21.9 +/- 8.9 ng/mL, and C(2) = 23 +/- 0.03 ng/mL. Although there was a significant correlation (P=.0975) between the dose and C(0), there was no correlation between the dose and C(0) level on the lymphocyte count P=.897. However, there was a strong correlation between SRL lymphocyte levels (pg/cell) and the lymphocyte count (r(2)=.6.06). The higher the concentration of the drug the lower the lymphocyte counts. The assay is sensitive to within 0.45 pg/cell, reproducible with a coefficient of variance (CV) of 6.4% within assay and 7.5% for intraassay.

Consanguinity-associated kidney diseases in Lebanon: an epidemiological study

Consanguineous marriages are common in many countries of the Middle East including Lebanon. Their impact on the repartition of kidney diseases and on the risk for familial nephritis is not known. We surveyed all of the dialysis centers in Lebanon. Nine hundred and twenty-five (925) patients and their private physicians were asked to answer a questionnaire. More than half of the hemodialysis (HD) patients had an unknown etiology of their kidney disease. Diabetes, polycystic kidney disease (PKD), chronic pyelonephritis and nephrosclerosis (NS) were the most commonly documented diagnoses. Consanguinity was present in 26% of the total HD population. More consanguineous patients with unknown renal etiology were diagnosed with their kidney diseases and initiated on dialysis before the age of 30 when compared with their non-consanguineous counter-parts (45% versus 33%, P<0.02 and 42% versus 27%, P<0.01), respectively. Similarly, consanguineous polycystic patients were diagnosed and started earlier on dialysis when compared with the non-consanguineous population (34% versus 12%, P<0.05 and 28% versus 8%, P<0.05), respectively suggesting a different disease pattern. Furthermore, the risk for family history of kidney disease was noticeable in the non-consanguineous population and significantly higher among the consanguineous patients (12% versus 18%, P<0.04). Consanguinity-associated kidney diseases affected all religious communities, in particular the Muslim and the Druze (36 and 39%), respectively versus 17% of the Christian community. Certain geographical areas were more involved than others such as the North, South and the Bekaa with the highest percentage (40%) in the latter. Socio-economical level was not a contributing factor. We conclude that the documentation of the underlying etiology in end-stage renal diseases (ESRD) seems to be deficient. Furthermore, consanguinity is prevalent in the Lebanese dialysis patients population, in particular the Muslim and the Druze communities. Consanguinity-associated kidney diseases pattern seems to differ from that of the general HD population by disease diagnosis and initiation at a younger age and a significantly higher risk for familial renal disease. It is a cultural phenomenon prevalent predominantly in the rural areas. We recommend a multi-approach including educational, informative and probably legislative strategy in order to limit and hopefully discourage consanguineous marriages.

HL-60 cells degrade alpha-actinin to produce a fragment that promotes monocyte/macrophage maturation

An amino-terminal fragment of alpha-actinin can promote monocyte/macrophage maturation. This fragment was initially isolated from media of HL-60 myeloid leukemia cells cultured on extracellular bone marrow matrix. To determine the source of this fragment in this culture system, we investigated whether HL-60 cells grown on bone marrow stroma have increased intracellular levels of alpha-actinin that may be released into the media during cell apoptosis. HL-60 cells grown on matrix showed no evidence of increased cellular alpha-actinin compared to cells grown on plastic substrata as measured by flow cytometry. In addition, there was no evidence of increased apoptosis as determined by DNA fragmentation assays or flow cytometry. However, 100 kD alpha-actinin was found in the extracellular matrix of bone marrow stroma by Western blot analysis and immunofluorescence microscopy. The alpha-actinin content in the stroma was markedly decreased after exposure to HL-60 cells. Furthermore, lysates of HL-60 cells or of peripheral blood monocytes can degrade exogenous alpha-actinin to produce a 31 kD fragment, which promotes monocyte/macrophage maturation. We conclude that when alpha-actinin is present in the extracellular matrix, it can be modified by HL-60 cells to produce a maturation promoting 31 kD fragment.

A fragment of alpha-actinin promotes monocyte/macrophage maturation in vitro

Conditioned media (CM) from cultures of HL-60 myeloid leukemia cells grown on extracellular bone marrow matrix contains a factor that induces macrophage-like maturation of HL-60 cells. This factor was purified from the CM of HL-60 cells grown on bone marrow stroma by ammonium sulfate precipitation, then sequential chromatography on DEAE, affi-gel blue affinity, gel exclusion, and wheat germ affinity columns, followed by C-4 reverse phase HPLC, and SDS-PAGE. The maturation promoting activity of the CM was identified in a single 31 kD protein. Amino acid sequence analysis of four internal tryptic peptides of this protein confirmed significant homology with amino acid residues 48-60, 138-147, 215-220, and 221-236 of human cytoskeletal alpha-actinin. An immunoaffinity purified rabbit polyclonal anti-chicken alpha-actinin inhibited the activity of HL-60 conditioned media. A 27 kD amino-terminal fragment of alpha-actinin produced by thermolysin digestion of chicken gizzard alpha-actinin, but not intact alpha-actinin, had maturation promoting activity on several cell types, including blood monocytes, as measured by lysozyme secretion and tartrate-resistant acid phosphatase staining. We conclude that an extracellular alpha-actinin fragment can promote monocyte/macrophage maturation. This represents the first example of a fragment of a cytoskeletal component, which may be released during tissue remodeling and repair, playing a role in phagocyte maturation.

Role of contralateral breast biopsy in infiltrating lobular cancer

BACKGROUND

Although infiltrating lobular carcinoma (ILC) is known to be associated with higher rates of bilaterality, contralateral breast biopsies are not routinely performed in such patients.

METHODS

The pathology reports of all patients with ILC admitted to Memorial Sloan-Kettering Cancer Center between 1970 and 1980 were retrospectively reviewed. The incidence of contralateral biopsies, random and directed, was determined. The findings on contralateral biopsy were evaluated with respect to age of the patient, nodal status of the ipsilateral cancer, and multicentricity of the primary lesion.

RESULTS

Of the 275 patients undergoing mastectomy for ILC, 130 (47%) had contralateral biopsies. Twenty-two were directed biopsies and 108 were random biopsies. On random biopsy 11 (10%) patients were found to have infiltrating carcinomas and seven (6%) were found to have intraductal cancer. Multicentric invasive disease in the ipsilateral breast was found to be predictive of a positive contralateral biopsy (p = 0.01).

CONCLUSIONS

Despite the current trend toward less extensive surgery for breast cancer, random contralateral breast biopsy is indicated in patients with ILC.

Alterations in plasma volume, plasma constituents, renin activity and aldosterone induced by maximal exercise in the horse

Plasma volume (PV) decreased by 13 per cent following the completion of 1,000 m of maximal exercise in the horse. This study demonstrated that the critical reduction in PV following maximal exercise occurred within 10 mins of completion of exercise, as previously reported in man. Total plasma protein (TPP) increased by 23 per cent at 2 and 5 mins, and by 21 per cent at 10 mins post exercise. Therefore, it does not appear to be an accurate measurement to assess the degree of PV contraction in the horse. Protein was apparently added to the intravascular space either during or following exercise. The changes in osmolality correlated strongly with those in sodium, which is the primary determinant of alterations in plasma tonicity. The increase in osmolality (12 per cent) was similar to the reduction in PV (13 per cent) concluding that a transient hypotonic fluid loss had occurred. The increase in plasma renin activity (PRA) following maximal exercise was followed by an increase in aldosterone (ALD) concentration in both magnitude and time course. Alterations in PV should be considered when interpreting electrolyte and serum enzyme activity data collected following maximal exercise.

Irreversible attachment of immunoglobulins and F(ab')2 fragments to their specific cell membrane antigens

Antiserum was raised in sheep against rat kidney glomerular basement membrane, and the antibodies and their F(ab')2 fragments were prepared. These were reacted with one arm of the bifunctional reagent toluene diisocyanate at pH 7.5 and injected into the tail vein of rats. Kidney sections were taken from the rats and, after washing, incubated at pH 8.5 to permit the other arm of the toluene diisocyanate to become reactive. This procedure resulted in the specific irreversible attachment of the antibodies and their F(ab')2 fragments to their corresponding glomerular basement membrane antigens.