Intestinal Drug Transporter Expression and the Impact of Grapefruit Juice in Humans

The goals of this study were to assess the extent of human intestinal drug transporter expression, determine the subcellular localization of the drug uptake transporter OATP1A2, and then to assess the effect of grapefruit juice consumption on OATP1A2 expression relative to cytochrome P450 3A4 and MDR1. Expression of drug uptake and efflux transporters was assessed using human duodenal biopsy samples. Fexofenadine uptake by different transporters was measured in a transporter-transfected cell line. We investigated the influence of grapefruit juice on pharmacokinetics of orally administered fexofenadine. The effect of grapefruit juice on the expression of intestinal transporters was determined using real-time polymerase chain reaction and Western blot analysis. In the duodenum of healthy volunteers, an array of CYP enzymes as well as uptake and efflux transporters was expressed. Importantly, uptake transporters thought to be liver-specific, such as OATP1B1 and 1B3, as well as OATP2B1 and 1A2 were expressed in the intestine. However, among OATP transporters, only OATP1A2 was capable of fexofenadine uptake when assessed in vitro. OATP1A2 colocalized with MDR1 to the brush border domain of enterocytes. Consumption of grapefruit juice concomitantly or 2 h before fexofenadine administration was associated with reduced oral fexofenadine plasma exposure, whereas intestinal expression of either OATP1A2 or MDR1 remained unaffected. In conclusion, an array of drug uptake and efflux transporters are expressed in the human intestine. OATP1A2 is likely the key intestinal uptake transporter for fexofenadine absorption whose inhibition results in the grapefruit juice effect. Although short-term grapefruit juice ingestion was associated with reduced fexofenadine availability, OATP1A2 or MDR1 expression was unaffected.

Taurine-diabetes interaction: from involvement to protection

Taurine is a sulfur amino acid (2-amino ethane sulfonic acid) and has been claimed for a number of beneficial actions ranging from anti-epilepsy to anti-hypertension. Taurine in diabetes has an age old story; taurine is involved in the development and protection of insulin apparatus. Taurine and insulin both have mutual stimulating actions with hypoglycemic properties. On the clinical front, taurine supplementation has an acceptable beneficial effect in platelet aggregation and, to name few more, in neuropathy, cardiomyopathy, and nephropathy to retinopathy. Recent studies have provided a role for taurine in fetal development and in blocking the transfer of diabetes from diabetic mother to offspring. A number of mechanisms for the actions of taurine have been advocated, from osmoregulation to anti-oxidation. Though sulfonylurea and recently introduced thiazolidinediones are effective, however they are not free from complications, thus there is a need to design new therapeutics. As taurine is also a sulfonyl derivative, it will be of great interest to develop taurine analogues as an alternative therapy. Considering the great involvement of taurine in diabetes, this review may provide a holistic view of taurine in diabetes and in its prevention in this century.

Outpatient parenteral antibiotic therapy in Singapore

Outpatient parenteral antibiotic therapy (OPAT) remains in its infancy in Singapore, with the first patients enrolled 4 years ago. Singapore's three largest hospitals, with over 3000 inpatient beds, now have designated and approved OPAT services. This study reviews the demographic, clinical and cost data of all patients enrolled in 2005 to facilitate benchmarking between services in Singapore and abroad and also to identify common needs for further development. In 2005, 225 OPAT enrollments in 208 different patients resulted in 4050 days of OPAT care. Orthopaedic diagnoses constituted 40% of admissions. Vancomycin was the most frequently used antibiotic (34%). The re-admission rate was 8.9%, but complications of OPAT care were only occasionally implicated. An estimated $207,200 was saved by patients despite there being significant financial disincentives to subsidised patients. OPAT is a safe, cost-efficient system that is becoming increasingly accepted in Singapore by patients, clinicians and management. Our three services have evolved independently into very similar practices. There is potential for further innovation, including outreach and carer-delivered dosing. However, major financial disincentives require review.

Quantitative and morphological assessment of early gestational sacs using three-dimensional ultrasonography

OBJECTIVE

Our main objective was to determine the value of three-dimensional ultrasonography (3DUS) and Virtual Organ Computer-aided AnaLysis (VOCAL) in the evaluation of gestational sac volume and morphology during early pregnancy.

METHODS

Twenty-eight normal early pregnancies were scanned approximately every 2 weeks using transabdominal (TAS) and transvaginal (TVS) sonography. The VOCAL technique was used to create computerized surface models to classify gestational sac shapes as discoid or ellipsoid. Serial sac volume changes were analyzed using repeated measures ANOVA. Bland-Altman plots determined examiner bias and limits of agreement (LOA) for sac volume measurements. Gestational sac volumes were compared between the two-dimensional (2D) ellipsoid and VOCAL techniques. Differences between volume measurements were tested using the two-tailed paired t-test with statistical significance at the P < 0.05 level.

RESULTS

Each subject was examined at a mean +/- SD menstrual age of 7.9 +/- 0.6 weeks (Scan 1), 9.9 +/- 0.6 weeks (Scan 2), and 11.9 +/- 0.6 weeks (Scan 3). Sac volumes significantly increased over time from 22 +/- 11 mL at Scan 1, to 57 +/- 21 mL at Scan 2 and 116 +/- 35 mL at Scan 3 (P < 0.001). Predominant sac shapes were classified as ellipsoid (76.2%) or discoid (23.8%). Additional descriptors included: concave (60.7%), irregular (53.6%), or smooth (7.1%), with 19% of the overall group having more than one additional shape attribute. Clinically acceptable volume measurement bias and agreement were found for the following comparisons: (1) TAS versus TVS; (2) interobserver volume measurements; and (3) intraobserver volume measurements. The VOCAL technique yielded slightly greater sac volumes (64 +/- 45.4 mL) when compared to the 2D ellipsoid model (48.6 +/- 36.8 mL) (28.9 +/- 24.3% (95% limit of agreement range, - 18.7 to 76.5%), P < 0.001).

CONCLUSIONS

Reproducible sac volume measurements can be obtained using VOCAL with either TAS or TVS. Early gestational sacs variably appear as discoid or ellipsoid structures with a concave indentation from the placenta. Sac volumes can be underestimated if an ellipsoid shape is assumed. Morphological and quantitative analysis of the gestational sac may provide baseline parameters for studying patients at risk for early pregnancy failure.

Minimal change disease following exposure to mercury-containing skin lightening cream

A 34-year-old woman developed nephrotic syndrome after using a skin lightening cream that contained an extremely high level of mercury. Blood and urine mercury levels were elevated and a renal biopsy revealed minimal change disease. Membranous nephropathy was excluded using immunofluorescence and electron microscopy. Her proteinuria remitted 9 months after she stopped using the cosmetic cream. This is the first reported case in the English literature of proven minimal change disease secondary to mercury exposure. It is important that mercury poisoning due to cosmetic cream is considered in the differential diagnoses for any woman who presents with nephrotic syndrome.

Induction chemotherapy with S-1 plus cisplatin in patients with locally advanced squamous cell carcinoma of the head and neck (SCCHN)

15501

Background: This study was to assess the efficacy and safety profiles of the combination treatment with S-1 and Cisplatin in patients with locally advanced SCCHN. Methods: Eligible patients were defined as histologically confirmed SCCHN, stage III or IV with no evidence of distant metastasis, evaluable lesions, adequate organ function, age of 20–80 years, and performance status 0,1 or 2. Cisplatin was infused over 1 hour on day 1 (75 mg/m2) and S-1 was administered orally for 14 consecutive days (day 2–15). The dosages of S-1 were assigned according to the patients’ body surface area (BSA): 50 mg twice a day (BSA < 1.5m2), 60 mg twice a day (BSA > 1.5m2). Each course was repeated every 3 weeks. After 2 course, tumor response were evaluated by CT scan and laryngoscopy. If the patients achieved a response (complete response: CR, or partial response: PR), they received one more course of chemotherapy before undergoing the radiotherapy or operation as a definitive local treatment. Results: All 22 patients were assessable for response and toxicity. The overall response was 80.9% (CR: 3, PR: 14). The adverse reactions occurred 120 times in 54 courses of 22 cases. The most common grade 3/4 adverse events were neutropenia, which occurred in 8 patients. Non-hematological toxicity of grade 3 and 4 included nausea and vomiting in 4 patients, fever in one patient and, fatigue in one patient. Since the observation period is short, the analysis about survival rate is not obtained so far. Conclusions: S-1 plus Cisplatin combination chemotherapy is effective against locally advanced SCCHN with mild toxicity.

No significant financial relationships to disclose.

Multiple primary cancers in patients with non-Hodgkin’s lymphoma

17562

Background: Multiple primary malignant tumors have been documented with increased frequency over the last two decades. An analysis of other primary cancers in individuals with non-Hodgkin’s lymphoma (NHL) can help to elucidate this cancer epidemics and etiology. Methods: The occurrence of multiple malignancy was studied in patients with NHL from 1985 to 2005. Results: One or more additional cancers were observed in 19 patients. Seven were diagnosed prior to, 5 concomitantly with, and 7 after the diagnosis of NHL. The diagnosis of 5 synchronous primary cancer were rectal cancer, squamous cell esophageal cancer, prostatic cancer, transitional cell bladder cancer, and non-small cell lung cancer. Each cases of colon cancer, breast cancer, hepatoma, small cell lung cancer, stomach cancer, cervical cancer, and rhabdomyosarcoma were diagnosed prior to NHL, and the second primary cancers were two squamous skin cancer and each cases of melanoma, colon cancer, thyroid cancer, adenocarcinoma of the salivary gland, and cholangiocarcinoma. The mean age of synchronous cases was 68.2 ± 4.8 years-old, and all 5 cases were primary extranodal NHL (2 gastric, 1 nasopharynx, 1 nasal, 1 rectal) and pathologic diagnosis were diffuse large cell in 4 cases and extranasal NK/T cell type in one case. The mean age of the second primary NHL was 57.6 ± 11.4 years-old, and 5 of 7 cases were extranodal origin (each one case of colon, tonsil, tongue, stomach, and CNS), and were diagnosed 11, 19, 24, 72, 73, 101, 168 months after the diagnosis of variable cancers. The mean age of the second primary cancer was 46.9 ± 15.9 years-old, and 3 of 7 cases were extranodal origin (2 gastric and 1 tonsil), and were diagnosed 55, 73, 75, 99, 144, 156, 161 months after the diagnosis of NHL. Conclusions: The synchronous cases of NHL were more older and more frequent extranodal manifestations than metachronous cases.

No significant financial relationships to disclose.

Kabuki syndrome: oral and general features seen in a 2-year-old Chinese boy

This report describes the case of a young Chinese boy with Kabuki syndrome (KS). KS is a congenital condition characterized by multiple anomalies, especially of the face, and is usually associated with mild to moderate mental retardation. The patient presented with the characteristic facial features of KS and some skeletal and neurological anomalies including a butterfly vertebrae with scoliosis, cerebral atrophy, and irregular dentition. Dental examination revealed screwdriver-shaped incisors and a high arched maxilla, features typical of patients with KS, as well as very poor oral hygiene and early childhood caries. This report includes discussion of the aetiology of KS as well as discussion of the long-term prognosis for this particular patient, and patients with KS in general, with consideration of associated dental and medical issues.

Three-dimensional ultrasound in the prenatal diagnosis of cleidocranial dysplasia associated with B-cell immunodeficiency

A patient with a singleton pregnancy was referred for three-dimensional ultrasonography (3DUS) at 18 + 3 weeks for suspected hypomineralization of the skull bones and absence of the nasal bones. Three-dimensional rendered images of the fetal skull revealed widening of the coronal sutures, absence of the squamous portion of the temporal bone, and absence of the occipital bone, except for two areas of ossification. In addition, a fractured right clavicle was identified. The remainder of the fetal anatomy was normal and biometry was appropriate for gestational age. Genetic amniocentesis revealed a 46,XX fetal karyotype. Family history was positive for a 5-year-old sibling with an open anterior fontanelle. Cleidocranial dysplasia was suspected. A female neonate was delivered by elective repeat Cesarean section at 40 + 3 weeks of gestation without complications and discharged home 3 days after delivery. Prenatal diagnosis was confirmed by physical and radiological evaluation. The infant died at 8 weeks of age due to respiratory syncytial virus pneumonia secondary to B-cell deficiency. RUNX2 mutations were not detected by molecular analysis. There are three relevant aspects to this case: (1) clear visualization of the widened fontanelles and hypomineralized occipital bones was possible with the use of 3DUS; (2) a clavicular fracture was identified in utero with combined high-resolution two-dimensional and 3DUS; and (3) although absence of the nasal bones is most commonly observed in fetuses with chromosomal disorders (e.g. trisomy 21 and trisomy 18), a careful examination of the skeleton should be considered in fetuses with absent nasal bones and a normal karyotype.

[Histoplasma capsulatum with aberrant morphology isolated in Argentina]

For the first time in Argentina, we describe a strain of Histoplasma capsulatum var. capsulatum with an aberrant morphology that was isolated from a single patient with AIDS. Mycelial phase cultures on agar Sabouraud at 25-28 degrees C showed white, glabrous, umbilicated and centrally radiated colonies. Unusual microscopic findings were the absence of typical conidia, the presence of terminal/intercalary chlamydoconidia with a diameter of 4 pm and of thickened hyphae. Fungal identification was confirmed by the detection of bands H and M species specific antigens in mycelial culture supernatants and reversion to the typical yeast phase on agar brain-heart-cysteine at 37 degrees C. The genomic DNA profile obtained by RAPD-PCR with primers 1281-1283 coincided with the predominant profile of H. capsulatum among isolates from Argentine patients.

Sodium ramping reduces hypotension and symptoms during haemodialysis

OBJECTIVES

To evaluate the effectiveness of sodium ramping (profiling) in reducing hypotensive episodes and symptoms during haemodialysis.

DESIGN

Prospective study.

SETTING

Regional hospital, Hong Kong.

PATIENTS

Thirteen patients who experienced frequent episodes of hypotension and/or symptoms such as cramps, dizziness, chest pain, nausea, vomiting, and headache during haemodialysis in the preceding 4 weeks.

INTERVENTIONS

Each patient was switched from standard haemodialysis with a constant dialysate sodium concentration of 135 to 140 mmol/L to a ramped sodium haemodialysis for a period of 4 weeks. During this time the dialysate sodium concentration was ramped linearly downwards from 150 mmol/L at the beginning of dialysis to 140 mmol/L at the end of dialysis.

MAIN OUTCOME MEASURES

Intradialytic hypotensive episodes, intradialytic symptoms, nursing interventions, systolic and diastolic blood pressures, and interdialytic weight gain.

RESULTS

A total of 248 haemodialysis sessions undertaken by 13 patients were analysed. Switching from constant sodium haemodialysis to ramped sodium haemodialysis resulted in a significant reduction in the number of intradialytic hypotensive episodes from 5.8 (standard deviation, 6.4) to 2.2 (3.3) [P<0.05], the total number of intradialytic symptoms from 7.1 (3.4) to 0.9 (1.3) [P<0.01], and nursing interventions from 11.3 (6.3) to 1.7 (3.9) [P<0.01]. Post-dialysis systolic and diastolic blood pressures were higher during ramped sodium haemodialysis compared with constant sodium haemodialysis (systolic blood pressure, 139 [standard deviation, 23] vs 133 [22] mm Hg, P<0.001; diastolic blood pressure, 77 [11] vs 74 [13] mm Hg, P<0.01), and there was a trend towards a smaller drop in blood pressure after dialysis. The interdialytic weight gain with sodium ramping haemodialysis was greater compared with constant sodium haemodialysis (3.1 [standard deviation, 1.0] vs 2.7 [1.1] kg, P<0.001).

CONCLUSION

Sodium ramping during haemodialysis effectively reduces hypotensive episodes and intradialytic symptoms. Post-dialysis blood pressure is better maintained. A side-effect of sodium ramping is a greater interdialytic weight gain.