Polymorphisms of the interleukin-4 gene in chinese patients with systemic lupus erythematosus in Taiwan

We aimed to evaluate the relationship between two polymorphisms of the IL4 gene (-590T/C and intron 3) and systemic lupus erythematosus in Chinese patients in Taiwan. This study included 91 patients with systemic lupus erythematosus (SLE) and 163 unrelated, age matched healthy controls living in the same area. The typing of -590T/C and intron 3 VNTR (variable number of tandem repeats) polymorphisms were performed by PCR-RFLP and PCR, respectively. Allelic frequencies and carriage rates between SLE patients and controls were compared, and the relationship between allelic frequencies and clinical manifestations of SLE was evaluated. The genotype frequencies of IL-4 intron 3 were found to differ significantly between SLE patients with and without discoid rash (chi-square test, P = 0.03 5). The allelic frequency of intron 3 RP1 was significant different in the patients with discoid rash when compared to patients without this clinical feature (OR = 3.70, 95% CI 2.04-6.72, chi2 test, P = 0.029). The RP1/RP1 homozygous carriage was significantly associated with patients with discoid rash when compared to patients without this clinical feature (OR = 6.04, 95% CI 2.81-12.95, P = 0.01). The allelic frequency of -590T was significant different in the patients with discoid rash when compared to patients without this clinical feature (OR = 3.44, 95% CI 1.88-6.31, chi-square test, P=0.04). The T/T homozygous carriage was significantly associated with patients with discoid rash when compared to patients without this clinical feature (OR = 5.41, 95% CI 2.50-11.68, P = 0.02). We describe a novel association between RPI/RPI and T/T homozygous carriage and patients with discoid rash. The role of the intron 3 polymorphism of the IL4 gene in SLE remains unclear and further substantiation based on larger patient samples is needed.

Association of vitamin D receptor gene BsmI polymorphisms in Chinese patients with systemic lupus erythematosus

The purpose of this study was to evaluate whether vitamin D receptor (VDR) genes BsmI polymorphisms were markers for susceptibility to or severity of systemic lupus erythematosus (SLE) in Chinese patients in Taiwan. The study included 47 Chinese patients with SLE. In addition, 90 unrelated, healthy individuals living in central Taiwan served as control subjects. Each polymorphism was detected as a result of polymerase chain reaction (PCR)-based restriction analysis. A PCR product length was determined to be 580bp (BB) whereas two fragments of 405 and 175bp were determined to be excisable lengths (bb) by BsmI endonuclease. The relationship between Bsm polymorphisms and clinical manifestations of SLE was evaluated. We found that BB was significantly more common and bb less common in SLE than in control group (chi2 = 54.2, P < 0.0001). In addition, the frequency of B allele was also significantly more common in patients with SLE than in the healthy control subjects (chi2 = 38.7, P < 0.0001), giving an odds ratio of 7.14 (95% confidence interval 3.53-14.4). In the SLE patients, we did not detect any associations of VDR genotype with the clinical, laboratory profiles, or lupus nephritis (chi2 = 2.34, P = 0.3). This study indicated an increased distribution of VDR BB genotype and B allelic frequencies in the Chinese SLE patients in Taiwan. However, there were no associations between the frequency of VDR allelic variations and clinical manifestations, laboratory profiles, or lupus nephritis.

Sensitization of a tumor, but not normal tissue, to the cytotoxic effect of ionizing radiation using Panax notoginseng extract

The aim of the present study was to investigate any sensitization effect of the Panax notoginseng extract (PNE) and the purified Saponin (Rb1) on the radiation response of an experimental tumor (KHT sarcoma) in mice, in comparison with any effects on a normal tissue (bone marrow). PNE at a concentration of 0.1-100 mg/kg produced an increase in tumor radiosensitivity. The sensitization effect was maximal at 10 mg/kg and at 30 minutes after injection. Higher doses were toxic to the bone marrow stem cells. Similarly Rb1 at a concentration 0.001 to 1 mg/kg also produced an increase in tumor radiosensitivity, with maximum effect at 1 mg/kg. Higher doses were not toxic to the bone marrow stem cells in this case. Radiosensitization factors were calculated as ratios of D0 (the radiosensitivity parameter), and these were highly significant for the tumor and very similar for both compounds at the doses used, namely 1.18-1.19. There was no significant effect for bone marrow stem cells (sensitization factors of 0.99 +/- 0.01 for both compounds). The differential effect on tumor, and the magnitude of the radiosensitization, suggest that further purified or synthetic versions of this extract may be useful not only in vascular-related diseases but also in cancer therapy.

Phenacetin O-deethylation in extrahepatic tissues of rats

Phenacetin O-deethylation is a marker reaction of CYP450 1A2 activity. The drug-metabolizing enzyme is constitutively expressed in liver. In this study, an in vivo rat model for assessment of extrahepatic metabolism was used to investigate phenacetin O-deethylation and the alterations in the disposition of phenacetin due to the loss of liver function. Rats were divided into the model and normal control groups. The model was established according to our previously described method. The concentrations of phenacetin and its major metabolites acetaminophen, glucuronate-acetaminophen and sulfate-acetaminophen in plasma and urine were determined by HPLC. 30 min after intravenous administration of 0.16% phenacetin 10 mg x kg(-1), plasma acetaminophen in the model group was only 3.6% of that in the control group (0.09+/-0.04 microg x mL(-1) vs 2.49+/-0.85 microg x mL(-1), n = 8). 30 min after intragastric injection of 0.4% phenacetin 30 mg x kg(-1), plasma acetaminophen formation was very slight, about 8.6% of plasma phenacetin in the model group (0.74+/-0.43 microg x mL(-1) acetaminophen vs 8.57+/-8.42 microg x mL(-1) phenacetin) and 6.8% in the control group (1.06+/-0.59 microg x mL(-1) acetaminophen vs 15.47+/-7.21 microg x mL(-1) phenacetin, n = 8); no significant differences were observed in plasma phenacetin, total acetaminophen and the ratio of acetaminophen to phenacetin between control and model groups. In the urine collected for 3 h after intravenous administration of 0.16% phenacetin 10 mg x kg(-1), the total recovery of acetaminophen (as free, glucuronate- and sulfate-acetaminophen ) in the model group was 4.6% of that in the control group (4.47+/-4.27 microg vs 96.63+/-8.50 microg, n = 6), but phenacetin recovery in the model group was 9 times higher than that in the control group (15.03+/-17.72 microg vs 1.66+/-0.50 microg). The results indicate that phenacetin O-deethylation in the extrahepatic tissues and the first-pass metabolism of the probe compound seem to be negligible in rats, but the renal excretion of phenacetin, as a compensation, dramatically increases in model rats.

Tomographic Small-Animal Imaging Using a High-Resolution Semiconductor Camera

We have developed a high-resolution, compact semiconductor camera for nuclear medicine applications. The modular unit has been used to obtain tomographic images of phantoms and mice. The system consists of a 64 x 64 CdZnTe detector array and a parallel-hole tungsten collimator mounted inside a 17 cm x 5.3 cm x 3.7 cm tungsten-aluminum housing. The detector is a 2.5 cm x 2.5 cm x 0.15 cm slab of CdZnTe connected to a 64 x 64 multiplexer readout via indium-bump bonding. The collimator is 7 mm thick, with a 0.38 mm pitch that matches the detector pixel pitch. We obtained a series of projections by rotating the object in front of the camera. The axis of rotation was vertical and about 1.5 cm away from the collimator face. Mouse holders were made out of acrylic plastic tubing to facilitate rotation and the administration of gas anesthetic. Acquisition times were varied from 60 sec to 90 sec per image for a total of 60 projections at an equal spacing of 6 degrees between projections. We present tomographic images of a line phantom and mouse bone scan and assess the properties of the system. The reconstructed images demonstrate spatial resolution on the order of 1-2 mm.

Expression of liver cancer associated gene HCCA3

AIM: To study and clone a novel liver cancer related gene, and to explore the molecular basis of liver cancer genesis.

METHODS: Using mRNA differential display polymerase chain reaction (DDPCR), we investigated the difference of mRNA in human hepatocellular carcinoma (HCC) and paired surrounding liver tissues, and got a gene probe. By screening a human placenta cDNA library and genomic homologous extend, we obtained a full-length cDNA named HCCA3. We analyzed the expression of this novel gene in 42 pairs of HCC and the surrounding liver tissues, and distribution in human normal tissues by means of Northern blot assay.

RESULTS: A full-length cDNA of liver cancer associated gene HCCA3 has been submitted to the GeneBank nucleotide sequence databases (Accession No. AF276707). The positive expression rate of this gene was 78.6% (33/42) in HCC tissues, and the clinical pathological data showed that the HCCA3 was closely associated with the invasion of tumor capsule (P = 0.023) and adjacant small metastasis satellite nodules lesions (P = 0.041). The HCCA3 was widely distributed in the human normal tissues, which was intensively expressed in lungs, brain and colon tissues, while lowly expressed in the liver tissues.

CONCLUSION: A novel full-length cDNA was cloned and differentiated, which was highly expressed in liver cancer tissues. The high expression was closely related to the tumor invasiveness and metastasis, that may be the late heredited change in HCC genesis.

Determination of random- and blockwise-type de-esterified pectins by capillary zone electrophoresis

Capillary zone electrophoresis (CZE) was employed to determine the correlations between migration time and degree of esterification (DE) of pectinesterase-de-esterified pectins (PDPs) and alkaline-de-esterified pectins (ADPs) using 50 mM phosphate buffer (pH 6.5) as carrier electrolyte solution and 15 KV as applied voltage. Results showed that pectins with higher DEs exhibited shorter migration times. Linear correlation (r = 0.995) between migration time and DE of ADPs was observed, whereas down-curve correlation in PDPs was observed, regardless of the capillary length used (effective length, 30 and 60 cm). In addition, PDP appeared to migrate faster than ADP with the same DE under the same experimental conditions.

Interleukin-1beta and interleukin-1 receptor antagonist gene polymorphisms in rheumatoid arthritis

The purpose of this study was to evaluate if IL-1beta (IL-1beta promoter and IL-1beta exon 5) and IL-1receptor antagonist (IL-1Ra) gene polymorphisms act as markers of susceptibility to or severity of RA. The study included 104 RA patients and 103 normal controls. No significant difference was observed in the cytokine allelic frequencies of IL-1beta promoter and IL-1beta exon 5 between patients with RA and healthy controls. In addition, there was no significant association in the cytokine carriage rates of I and II allele of IL-1Ra between RA patients and healthy controls. In contrast, the IV allele of IL-1Ra was significantly increased in RA patients with low inflammatory activity (P=0.03). This study indicated that allelic frequency and carriage rate of IL-1beta (IL-1beta promoter and IL-1beta exon 5) and IL-1Ra (I and II allele) do not differ significantly between normal controls and RA patients in Taiwan. However, the carriage rate of IV allele of IL-1Ra was high in the RA patients with low inflammatory activity.

Identification and characterization of a novel human hepatocellular carcinoma-associated gene

To investigate liver cancer-associated genes and to explore the molecular basis of liver cancer genesis, we have cloned a novel hepatocellular carcinoma (HCC)-related gene with a transcript of 2520 base pairs in length named HCCA2 by mRNA differential display polymerase chain reaction (DDPCR) and screening a placenta cDNA library. No significant homologous protein with known genes was found. Western blot analysis showed that HCCA2 could be expressed in transfected 293 cells. Northern hybridization analysis showed that HCCA2 mRNA was expressed in 79% (34/43) patients with HCC, most of whom had significantly high expression in HCC tissues, while not expressed in corresponding noncancerous liver tissues. The clinical pathological data showed that the HCCA2 was significantly associated with the invasion of tumour capsule (P = 0.0007) and the expression of ki-67 protein (P = 0.0022). Immunohistochemical staining confirmed that the HCCA2 protein was localized in cytoplasm of liver cancer tissues. According to amino acid analysis of the protein and its localization, it may play a role in a cascade of intracellular signal transduction because the protein was characterized with two Src homology 3 (SH3) binding-domains and several functional motifs of phosphorylation.

Flow cytometry compared with indirect immunofluorescence for rapid detection of dengue virus type 1 after amplification in tissue culture

Dengue virus (DV) was detected early in infected mosquito C6/36 cells by using indirect immunofluorescence (IF) in conjunction with flow cytometry. Three fixation-permeabilization methods and three DV serotype 1 (DEN-1)-specific monoclonal antibodies, 8-8 (anti-E), 16-4 (anti-NS1), and 15F3-1 (anti-NS1), were evaluated for the detection of DEN-1 in infected C6/36 cells. We found that these three monoclonal antibodies were capable of detecting DV in C6/36 cells as early as 24 h postinoculation by using a conventional indirect IF stain. Both 8-8 and 16-4 detected DV earlier and showed a greater number of DV-positive cells than 15F3-1. In flow cytometry, 3% paraformaldehyde plus 0.1% Triton X-100 with 16-4, the best fixation-permeabilization method for testing DV, showed higher sensitivity (up to 1 PFU) than indirect IF stain. The higher sensitivity of 16-4 in detecting DEN-1 was found with both IF and flow cytometry. Flow cytometry, which had a sensitivity similar to that of nested reverse transcription-PCR, was more sensitive in detecting DV in the infected mosquito cells 10 h earlier than the conventional IF stain. When clinical specimens were amplified in mosquito C6/36 cells and then assayed for DV using flow cytometry and conventional virus isolation at day 7 postinfection, both methods had 97.22% (35 out of 36) agreement. Moreover, among 12 positive samples which were detected by conventional culture method, the flow cytometry assay could detect DV in 58.33% (7 out of 12) of samples even at day 3 postinfection. In conclusion, both monoclonal antibodies 8-8 and 16-4 can be used for the early detection of DEN-1-infected C6/36 cells, with 16-4 (anti-NS1) being the best choice for the rapid diagnosis of DV by both the IF staining and flow cytometry methods.

Interleukin-1beta gene and receptor antagonist gene polymorphisms in patients with calcium oxalate stones

Interleukin-1 (IL-1) might play a role in the process of bone loss and hypercalciuria and is therefore considered to be involved in the formation of urinary stones. The aim of this study is to test whether the IL-1beta promoter region, exon 5 region and IL-1 receptor antagonist gene intron 2 polymorphisms could be genetic markers for the susceptibility to the formation of urinary stones. A control group of 152 healthy people and a group of 105 patients with recurrent calcium oxalate stone were examined in this study. Polymerase chain reaction (PCR) analyzed the variable number tandem repeats at intron 2 of the IL-1Ra gene for the polymorphisms. PCR-based restriction analysis was done for the IL-1beta gene polymorphisms of the promoter region and exon 5 by the endonucleases Ava I and Taq I, respectively. The polymorphisms studied in the IL-1beta genes did not reveal a strong association with calcium oxalate stone disease when compared with the control group (promoter region by chi-square test, P=0.627: exon 5 region by Fisher's exact test, P = 0.403). Only two frequent alleles of the IL-1Ra gene corresponding to one and two copies of an 86-bp sequence repeat were identified by PCR. The result revealed significant differences between control individuals and stone patients (P < 0.01. Fisher's exact test). In addition, the frequency of the type I allele in the stone group (99.0%) was higher than in the control group (94.0%). The odds ratio for the type I allele of the IL-1Ra gene in calcium oxalate stone disease is 6.041 (95% CI: 1.683 approximately 21.687). There is an association between urolithiasis and polymorphism in the IL-1Ra gene. No significant difference was found when dividing the stone patients into groups with normocalciuria and hypercalciuria in relation to these genetic polymorphisms. Further studies of the type I allele of the IL-IRa gene are worthwhile because of its correlation with stone disease. In our study, neither the IL-1beta promoter region nor the exon 5 polymorphisms were significantly different when comparing control subjects and calcium oxalate stone patients.

The association of androgen- and oestrogen-receptor gene polymorphisms with urolithiasis in men

OBJECTIVE

To evaluate the association of urolithiasis with polymorphic microsatellite (encoding cytosine, adenine, and guanine, CAG) repeats in the exon 1 region of the androgen receptor (AR) gene and thymine/adenine (TA) repeats in the oestrogen receptor (ER).

PATIENTS AND METHODS

Patients with urolithiasis (149) and a group of normal controls (102) were examined and compared. The CAG repeats of the AR gene and TA repeats of the ER gene were detected by polymerase chain reaction. The CAG repeats ranged from 171 bp (10 CAG repeats with 141 bp of amplified flanking sequences) to 270 bp (43 CAG repeats). The TA repeats ranged from 160 bp to 194 bp. Associations between calcium oxalate stone disease and the CAG repeats in AR gene and TA repeats in ER gene were then evaluated. The results were classified according to sex and peaks in allelic frequency distribution.

RESULTS

There was a significant difference between the male stone patients and the normal controls in the distribution of CAG repeats in the AR gene. Both groups showed a high percentage of 21-repeats in the allelic distribution, at 17 (16%) and 20 (37%) in stone patients and normal controls, respectively. The results indicate that 21-CAG repeats might be related to a lower risk of stone formation in men (P < 0.05). In the ER gene, the peak allelic distribution of TA repeats was 14, showing a significant difference between male stone patients and the normal control subjects (P < 0.01). There were no statistical differences between female stone patients and the control subjects in either the AR or the ER gene.

CONCLUSION

Urolithiasis among men appears to be associated with AR gene CAG repeat and ER gene TA repeat polymorphisms, whereas there was no significant association among female stone patients. These sex hormone receptors seem to be related to the higher incidence of stone formation among men.

Change in particle size of pectin reacted with pectinesterase isozymes from pea (Pisum sativum L.) sprout

Four pectinesterase (PE) isozymes were isolated by CM-Sepharose CL-6B chromatography from etiolated pea (Pisum sativum L.) sprouts and then reacted with citrus pectin (degree of esterification = 68%, 30-100 kDa) to observe the change in pectin particle size using a laser particle size analyzer. After incubation of a pectin-PE mixture (pH 6.5) at 30 degrees C for 4 h, PE 1 was observed to catalyze the transacylation reaction most remarkably, increasing the particle size from approximately 50-70 to approximately 250-350 nm, followed by PE 3, PE 2, and PE 4.

Cloning and characterization of a novel gene (C17orf25) from the deletion region on chromosome 17p13.3 in hepatocelular carcinoma

Using a combination of hybridization of PAC to a cDNA library and RACE technique, we isolated a novel cDNA, designated as C17orf25 (Chromosome 17 open reading frame 25, previously named it HC71A), from the deletion region on chromosome 17p13.3. The cDNA encodes a protein of 313 amino acids with a calculated molecular mass of 34.8 kDa. C17orf25 is divided into 10 exons and 9 introns, spanning 23 kb of genomic DNA. Northern blot analysis showed that the mRNA expression of C17orf25 was decreased in hepatocellular carcinoma samples as compared to adjacent noncancerous liver tissues from the same patients. The transfection of C17orf25 into the hepatocellular carcinoma cell SMMC7721 and overexpression could inhibit the cell growth. The above results indicate that C17orf25 is a novel human gene, and the cloning and preliminary characterization of C17orf25 is a prerequisite for further functional analysis of this novel gene in human hepatocellular carcinoma.

Mutation analysis of type II Gaucher disease in five Taiwanese children: identification of two novel mutations

Gaucher disease (GD), one of the most prevalent lysosomal storage diseases, is caused by deficiency of lysosomal acid beta-glucosidase (GBA). It is divided into three types according to the presence and progression of neurologic symptoms. Of those, type II is relatively rare and most severe; patients usually die before the age of two years. Using polymerase chain reaction (PCR) and direct sequencing of GBA gene in five Taiwanese type II GD patients, we identified two novel mutations: G355D and three-nucleotide insertion in exon 7 of GBA. The latter resulted in an in-frame insertion of a methionine residue between Leu241 and Ser242. L444P, the second most common GD allele among non-Jewish Caucasian population, was found in all five type II GD patients (50%). Overall, 9 out of 10 GD alleles were identified in this study. Direct sequencing of all PCR products led to high detection rate of GD alleles and identification of the RecNci 1 alleles. In the future, high throughput sequencing will make it possible identifying more rare mutations in type II GD patients.

Endoscopic treatment of colorectal polyps and early cancer

To analyze the efficacy and outcome of colonoscopic resection for colorectal neoplastic lesions, we retrospectively reviewed 338 colorectal lesions from 232 patients regarding the clinical profiles, colonoscopic findings, histological findings, complications, and outcome. Morphologically, these lesions were classified into three categories: pedunculated (n = 140), sessile (n = 176); and flat (n = 22). Histological findings of lesions included adenoma (n = 248), carcinoma in situ (n = 17), submucosal carcinoma (n = 2), hyperplastic polyp (n = 57), and inflammatory polyp (n = 14). Neoplastic lesions are generally larger than nonneoplastic lesions (chi2 test, P < 0.05). The incidence of carcinoma was 5.6% of 338 resected lesions. The rate of cancer or high-grade dysplasia in flat polyps was greater than in pedunculated and sessile polyps (13.6 vs 4.54 vs 5.71%; P < 0.05). There were no perforations or deaths after colonoscopic treatment, and only mild bleeding occured in two patients. To date, 19 patients with early colorectal cancer were treated successfully by endoscopy with no recurrence or metastasis. To reduce the incidence and mortality of colorectal cancer, colonoscopic resection is a simple and safe procedure for removing neoplastic lesions. Detailed histological examinations are essential to decide the indications of surgery.

Absolute quantification of regional myocardial uptake of 99mTc-sestamibi with SPECT: experimental validation in a porcine model

We have evaluated a method for absolute in vivo quantification of 99mTc-sestamibi uptake in a porcine model of myocardial perfusion.

METHODS

Correlated CT and radionuclide images were obtained from eight adult pigs using a combined CT-SPECT imaging system. In each case, the CT image is used to generate an object-specific attenuation map that is incorporated into an iterative algorithm for reconstruction and attenuation correction of the radionuclide image. Anatomic information available from the correlated CT image is used to correct the radionuclide image for partial-volume errors by mathematically modeling the radionuclide imaging process. A volume of interest, or template, that approximates the geometric extent of the myocardium is defined from the CT image. Once defined, the template is assigned unit activity and is mathematically projected using a realistic physical model of the radionuclide imaging process including nonideal collimation and object-specific attenuation. The template is then reconstructed from these projections to obtain a pixel-by-pixel partial-volume correction for the myocardium in the radionuclide image. The CT image is also used to delimit the anatomic boundaries of the myocardium for quantification of the radionuclide images. The pixel intensities in the corrected radionuclide image are calibrated in units of activity concentration (MBq/g) and compared with the ex vivo activity concentration measured directly from the excised myocardium.

RESULTS

Without corrections, the measured in vivo activity concentration in the porcine myocardium was only 10% of the true value. Correcting for object-specific attenuation improved the accuracy of this measurement but resulted in values that were still only 42% of the true value. By correcting for both attenuation and partial-volume errors, we were able to achieve absolute quantification with an accuracy error near 10%.

CONCLUSION

We have shown that, by applying object-specific attenuation corrections and suitable partial-volume corrections, absolute regional activity concentration can be measured accurately in the porcine myocardium.

Quantification of L-ascorbic acid and total ascorbic acid in fruits and spinach by capillary zone electrophoresis

A standard curve for the quantification of L-ascorbic acid (L-AA) by capillary zone electrophoresis (CZE) was established, and the quantification of ascorbic acid and total ascorbic acid in fruits (lemon, Sunkist, and pineapple) and spinach were performed using D-isoascorbic acid (D-IAA) as an internal standard. The minimum detection limits (MDLs) for L-AA and D-IAA were determined to be 1 and 2 microg/mL, respectively, at 265 nm. Dehydroascorbic acid (DHAA) in fruits and spinach was quantified in the presence of DL-homocysteine. The recoveries for L-AA in these juices were between 95 and 105%.

Crossed cerebellar diaschisis in herpes simplex encephalitis

Diaschisis is extremely rare in patients with viral encephalitis. We report the phenomenon of crossed cerebellar diaschisis (CCD) in a 73-year-old man with acute herpes simplex type-1 (HSV-1) encephalitis. The diagnosis of HSV-1 encephalitis was confirmed by detecting HSV-1 deoxyribonucleic acid in the cerebrospinal fluid (CSF). Magnetic resonance images (MRI) showed enhancing lesions at bilateral temporal lobes, insular cortices, and right frontoparietal lobes. Increase signal intensity on T2-weighted images was seen in the mesecephalon. Technetium-99m ethyl cysteinate dimer (99mTc-ECD) single photon emission computed tomography (SPECT) of the brain showed a large area of hypoperfusion in the right frontotemporoparietal lobes. The side-to-side cerebellar count revealed 19% reduction of the radioisotope tracer uptake in the left cerebellum. The phenomenon of CCD was proposed to be due to both anterograde disconnection of the corticopontocerebellar tracts and retrograde deafferentation of dentatothalamocortical projections.

Adjusting for drop-out in clinical trials with repeated measures: design and analysis issues

Recently, Wu and Follmann developed summary measures to adjust for informative drop-out in longitudinal studies where drop-out depends on the underlying true value of the response. In this paper we evaluate these procedures in the common situation where drop-out depends on the observed responses. We also discuss various design and analysis strategies which minimize the bias obtained with this type of drop-out. Of particular interest is the use of multiple measurements of the response at each visit to reduce bias. These strategies are evaluated with a simulation study. The results are highlighted with applications to both a hypertensive and a respiratory disease clinical trial, where multiple measurements of the primary response were made for all participants at each visit.