Cloves syndrome: a case report and perinatal diagnostic findings.

We report a neonate with prenatal ultrasound imaging features suggestive of CLOVES syndrome, confirmed postnatally by clinical and imaging findings of the constellation of truncal overgrowth, cutaneous capillary malformations, lymphatic and musculoskeletal anomalies. The clinical, radiological and histopathological findings noted in our patient help differentiate from other overgrowth syndromes such as Proteus syndrome. We report perinatal findings and add new clinical findings of this rare syndrome.

Partial trisomy 3p24.3 and partial monosomy 5p15.33: case report and a literature review.

We report on a preterm neonate with a deletion of the distal short arm of chromosome 5p15.33 and partial trisomy of the distal short arm of chromosome 3p24.3. The patient was the first-born monozygotic twin. There were no pertinent facial or physical features except a small lower lip hemangioma. The neonate presented with cardiac defects, which included a patent ductus arteriosus, an atrial septal defect and ventricular septal defects. After 94 days of age, however, the patient died from superior vena cava syndrome, recurrent chylothoraces and generalized anasarca. Array comparative genomic hybridization (aCGH) using a custom oligonucleotide microarray (Agilent 180,000 probe platform revealed a terminal duplication of 1,128 oligonucleotide probes from 3pter to 3p24.3, spanning approximately 20.4 megabases (Mb), and a terminal deletion of 271 oligonucleotide probes from 5pter to 5p15.33, spanning approximately 4.3 Mb. This is the first report of a patient with partial trisomy 3p24.3 and partial monosomy 5p15.33 without major dysmorphic features.

Spectrophotometric determination of tranexamic acid using vanillin.

A new spectrophotometric method has been examined for the determination of the tranexamic acid (TA) by derivatization with vanillin (VAN). The molar absorptivity of TA was calculated 25,160 L x mol(-1) x cm(-1) at lambdamax 354 nm and obeyed the Beer's law within 0.5-2.5 microg x mL(-1). The color reaction was highly stable and did not show any change in absorbance up to 24 h. The method was applied for the analysis of TA from capsules, injections and tooth pastes. The amounts of TA found in capsules, injections and tooth pastes of various pharmaceutical companies were observed with 249.0-250.9 mg/capsule, 249.3-250.7 mg/injection and 0.048%-0.049% in tooth pastes with relative standard deviation (RSD) 0.2%-5.0% (n = 3).

Counterfeiting attacks on oblivious block-wise independent invisible watermarking schemes.

In this paper, we describe a class of attacks on certain block-based oblivious watermarking schemes. We show that oblivious watermarking techniques that embed information into a host image in a block-wise independent fashion are vulnerable to a counterfeiting attack. Specifically, given a watermarked image, one can forge the watermark it contains into another image without knowing the secret key used for watermark insertion and in some cases even without explicitly knowing the watermark. We demonstrate successful implementations of this attack on a few watermarking techniques that have been proposed in the literature. We also describe a possible solution to this problem of block-wise independence that makes our attack computationally intractable.

Context-based lossless interband compression--extending CALIC.

This paper proposes an interband version of CALIC (context-based, adaptive, lossless image codec) which represents one of the best performing, practical and general purpose lossless image coding techniques known today. Interband coding techniques are needed for effective compression of multispectral images like color images and remotely sensed images. It is demonstrated that CALIC's techniques of context modeling of DPCM errors lend themselves easily to modeling of higher-order interband correlations that cannot be exploited by simple interband linear predictors alone. The proposed interband CALIC exploits both interband and intraband statistical redundancies, and obtains significant compression gains over its intrahand counterpart. On some types of multispectral images, interband CALIC can lead to a reduction in bit rate of more than 20% as compared to intraband CALIC. Interband CALIC only incurs a modest increase in computational cost as compared to intraband CALIC.

Scan predictive vector quantization of multispectral images.

Conventional vector quantization (VQ)-based techniques partition an image into nonoverlapping blocks that are then raster scanned and quantized. Image blocks that contain an edge result in high-frequency vectors. The coarse representation of such vectors leads to visually annoying degradations in the reconstructed image. The authors present a solution to the edge-degradation problem based on some earlier work on scan models. The approach reduces the number of vectors with abrupt intensity variations by using an appropriate scan to partition an image into vectors. They show how their techniques can be used to enhance the performance of VQ of multispectral data sets. Comparisons with standard techniques are presented and shown to give substantial improvements.

On ordering color maps for lossless predictive coding.

Linear predictive techniques perform poorly when used with color-mapped images where pixel values represent indices that point to color values in a look-up table. Reordering the color table, however, can lead to a lower entropy of prediction errors. In this paper, we investigate the problem of ordering the color table such that the absolute sum of prediction errors is minimized. The problem turns out to be intractable, even for the simple case of one-dimensional (1-D) prediction schemes. We give two heuristic solutions for the problem and use them for ordering the color table prior to encoding the image by lossless predictive techniques. We demonstrate that significant improvements in actual bit rates can be achieved over dictionary-based coding schemes that are commonly employed for color-mapped images.

A buyer-seller watermarking protocol.

Digital watermarks have previously been proposed for the purposes of copy protection and copy deterrence for multimedia content. In copy deterrence, a content owner (seller) inserts a unique watermark into a copy of the content before it is sold to a buyer. If the buyer sells unauthorized copies of the watermarked content, then these copies can be traced to the unlawful reseller (original buyer) using a watermark detection algorithm. One problem with such an approach is that the original buyer whose watermark has been found on unauthorized copies can claim that the unauthorized copy was created or caused (for example, by a security breach) by the original seller. In this paper, we propose an interactive buyer-seller protocol for invisible watermarking in which the seller does not get to know the exact watermarked copy that the buyer receives. Hence the seller cannot create copies of the original content containing the buyer's watermark. In cases where the seller finds an unauthorized copy, the seller can identify the buyer from a watermark in the unauthorized copy and furthermore the seller can prove this fact to a third party using a dispute resolution protocol. This prevents the buyer from claiming that an unauthorized copy may have originated from the seller.

Secret and public key image watermarking schemes for image authentication and ownership verification.

We describe a watermarking scheme for ownership verification and authentication. Depending on the desire of the user, the watermark can be either visible or invisible. The scheme can detect any modification made to the image and indicate the specific locations that have been modified. If the correct key is specified in the watermark extraction procedure, then an output image is returned showing a proper watermark, indicating the image is authentic and has not been changed since the insertion of the watermark. Any modification would be reflected in a corresponding error in the watermark. If the key is incorrect, or if the image was not watermarked, or if the watermarked image is cropped, the watermark extraction algorithm will return an image that resembles random noise. Since it requires a user key during both the insertion and the extraction procedures, it is not possible for an unauthorized user to insert a new watermark or alter the existing watermark so that the resulting image will pass the test. We present secret key and public key versions of the technique.

An analysis of some common scanning techniques for lossless image coding.

Though most image coding techniques use a raster scan to order pixels prior to coding, Hilbert and other scans have been proposed as having better performance due to their superior locality preserving properties. However, a general understanding of the merits of various scans has been lacking. This paper develops an approach for quantitatively analyzing the effect of pixel scan order for context-based, predictive lossless image compression and uses it to compare raster, Hilbert, random and hierarchical scans. Specifically, for a quantized-Gaussian image model and a given scan order, it shows how the encoding rate can be estimated from the frequencies with which various pixel configurations are available as previously scanned contexts, and from the corresponding conditional differential entropies. Formulas are derived for such context frequencies and entropies. Assuming an isotropic image model and contexts consisting of previously scanned adjacent pixels, it is found that the raster scan is better than the Hilbert scan which is often used in compression applications due to its locality preserving properties. The hierarchical scan is better still, though it is based on nonadjacent contexts. The random scan is the worst of the four considered. Extensions and implications of the results to lossy coding are also discussed.

Dual-lumen femoral vein catheterization as vascular access for hemodialysis--a prospective study.

Prospectively from January 1991 to January 1993, the efficacy and complications of 104 polyurethane, double-lumen femoral vein catheterizations (FVC) in 96 renal failure patients were studied. Ambulation was allowed in the hospital as well as at home while the catheter was in. There were 53 males and 43 females, with ages ranging from 13 to 87 (mean, 48.3 +/- 19.7) years. Forty-eight patients had chronic renal failure and 48 had acute renal failure. The catheters were used for 1 to 26 days (mean, 8 +/- 5 days). Fifty-two (50%) of the FVC were used for 2 weeks and 14 (13.5%) for 3 weeks or longer. The various complications encountered were infection (n=31), poor blood flow (n=8), displaced catheter (n=6), thrombosis of the catheter (n=4), hematoma (n=4), bleeding (n=3), exit site infection (n=3), ileofemoral vein thrombosis (n=2), and tear in the catheter wall (n=2). On removal, bacterial colonization was present in 34 out of 93 catheter tips (36.5%); Staphylococcus epidermidis (n=12) was the commonest organism grown. There was no significant difference of infection between diabetic and nondiabetic chronic renal failure patients. The duration of catheterization was found to have no relation with either thrombosis or infection. Femoral vein catheters can be used for hemodialysis for 2 to 3 weeks and ambulation during cannulation may be allowed.

Context-based lossless and near-lossless compression of EEG signals.

In this paper, we study compression techniques for electroencephalograph (EEG) signals. A variety of lossless compression techniques, including compress, gzip, bzip, shorten, and several predictive coding methods, are investigated and compared. The methods range from simple dictionary-based approaches to more sophisticated context modeling techniques. It is seen that compression ratios obtained by lossless compression are limited even with sophisticated context-based bias cancellation and activity-based conditional coding. Though lossy compression can yield significantly higher compression ratios while potentially preserving diagnostic accuracy, it is not usually employed due to legal concerns. Hence, we investigate a near-lossless compression technique that gives quantitative bounds on the errors introduced during compression. It is observed that such a technique gives significantly higher compression ratios (up to 3-bit/sample saving with less than 1% error). Compression results are reported for EEG's recorded under various clinical conditions.

Non-peritonitis complications of continuous ambulatory peritoneal dialysis in Saudi Arabia.

Although peritonitis is the major complication and leading cause of morbidity in patients undergoing continuous ambulatory peritoneal dialysis (CAPD), there are other complications of this long-term renal replacement therapy (RRT) modality. In order to evaluate the non-peritonitis complications, we retrospectively studied 60 new patients who were accepted in our CAPD program over a period of eight years from 1984 to 1993. Out of the 60 patients, 31 were females and 29 were males, with a mean age of 37.0 +/- 18 years. Tenckhoff's catheter was implanted by surgeons under direct vision in the operating theater through a midline incision. Nine of our patients had previous abdominal surgery and 11 females had pregnancies before CAPD, ranging from one to 10 with a mean of four. A total of 49 episodes of complications were observed, 32 early and 17 late. Early complications were defined if they occurred within three months from starting the procedure and late complications were defined as occurring after this period. There were 15 catheter blocks (25%), nine dialysate leaks (15%) and five hemoperitoneums (8.3%). Two serious and unusual complications were observed. In one of our patients, a mesenteric blood vessel injury occurred during catheter insertion, which necessitated massive blood transfusions and laparotomy. The other patient developed intestinal obstruction due to obstruction of intestinal loops around the catheter; this was corrected by removal of the catheter without the need for laparotomy. The late complications included six hernias, three hydroceles, three exit site infections, three tunnel infections and one case of loss of ultrafiltration.

Serum cystatin C as a marker of renal function in patients with acute renal failure.

Serum creatinine level is the traditionally used tool to detect changes in renal function. Serum cystatin C (CC) has been suggested to be an equally effective marker of renal function. We measured the serum levels of creatinine and CC in 73 patients with acute renal failure (ARF) and 300 age and sex matched healthy controls. The serum CC was measured by particle enhanced nephlometric immunoassay (PENIA). As expected, the serum creatinine and CC levels were significantly higher in ARF patients than the healthy controls and serum CC levels correlated significantly with serum creatinine (r = 0.47, p< 0.0001). This correlation further increased for multiple measurements, (r = 0.51, p< 0.0001. No gender difference was noted. Serum CC also correlated significantly with calculated GFR. Correlation of serum CC with serum creatinine and calculated GFR was much greater in patients with deteriorating renal function, compared to patients with improving renal function (p< 0.0001). Our study further suggests that the serum CC is a good marker of renal function in ARF patients, especially those with worsening renal function. Further larger studies are needed to evaluate its role in detecting early ARF and institute possible intervention.

The effect of contrast media of low osmolality on the peripheral arterial blood flow in the dog.

The intravascular contrast media in current use are solutions of salts of tri-iodinated substituted benzoic acids. Haemodynamic changes following injection of these contrast media are due mainly to their high osmolar concentration which is five to eight times physiological levels. In this study we compare the effect in dogs on femoral arterial flow following femoral arterial injection of three new low osmolality contrast media (Amipaque, Iopamidol and Hexabrix) compared to conventional contrast media (Coronary 280). Conventional salts such as Conray 280 cause a marked vasodilatation and increase in femoral blood flow to about twice pre-injection levels. The three new low osmolality contrast media cause much less vasodilation and increase in femoral blood flow (+32%). There was no significant difference between the effects of any of the three new media. The experiment suggests that any of three new low osmolality contrast media should be suitable for femoral arteriography as they cause much less vasodilatation (and therefore discomfort) than conventional contrast media. Our results do not indicate a preference for any of the three new contrast agents.

Effect of recombinant human erythropoietin on lymphocyte phenotyping and phagocyte activity in hemodialysis patients.

The effect of recombinant human erythropoietin (rHmEPO) on lymphocytic phenotyping as well as on the phagocyte activity of polymorphonuclear cells and monocytes was evaluated in 16 patients on maintenance hemodialysis. The mean age of the patients was 38.2 +/- 16.2 years. There were seven men and nine women. All patients were started on 50 U/kg of rHmEPO intravenously three times per week, and the dosage was increased gradually to achieve target haemoglobin of 12 g/dL. Predialysis blood samples were taken monthly for 3 months, and phagocyte respiratory burst as well as lymphocyte subsets were studied. Healthy blood donors were taken as controls. By 3 months of rHmEPO treatment, there was no significant increase in total T and B cells, but there was a significant increase in both CD4 (P < 0.001) and CD8 (P < 0.005): however, there was no significant change in the CD4/CD8 ratio. There was significant reduction in the natural killer cells (P < 0.005). The phagocyte activity studies showed a significant increase in the respiratory burst in whole blood (P < 0.001) and opsonized zymosan (P < 0.001) as well as improvement in the suppressed polymorphonuclear cell and monocyte activity by uremia. Phagocytosis studied by yeast uptake showed significant improvement from the pretreatment suppressed phagocytes to normal activity posttreatment. In conclusion, treatment with rHmEPO increases CD4 and CD8 cell counts without affecting the CD4/CD8 ratio, decreases the natural killer cells, and improves the impaired phagocyte activity in hemodialysis patients.

Long-term effect of intravenous calcitriol on the treatment of severe hyperparathyroidism, parathyroid gland mass and bone mineral density in haemodialysis patients.

We conducted this study on 15 chronic haemodialysis patients to evaluate the efficacy of i.v. calcitriol over a 1-year period in the treatment of severe secondary hyperparathyroidism (HPT), in particular its effect on bone mineral density (BMD) and parathyroid gland mass. Mean age was 39 +/- 11.9 (20-65) years and dialysis duration was 58 +/- 3 (19-130) months. i.v. calcitriol was given at a dose of 1 microg post-dialysis 3 times/week for 3 weeks; the dose was then adjusted to maintain the total serum calcium at less than 2.88 mmol/l. The maximum dose was 3 microg 3 times/week. Serum calcium (Ca) and phosphorus (P) were determined prior to treatment, then weekly for 6 weeks and every 2 weeks thereafter. Skeletal survey, dual photon densitometry and parathyroid ultrasound (US) were done prior to treatment and after 1 year. Bone biopsy was done in 10 patients at the beginning of treatment. There was a significant reduction (p < 0.01) in pre-treatment mid-region serum parathyroid hormone (PTH) from 1,476 +/- 895 to 489 +/- 485 P mol/l, as well as alkaline phosphatase (p < 0.04) from 236.5 +/- 221 to 116.3 +/- 49 U/l. This was without a significant increase in serum Ca (2.15 +/- 0.25 to 2.44 +/- 0.26 mmol/l, p = 0.08). Three patients had recurrent hypercalcaemia which responded to reduction of Ca in dialysate. There was a significant increase in BMD over the spine from 1.071 +/- 0.25 to 1.159 +/- 0.22 g/cm2 (p < 0.003) with a percent increase of 9.3 +/- 8.9% as well as over the femoral neck from 0.834 +/- 0.002 to 0.89 +/- 0.09 g/cm2 (p < 0.001) with a percent increase of 7.45 +/- 6.81%. Five patients had enlarged parathyroid glands by US and in 3 of these, there was a significant reduction to normal with treatment. Bone biopsy was done in 10 patients. Six patients had predominant hyperparathyroid bone disease and 4 had mixed uraemic osteodystrophy. In conclusion, long-term i.v. treatment with calcitriol is effective in the treatment of severe secondary HPT. PTH decreased without a significant increase in serum Ca. BMD also increases during this therapy.

One-year experience of very low doses of subcutaneous erythropoietin in continuous ambulatory peritoneal dialysis and its effect on haemostasis.

Recombinant human erythropoietin (rHuEpo) is now well established in the management of the anaemia associated with chronic renal failure. The aim of this study was to assess the efficacy and safety of low doses of subcutaneous (s.c.) erythropoietin in continuous ambulatory peritoneal dialysis (CAPD) patients and particularly its effects on haemostasis. Seven CAPD patients were given s.c. erythropoietin for more than 1 year. Their mean age was 36.2 +/- 9.2 years and their mean pretreatment haemoglobin (Hb) was 7.05 +/- 0.53 g/dl. All patients were started on 20 U/kg, 3 times/week, to be doubled every 4 weeks if no response was obtained. Five patients had a good response and attained the target Hb of 10-12 g/dl and were maintained on low doses of rHuEpo (20 U/kg s.c., twice a week). A marked improvement in haemostatic function was noted when comparing the pre- with the post-treatment measurements. There was a significant reduction in the bleeding time, significant increases in fibrinogen and factor VIII clotting activity but not in von Willebrand factor antigen or ristocetin cofactor. There was also simultaneous enhancement of the platelet aggregation responses to adrenalin, collagen, arachidonic acid and ADP. In conclusion, long-term treatment with small doses of s.c. rHuEpo is safe, convenient and effective in correcting anaemia in patients on CAPD, rHuEpo caused significant improvement of bleeding time which can be explained partly through the correction of anaemia and in part by the improvement in haemostatic function.

Peritonitis in Patients on CAPD at King Khalid University Hospital: Less Infection-rate with More Center-experience.

Continuous ambulatory peritoneal dialysis (CAPD) was started at the King Khalid University Hospital in 1986. Peritonitis remains the most significant complication of the procedure. Earlier rates of peritonitis were high, but after gaining sufficient experience, the rates are declining. To evaluate the change in peritonitis trend, 55 new patients who were recruited to our CAPD program between the periods October 1993-October 1996 were analyzed for the development of peritonitis on annual basis. There were 37 (67%) males and 18 (33%) females with a mean age of 43.3 years (range 12-72 years). A total of 34 episodes of peritonitis were recorded with a rate of 1.5 episode/patients year in 1993, 0.5 episode/patient year in 1994 and 0.8 in 1995. only 40% of episodes showed positive cultures whereas 60% remained culture-negative despite use of recommended modified culture techniques. Organisms causing peritonitis included staphylococcus eipdermides (6.7%), E. coli (3.3%), Streptococcus fecalis (3.3%) and pseudomonas (6.7%). Out of 34 episodes of peritonitis, 29 (85.3%) showed response to treatment and five episodes could only be treated after removal of catheter. Of the 29 episodes that responded to treatment, three relapsed and one had recurrent infection . However, all were successfully treated though one responded only after removal of catheter. Thus, a total of six catheters (20%) necessitated removal and replacement. In spite of high diabetic patients population in our series (27.2%) only one died of peritonitis related sepsis and another died of myocardial infarction after clearing the infection. Thus mortality remains low in spite of potential risk. Although we still use straight system CAPD rather than Y system peritonitis rates have declined considerable and we hope that the procedure will gain more acceptability amongst patients with ESRD in Saudi Arabia.