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Biomedical subjects

W K Lo

Publications and source records attributed to W K Lo.

At least 73 records · Page 4Linked to original sources
PubMed1994

Changes in the peritoneal equilibration test in selected chronic peritoneal dialysis patients.

Fifty-five patients on chronic peritoneal dialysis with two or more peritoneal equilibration tests (PET) performed between 1983 and 1992 with a mean interval of 21.9 +/- 22.7 months were studied retrospectively. Repeated PET were performed when transport changes were suspected rather than routinely. According to the initial PET, there were 16 high (HI), 17 high-average (HA), 15 low-average (LA), and 7 low (LO) transporters. There was a significant decrease in the mean creatinine dialysate to plasma ratio (D/P creatinine) in the HI transporters and an increase in the LA and LO transporters. The mean dialysate to instilled glucose ratio (D/Do) significantly increased in the HI transporters. The change in both the D/P creatinine and the D/Do of an individual strongly and inversely correlated to their respective initial values. The change in D/P creatinine and D/Do were significantly and inversely correlated to each other, indicating an actual transport change. No correlation was found between the change in transport with peritonitis episodes or frequencies. The centripetal [corrected] change of transport toward average described here may explain why low clearances or low ultrafiltration rates due to rapid transport are infrequent causes of peritoneal dialysis technique failure, and why patients who have been dialyzed for a long period are usually HA transporters.

Biological Transport, Active↗
PubMed1994

A randomized prospective study of the cost-effectiveness of the conventional spike, O-set, and UVXD techniques in continuous ambulatory peritoneal dialysis.

OBJECTIVE: To compare the clinical outcome and cost-effectiveness of three techniques for continuous ambulatory peritoneal dialysis (CAPD): the conventional spike technique (C), the O-set (O), and UVXD (U, ultraviolet irradiation connection box). DESIGN: A randomized and prospective comparison of three CAPD techniques. SETTING: A tertiary referral and a satellite dialysis center. PATIENTS: One hundred patients with end-stage renal failure between 10 and 70 years of age, with good hand-eye coordination and not anticipated to receive a living related transplant within 6 months. INTERVENTIONS: Patients were randomized by referral to a table of random numbers to perform one of the three CAPD techniques. MAIN OUTCOME MEASURES: Training time, details of peritonitis and exit-site infection (ESI) including the costs of antibiotic treatment, outpatient visits, hospital stays, technique, and patient survival were analyzed after a minimum follow-up period of one year. RESULTS: There were 38, 31, and 31 patients in groups C, O, and U, respectively, and the total observation periods were 838, 802, and 745 patient-months, respectively. The peritonitis rates for C, O, and U were 21.5, 30.8, and 29.8 patient-months/episode, respectively. The corresponding ESI rates were 16.4, 14.9, and 24 patient-months/episode, respectively. When the time from the commencement of CAPD to the first infection was expressed using the Kaplan-Meier life table analysis, 39.5%, 67.7%, and 61.3% of patients in Groups C, O, and U were free from peritonitis at one year (p = 0.088). The corresponding figures for ESI were 52.6%, 48.4%, and 61.3% (p = 0.35). There was no significant difference in technique survival in the three treatment groups. An analysis of the costs related to the use of antibiotics, outpatient visits, and hospital stays necessary for the treatment of peritonitis and ESI and those related to training time, additional equipment, and consumables required for the three CAPD techniques showed that, overall, the cost in O was the lowest, followed by U and C (U.S. $158, $170, and $179 per patient-month, respectively). CONCLUSION: It was concluded that the O-set is a more cost-effective CAPD technique than UVXD, while both are more cost-effective than the conventional spike technique.

Adolescent↗
PubMed1993

Ciprofloxacin-induced nephrotoxicity in patients with cancer.

Nephrotoxicity associated with ciprofloxacin is uncommon. Five patients with cancer who developed acute renal failure that followed treatment with ciprofloxacin are described and an additional 15 cases reported in the literature are reviewed. Other than elevation of serum creatinine levels, characteristic clinical manifestations and abnormal laboratory findings are not frequently present. Allergic interstitial nephritis is believed to be the underlying pathological-process. Definitive diagnosis requires performance of renal biopsy, although this is not always feasible. An improvement in renal function that followed the discontinuation of the offending antibiotic supports the presumptive diagnosis of ciprofloxacin-induced acute renal failure.

Acute Kidney Injury↗
PubMed1993

The altricial pigeon is born blind with a transient glycogen cataract.

The lens nucleus of altricial birds contains a large amount of glycogen. It is not known why glycogen in such concentration does not cause a trace of lens opalescence. Here we report that the altricial pigeon is born with a dense nuclear opacity; this opacity has practically disappeared by 4 weeks of age. Thin-section electron microscopy revealed that the opacity was specifically associated with an enormous number of large glycogen aggregates in nuclear fiber cells. These aggregates of various sizes (up to approximately 5 microns) were composed of smaller individual 35-nm beta glycogen particles. In contrast, glycogen aggregates were not seen in nuclear fiber cells of all transparent older lenses. The glycogen aggregates have gradually dissociated into a homogeneous distribution of individual beta particles in the entire cytoplasm of nuclear fibers which accompanies the development of lens transparency. This study suggests that an extensive accumulation of glycogen aggregates in the lens nucleus is the cause of light scattering and opacification. The transparency of the altricial pigeon lens during normal development is therefore regulated by two different forms of glycogen. Precocial birds such as chick have no lens glycogen, therefore never develop a glycogen cataract and have excellent visual acuity upon hatching.

Agglutination↗
PubMed1993

Characterization of murine Caraparu Bunyavirus liver infection and immunomodulator-mediated antiviral protection.

A rapid, peripheral disease model utilizing the Bunyavirus, Caraparu, was established in mice for the evaluation of antiviral therapy with immunomodulators. 4-6-week-old B6C3F1 female mice, inoculated intraperitoneally with virus, developed coagulative liver necrosis and died between 4-6 days after infection. This Caraparu disease model was relatively resistant to treatment with immunomodulators, such as ABMP, Ampligen, alpha-interferon (IFN-alpha) or beta-interferon (IFN-beta). However, a significant increase in median survival time (MST) was consistently observed upon treatment with gamma-interferon (IFN-gamma). The nucleoside analog--ribavirin--was highly effective against Caraparu virus in repeated treatment schedules begun on either day -1, day 0, or day +1 of infection. Ribavirin gave little protection when initiation of treatment was delayed until day +2. However, combined treatment with IFN-gamma, starting on day 0 and ribavirin starting on day +2, significantly reduced mortality.

Adjuvants, Immunologic↗
PubMed1993

Isoniazid induced encephalopathy in dialysis patients.

Three dialysis patients with extrapulmonary tuberculosis developed confusion 4-14 days after commencement of treatment with anti-tuberculosis drugs, despite the use of prophylactic pyridoxine. Full recovery of conscious state resulted within 1 week in all patients after stopping isoniazid. In 2 patients confusion recurred on rechallenge of the drug. The risk factors of isoniazid induced encephalopathy and the dosage of isoniazid in uraemic patients were discussed.

Adult↗
PubMed1993

Leptomeningeal toxoplasmosis after allogeneic marrow transplantation. Case report and review of the literature.

A 37-year-old woman with chronic myelogenous leukemia underwent allogeneic bone marrow transplantation with CD8-depleted marrow from an HLA-identical sister. On day 43 post-transplant, the patient developed a headache and became lethargic and tremulous. Magnetic resonance imaging (MRI) of the brain showed abnormal meningeal and superficial parenchymal enhancement anteriorly. The spinal fluid had an elevated protein level with normal glucose and a neutrophilic pleocytosis. At autopsy, Toxoplasma meningoencephalitis was seen. On review of the literature, headache and confusion at 1-2 months post-transplant are common presenting signs of central nervous system toxoplasmosis. The predominance of neutrophils in the spinal fluid in this patient probably reflects the meningeal component of the infection and is an unusual finding. The presentation of toxoplasmosis in marrow transplant recipients is quite pleomorphic, and a definite diagnosis is difficult to obtain antemortem. Empiric therapy with pyrimethamine and sulfadiazine should be considered for marrow transplant recipients with neurologic deficits for which there is no other apparent etiology.

Adult↗
PubMed1993

Multiple structural types of gap junctions in mouse lens.

Gap junctions in the epithelium and superficial fiber cells from young mice were examined in lenses prepared by rapid-freezing, and processed for freeze-substitution and freeze-fracture electron microscopy. There appeared to be three structural types of gap junction: one type between epithelial cells and two types between fiber cells. Epithelial gap junctions seen by freeze-substitution were approximately 20 nm thick and consistently associated with layers of dense material lying along both cytoplasmic surfaces. Fiber gap junctions, in contrast, were 15-16 nm (type 1) or 17-18 nm thick (type 2), and had little associated cytoplasmic material. Type 1 fiber gap junctions were extensive in flat expanses of cell membrane and had a thin, discontinuous central lamina, whereas type 2 fiber gap junctions were associated with the ball-and-socket domains and exhibited a dense, continuous central lamina. Both types of fiber gap junction had a diffuse arrangement of junctional intramembrane particles, whereas particles and pits of epithelial gap junctions were in a tight, hexagonal configuration. The type 2 fiber gap junctions, however, had a larger particle size (approximately 9 nm) than the type 1 (approximately 7.5 nm). In addition, a large number of junctional particles typified the E-faces of both fiber types but not the epithelial type of gap junction. Gap junctions between fiber and epithelial cells had structural features of type 1 fiber gap junctions.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Primary sternal osteomyelitis presenting as a pleural-based mass.

Osteomyelitis in uncommon locations can present unusual diagnostic difficulties. A patient with primary sternal osteomyelitis who presented with pain over the right supraclavicular area and a radiologic picture of a pleural-based right upper lung mass is discussed. A triple-phase bone scan was consistent with the diagnosis, and a needle aspiration of the mass revealed a staphylococcal abscess. Percutaneous drainage of the contiguous abscess and a prolonged course of antibiotic therapy cured the infection.

Abscess↗
PubMed1993

The requirement of low calcium dialysate in patients on continuous ambulatory peritoneal dialysis receiving calcium carbonate as a phosphate binder.

In the present study we investigated the requirement of low calcium dialysate in 35 patients on continuous ambulatory peritoneal dialysis (CAPD) receiving calcium carbonate as the sole phosphate binder over a 12-month period. Patients with corrected serum calcium > or = 2.85 mmol/L after switching to oral calcium carbonate were given 1 to 3 2-litre exchanges of 2.5 mEq/L calcium dialysate. Serum phosphate level dropped from the pretreatment value of 2.95 +/- 0.62 to a level of between 1.70 +/- 0.41 to 2.03 +/- 0.44 mmol/L 2 weeks after therapy. Corrected serum calcium level increased significantly from 2 weeks onwards. Serum alkaline phosphatase rose initially at 2 and 6 weeks and decreased from 3 months onwards. Serum parathyroid hormone level dropped significantly from a mean pretreatment level of 569 to 320 pg/ml after 12 months (p < 0.001). Serum aluminum decreased significantly from a mean of 1.04 to 0.65 umol/L (p < 0.01). Daily calcium carbonate requirement fluctuated but tended to increase till 8 months and plateaued and ranged from 2.61 +/- 0.57 to 3.98 +/- 2.11 gm. The daily requirement of low calcium dialysate followed a similar trend with approximately three-quarters of patients ultimately requiring at least 1 bag of low calcium dialysate. Eight patients did not require low calcium dialysate. Patients who required low calcium dialysate were significantly older, had a significantly lower pretreatment serum parathyroid hormone and higher serum aluminum levels than those who did not.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

A randomized prospective comparison of oral versus intraperitoneal ciprofloxacin as the primary treatment of peritonitis complicating continuous ambulatory peritoneal dialysis.

The present study compared oral versus intraperitoneal (ip) ciprofloxacin (ciproxin) as primary treatment of bacterial peritonitis in patients receiving continuous ambulatory peritoneal dialysis (CAPD) in a randomized, prospective trial. A total of 54 episodes in 46 patients were recruited for study. After excluding nonbacterial episodes and those not treated according to protocol, 48 episodes evenly divided between the two treatment arms were eligible for analysis. The primary cure rate was 41.7% and 66.7%, respectively, in the oral and ip treatment group. Half of those who failed or relapsed were due to infection with resistant, mostly gram-positive bacteria, which accounted for 79% of culture-positive episodes. Of the gram-positive isolates 42.3% were either resistant or intermediately susceptible to ciproxin compared to 16.7% of gram-negative isolates. The high level of bacterial resistance to ciproxin and treatment failure rate were related to the previous exposure to fluoroquinolones. Inadequate trough peritoneal drug levels also accounted for the failures in the ip but not the oral treatment group. We conclude that oral ciproxin is ineffective as a primary treatment of CAPD peritonitis in patients previously exposed to fluoroquinolones and that when administered ip, a dose of 50 mg/L instead of 25 mg/L of ciproxin should be used as maintenance in order to achieve adequate trough peritoneal drug levels.

Administration, Oral↗
PubMed1992

Nature and localization of avian lens glycogen by electron microscopy and Raman spectroscopy.

Electron microscopy confirms the presence of a high concentration of glycogen particles in the lens nuclear region of birds of flying habit such as the ring-neck dove and pigeon. This observation is consistent with Raman spectroscopy. The glycogen particles in the dove lens, which are approximately 35 nm in diameter, are classified as beta type particles. Although this type has been previously characterized by high rates of glycogen turnover in other tissues, its localization in the lens nucleus indicates that it may serve a structural function rather than as a storage depot of carbohydrate in the lens. In a comparative electron microscopy study, glycogen particles were not observed in the chicken lens.

Animals↗
PubMed1991

Polarized distribution of coated pits and coated vesicles in the rat lens: an electron microscopy and WGA-HRP tracer study.

The presence and distribution of coated pits (CPs) and coated vesicles (CVs) in the rat lens were studied by thin-section electron microscopy (TEM) and wheat germ agglutinin-horseradish peroxidase (WGA-HRP) as a tracer. TEM revealed that CPs and CVs were approximately 150 nm in diameter, of which the characteristic clathrin coat was approximately 20 nm thick. CPs and CVs were found in both epithelium and superficial fiber cells of the entire lens, and were distributed preferentially along the basal membrane facing the lens capsule. It was estimated that more than 80% of CPs and CVs in the entire epithelium were seen along the basal membrane. The number of CPs and CVs along the basal membrane in the equatorial epithelium (4.4 per 10 microns membrane) was similar to that at the central zone (3.8 per 10 microns membrane), but there was a significant increase along the apical and lateral surfaces of the equatorial epithelium compared to that of the central epithelium, although the overall number was considerably smaller. In the lens fibers, CPs and CVs were usually found within 2-3 superficial layers of fiber cells. The number of CPs and CVs along the basal membrane of young fibers at the post-equatorial region (3.1 per 10 microns membrane) was 3-fold greater than that of the mature fibers at the posterior polar area (1 per 10 microns membrane). Thus, CPs and CVs along the entire basal membrane showed a gradual decrease in number from the anterior (and equatorial) regions to the posterior polar surface of the lens. WGA-HRP experiments showed that approximately 80% of tracer-carrying pits and vesicles were also found along the basal surface of the equatorial epithelium. This study suggests that a polarized distribution of CPs and CVs along the basal surface of epithelium and superficial fiber cells may facilitate receptor-mediated endocytosis of important macromolecules directly from the aqueous humor and vitreous body into metabolically active lens cells.

Animals↗
PubMed1991

Sclerosing peritonitis complicating prolonged use of chlorhexidine in alcohol in the connection procedure for continuous ambulatory peritoneal dialysis.

Sclerosing peritonitis (SP) is an uncommon but serious complication of CAPD with various suggested etiologies. We have documented 14 cases of SP in 18 patients who had used chlorhexidine in alcohol (ChA) in the connection procedure for CAPD. Thirteen died. Nine of the 14 patients had been transferred to hemodialysis or renal transplantation, yet all still developed symptoms of SP within a few months after transfer - even the 5 who were originally asymptomatic. The main symptoms of SP were peritoneal ultrafiltration failure, exudative bloody ascites and intestinal obstruction. They presented at around 5 years (30-80 months) after commencement of CAPD. Most deaths were related to intestinal obstruction. Four other patients with a comparable duration of ChA exposure were continued on CAPD with the Travenol Spike System (TSS), without further exposure to ChA. They were all asymptomatic of SP after 9-12 months. Comparing the 2 groups of asymptomatic patients, those transferred to TSS had a much better outcome after 9 months than those transferred to HD or renal transplantation (P = 0.0476). We suggest that ChA is the main cause of SP in our patients and that continuing CAPD without further exposure to ChA is a better alternative than stopping CAPD to prevent the progression of SP.

Adult↗
PubMed1990

Alterations of urea-insoluble membrane fraction, MP26, of Emory mouse lenses in aging and cataractogenesis.

Purified lens fiber membrane fractions from Emory mouse lenses and cataract-resistant control lenses were compared by SDS-PAGE. The differences in polypeptide patterns were determined for three ages. There was a striking alteration in MP24/MP26 ratio during aging and cataractogenesis which appears to be due to a normal age-dependent conversion of MP26 to MP24, and which is accelerated during cataractogenesis.

Aging↗