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Biomedical subjects

H P Tan

Publications and source records attributed to H P Tan.

18 recordsLinked to original sources
PubMed2006

Living donor renal transplantation using alemtuzumab induction and tacrolimus monotherapy.

Alemtuzumab was used as an induction agent in 205 renal transplant recipients undergoing 207 living donor renal transplants. All donor kidneys were recovered laparoscopically. Postoperatively, patients were treated with tacrolimus monotherapy, and immunosuppression was weaned when possible. Forty-seven recipients of living donor renal transplants prior to the induction era who received conventional triple drug immunosuppression without antibody induction served as historic controls. The mean follow-up was 493 days in the alemtuzumab group and 2101 days in the historic control group. Actuarial 1-year patient and graft survival were 98.6% and 98.1% in the alemtuzumab group, compared to 93.6% and 91.5% in the control group, respectively. The incidence of acute cellular rejection (ACR) at 1 year was 6.8% in the alemtuzumab group and 17.0% (p < 0.05) in the historic control group. Most (81.3%) episodes of ACR in the alemtuzumab group were Banff 1 (a or b) and were sensitive to steroid pulses for the treatment of rejection. There was no cytomegalovirus disease or infection. The incidence of delayed graft function was 0%, and the incidence of posttransplant insulin-dependent diabetes mellitus was 0.5%. This study represents the largest series to date of live donor renal transplant recipients undergoing alemtuzumab induction, and confirms the short-term safety and efficacy of this approach.

Adult↗
PubMed2006

ART and conventional root restorations in elders after 12 months.

Successful use of atraumatic restorative treatment (ART) in children has been reported, but little information is available regarding its use in older adults. The hypothesis of this study was that survival rates of root restorations placed by both ART and the conventional technique were similar. Root-surface caries lesions in 103 institutionalized elders in Hong Kong were treated randomly by either: (1) the conventional approach-caries removed by dental burs, and the cavity filled with light-cured resin-modified glass ionomer; or (2) the ART approach-caries removed by hand instruments, and the cavity filled with chemically cured high-strength glass ionomer. In total, 84 conventional and 78 ART restorations were placed. After 12 months, 63 conventional and 59 ART restorations were reviewed, and the respective 12-month survival rates were 91.7% and 87.0% (p > 0.05). It is concluded that the survival rates of both types of root restorations were high and similar.

Age Factors↗
PubMed2005

Reversal of acute cellular rejection after renal transplantation with Campath-1H.

Between September 2002 and February 2004, 40 kidney transplant (27 from deceased and 13 from living donors) recipients (25 male and 15 female, aged 50.3 +/- 15.1 years) were treated with Campath 1H (C 1H; 30 mg/dose IV) for biopsy-proven steroid-resistant rejection (SRR) or rejections equal to or worse than Banff 1B. All transplantations occurred between August 2001 and May 2003. All patients had received antibody preconditioning (RATG 5 mg/kg, n = 34; C 1H 60 mg, n = 4; C 1H 30 mg, n = 2) preoperatively and were treated with Tacrolimus monotherapy (target level 10 ng/ml) postoperatively and subsequent spaced weaning. Elevated creatinine levels at follow-up were evaluated by renal transplant biopsy. Rejection was treated with steroids, reversal of weaning, addition of sirolimus, and/or antibody treatment, depending on grade of rejection. The mean duration of follow-up was 453 +/- 163 days after C 1H administration. Twenty-nine patients received C 1H for SRR and 11 patients for Banff 1B or worse rejections; 26 patients received more than 1 dose of C 1H. Graft survival was 62.5% (25 patients); 6 of the 15 allografts (40%) that failed had presented with rejections because of noncompliance. Graft survival in compliant patients with SRR or rejections equal to or worse than Banff 1B was 73.5% (25 of 34). Fourteen patients (35%) had infectious complications, of whom 2 patients (5%) died. C 1H is an effective agent for SRR and Banff 1B or worse rejections, with 95% patient survival and 73.5% graft survival (in compliant patients). The number of doses of 30 mg C 1H should be restricted to two, as there is a high incidence of potentially fatal infectious complications.

Acute Disease↗
PubMed2005

Steroid-free tacrolimus monotherapy after pretransplantation thymoglobulin or Campath and laparoscopy in living donor renal transplantation.

Living donor renal transplantation was performed under a regimen of recipient pretreatment and low-dose postoperative immunosuppression with subsequent weaning. From October 9, 2002, to December 31, 2004, 196 consecutive, unselected laparoscopic live donor nephrectomies resulting in 196 living donor renal transplantations were performed. Recipients were pretreated with rabbit antithymocyte globulin (thymoglobulin; 24 patients or [12%]) or Campath 1H (alemtuzumab; 166 patients [85%]), or were not in protocol (6 patients [3%]), and were given postoperative steroid-free low-dose tacrolimus immunosuppressive monotherapy with subsequent weaning. There was no donor mortality. Major and minor donor morbidities were 2.6% and 4.2%, respectively. Laparoscopic live donor nephrectomy recipient outcomes with a mean follow-up of 401 days included (1) recipient and graft survival of 99.0% and 97.4%, respectively; (2) no ureteral stenosis; (3) 0.5% delayed graft function, from recurrent focal segmental glomerulosclinosis; and (4) no vascular thrombosis. The incidence of acute rejection at 30, 90, and 401 days was 1.5%, 3.8%, and 11.2% (all 196 recipients), 0%, 25%, and 29.2% (thymoglobulin recipients), and 1.8%, 3.9%, and 8.4% (Campath 1H recipients), respectively. Sixty-six patients (33.7%) are receiving spaced-dose immunosuppressive monotherapy. The mean creatinine concentration in all recipients was 1.5 +/- 1.1 mg/dL. There were no instances of cytomegalovirus tissue invasive disease or posttransplantation lymphoproliferative disease. The incidence of new-onset posttransplantation insulin-dependent diabetes was 0.5%. At current follow-up, the use of Campath 1H rather than thymoglobulin for pretreatment seems to have significantly improved the efficacy of our regimen.

Adult↗
PubMed2005

Prevalence of dengue fever and dengue hemorrhagic fever in Hospital Tengku Ampuan Rahimah, Klang, Selangor, Malaysia.

Dengue fever and dengue hemorrhagic fever have been known to be endemic and reportable diseases in Malaysia since 1971. Major outbreaks occurred in 1973, 1982 and in 1998. For the past few decades until now. many studies have been performed to investigate the importance of these two diseases in Malaysia. A retrospective study was carried out in Hospital Tengku Ampuan Rahimah Klang to find the prevalence of these diseases. The data was collected from the record department of this hospital starting from the year 1999 until 2003 (5 years). A total of 6,577 cases of dengue fever and 857 cases of dengue hemorrhagic fever were reported. From the year 2000 onwards, cases of dengue fever had increased tremendously. However for the year 2001, there was a slight decrease in the reported cases. Most cases occurred in 2003, increasing from 674 in 1999 to 2,813 in 2003. Highest incidence was seen in Malay males more than 12 years of age. However, the cases of dengue hemorrhagic fever declined tremendously throughout the years. Most cases occurred in 1999 with 674 cases, then declining to only one in the year 2001 before it increased to 60 and 72 in the years 2002 and 2003, respectively. Most cases occurred in patients above 12 years old, the majority of which were Malay males.

Adolescent↗
PubMed2004

Cytomegalovirus prophylaxis using oral ganciclovir or valganciclovir in kidney and pancreas-kidney transplantation under antibody preconditioning.

We investigated retrospectively the risk factors for cytomegalovirus (CMV) infection under ganciclovir or valganciclovir prophylaxis (oral ganciclovir 1 g tid, valganciclovir 450 mg/d) in our kidney and simultaneous pancreas-kidney (SPK) transplant patients undergoing transplantation between July 1, 2001 and February 28, 2003. Two hundred eleven patients receiving prophylactic oral ganciclovir or valganciclovir were included in the study. All patients were given antibody preconditioning (thymoglobulin 178, alemtuzumab 33). Duration of prophylactic treatment was between 3 and 8 months. Fifteen (7.1%) patients developed a positive CMV antigenemia in the first 6 months after transplantation, and 18 of 176 (10.2%) patients developed a positive CMV antigenemia during the first year. No patient developed tissue invasive CMV disease. At 6 months after transplantation, valganciclovir was slightly more effective than ganciclovir prophylaxis (P=.052). Positive donor CMV serology significantly increased the risk of CMV infection compared to CMV-negative donors (P=.014 and P=.003 at 6 and 12 months, respectively). Duration of CMV prophylaxis for more than 3 months decreased the risk of CMV infection (P=.04 and P=.009 at 6 and 12 months, respectively). Either valganciclovir prophylaxis (450 mg/d) or high-dose oral ganciclovir (1 g tid) is effective in preventing tissue-invasive CMV disease, and results in a low incidence of CMV antigenemia in patients undergoing kidney and SPK transplantation.

Antiviral Agents↗
PubMed2001

Donor horseshoe kidneys for transplantation.

BACKGROUND: Experience with donor horseshoe kidneys for transplantation is very limited. Currently, horseshoe kidneys may be underutilized for transplantation because of the greater incidence of vascular anomalies, associated renal anomalies, and predisposition to renal disease. METHODS: In this report, we review five transplantations using horseshoe kidneys: the largest reported institutional experience. In addition, a review of all published cases in the English literature is performed. RESULTS: All five patients underwent successful renal transplantations with a median follow-up of 35 months. One patient lost his kidney from recurrent disease soon after transplantation. CONCLUSION: With appropriate reconstruction of the vessels, careful division of the isthmus, and avoidance of ureteral obstruction, long-term data revealed good graft survival of donor horseshoe kidneys in renal transplantation.

Adult↗
PubMed2001

Successful renal transplantation after endovascular bifurcated stent graft repair of an abdominal aortic aneurysm.

Renal transplantation after repair of aortoiliac aneurysms with traditional prosthetic vascular grafts has been shown to be effective. Vascular surgery continues to rapidly evolve, most notably with the advancement of endovascular repair of abdominal aortic aneurysms. Controlled trials continue to support the trend toward the use of endovascular bifurcated aortic stent grafts. For this we describe the first renal transplant in a patient with an endovascular bifurcated aortoiliac stent graft. No intraoperative difficulties were encountered. At 1-year follow-up, the transplanted kidney is functioning well with a normal serum creatinine level of 1.3 mg/dl, and the patient has no worsening of peripheral vascular disease. We recommend that the presence of an endovascular aortic graft not be a contraindication to renal transplantation.

Aged↗
PubMed2001

Human monocytic ehrlichiosis: an emerging pathogen in transplantation.

BACKGROUND: The spectrum of disease caused by Ehrlichia spp. ranges from asymptomatic to fatal. Awareness and early diagnosis of the infection is paramount because appropriate therapy leads to rapid defervescence and cure. If left untreated, particularly in immunosuppressed patients, ehrlichioses may result in multi-system organ failure and death. METHODS: We report the second case of human monocytic ehrlichiosis (HME) in a liver transplant recipient, and review the literature. RESULTS: The patient presented with fever and headache, had negative cultures, and despite broad-spectrum antimicrobial coverage appeared progressively septic. After eliciting a history of tick exposure we treated the patient empirically with doxycycline. The diagnosis of HME was confirmed by 1) polymerase chain reaction (PCR) for Ehrlichia chaffeensis, 2) acute and convalescent serum titers, and 3) in vitro cultivation of E chaffeensis from peripheral blood. CONCLUSION: Although human ehrlichioses are relatively uncommon, they are emerging as clinically significant arthropod-borne infections. Although epidemiological exposure is responsible for infection, immunosuppression makes patients more likely to succumb to disease. A high index of suspicion and early treatment results in a favorable outcome.

Animals↗
PubMed2001

Liver transplantation in patients with severe portopulmonary hypertension treated with preoperative chronic intravenous epoprostenol.

Portopulmonary hypertension (PPHTN) is no longer an absolute contraindication to orthotopic liver transplantation (OLT). The pre-OLT management of patients with PPHTN requires early diagnosis and chronic therapy with intravenous epoprostenol to decrease pulmonary vascular resistance (PVR). Close follow-up is necessary to reassess pulmonary artery pressures (PAPs) and evaluate right ventricular (RV) function. This assists in the optimal timing of OLT. Successful management also necessitates reassessment of pulmonary artery hemodynamics just before OLT, with clearly defined parameters used to determine whether to proceed. Even with the intraoperative and postoperative availability of potent pulmonary vasodilators, clinical management may be suboptimal in reducing PAP. Adequate reduction in PVR and improvement in RV function in response to chronic epoprostenol therapy may facilitate successful OLT. We present a case report and review the limited experience with this treatment.

Adult↗
PubMed2000

Successful liver transplantation in a patient with Budd-Chiari syndrome caused by homozygous factor V Leiden.

Budd-Chiari syndrome (BCS) is a rare form of portal hypertension characterized by hepatic venous outflow obstruction. Although hematologic disorders are the most common cause of this syndrome, to date, 30% of the cases have been classified as idiopathic. Resistance to activated protein C caused by factor V Leiden is the most common cause of thrombophilia; its role in the pathogenesis of BCS is now becoming apparent. We report successful liver transplantation in a patient with BCS caused by homozygous factor V Leiden. The patient was administered standard heparin anticoagulation until activated protein C resistance was normalized by the liver allograft. Liver transplantation corrected the thrombophilic state. The patient has excellent graft function, is not on anticoagulation therapy, and has had no recurrent venous thrombosis at 5 months posttransplantation. Activated protein C resistance caused by the factor V Leiden mutation may be responsible for idiopathic cases of BCS. To avoid unnecessary long-term anticoagulation after liver transplantation, factor V Leiden should be considered as a pathogenic factor in BCS. In addition, because of the high prevalence of factor V Leiden in the world population, cadaveric organ donors with a history of venous thrombosis should be screened for activated protein C resistance lest thrombophilia be transmitted to the recipient.

Adult↗
PubMed1999

Pulmonary Rhizopus rhizopodiformis cavitary abscess in a cardiac allograft recipient.

Pulmonary mucormycosis is rare in solid organ transplant recipients. Only one case has been reported previously in a cardiac allograft recipient. However, the Rhizopus species in that study was not identified. We report a case of successful surgical treatment of pulmonary cavitary mucormycosis due to Rhizopus rhizopodiformis in a cardiac allograft transplant recipient. A review of the literature on pulmonary mucormycosis occurring in solid organ transplant recipients is also presented.

Amphotericin B↗
PubMed1992

Regulatory role of cytokines in IgE-mediated allergy.

The discovery of immunoglobulin E (IgE) is considered the most important contribution, to date, in the field of clinical allergy. Studies in rodents and humans have suggested that IgE production could be regulated by antigen-specific helper and suppressor T cells and by isotype-specific factors having affinity for IgE. In recent years, the synthesis of IgE has been shown to be regulated, in part, by a cytokine network. This review summarizes the cytokines that up-regulate (interleukins-4, 5, and 6) and down-regulate (interferon-gamma and interleukin-2) the production of IgE. Emphasis is placed on IL-4 and IFN-gamma, two lymphokines known to play a major, but reciprocal, role in IgE synthesis. Increased insight into the various mechanisms of IgE control by cytokines and their receptors will eventually lead to improved treatment strategies in the clinical management of IgE-mediated allergy.

Cytokines↗
PubMed1991

Recombinant interleukin-4 enhances the chemiluminescent oxidative burst of murine peritoneal macrophages.

We evaluated the effects of murine recombinant interleukin-4 (rIL-4) on murine peritoneal macrophages. We showed a marked, dose-dependent stimulation of respiratory oxidative burst by IL-4 in peptone-elicited murine peritoneal macrophages. This effect was abolished by a neutralizing monoclonal antibody (mAb) to rIL-4 confirming that the enhanced chemiluminescence was due to IL-4. In contrast, rIL-4 depressed the respiratory oxidative burst of a transformed murine macrophage cell line, J774, in a dose-dependent mAb-reversible manner.

Animals↗
PubMedDate not supplied

Aureobasidium pneumonia in a post liver transplant recipient: a case report.

This is the first report of Aureobasidium (A.) pullulans as an opportunistic pulmonary infection in a liver transplant recipient. A 46-year-old caucasian man had an orthotopic liver transplant in 1988. His liver disease was primary sclerosing cholangitis. He required 2 subsequent liver re-transplants for primary graft non-function and acute rejection. The patient had been living in the California desert for two months prior to admission and presented with ventilator-dependent acute respiratory failure and hemodialysis-dependent acute renal failure. Imaging studies revealed severe bilateral infiltrates. His initial bronchoalveolar lavage (BAL) and brushings grew A. pullulans. Pancultures, including sputum and throat cultures, were negative for bacterial or other fungal organisms. The patient responded to pulmonary support and aggressive systemic antifungal agents while being maintained on cyclosporine and prednisone for immunosuppression. He was discharged to a skilled nursing facility 37 days after hospitalisation. Delay in discharge was primarily due to severe malnutrition and renal impairment. Opportunistic fungal infections continue to be a major problem in immunosuppressed patients including liver transplant recipients. Here we report a pulmonary infection with Coccidioides (C.) immitis and superinfection with A. pullulans. Opportunistic infections such as A. pullulans can be treated successfully with systemic fluconazole when amphotericin B is not well tolerated.

Antifungal Agents↗