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Biomedical subjects

N Singh

Publications and source records attributed to N Singh.

At least 289 records · Page 16Linked to original sources
PubMed1997

Human herpesvirus-6 infection in liver transplant recipients: documentation of pathogenicity.

BACKGROUND: The new herpesvirus, human herpesvirus-6 (HHV-6), is able to cause clinical illness after transplantation; however, the pathogenic potential and the clinical features of HHV-6 have not been defined in liver transplant recipients. METHODS: We report the first cases of invasive and symptomatic infection due to HHV-6 in liver transplant recipients. RESULTS: HHV-6 infection occurred in four liver transplant recipients at a median of 50 days after transplant (range 17-90 days). Severe cytopenia was observed in all patients; leukopenia (with median leukocyte count of 1400/mm3) was the most commonly effected bone marrow lineage. One of the four patients had interstitial pneumonitis due to HHV-6. No other virus (e.g., cytomegalovirus) or another pathogen was detected in the lungs, blood, or bone marrow in any of the above patients. CONCLUSIONS: Our data suggest that HHV-6 can be a pathogen in liver transplant recipients; idiopathic bone marrow suppression is its predominant clinical sequelae. Recognition of HHV-6 infection is clinically pertinent because HHV-6 is potentially treatable with the currently available antiviral agents.

Adult↗
PubMed1997

Invasive aspergillosis in liver transplant recipients in the 1990s.

Invasive aspergillosis occurred in 26 liver transplant recipients since 1990 at five liver transplant centers. The median time to onset was 17 days after transplantation. Twenty-seven percent of the patients had undergone retransplantation. Invasive aspergillosis occurred significantly earlier after transplantation in smokers than in nonsmokers (P=0.017). Patients with late-onset aspergillosis (occurring after posttransplant day 90) were more likely to have had prior cytomegalovirus infection than those with early-onset aspergillosis (occurring within 90 days of transplantation) (67% vs. 10%, respectively, P=0.013). Only 8% of the patients had received additional corticosteroids or OKT3, which suggests that augmented immunosuppression may not be a relevant risk factor for invasive aspergillosis in the 1990s due to less frequent use of these agents. The median serum bilirubin level of the patients was 21.8 mg/dl, 85% of the patients had renal insufficiency, and 54% were on dialysis before the onset of invasive aspergillosis, which suggest that overall severity of illness, including poorly functioning hepatic allograft and renal failure may be the major determinants of disease occurrence. Overall mortality was 92% (24/26). No difference in mortality could be shown for the patients who received amphotericin B versus liposomal amphotericin B preparations (100% vs. 89%); however, the mean time to death after the initiation of therapy was 20 days in patients who received amphotericin B and 43 days in those who received liposomal amphotericin B preparations.

Adolescent↗
PubMed1997

Hepatitis G virus coinfection in hepatitis C virus-infected liver transplant recipients.

BACKGROUND: In this study, we determined the prevalence of hepatitis G virus (HGV) infection in end-stage hepatitis C virus (HCV)-related liver disease and examined the influence of HGV coinfection on the outcome of liver transplantation. METHODS: HGV was detected by reverse transcriptase-polymerase chain reaction and Southern blotting in sera drawn from 159 patients who were known to be HCV infected before transplantation. Patients were followed up for a mean of 28.4 months after transplantation. RESULTS: Forty-one (25.3%) patients were HGV positive and the prevalence of HGV infection was similar for different HCV genotypes. Both HGV-positive and -negative groups had similar survival, recurrence rates, inflammatory activity scores, and degree of fibrosis at the time of recurrence. CONCLUSION: Infection with HGV is common in end-stage HCV-infected patients presenting for liver transplantation. It influences neither the outcome of liver transplantation nor the recurrence of hepatitis in the graft.

Adult↗
PubMed1997

Hepatitis C virus genotypes in liver transplant recipients: impact on posttransplant recurrence, infections, response to interferon-alpha therapy and outcome.

BACKGROUND: End-stage liver disease due to hepatitis C virus (HCV) is the most common indication for liver transplantation in U.S. veterans. We investigated the influence of HCV genotypes on the incidence and timing of recurrent HCV hepatitis, survival, infectious morbidity, and response to interferon-alpha therapy in this unique patient population. METHODS: HCV genotype was determined by direct sequencing of the NS5 region of HCV with type-specific primers. RESULTS: Genotype 1a (66%, 32/47) was the predominant genotype. Type 1b was found in 25% (12/47) of patients and type 2b was found in 9% (4/47). Histopathologically recurrent HCV hepatitis developed in 53% (25/47) of the patients after transplantation. This group included 45% (14/31) of the patients with type 1a, 67% (8/12) of the patients with type 1b, and 25% (1/4) of the patients with type 2b (P>0.5). The time to recurrence and the severity of HCV recurrence as defined by aminotransferase levels or Knodell scores were not different among the three genotypes. There was a trend toward a higher incidence of major infections in patients with type 1b (75%) versus type 1a (48%) and type 2b (50%) (P=0.11). The response to interferon-a therapy did not differ significantly among the genotypes. Mortality at 5 years was 16% (5/31) in patients with genotype 1a, 42% (5/12) in patients with genotype 1b, and 50% (2/4) in patients with genotype 2b (P=0.06). CONCLUSIONS: The incidence, time to recurrence, and response to interferon-alpha therapy did not differ between the various genotypes in our liver transplant recipients. However, there was a trend toward higher infectious morbidity and overall mortality in patients with genotype 1b after transplantation.

Adult↗
PubMed1997

Pretransplant famciclovir as prophylaxis for hepatitis B virus recurrence after liver transplantation.

Liver transplantation in patients with detectable hepatitis B virus (HBV) DNA is associated with a high rate of HBV recurrence and detectable HBV DNA is often considered a contraindication for liver transplantation. Famciclovir, an oral form of the purine nucleoside penciclovir, has been shown to inhibit HBV replication. This pilot study was conducted to determine whether a 6-month course of famciclovir, administered before transplantation, was effective in inhibiting HBV replication in patients with end-stage liver disease caused by HBV and detectable HBV DNA and to assess the posttransplant clinical and virologic outcome of patients becoming HBV DNA negative with famciclovir prior to transplantation. All eight patients enrolled were hepatitis B surface antigen (HBsAg) positive; their HBV DNA levels at baseline ranged from 4.3 to 25,321 pg/ml (mean 3,661 pg/ml). Six of the eight patients were also seropositive for HBeAg. An initial decline in HBV DNA titers occurred in all patients; however, only 25% (two of eight) of the patients became HBV DNA negative before transplantation and underwent liver transplantation. Seroconversion to hepatitis B surface antibody (HBsAb) (and HBeAb in HBeAg-positive patient) was demonstrated at the conclusion of famciclovir in the transplanted patients. Both patients remain HBV DNA negative at nearly 2 years of follow-up after transplantation. HBV DNA remained detectable in 63% (five of eight) of the patients. The mean HBV DNA level for patients who became HBV DNA negative was 5.1 pg/ml versus 424 pg/ml in nonresponders. Adverse effects attributable to famciclovir were not observed in any of the patients. Future studies should assess the predictors of response to famciclovir so that patients likely to achieve good virologic outcome can be targeted for such a therapy.

2-Aminopurine↗
PubMed1997

Adriamycin induces apoptosis in rat thymocytes.

Apoptosis is a controlled form of cell death accompanied by distinct morphological and biochemical changes. In this study the nature of cytotoxicity induced by adriamycin (ADM) in rat thymocytes was evaluated. Morphological and biochemical changes characteristic of apoptosis were found to precede adriamycin-induced cell death. Our findings demonstrate the involvement of c-Myc, c-Jun, antioxidant enzymes CuZn superoxide dismutase and catalase, and perhaps poly ADP ribosylation in ADM-induced cell death.

Animals↗
PubMed1997

Predictors and outcome of early- versus late-onset major bacterial infections in liver transplant recipients receiving tacrolimus (FK506) as primary immunosuppression.

Major bacterial infections and the predictors of early (within 100 days of transplantation) versus late onset (after 100 days post-transplant) bacterial infections were prospectively assessed in 130 consecutive liver transplant recipients receiving tacrolimus (FK506) as primary immunosuppression. The median follow-up period was 38 months. Overall, 35% (45/130) of the patients developed 67 episodes of major bacterial infections (0.52 episodes/patient). Sixty-three percent of the major bacterial infections occurred early, and 37% occurred in the late post-transplant period. Eighty-four percent of the abdominal infections occurred early, whereas 38% of the cases of pneumonia, 60% of the cases of primary bacteremia, and 50% of the biliary infections occurred late. By logistic regression analysis, portal vein thrombosis was the most significant independent risk factor for early-onset major bacterial infection (odds ratio 4.1; 95% CI 1.4-12.2), and recurrent hepatitis C was the most significant independent predictor of late-onset major bacterial infections (odds ratio 6.21; 95% CI 1.9-20.2). Thus, sources and risk factors differ for early versus late-onset bacterial infections after liver transplantation. Knowledge of the differences in the potential sources, the pathogens, and the predictors of early versus late-onset bacterial infections can be valuable in the evaluation and empiric treatment of liver transplant recipients with bacterial infections.

Adult↗
PubMed1997

Functional suitability of commercially milled rice bran in India for use in different food products.

The effect of blending of commercially available full fat and defatted rice brans in India from modern multistage rice mills with parboiling/stabilizing facilities in different food products in comparison to those obtained from laboratory milling of rice is reported. Bread volume and cookie spread decreased but muffin volume increased with the addition of different types of bran to wheat flour, however, the cookie spread factor was not affected by addition of full fat rice bran. The yields of the extrudate were increased by the blending of full fat rice bran but were decreased by the addition of defatted rice bran. Rice brans could be added to different food products to the extent of 5-10%. However, the full fat rice bran could not be used for production of extruded snack food.

Bread↗
PubMed1997

Patient selection criteria for lung volume reduction surgery.

OBJECTIVE: Our intent was to refine the patient selection criteria for lung volume reduction surgery because various centers have different criteria and not all patients benefit from the procedure. METHODS: Patient information, x-ray results, arterial blood gases, and plethysmographic pulmonary function tests in 154 consecutive patients who underwent bilateral thoracoscopic staple lung volume reduction surgery were compared with clinical outcome (change in forced expiratory volume in 1 second and dyspnea scale) with t tests and analysis of variance. RESULTS: Three hundred thirty-three of 487 (69%) patients evaluated for lung volume reduction surgery were rejected for lack of heterogeneous emphysema (n = 212), medical contraindications (n = 88), hypercapnia (n = 20), uncontrolled anxiety or depression (n = 10), or pulmonary hypertension (n = 1). Two patients died during the evaluation process. When tested by analysis of variance, there was no difference in clinical outcome associated with preoperative forced expiratory volume in 1 second, residual volume, total lung capacity, single-breath diffusing, and arterial oxygen or carbon dioxide tension. All patients selected for the operation had a heterogeneous pattern of emphysema. The upper lobe heterogeneous pattern of emphysema on chest computed tomography and lung perfusion scan was strongly associated with improved outcome with a mean (95% confidence interval) improvement in forced expiratory volume in 1 second of 73.2% (63.3 to 83.1) for the upper lobe compared with a mean (95% confidence interval) improvement of 37.9% (22.9 to 53.0) for the lower lobe or diffuse pattern of emphysema. CONCLUSION: The most important selection criteria for lung volume reduction surgery is the presence of a bilateral upper lobe heterogeneous pattern of emphysema on chest computed tomography and lung perfusion scan. After patients have been selected on the basis of a heterogeneous pattern of emphysema, clinical factors and physiology are not associated with clinical outcome well enough to further refine patient selection criteria. These results do not support the arbitrary patient selection criteria for lung volume reduction surgery reported in the literature.

Age Factors↗
PubMed1997

Antitumor activity studies of newly synthesized N-salicyloyl-N'-(p-hydroxybenzthioyl)hydrazine and its copper(II) complex both in vivo and in vitro.

A new ligand N-salicyloyl-N'-(p-hydroxybenzthioyl) hydrazine (H2STPH) and its Cu(II) complex [Cu(SPTH)] were prepared and characterized by analytical and physicochemical studies. In vivo antitumor activity of [Cu(STPH)] has been tested against breast tumor in C3H/J strain mice and in vitro on P-815 (murine mastocytoma) and K-562 (human erythroleukemia) cells. LD50 values were estimated at a dose level of 100 mg/kg body weight and a light microscopic study also carried out.

Animals↗
PubMed1997

Depression in patients with cirrhosis. Impact on outcome.

The impact of depression (assessed by the Beck Depression Inventory) on quality of life and outcome was prospectively assessed in adult patients with cirrhosis. Patients with depression had significantly poorer perceived quality of life (P = 0.006), poorer adaptive coping (P = 0.001), and lower functional status, i.e., Karnofsky performance score (P = 0.06), as compared to the nondepressed patients. Survival after transplantation was not different between depressed and nondepressed patients. However, the patients with depression were significantly more likely to die while awaiting transplantation than the nondepressed patients (P = 0.02). The difference in mortality between the depressed and the nondepressed patients with end-stage liver disease could not be explained by the severity of illness variables; Child-Pugh score, complications of liver disease, renal function, serum albumin, prothrombin time, frequency and duration of hospitalizations were not significantly different for depressed and nondepressed patients. Symptoms of depression should be sought in patients with cirrhosis since depression is a modifiable illness that is amenable to treatment.

Depression↗
PubMed1997

A photoreceptor cell-specific ATP-binding transporter gene (ABCR) is mutated in recessive Stargardt macular dystrophy.

Stargardt disease (STGD, also known as fundus flavimaculatus; FFM) is an autosomal recessive retinal disorder characterized by a juvenile-onset macular dystrophy, alterations of the peripheral retina, and subretinal deposition of lipofuscin-like material. A gene encoding an ATP-binding cassette (ABC) transporter was mapped to the 2-cM (centiMorgan) interval at 1p13-p21 previously shown by linkage analysis to harbour the STGD gene. This gene, ABCR, is expressed exclusively and at high levels in the retina, in rod but not cone photoreceptors, as detected by in situ hybridization. Mutational analysis of ABCR in STGD families revealed a total of 19 different mutations including homozygous mutations in two families with consanguineous parentage. These data indicate that ABCR is the causal gene of STGD/FFM.

ATP-Binding Cassette Transporters↗
PubMed1997

Transthoracic fine needle aspiration cytology of lung for suspected malignancy: an audit of cytological findings with histopathological correlation.

Transthoracic fine needle aspiration cytology (TFNAC) is an invasive procedure and should therefore be subject to regular review. We report an audit of TFNAC from 146 patients. One hundred and thirty-six samples (93%) were adequate and 86 were malignant, 16 suspicious and 34 contained no malignant cells. TFNAC was the sole means of diagnosis of malignancy in 55 patients. However, further pathological data were available in 58 of the adequate samples; TFNAC was malignant in 31, suspicious in eight and contained no malignant cells in 19. All malignant TFNAC were confirmed (absolute sensitivity = 85%; positive predictive value = 100%); as were five of eight with suspicious cytology. Of 19 patients with negative TFNAC, nine were subsequently found to have a malignancy (specificity = 68%).

Adult↗