Biomedical subjects

P Ho

Publications and source records attributed to P Ho.

At least 19 recordsLinked to original sources

PubMed2004

Different presentation of hepatitis B-related hepatocellular carcinoma in a cohort of 1863 young and old patients - implications for screening.

AIM: To compare the clinico-pathological features of hepatitis B virus-related hepatocellular carcinoma in young and old patients. METHODS: The clinico-pathological characteristics of hepatitis B virus-related hepatocellular carcinoma were compared in 1863 consecutive patients (121 patients, </=40 years; 1742 patients, > 40 years) seen at a single institution over the last 13 years. RESULTS: Young patients presented more often with pain (P < 0.0001), hepatomegaly (P = 0.01) and ruptured hepatocellular carcinoma (P = 0.02), whereas old patients presented with ankle oedema (P = 0.001), ascites (P = 0.002) and by routine screening (P = 0.035). Liver function, Child-Pugh grading and indocyanine green test were better preserved in young patients. They also had a higher alpha-foetoprotein concentration (P = 0.001), larger tumour size (P = 0.001) and more frequent metastasis (P = 0.008), but a similar surgical resection rate (33.6% vs. 28%), to old patients. There was no difference between the two groups in the overall post-resection survival rate, but there was a shorter survival in young patients with unresectable disease (3.6 months vs. 4.6 months, P = 0.004). Young patients with hepatocellular carcinoma often show a later presentation, but a higher resectability rate and similar survival rates, than old patients. The screening programme should include young hepatitis B virus carriers, even in the absence of cirrhosis.

Adolescent↗

PubMed2004

Laparoscopic transperitoneal clipping of the inferior mesenteric artery for the management of type II endoleak after endovascular repair of an aneurysm.

We report the case of a high risk patient with an abdominal infrarenal aortic aneurysm (AAA) who was treated by endovascular technique and the subsequent management of a type II endoleak by the laparoscopic approach. In this case, a 74-year-old woman with a 6-cm infrarenal AAA underwent endovascular repair using a bifurcated stent-graft device. Surveillance CT scan showed a persistent type II endoleak at 1 week and 3 months after the operation. Angiography confirmed retrograde flow from the inferior mesenteric artery (IMA). Attempted transarterial embolization of the IMA via the superior mesenteric artery was not successful. Laparoscopic transperitoneal IMA clipping was performed. Subsequent aortic duplex scan and CT scan confirmed complete elimination of the type II endoleak. We conclude that a combination of endovascular and laparoscopic procedures can be used to manage AAA successfully.

Aged↗

PubMed2004

An analysis of an open access general practitioner bone densitometry service.

General practitioners (GPs) are increasingly involved in the selective opportunistic case finding of osteoporosis and treatment of this condition. An open access bone densitometry service has existed for GPs in the Cardiff area since 1993. The purpose of this study was to assess the effectiveness of this service, particularly with respect to the appropriateness of bone densitometry requests and the impact of the service on hospital outpatient referrals. Over a period of 12 months, 560 patients were referred to the open access service by 154 GPs. A total of 229 (41%) patients were given a clinical diagnosis of osteoporosis. Four hundred and seventy-three (84%) referrals followed the clinical referral criteria. In 85% of cases, GPs claimed that they would have referred patients to the hospital outpatient department, if there were no open access bone densitometry service. The majority of the referrals were appropriate, and the service appears to have reduced GP referrals to the specialist clinic.

Absorptiometry, Photon↗

PubMed2004

The incidence of deep vein thrombosis in elderly Chinese suffering hip fracture is low without prophylaxis: a prospective study using serial duplex ultrasound.

PURPOSE: To investigate the incidence of deep vein thrombosis (DVT) among elderly Hong Kong Chinese patients suffering from acute hip fracture and to analyse the risk factors associated with DVT. METHODS: A total of 100 consecutive Chinese hip fracture patients with a mean age of 80 years were investigated serially using duplex ultrasound scans preoperatively and at 1 week, 3 to 6 weeks, and 3 months postoperatively. No chemoprophylaxis or prophylaxis against DVT was given. RESULTS: 95 patients completed 3 duplex scans during hospitalisation; 5 (5.3%) of them were found to have developed DVT over the ilio-femoral venous segment. Of the 90 patients who had no DVT, 73 were reassessed 3 months after operation; one of them was found to have developed calf DVT. Older patients, chairbound or dependent patients, and patients living in institutions carried a higher risk of developing DVT. CONCLUSION: This prospective study shows that the incidence of DVT developing after acute hip fracture in Chinese geriatric patients was low. We therefore do not recommend routine chemoprophylaxis for elderly patients with hip fracture.

Aged↗

PubMed2003

Clinical outcomes and changes in venous hemodynamics after subfascial endoscopic perforating vein surgery.

BACKGROUND: We evaluated the clinical results of subfascial endoscopic perforating vein surgery (SEPS) in patients with severe chronic venous insufficiency (CVI) (clinical class 4-6) and assessed the hemodynamic changes associated with SEPS using air plethysmography (APG). METHODS: Forty-five patients with severe CVI who had undergone SEPS were evaluated. Clinical score and venous hemodynamics, as measured by APG before operation and at 1 month and 1 year after operation, were compared using the Wilcoxon signed rank test. Patient satisfaction (on a visual analogue scale of 0 to 100%) was also assessed. RESULTS: There were 29 men and 16 women; their mean age was 60 years (range, 37-83). Thirty-five patients (78%) had active venous ulcers; the ulcers' mean size was 7.8 +/- 11.9 cm2 and the mean duration of ulceration was 9 +/- 10 months. There were no hospital deaths. Postoperative complications were uncommon (one groin wound infection and one case of thrombophlebitis). At a mean follow-up of 15 +/- 9 months, 34 ulcers (97%) had healed. The cumulative ulcer healing was 82% at 3 months. There were five recurrent ulcers (15%). Significant improvement was seen in the clinical scores (10 +/- 3 before operation, 6 +/- 4 at 1 month, and 4 +/- 3 at 1 year after operation). The venous filling index was also significantly improved after operation; this improvement was maintained at 1-year follow-up (7.36 +/- 6.23 ml/sec before operation, 3.63 +/- 3.90 ml/sec at 1 month, and 3.14 +/- 2.06 ml/sec at 1 year). The degree of patient satisfaction was also remarkable, with 74 +/- 17% and 90 +/- 12% satisfaction at 1-month and 1-year follow-up, respectively. CONCLUSIONS: SEPS is a safe and effective treatment for patients with severe CVI. It leads to hemodynamic improvement, with rapid ulcer healing, and it is associated with a high degree of patient satisfaction.

Adult↗

PubMed2003

O(2) affinity of cross-linked hemoglobins modifies O(2) metabolism in proximal tubules.

Previous experiments using cross-linked tetrameric hemoglobins (XLHb) to perfuse isolated rat kidneys showed that high-O2-affinity XLHb improved proximal tubule function more effectively than low-O2-affinity XLHb. To determine how function was improved, proximal tubule fragments were incubated with albumin, Hb34 [half-saturation point (P50) 34 Torr], or Hb13 (P50 13 Torr) with Po2 values ranging from 22 to 147 Torr. ATP content reflected O2 delivery to mitochondria. Both XLHb increased ATP, Hb34 with Po2 >or= 47 Torr and Hb13 with Po2 <or= 47 Torr. XLHb increased Na-K-ATPase activity (86Rb uptake) in similar Po2-dependent patterns. O2 consumption (Qo2) was measured in a closed, well-stirred chamber. Ouabain- and oligomycin-inhibited Qo2, reflecting Na-K-ATPase activity and oxidative phosphorylation, respectively, mirrored the Po2-dependent patterns of ATP and 86Rb uptake. As Po2 fell below the midpoint of XLHb desaturation, Qo2, uncoupled from oxidative phosphorylation, transiently increased. The increase was most pronounced with Hb34. Nitro-l-arginine methyl ester had no effect on Qo2. Inhibitors of NAD(P)H oxidases and diamine oxidase partially prevented the Qo2 surge with Hb34. In conclusion, facilitated diffusion accounts for Po2-dependent XLHb effects on ATP content and Na-K-ATPase and for Hb13's effectiveness in hypoxic perfused kidneys. NO scavenging was not a factor. O2-binding characteristics influence XLHb effects on mitochondria and O2-sensitive enzymes such as oxidases.

Adenosine Triphosphate↗

PubMed2003

Effect of various growth media upon survival during storage of freeze-dried Enterococcus faecalis and Enterococcus durans.

AIMS: The effects of three different growth media (MRS, M17 and Lee's) on survival during freeze-drying and subsequent storage of six strains of Enterococcus faecalis and two strains of E. durans were investigated. METHODS AND RESULTS: Distinct Enterococcus spp. strains were grown on M17, MRS and Lee's broth, freeze-dried and stored at 20 degrees C in air under darkness. At regular intervals throughout storage, freeze-dried samples were rehydrated and then plated on M17 agar. CONCLUSIONS: A higher survival rate during storage of dried E. durans was obtained when growth occurred in MRS. The same effect was not observed, however, for the majority of E. faecalis strains, which clearly survived better in the dried state when this organism had been grown in M17 or Lee's medium. SIGNIFICANCE AND IMPACT OF STUDY: The survival of the dried Enterococcus spp. tested during storage was shown to be strain-specific and dependent on the growth medium.

Culture Media↗

PubMed2001

Direct determination of particle-particle interactions in a 2D plasma dust crystal.

Particle interactions were directly determined from the lateral compression of two-dimensional plasma dust crystals confined in a parabolic potential well. Measured particle separations combined with an equation of state for the crystal were used to derive values for the particle screening length and the charge on the particles. The shape of the parabolic potential well was confirmed by observing trajectories of single particles falling within the well. No evidence of a lateral particle-particle binding was observed.

Journal Article↗

PubMed2001

Diagnosis of primary HIV-1 infection. Los Angeles County Primary HIV Infection Recruitment Network.

BACKGROUND: The optimal approach for diagnosing primary HIV-1 infection has not been defined. OBJECTIVE: To determine the usefulness of symptoms and virologic tests for diagnosing primary HIV-1 infection. DESIGN: Prospective cohort study. SETTING: A teaching hospital in Los Angeles and a university research center in San Diego, California. PATIENTS: 436 patients who had symptoms consistent with primary HIV infection. MEASUREMENTS: Clinical information and levels of HIV antibody, HIV RNA, and p24 antigen. RESULTS: Primary infection was diagnosed in 54 patients (12.4%). The sensitivity and specificity of the p24 antigen assay were 88.7% (95% CI, 77.0% to 95.7%) and 100% (CI, 99.3% to 100%), respectively. For the HIV RNA assay, sensitivity was 100% and specificity was 97.4% (CI, 94.9% to 98.9%). Fever, myalgia, rash, night sweats, and arthralgia occurred more frequently in patients with primary infection (P < 0.05). CONCLUSIONS: No sign or symptom allows targeted screening for primary infection. Although assays for HIV RNA are more sensitive than those for p24 antigen in diagnosing primary infection, they are more expensive and are more likely to yield false-positive results.

Antibodies, Viral↗

PubMed2001

The incidence of cytoplasmic fragmentation in mouse embryos in vitro is not affected by inhibition of caspase activity.

OBJECTIVE: To investigate the relationship between cytoplasmic fragmentation and caspase activity in the mouse embryo. DESIGN: Experimental laboratory study. SETTING: University gynacology unit. ANIMAL(S): One-cell zygote of mouse (MF1 x BALB/c). INTERVENTION(S): Mouse embryos were treated with caspase inhibitors: benzyloxycarbonyl-Val-Ala-Asp fluoromethylketone (z-VAD-fmk) and benzyloxycarbonyl-Asp-glu-Val-Asp-fluoromethyl ketone (Z-DEVD-fmk). MAIN OUTCOME MEASURE(S): Morphological development of the embryo, proportion of fragmented embryos, caspase-3-like activity, DNA breakage, and phosphatidylserine exposure in blastomeres. RESULT(S): The proportion of embryo reaching two-cell, three- to four-cell, and morula stage at 48, 72, and 96 hours after hCG administration, respectively, were comparable between the control embryos and those treated with either z-VAD-fmk or z-DEVD-fmk, at three concentrations (10 microM, 50 microM, and 200 microM). Although the inhibitors suppressed the caspase-3-like activity in the embryo fragment before compaction and decreased DNA breakages, there was no statistically significant difference in the percentage of fragmented embryo between the control and those treated with caspase inhibitors. The inhibitors did not affect the incidence of phosphatidylserine exposure in the blastomere of the treated embryos. CONCLUSION(S): Cytoplasmic fragmentation in precompaction mouse embryos is not a consequence of caspase-related apoptosis.

Amino Acid Chloromethyl Ketones↗

PubMed2001

A case of disseminated Mycobacterium marinum infection following systemic steroid therapy.

We describe the dissemination of Mycobacterium marinum infection from the right middle finger to the whole extremity and two legs, with the involvement of tendons and joints, in a patient who was treated with a steroid when Mycobacterium marinum infection was not suspected. The patient was successfully treated with a combined surgical and medical approach.

Aged↗

PubMed2001

Evaluation of current methods for detection of staphylococci with reduced susceptibility to glycopeptides.

The sensitivity and specificity of seven methods (agar dilution, broth microdilution, Etest at 0.5 and 2.0 McFarland (McF) inocula, two agar screening methods, and population studies [PS]) were evaluated in a double-blind study involving 284 methicillin-resistant Staphylococcus aureus (MRSA) strains and 45 Staphylococcus strains with reduced susceptibilities to vancomycin (SRSV). The results were compared to the population analysis profile-area under the curve ratio method (PAP-AUC ratio compared to that of Mu3) as described by Wootton et al. The agar screening method using brain heart infusion agar (6 microg of vancomycin per ml) gave a sensitivity of 22% and a specificity of 97%. A similar method using Mueller-Hinton agar (5 microg of vancomycin per ml) gave a sensitivity of 20% and a specificity of 99%. The PS method detected 34 false positives (12%) and gave a sensitivity of 71% and a specificity of 88%. Etest using 0.5 and 2.0 McF inocula gave sensitivities and specificities of 82 and 93% and of 96 and 97%, respectively. The best Etest interpretative criteria for the 2.0 McF inoculum was > or =8 mg of vancomycin per liter and > or =8 microg teicoplanin per ml or > or =12 microg of teicoplanin per ml. The direct colony suspension inoculum for this method was found to be equally accurate in detecting (hetero-)glycopeptide-intermediate S. aureus compared to the overnight broth inoculum preparation method. Agar dilution and broth microdilution using the NCCLS breakpoint criteria for vancomycin gave sensitivities and specificities of 20 and 100% and of 11 and 100%, respectively. Using the Etest with a 2.0 McF inoculum, six different media were assessed against a selection of SRSV (n = 48) and MRSA (n = 12). Brain heart infusion agar yielded the highest sensitivity and specificity values: 88 and 88%, respectively.

Anti-Bacterial Agents↗

PubMed2000

Hormonal receptor determination of 1,052 Chinese breast cancers.

BACKGROUND AND OBJECTIVES: Hormonal receptors are important prognostic factors for breast cancer. The reported figures in the literature are mostly on Caucasians. This study analyzes the receptor profile of 1,052 Chinese patients. METHODS: The age of the patients ranged from 20-93 years; 48% were premenopausal and 52% postmenopausal. Estrogen receptor (ER) and progesterone receptor (PgR) were measured quantitatively by enzyme immunoassay (EIA) using the rat monoclonal antibody (ABBOTT ER-EIA). Specimens with values >15 fmol/mg were considered positive according to manufacturer's recommendation. RESULTS: ER was positive in 53% and 61.6% of the pre- and postmenopausal women respectively (P < 0.0075); PgR was positive in 51.5% and 46.2% respectively (P > 0.05). The mean values of ER were higher for postmenopausal women (P < 0.0001) but the values for PgR were similar between the two groups (P > 0.05). When the values were analyzed with respect to age, there was an increasing trend for ER. No such trend was noted for PgR. Subgroup analysis showed that there were more ER+PgR+ tumors among postmenopausal than among premenopausal women. Tumors with dubious receptor status (ER+PgR- or ER-PgR+) were more prevalent at perimenopausal age. CONCLUSIONS: Chinese patients have lower receptor values and positivity rates than those reported for Caucasians. Receptor-positive tumors tend to occur in postmenopausal women.

Adult↗

PubMed2000

Effects of human follicular fluid on the capacitation and motility of human spermatozoa.

OBJECTIVE: To investigate the capacitation and motility kinetics of spermatozoa treated with human follicular fluid (FF). DESIGN: Controlled, experimental laboratory study. SETTING: University-based gynecology unit. PATIENT(S): Human FF was collected from women undergoing assisted reproductive treatment. Semen samples were obtained from men visiting subfertility clinics. INTERVENTION(S): Spermatozoa were incubated with human FF under various experimental conditions. Spermatozoa incubated with Earle's balanced salt solution were used as the control. MAIN OUTCOME MEASURE(S): Chlortetracycline staining patterns and sperm motility parameters. RESULT(S): The rate of capacitation in the human FF-treated spermatozoa was significantly higher than that in the control spermatozoa after 1 hour and 3 hours of treatment. The percentage of acrosome-reacted spermatozoa also was significantly higher after human FF treatment than after control treatment. These effects of human FF were dose-dependent. Human FF-treated spermatozoa maintained their velocities at the zero-hour level for 5 hours, whereas the velocities of the control spermatozoa decreased significantly after 1 hour. Human FF treatment significantly increased the beat cross-frequency above the rate at zero hour for 5 hours. The hyperactivation of the human FF-treated spermatozoa remained stable for 3 hours, whereas that of the control spermatozoa decreased significantly after 1 hour of incubation. Significantly more human FF-treated spermatozoa underwent hyperactivation than did control spermatozoa after 1 hour and 3 hours of treatment. The effects of human FF on beat cross-frequency and hyperactivation were dose-dependent. CONCLUSION(S): Human FF promotes capacitation and the acrosome reaction within a short period. It also stimulates or maintains various sperm motility parameters.

Acrosome Reaction↗

PubMed2000

Modulation of rat epididymal gamma-glutamyl transpeptidase by nonylphenols.

1. gamma-Glutamyl-transpeptidase (gamma-GTP), present at low levels in the testis, seminal vesicle, prostate gland and epididymis in rat at 4 days of age, showed rapid developmental increases at the time of weaning. 2. Administration of nonylphenols (NP) to the neonatal male rat pup (from days 1 to 15) impaired the subsequent development of gamma-GTP in the epididymis but not in the testis, seminal vesicles or prostate gland. 3. Single injection of NP to weaned pups at approximately 22 days of age decreased gamma-GTP in the epididymis but not in other male accessory sex organs. This effect was transient, dose-dependent and blocked by the oestrogen receptor-specific antagonist ICI 182,780. 4. Single injection of oestradiol to weaned rat at approximately 22 days of age also decreased gamma-GTP in the epididymis but not in the testis, prostate gland or seminal vesicles. 5. In in vitro assays, NP did not inhibit epididymal gamma-GTP activity even at 100 microM final concentration. Under similar conditions, acivicin, a specific inhibitor for gamma-GTP, showed a dose-dependent inhibition of gamma-GTP activity. 6. It is suggested that NP impair gamma-GTP expression in the epididymis of developing male rat and act in part via the oestrogen receptor.

Aging↗

PubMed2000

Assessment of visually lossless irreversible image compression: comparison of three methods by using an image-comparison workstation.

PURPOSE: To determine the degree of irreversible image compression detectable in conservative viewing conditions. MATERIALS AND METHODS: An image-comparison workstation, which alternately displayed two registered and magnified versions of an image, was used to study observer detection of image degradation introduced by irreversible compression. Five observers evaluated 20 16-bit posteroanterior digital chest radiographs compressed with Joint Photographic Experts Group (JPEG) or wavelet-based trellis-coded quantization (WTCQ) algorithms at compression ratios of 8:1-128:1 and x2 magnification by using (a) traditional two-alternative forced choice; (b) original-revealed two-alternative forced choice, in which the noncompressed image is identified to the observer; and (c) a resolution-metric method of matching test images to degraded reference images. RESULTS: The visually lossless threshold was between 8:1 and 16:1 for four observers. JPEG compression resulted in performance as good as that with WTCQ compression at these ratios. The original-revealed forced-choice method was faster and as sensitive as the two-alternative forced-choice method. The resolution-metric results were robust and provided information on performance above visually lossless levels. CONCLUSION: The image-comparison workstation is a versatile tool for comparative assessment of image quality. At x2 magnification, images compressed with either JPEG or WTCQ algorithms were indistinguishable from unaltered original images for most observers at compression ratios between 8:1 and 16:1, indicating that 10:1 compression is acceptable for primary image interpretation.

Algorithms↗

PubMed2000

Sputum elastase in steady-state bronchiectasis.

STUDY OBJECTIVES: To study the correlations between sputum elastase output with clinical and sputum inflammatory and microbial factors in steady-state bronchiectasis. DESIGN: Prospective recruitment of patients with bronchiectasis (17 women; 48.5 +/- 16.5 years old; FEV(1)/FVC, 1.3 +/- 0.6/2.1 +/- 0.9) for assessment of 24-h sputum output of elastase, bacteria, leukocytes, interleukin (IL)-1beta, IL-8, tumor necrosis factor-alpha, and leukotriene B(4). Clinical variables assessed concomitantly included 24-h sputum volume, lung spirometry, number of lung lobes affected by bronchiectasis, and exacerbation frequency. SETTING: Consecutive recruitment of outpatients (n = 30) in steady-state bronchiectasis. MEASUREMENTS AND RESULTS: Twenty-four-hour sputum elastase output correlated with 24-h sputum volume (r = 0.79, p = 0.0001); number of bronchiectatic lung lobes (r = 0.54, p = 0.0026); percent predicted FEV(1) (r = -0. 48, p = 0.0068); percent predicted FVC (r = -0.49, p = 0.001); and leukocyte output (r = 0.75, p = 0.0001). There was no correlation between the sputum output of bacteria with either inflammatory or enzymatic factors (p > 0.05). CONCLUSION: Our data highlight the importance of elastase and the possibility of independent roles for enzymatic, inflammatory, and microbial components in the pathogenesis of bronchiectasis. Further research on novel therapy targeting each of these components should be pursued.

Adult↗

PubMed1999

Effects of mutant and antisense RNA of phospholamban on SR Ca(2+)-ATPase activity and cardiac myocyte contractility.

BACKGROUND: The delayed cardiac relaxation in failing hearts has been attributed to a reduced activity of sarcoplasmic reticulum Ca(2+)-ATPase (SERCA2). Phospholamban (PLB) inhibits SERCA2 activity and is therefore a potential target to improve the cardiac performance in heart failure. METHODS AND RESULTS: Mutants of PLB (Adv/mPLB) or antisense RNA of PLB (Adv/asPLB) was expressed in cardiac myocytes by recombinant adenovirus, and their effects on SERCA2 activity and myocyte contractility were studied. One mPLB, K3E/R14E, pentamerized with endogenous PLB in neonatal myocytes and resulted in a 45% increase in the affinity of SERCA2 for Ca(2+) and 27% faster diastolic Ca(2+) decline as determined by SR (45)Ca uptake assays and by indo 1-facilitated Ca(2+) transient measurement, respectively. Edge-detection analysis of adult myocyte contractility showed a 74% increase in fractional shortening, accompanied by 115% increase in velocity of relengthening and 25% decrease in time to half-maximal relengthening. In parallel, infection of neonatal cardiac myocytes by Adv/asPLB decreased the endogenous PLB level by 54%, which was associated with a 35% increase in Ca(2+) affinity of SERCA2 and 21% faster diastolic Ca(2+) decline. However, in adult cardiac myocytes, Adv/asPLB failed to significantly alter the endogenous PLB level, the SERCA2 activity, or most of the contractile parameters. CONCLUSIONS: K3E/R14E is a dominant negative mutant of PLB that disrupts the structural integrity and function of the endogenous PLB and consequently enhances SERCA2 activity and myocyte contractility. In neonatal myocytes, the decrease in steady-state abundance of PLB by asPLB also leads to increased SERCA2 activity.

Adenoviridae↗