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Biomedical subjects

S Liu

Publications and source records attributed to S Liu.

At least 991 records · Page 55Linked to original sources
PubMed1992

Use of the ASI titanium stent in the management of bladder outflow obstruction due to benign prostatic hyperplasia.

An expandable titanium intraprostatic stent was inserted into 30 patients with infravesical obstruction due to benign prostatic hyperplasia (BPH). All of the men were considered unsuitable for transurethral resection of the prostate as a result of comorbid conditions. In 25 patients effective micturition was reestablished with this technique. In 21 of these men, who have been followed for longer than 1 year, the mean maximum flow rate at 1 year was 10.8 ml. per second and the mean residual urine was 56 ml. Although urinary tract infections occurred subsequent to stent insertion in 10 individuals, these resolved after appropriate antibiotic treatment and no stents have had to be removed for this reason. Followup cystoscopy or examination by electron microscopy of those stents that have been removed has shown partial epithelialization of the stent surface in a proportion of patients, and a minor degree of incrustation occurred in 1 case. We conclude that an expandable intraprostatic titanium stent is an acceptable alternative to transurethral resection of the prostate or long-term catheterization in this particular group of high risk patients.

Aged↗
PubMed1992

Intrauterine death in multiple gestation.

Intrauterine death of one fetus in a multiple gestation is associated with significant morbidity and mortality in the surviving infant. This study is a retrospective review of 38 twin and 3 triplet gestations involving the intrauterine death of at least one fetus. The obstetrical history, placental pathology, autopsy findings, and neonatal history of the surviving infant are reviewed. Three cases involved the recent stillbirth of both twins, the remaining cases involved a surviving infant. In one case, neonatal death of a surviving twin occurred on day 19. In two sets of triplets, two stillbirths occurred, in the third case two infants were liveborn. The incidence of preterm delivery was 34%, which decreased to 18% if fetal cotwin death had occurred before 20 weeks gestation. Cesarean section was the method of delivery in 16 cases. There was an excess of velamentous cord insertions, which was most pronounced in the stillborn twin. Monochorionic placentation was found in 72%, also an excess. Neurological damage was known to have occurred in 19 of the 39 surviving infants. Fifteen of these 19 (79%) were associated with monochorionic placentation. The neurologically damaged twin infants, when compared to the normal infants, had the cotwin die later in gestation (31 vs 16.5 weeks), had a shorter duration between the death of the cotwin and delivery (2.5 vs 21 weeks), and delivered earlier in gestation (36.5 vs 39.5 weeks). The probable cause of neurological damage, in our opinion, was either exsanguination into the dead twin fetus, or disseminated intravascular coagulation which occurred in at least 13 cases. The incidence of antepartum death in a multiple gestation, and the potential for neurological damage is probably higher than previously thought. A review of the literature is presented and the clinical implications of this phenomenon are discussed.

Brain Damage, Chronic↗
PubMed1992

Inducible phytoalexins in juvenile soybean genotypes predict soybean looper resistance in the fully developed plants.

The hypocotyl of different soybean genotypes was tested for its inducible phytoalexin (i.e. glyceollin or coumestrol) accumulation and its inducible soybean looper resistance in response to chemical elicitation. A very highly insect-resistant soybean genotype (PI 227687) produced significantly more phytoalexins than a relatively insect-susceptible one (Davis) in response to the same chemical elicitation. The resultant standardized hypocotyl assay allowed quick categorization of unknown soybean genotypes regarding the level of insect resistance in the fully developed plants. Glyceollin was a better indicator of inducible resistance than coumestrol. Elicitor concentration influenced the amount of glyceollin and coumestrol accumulated. Younger seedlings (4-5 d old) responded stronger to chemical elicitation than did older ones (7-10 d old). The elicited accumulation of glyceollin showed a temporal pattern that peaked at 72 h. Accumulation of coumestrol showed a gradual increase. Elicitation of phytoalexins in juvenile soybean plants by sulfhydryl-binding reagents was found to be useful for the prediction of genotypic differences in the level of insect resistance in the fully developed plants.

Journal Article↗
PubMed1992

Eosinophilic prostatitis and prostatic specific antigen.

Eosinophilic prostatitis is a rare form of abacterial prostatitis with uncertain aetiology. Its clinical presentation, like other types of abacterial prostatitis, commonly mimics carcinoma of the prostate. Transrectal ultrasound may be helpful in the diagnosis of prostatitis but histological confirmation is necessary. Prostatic specific antigen has been widely used in the diagnosis and follow-up of patients with prostatic carcinoma. High levels of this antigen (greater than 30 micrograms/l) have been claimed to be highly specific for prostate cancer, although lesser elevations may also occur in patients with large benign prostate glands and in bacterial prostatitis. We report 3 patients with histologically proven eosinophilic prostatitis and high levels of prostatic specific antigen. This diagnosis may closely mimic carcinoma of the prostate and must be excluded by histological examination of biopsy material before treatment for presumed prostate carcinoma is initiated.

Antigens, Neoplasm↗
PubMed1992

Sphincter electromyography in patients after radical prostatectomy and cystoprostatectomy.

Urethral sphincter weakness may occur after major pelvic surgery and urinary incontinence, either temporary or permanent, may result. In order to determine whether the cavernous nerves described by Donker and Walsh carry fibres to the distal urethral sphincter as well as those supplying the corporal bodies, we have studied prospectively the sphincter electromyography in 2 groups of 10 patients: (1) those who had undergone nerve-sparing radical prostatectomy for prostatic carcinoma and (2) those who has undergone radical cystoprostatectomy for bladder carcinoma. This study group was compared with a control group of normal individuals. The results showed significant differences in duration of motor units between the control group and prostatectomy group and between the control group and cystectomy group but no significant difference between the 2 operated groups. There was no significant difference in amplitude of the motor units, the sacral reflex latencies or the pudendal somatosensory evoked potentials between all 3 groups. It was therefore concluded that division of the cavernous nerve of Walsh does not compromise distal urethral sphincter function. Furthermore, radical transabdominal lower urinary tract surgery may induce significant electromyographic changes in the external sphincter which may not be clinically evident. This may potentially affect continence later if second-stage urinary reconstructive surgery is undertaken.

Aged↗
PubMed1992

Finasteride in the treatment of benign prostatic hyperplasia. A urodynamic evaluation.

A group of 69 men with bladder outflow obstruction due to benign prostatic hyperplasia (BPH) were treated in a double-blind, placebo-controlled study with finasteride (Proscar, MK-906), a 5-alpha reductase inhibitor, 5 mg or 10 mg/day or placebo for 3 months; subsequently, 20 patients received finasteride 5 mg/day for a further 9 months in an open extension study. In treated patients dihydrotestosterone declined by over 60%, remaining unchanged with placebo. Symptom scores fell significantly in all 3 groups. Mean maximum flow rates fell slightly in placebo-treated patients but improved by 1.5 ml/s in the 10 mg group and by 3.3 ml/s in the 5 mg group. After 1 year's treatment, the reduction in symptom score and increase in flow rate were well maintained; the mean prostate volume was reduced by 14% and prostatic specific antigen declined by 28%. It was concluded that finasteride shows some efficacy in the treatment of BPH, with minimal toxicity, but 12 months of therapy or longer may be necessary to achieve maximal effect.

Aged↗
PubMed1992

Chronic hypoxia impairs soluble guanylyl cyclase-mediated pulmonary arterial relaxation in the rat.

We have examined the effects of exposing rats to hypoxia (10% fractional inspired O2 concentration) for 2 and 7 days on endothelium-dependent and -independent vasodilation and also on the ability of guanosine 3',5'-cyclic monophosphate (cGMP) to activate cGMP-dependent protein kinase (G-kinase) in rat conduit pulmonary arteries (PA). The ability of acetylcholine (ACh) and sodium nitroprusside (SNP) to both relax PA rings and elevate tissue cGMP levels was significantly attenuated in PA from hypoxic animals. The ability of atrial natriuretic peptide to relax and generate cGMP in PA rings was unchanged by hypoxia. Relaxation and elevation of cGMP levels induced by SNP in aortic rings was unaltered by hypoxia. Similarly, hypoxia did not alter the concentration-dependent activation by exogenous cGMP of G-kinase. We conclude that chronic exposure of rats to hypoxia results in a selective impairment of soluble guanylyl cyclase in rat PA, leading to an attenuation of ACh- and SNP-induced cGMP accumulation and relaxation.

Animals↗
PubMed1992

Surgical reinforcement of gender identity in adolescent intersex patients.

The presentation of phenotypic gender ambiguity at the time of adolescence is uncommon. Surgical reinforcement of gender, or reassignment is often complex and multistage. We present 2 cases of children who developed secondary sexual characteristics contrary to their chromosome status who, because of their late presentation, required significant surgical intervention to reinforce the gender assigned to them. We review some of the surgical techniques involved.

Adolescent↗
PubMed1992

Immunolocalization and expression of functional and nonfunctional cell-to-cell channels from wild-type and mutant rat heart connexin43 cDNA.

The carboxyl terminal cytoplasmic domain of distinct gap junction proteins may play an important role in assembly of functional channels as well as differential responsiveness to pH, voltage, and intracellular second messengers. Oligonucleotide-directed site-specific mutagenesis in a paired Xenopus laevis oocyte expression system was used to examine the expression of mRNAs encoding wild-type and carboxyl terminal mutant connexin43 (Cx43) proteins. Oocytes were stripped, injected with mRNA or distilled water (dH2O), preincubated for 16-20 hours, and then paired for 5-10 hours; this process was followed by electrophysiological recording using the dual voltage-clamp technique. Initial experiments compared the relative junctional conductances (Gjs) in oocyte pairs expressing Cx43 (382 amino acid residues) and two truncated mutants lacking most or a portion of the cytoplasmic carboxyl terminal. The shortest mutant (M241) contained 240 amino acid residues and was devoid of all phosphorylatable serine residues in the cytoplasmic tail; its length approximated the length of liver connexin26. The longest mutant (M257) tested contained 256 amino acid residues, including two serine residues. Oocyte pairs expressing M241 yielded a Gj similar to that of oocytes injected with dH2O, whereas M257 yielded a Gj similar to that of oocytes injected with Cx43. Immunoprecipitation studies showed that Cx43, M257, and M241 proteins were readily detectable in oocytes injected with their respective mRNAs, indicating that the lack of Gj observed with the M241 mRNA was not due to reduced translation. Immunocytochemical studies revealed that wild-type and both truncated mutants were localized to the area of cell-to-cell contact between the paired oocytes, indicating that protein targeting to the membrane was not inhibited in oocytes injected with M241 mRNA. Oocyte pairs expressing mutants in which serine residues were replaced with nonphosphorylatable amino acids (serine codon No. 255 AGC was converted to GCC, alanine, designated as M255S----A, and serine codon No. 244 AGC was converted to GGC, glycine, designated as M244S----G) showed Gjs similar to M257, indicating that these serine residues and, by inference, their phosphorylation state are not critical for expression of functional channels. The importance of the length of the carboxyl terminus was assessed by comparing the Gjs in a series of mutants that were intermediate in length between M257 and M241. Gradual shortening of the carboxyl terminus produced a gradual reduction of Gj relative to M257. However, simple deletion of amino acid residues 241-257 from the wild-type Cx43 did not affect Gj relative to M257.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1992

The production of hybridoma cell line secreting monoclonal antibodies against Xanthomonas campestris pv. oryzae and its application in the classification of strains.

By the fusion of mouse myeloma cells (SP2/0-Ag14) and spleen cells derived from BALB/c mice immunized with the preparation of Xanthomonas campestris pv. oryzae Ks-6-6, Os-213, Yz-32 and Yz-24, we obtained 12 hybridoma cell lines secreting monoclonal antibodies. None of the McAbs cross-reacted with the other varieties of plant pathogenetic and non-pathogenetic bacteria. The McAbs could distinguish three variant serotypes of strains. Antibody titers of ascites were about 1:10(3)-1:10(6) when measured by ELISA method. The McAbs could differentiate 6 epitopes. Based on the epitopes, the 63 strains of X. campestris pv. oryzae we collected were grouped into nine groups.

Animals↗