Search PubMed⌕ Search

Biomedical subjects

J Hsu

Publications and source records attributed to J Hsu.

At least 73 records · Page 4Linked to original sources
PubMed1992

Strategies in the surgical treatment of malignant ventricular arrhythmias. An 8-year experience.

Introduction of the automatic implantable cardioverter defibrillator (AICD) has dramatically affected the surgical treatment of malignant ventricular tachyarrhythmias. The authors continue to perform electrophysiologically directed subendocardial resection (SER) of left ventricular (LV) scars in selected patients, and we revascularize (CABG) those patients undergoing AICD implantation who have significant myocardial ischemia. In an attempt to define the optimal role of each procedure, this report analyzes our 8-year experience with 348 consecutive patients treated surgically for these arrhythmias (SER since 1983 and AICD since 1986). All patients undergoing SER had organized ventricular tachycardia (VT) as a result of myocardial infarction, and most had LV aneurysms; of those undergoing AICD or AICD/CABG, 60% had VT, 15% had ventricular fibrillation, and 25% had both or were noninducible. The thirty-day mortality rate was 1.5% (3/197) for AICD, 5.4% (5/93) for AICD/CABG, and 8.6% (5/58) for SER; these mortality figures are not significant different. Late deaths in all groups were predominantly due to congestive heart failure, and actuarial survival as well as freedom from sudden death was similar between the groups at 4 years. Recurrent VT occurred in 167 of 282 (59%) of long-term survivors of AICD or AICD/CABG during follow-up and in nine of 53 (17%) of those with SER. Forty-eight per cent of survivors of AICD or AICD/CABG required antiarrhythmic medications, whereas only 11% of those with SER required antiarrhythmics. Long-term survival in each group is much higher than that reported for comparable patients with severe LV dysfunction treated medically. In those patients with organized VT and LV aneurysm who are judged able to survive the procedure, SER offers a high likelihood of cure rather than simple prevention of sudden death.

Actuarial Analysis↗
PubMed1992

Selective stimulation of parasympathetic nerve fibers to the human sinoatrial node.

BACKGROUND: In animals, parasympathetic nerve fibers that innervate the sinoatrial node can be selectively stimulated to increase atrial cycle length. These nerve fibers course through an epicardial fat pad at the margin of the right superior pulmonary vein, the superior vena cava, and the right atrium. We hypothesized that similar nerves exist and can be selectively stimulated in humans. METHODS AND RESULTS: Microscopic examination of fat pads excised from the margin of the right superior pulmonary vein, the superior vena cava, and the right atrium during two human autopsies revealed the presence of nerve fibers and ganglia. We electrically stimulated this epicardial fat pad in 16 patients during cardiac surgery. The fat pads were stimulated with continuous-pulse trains for 15 seconds via a hand-held bipolar electrode using constant current (10-15 mA), constant pulse width (0.02-0.05 msec), and at 6.6, 10, 20, 25, and 30 Hz. The mean atrial cycle length +/- 1 SEM increased from 734 +/- 34 msec at baseline to a maximum of 823 +/- 61 msec at 6.6 Hz, 1,167 +/- 125 msec at 10 Hz, 1,734 +/- 281 msec at 20 Hz, 2,993 +/- 661 msec at 25 Hz, and 2,461 +/- 668 msec at 30 Hz during nerve stimulation. Linear regression analysis showed that the response of atrial cycle length to sinoatrial parasympathetic nerve stimulation was frequency dependent. The maximum response and complete decay of the response occurred within 4-8 seconds of initiation or termination of sinoatrial parasympathetic nerve stimulation. Atrioventricular conduction time and the PR interval did not change during sinoatrial parasympathetic nerve stimulation, even when the atria were paced at the baseline heart rate. CONCLUSIONS: Electrical stimulation of parasympathetic nerve fibers in a fat pad near the sinoatrial node increased atrial cycle length without affecting atrioventricular nodal conduction. This is the first study in which such nerve fibers that innervate the sinoatrial node have been selectively stimulated in humans.

Adipose Tissue↗
PubMed1991

Purification of casein kinase I and isolation of cDNAs encoding multiple casein kinase I-like enzymes.

We have purified casein kinase I (CKI) over 6000-fold from bovine thymus and have sequenced seven tryptic peptides that account for nearly 25% of the primary sequence of the enzyme. By using PCR, partial cDNAs encoding CKI and a related enzyme (CKI-delta) were isolated. A product that may correspond to an alternatively spliced form of CKI was also detected. The CKI PCR product was used to probe a bovine brain cDNA library from which cDNAs corresponding to CKI (CKI-alpha) and two homologous enzymes (CKI-beta and CKI-gamma) were identified. The finding that there are at least four CKI-like enzymes suggests that CKI activity in tissues or cell extracts may be composed of multiple related but distinct protein kinases. This group of enzymes is not similar to any other known protein kinases and may, therefore, represent an additional branch of the protein kinase family.

Amino Acid Sequence↗
PubMed1990

An insulin-stimulated protein kinase similar to yeast kinases involved in cell cycle control.

A protein kinase characterized by its ability to phosphorylate microtubule-associated protein-2 (MAP2), is thought to be an early intermediate in an insulin-stimulated phosphorylation cascade and in a variety of other mammalian cell responses to extracellular signals. A complementary DNA that encodes this protein serine-threonine kinase has been cloned, and the protein designated extracellular signal-regulated kinase 1 (ERK1). ERK1 has striking similarity to two protein kinases, KSS1 and FUS3, from yeast. The yeast kinases function in an antagonistic manner to regulate the cell cycle in response to mating factors. Thus, ERK1 and the two yeast kinases constitute a family of evolutionarily conserved enzymes involved in regulating the response of eukaryotic cells to extracellular signals.

Amino Acid Sequence↗
PubMed1990

Probe placement and power levels in contact transscleral neodymium:YAG cyclophotocoagulation.

Transscleral cyclophotocoagulation using a free-running, thermal-mode neodymium:YAG laser with a 2.2-mm-diameter sapphire-tipped contact probe was performed on 27 enucleated human eyes to investigate the effect of probe placement and power levels. We concluded from gross, light, and scanning electron microscopic examinations that a tissue destructive effect on ciliary body and epithelium was produced by positioning the anterior edge of the probe tip 0.5 to 1.0 mm from the visible limbus using a 5- to 9-W power setting for 0.7 second. An 11-W power setting resulted in extensive loss of anatomic integrity of the ciliary body. Limbal probe placement produced significant iris and lens damage while positioning the probe 1.5 mm posterior to the limbus affected primarily pars plana. Damage to the sclera was not observed using this method of cyclophotocoagulation.

Aged↗
PubMed1990

Evolving patterns in the surgical treatment of malignant ventricular tachyarrhythmias.

The advent of the automatic implantable cardioverter defibrillator (AICD), generally viewed as a safe and effective intervention, has in some measure discouraged the use of electrophysiologically directed endocardial resection for intractable ventricular arrhythmias. We reviewed the records of 127 patients undergoing either AICD procedures or resection over a 6-year period. Thirty-day mortality was 5.6% (5/89 patients) for all AICD procedures, 10.7% (3/28) for AICD placement plus coronary artery bypass grafting, and 11.8% (4/34) for resection. These mortality figures are not significantly different. Patients undergoing resection were less likely to require antiarrhythmic agents than patients given an AICD (33% versus 61%). Survival at 2 years was 78% in the resection group and 72% in the AICD group. Survival at 4 years was still 78% in the resection group. Only 1 late sudden death occurred in the AICD group and none in the resection group. We conclude that resection continues to be a valuable alternative, offering a greater overall benefit at only slightly increased risk.

Adolescent↗
PubMed1990

Comparative study of Filshie clip and Pomeroy method for postpartum sterilization.

A prospective randomized comparison of the peri-operative complications and long-term sequelae between the Filshie clip and Pomeroy methods was undertaken in 200 postpartum women at Tri-Service General Hospital, Taipei, Taiwan. The peri-operative complications in either group were mild and infrequent. One pregnancy in the Pomeroy group was reported after follow-up for 24 months. No significant difference between the two groups was found in respect to long-term sequelae.

Adult↗
PubMed1990

A family of glycolipid linked proteins in Eimeria tenella.

A number of proteins in Eimeria tenella are shown to possess a carbohydrate similar to that found on the carboxyl terminus of the variant surface glycoprotein from Trypanosoma brucei. In trypanosomes, this carbohydrate is part of a glycolipid structure responsible for membrane attachment. In common with the variant surface glycoprotein and with other glycolipid linked proteins, the E. tenella proteins were shown to be hydrophobic. Treatment with a crude lipase preparation from T. brucei modifies these proteins to a water-soluble form.

Animals↗
PubMed1989

The function of Gp170, the multidrug resistance gene product, in rat liver canalicular membrane vesicles.

Gp170 (also known as P-glycoprotein) is a transmembrane glycoprotein which is overexpressed in multidrug-resistant tumor cells and is also found in the apical plasma membrane domain of several normal human and animal tissues. Gp170 has been postulated to function as an energy-dependent efflux pump for cytotoxic drugs. In rat liver, Gp170 is restricted to the bile canalicular domain of the plasma membrane. Canalicular membrane vesicles (CMV), but not sinusoidal membrane vesicles, contained a approximately 160-kDa protein which reacts with anti-Gp170 monoclonal antibody and manifest ATP-dependent [3H]daunomycin transport which is temperature dependent, osmotically sensitive, and saturable. Among several nucleotides, ATP was a potent stimulator of transport whereas non- or slowly hydrolyzable analogues (adenosin-5-O-(3-thiotriphosphate, adenyl-5-yl-imidodiphosphate) were ineffective. ATP-dependent daunomycin transport was inhibited by cytotoxic drugs (vinblastine, vincristine, and adriamycin) and other drugs, such as verapamil and quinidine, which restore anti-cancer drug sensitivity in resistant cells. Inside-out CMV were separated from right side-out CMV by antibody-induced affinity density perturbation. Only inside-out CMV manifested ATP-dependent daunomycin transport. These results suggest that Gp170 is an ATP-dependent efflux pump which is responsible for the undirectional, energy-dependent transport of daunomycin and other drugs by rat liver into the bile.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1989

Survival of a recipient of renal transplantation after pulmonary phycomycosis.

A 48-year-old nondiabetic man maintained on prednisone, azathioprine, and cyclosporine after cadaveric renal transplantation developed multiple unilateral phycomycotic pulmonary abscesses. Despite treatment with amphotericin B the patient remained febrile. Surgical resection of these pulmonary abscesses was performed and the patient remains free of disease 1 year after operation. To our knowledge, this patient represents the first reported case of pulmonary phycomycosis in a recipient of renal transplantation without diabetes mellitus.

Humans↗
PubMed1989

Infections in mortally ill cardiac transplant recipients.

A total of 351 cardiac transplantations performed between June 1, 1980, and Sept. 30, 1987, were reviewed to determine if infectious complications were more frequent in those patients requiring preoperative intravenous inotropic support, placement of an intraaortic balloon pump, or mechanical support with a left ventricular assist device or total artificial heart. One hundred forty-nine transplants (45%) were performed in these mortally ill patients. There was no statistically significant difference between patients with and without infection within each support group for the following: the number of in-patient days awaiting a donor heart, the number of days receiving support, the percent of patients with preoperative tracheal intubation, the length of the operation, and the percent of patients requiring reoperation for bleeding. The need for invasive methods of support (intraaortic balloon pump, left ventricular assist device, or total artificial heart) in patients awaiting heart transplantation increases the prevalence of perioperative nonviral infection. Preoperative mechanical support with a left ventricular assist device or total artificial heart significantly increases the risk of infection-related mortality.

Adult↗
PubMed1988

Family planning and child mental health in China: the Nanjing Survey.

The authors studied the impact of China's one-child-per-couple family planning policy on child development in 697 preschool children in the city of Nanjing and in two rural areas surrounding Nanjing. A home-visit questionnaire survey including a Chinese version of Achenbach's Child Behavior Checklist was used. The behavior problem profiles of children who were their parents' only children and those who had siblings were compared, revealing a significant difference between girls who were only children and those who had siblings. Girls who were only children tended to have slightly higher scores on the factors of depression, moody, and temper.

Adolescent↗
PubMed1988

A sociocultural study of koro epidemics in Guangdong, China.

Koro, a culture-related psychiatric disorder characterized by panic due to fear of genital retraction, occurred as the rare phenomenon of koro epidemics in a remote region of Guangdong, China, in 1984-1985 and 1987. The sociocultural and historical backgrounds of the area are described. The life pattern and attitudes toward supernatural beings and the commonly shared folk belief of evil-induced genital retraction were considered grounds for the panic, while the community's anxious reaction and hysterical atmosphere facilitated the intensification and recurrence of the episodes. Geographic seclusion associated with localism in folk beliefs and practices may have kept the epidemics confined to the region.

Adult↗
PubMed1987

Brain cellular and mitochondrial respiration in media of altered pH.

This study was designed to investigate the effects of altered pH on cellular aerobic energy metabolism in the immature and adult rat cerebral cortex. Cerebral cortical slice respiration was measured polarographically in acid and alkaline media. In separate experiments, the extracellular pH was changed by altering the HCO3- concentration or the intracellular pH and extracellular pH were changed by altering the CO2. Respiratory rates and oxidative phosphorylation in adult rat cerebral mitochondria also were measured in media with an altered pH. Increased intracellular pH inhibited respiratory rates in cortical slices from immature rats more than in tissue from adults. Decreasing the pH to 6.7 produced no changes in respiration in mature cortical slices and moderate inhibition of immature tissue respiration. In cerebral mitochondria, altered pH caused inhibition of State 3 respiration, respiratory control ratios, and ADP/O ratios. These changes were greater and occurred with smaller pH changes in the alkaline compared to the acid direction. From the results of these studies, we conclude that brain cellular respiration is not affected by moderate decreases in intracellular pH. With increased pH, there is inhibition of cellular and mitochondrial respiration, which may be the mechanism for the rise in lactic acid previously observed to result from hypocarbia in vivo.

Aging↗
PubMed1986

Diagnostic pattern for neuroses in China, Japan, and the United States.

To investigate the diagnostic patterns for neuroses in China, Japan, and the United States, the authors showed videotapes and brief written case histories of six Chinese patients to psychiatrists and psychiatrists-in-training in Beijing, Tokyo, and Honolulu. In cases with a well-distinguished clinical picture the diagnoses were congruent in the three countries. Diagnostic disagreement occurred in cases with symptoms of decline in mental function, which were overwhelmingly diagnosed as neurasthenia by the Chinese clinicians, and cases with situational stress, which were diagnosed as adjustment reaction by the Americans. This illustrates that different professional concepts and classification systems are used in different countries.

Adjustment Disorders↗