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Biomedical subjects

H Z Wang

Publications and source records attributed to H Z Wang.

At least 19 recordsLinked to original sources
PubMed1992

Sensory nerve endings in the puborectalis and anal region of the fetus and newborn.

The study was carried out in seven fetuses (ovulation ages were 16, 18, 20, 22, 26, 28, and 31 weeks, respectively) and in five full-term newborn babies. The modified Bielschowsky method and Barker's block silver impregnation were used. It was found that the muscle spindle was arranged in the puborectalis and the external sphincter muscles from the 20th week onward; the tendon organ was located in association with the musculo-tendinous junction of the puborectalis from the 20th week onward; the Pacinian corpuscle lay in the plane of cleavage between the internal anal sphincter and the external anal sphincter from the 22nd week onward, and in the presacral space from the 28th week onward, and the later lagged behind the former in development; the globular endings lay in the presacral space from the 28th week onward; and the free nerve ending was distributed in the epithelium of the anal mucosa and the epidermis around the anus from the 31st week onward. These sensory nerve endings tend to mature gradually with increasing age. It was concluded that these endings may be responsible for the reflex of the external anal sphincter and the anal sensation.

Anal Canal↗
PubMed1992

Gating of mammalian cardiac gap junction channels by transjunctional voltage.

Numerous two-cell voltage-clamp studies have concluded that the electrical conductance of mammalian cardiac gap junctions is not modulated by the transjunctional voltage (Vj) profile, although gap junction channels between low conductance pairs of neonatal rat ventricular myocytes are reported to exhibit Vj-dependent behavior. In this study, the dependence of macroscopic gap junctional conductance (gj) on transjunctional voltage was quantitatively examined in paired 3-d neonatal hamster ventricular myocytes using the double whole-cell patch-clamp technique. Immunolocalization with a site-specific antiserum directed against amino acids 252-271 of rat connexin43, a 43-kD gap junction protein as predicted from its cDNA sequence, specifically stained zones of contact between cultured myocytes. Instantaneous current-voltage (Ij-Vj) relationships of neonatal hamster myocyte pairs were linear over the entire voltage range examined (0 less than or equal to Vj less than or equal to +/- 100 mV). However, the steady-state Ij-Vj relationship was nonlinear for Vj greater than +/- 50 mV. Both inactivation and recovery processes followed single exponential time courses (tau inactivation = 100-1,000 ms, tau recovery approximately equal to 300 ms). However, Ij recovered rapidly upon polarity reversal. The normalized steady-state junctional conductance-voltage relationship (Gss-Vj) was a bell-shaped curve that could be adequately described by a two-state Boltzmann equation with a minimum Gj of 0.32-0.34, a half-inactivation voltage of -69 and +61 mV and an effective valence of 2.4-2.8. Recordings of gap junction channel currents (ij) yielded linear ij-Vj relationships with slope conductances of approximately 20-30 and 45-50 pS. A kinetic model, based on the Boltzmann relationship and the polarity reversal data, suggests that the opening (alpha) and closing (beta) rate constants have nearly identical voltage sensitivities with a Vo of +/- 62 mV. The data presented in this study are not consistent with the contingent gating scheme (for two identical gates in series) proposed for other more Vj-dependent gap junctions and alternatively suggest that each gate responds to the applied Vj independently of the state (open or closed) of the other gate.

Animals↗
PubMed1992

Control of inhibin production by dispersed human luteal cells in vitro.

The production of inhibin in vitro by dispersed cells from early to mid (Days 16-19) and late stage (Day 23) human corpus luteum (CL) was examined, and the effects of human chorionic gonadotrophin (hCG), follicle stimulating hormone (FSH), oestradiol and testosterone on inhibin production were determined. Corpora lutea from five subjects in the early to mid luteal stage and three subjects in late luteal stage were dispersed with enzymes and the luteal cells cultured in medium supplemented with 5% calf serum and either FSH (1, 10 or 100 ng mL-1), oestradiol-17 beta (2.5, 5 or 10 micrograms mL-1) or testosterone (0.25, 1 or 5 micrograms mL-1) with or without hCG (1 I.U. mL-1). Cells were cultured for 1 to 3 days without changes of medium, and the concentrations of progesterone, oestradiol and immunoreactive inhibin in the medium were measured by radioimmunoassay. Cells from both types of CL produced inhibin in vitro under basal conditions, but only cells from early to mid CLs responded to hCG with a significant increase in inhibin production. Both progesterone and oestradiol production were stimulated by hCG in both groups of CL. Inhibin concentrations in the cell cultures declined with time in culture, particularly in the late CL group, whereas the concentration of steroids increased. Neither FSH, oestradiol nor testosterone significantly changed inhibin production in either CL group. It was concluded that inhibin production by human luteal cells in vitro is influenced by the age of the CL, and is dependent on LH (hCG) but not on FSH or sex steroids.

Adult↗
PubMed1992

Image analysis of neuropil threads in Alzheimer's, Pick's, diffuse Lewy body disease and in progressive supranuclear palsy.

Neuropil threads (NT) in the middle temporal gyrus (MTG) were quantitated by computerized image analysis from five patients each with Alzheimer's disease (AD), Pick's disease (PD), and diffuse Lewy body disease (DLBD), four patients with progressive supranuclear palsy (PSP), and five cognitively normal control subjects (24 patients total). All disease groups met clinical and pathological criteria for their respective diseases. The DLBD subjects did not have pathological features of AD. Using the Gallyas silver method, the percentage of cortical area occupied by NT was calculated for each case examined and compiled for each group. Intergroup comparison revealed the percentage of cortical area occupied by NT as follows: AD, 6.87%; PSP, 1.12%; PD, 0.37%; DLBD, 0.04%; control 0.02%. The evaluation disclosed a significance level of p < 0.0001 when AD was compared to control, PD and DLBD cases and a p < 0.001 when compared to PSP. There was no statistically significant difference between control-DLBD, control-PD, control-PSP, DLBD-PSP, PD-PSP, or PD-DLBD cases (p > 0.05). These data indicate the density of neocortical threads is much greater in AD than in other dementing disorders. It also suggests that NT are not related to the intellectual decline in PD, DLBD, and PSP.

Aged↗
PubMed1992

Gap junctional channels in adult mammalian sinus nodal cells. Immunolocalization and electrophysiology.

The subcellular mechanism of cell-to-cell communication in the natural pacemaker region of the mammalian heart was studied using electrophysiological and immunofluorescence techniques in isolated pairs of rabbit sinus nodal cells. By measuring whole-cell currents using a double patch-clamp approach, it was demonstrated that communication in the sinus node is mediated through gap junctional channels similar to those in other types of adult cardiac cell pairs. Macroscopic sinus nodal junctional resistance had a mean value of 387.9 +/- 97.1 M omega (mean +/- SEM, n = 10) and was greatly increased by superfusion with alkanols. Single-channel junctional conductance could be resolved in three cell pairs. Given their high membrane resistance (1.16 +/- 0.32 G omega, n = 12), the electrical coupling provided by as few as three gap junctional channels between nodal cells will allow for pacemaker synchronization. Further evidence for the presence of the channels was obtained from immunofluorescent double-labeling of desmin and the gap junction protein (connexin43) in sinus nodal tissue as well as in cultured sinus nodal cells. Using antisera against residues 243-257 of the connexin43 protein, a specific staining at the site of cell-to-cell apposition was demonstrated. These data provide direct evidence in favor of electronic coupling as the means for achieving pacemaker synchronization in the rabbit sinus node.

Animals↗
PubMed1992

Multiple connexins confer distinct regulatory and conductance properties of gap junctions in developing heart.

Multiple gap junction proteins (connexins) and channels have been identified in developing and adult heart. Functional expression of the three connexins found in chick heart (connexin42, connexin43, and connexin45) by stable transfection of communication-deficient neuro2A (N2A) cells revealed that all three connexin cDNAs are capable of forming physiologically distinct gap junctions that differ in their transjunctional voltage dependence and unitary channel conductances. The transjunctional voltage dependences of connexin45 and connexin42 closely resembled those of 4-day and 18-day embryonic chick heart gap junctions, respectively. The multiple channel conductances between 80 and 240 pS, including the predominant 160 pS channel, observed in embryonic chick heart were also common to connexin42. The expression of multiple gap junction channels with distinct conductance and regulatory properties within a given tissue may account for developmental changes in intercellular communication.

Animals↗
PubMed1992

[Sclerotherapy of gastric varices].

160 patients, 128 males, 32 females, with portal hypertension were admitted into our department for sclerotherapy from May 1987 to August 1990. Gastric fundus could be observed clearly in 145 of these patients who were examined with endoscope. Gastric varices were found in 105 of the 145 patients. Sclerotherapy of gastric varices were carried out in 47 of the 105 patients by intravenous injection with the method of lesser injection points and larger dosage. The results showed that a satisfactory effect was obtained with a rate of immediate stoppage of bleeding by 95.7%; and a rate of disappearance of gastric varices by 95.3%. The rate of recurrent bleeding was 7.9%. In addition, the occurrence rate, the severity, the manifestations under endoscopy and the classification of gastric varices as well as the indication, and complications of sclerotherapy of gastric varices were discussed in detail.

Adolescent↗
PubMed1992

Inhibitory effect of interferon and tumor necrosis factor on human luteal function in vitro.

OBJECTIVE: To investigate whether immunological mechanisms may be involved in human luteal function. DESIGN: The effects of the cytokines, interferon-alpha (IFN-alpha), interferon-gamma (IFN-gamma) and tumor necrosis factor alpha (TNF-alpha) on steroidogenesis by human luteal cells were examined in vitro. The dispersed human luteal cells, obtained from a total of 17 women at laparotomy, were cultured separately in the presence or absence of human chorionic gonadotropin (hCG) and IFNs/TNF-alpha with the medium being replaced at 48 hours. The medium was collected at 48 and 96 hours for steroid assays. RESULTS: The IFN-alpha had no significant effect on the production of estradiol or progesterone (P), whereas a dose-related inhibition of basal, as well as hCG-stimulated P formation, was observed after the addition of IFN-gamma (10 to 1,000 U/mL). Progesterone production was inhibited to about 45% of the control at 48 hours and even lower at 96 hours (n = 6, P < 0.001). The combination of IFN-gamma and low doses of TNF-alpha induced a further significant inhibition, whereas there was no effect of TNF-alpha alone. This inhibitory effect of IFN-gamma could be completely neutralized with a monoclonal antibody to IFN-gamma. Incubation with the antibody alone increased the production of P from luteal cells in culture, suggesting a local tonic inhibitory action of endogenous IFN-gamma. CONCLUSION: Interferon-gamma and TNF-alpha, whose function classically is known as antiviral, also may play a role in human luteal regression by inhibiting luteal P production.

Adult↗
PubMed1991

Heparinization of blood decreases ionized calcium concentration.

To evaluate whether heparin in the plasma sample may affect the ionized calcium level, we compared the ionized calcium levels of blood samples of three different heparin concentrations in 25 normal healthy volunteers: Group A contained no heparin (control group); Group B contained 4.7 IU/ml heparin; and Group C contained 37.5 IU/ml heparin. The result showed ionized calcium to be 4.99 +/- 0.28 mg/dl (Mean +/- SEM) in group A; 4.64 +/- 0.26 mg/dl (Mean +/- SEM) in group B and 4.25 +/- 0.24 mg/dl (Mean +/- SEM) in group C. These three values were significantly different (p less than 0.001). So, heparin might artificially lower the plasma ionized calcium concentration. It is concluded that: (1) samples for accurate ionized calcium measurement should contain no heparin; and (2) in spite of the careful measurement by conventional technique, an introduction of an excessive amount of heparin into the deadspace of the syringe may significantly reduce the ionized calcium concentration.

Adult↗
PubMed1991

Comprehensive assessment of long-term postoperative continence in pediatric imperforate anus. Clinical, manometric and contrast studies.

109 patients with imperforate anus were followed up postoperatively for 5 to 28 years. Postoperative continence was evaluated by anorectal manometry, barium enema and clinical symptoms. A comprehensive assessment system, combining the clinical and objective systems was designed which can reflect postoperative anal continence function completely and objectively. It is useful for determining the causes of incontinence and its treatment.

Adolescent↗
PubMed1991

Ocular refraction and its components among younger children in Kaohsiung: a 4-year longitudinal study.

A four-year longitudinal study was made on refraction and its components among 50 children of Kaohsiung, Taiwan, R.O.C. aged from 7 to 10.6 years. The methods of examination of the eyes were the same as that of four years ago, including Mydriacyl refraction, keratometry for corneal curvature radius, and ultrasonic measurement of the refractive components. One eye with amblyopia was excluded. The results of our study showed that all of our cases over 6 years of age had a corrected visual acuity of 0.8 or better, and that the refractive state shifted to myopia in our 4-year follow up. The rate of myopia increased from 2% to 27.3%. Comparisons of refractive components between the years 1983 and 1987 showed significant increases in refractive power, length of vitreous cavity and total axial length of the eyes. Corneal refractive power and lens thickness, however decreased significantly. As for differences in gender, several results were the same for both 1983 and 1987: corneal curvature radius, the length from anterior corneal surface to anterior lens surface, length of vitreous cavity and total axial length were larger in males than females. Finally, total axial length and corneal curvature radius were the factors most affecting the refractive state in younger children.

Child↗
PubMed1990

CNR enhancement in the presence of multiple interfering processes using linear filters.

Given several images of the same slice, a linear filter can produce an image in which the contrast-to-noise ratio (CNR) between pathological and normal tissues is greater than in any of the initial images. To distinguish the pathology from more than one tissue, the filter should optimize the set of CNRs between the pathology and each of the interfering tissues. We define the optimal filter as the one which provides the largest value for the minimum CNR in the set and show how it is selected from a field of only four possibilities. The filter is demonstrated with both experimental phantom studies and clinical cases. Filter performance is compared with that of other techniques for distinguishing a desired feature from more than one interfering process.

Image Enhancement↗
PubMed1990

A spoiling sequence for suppression of residual transverse magnetization.

We present a spoiler sequence which substantially eliminates residual transverse magnetization in rapid magnetic resonance imaging. Such magnetization is due to the repetition time TR being on the order of or shorter than the transverse relaxation time T2. This sequence was designed using computer simulation methods to model the slice profile and signal. The spoiler pulse is applied in the slice-selecting direction and the magnitude of the gradient spoiler is incremented with each repetition as an arithmetic series. A finite number of different spoiler amplitudes is repeated with a cycle time several times greater than the anticipated T2. Each spoiler is shown to nullify the residual transverse magnetization from the just-measured signal of the experiment as well as that from preceding repetitions. It is shown experimentally that the spoiler pulse can be as short as 2 ms. This is considerably shorter than existing methods using constant spoiling or phase-tagged spoiling. This sequence was used to acquire T1-weighted images free of the central line artifact of FLASH imaging. Furthermore, images formed with the new spoiled technique are shown to have contrast-to-noise comparable if not superior to standard T1-weighted spin-echo images while taking only a fifth of the scan time.

Brain↗
PubMed1990

Sensory nerve endings in puborectalis and anal region: normal findings in the newborn and changes in anorectal anomalies.

This study was carried out in five full-term newborn babies and 11 patients with anorectal anomalies (five of whom had high deformity, five had intermediate, and one had low), using the modified Bielschowsky method. The following four kinds of sensory nerve ending were found: muscle spindle in the puborectalis and the external anal sphincter, Pacinian corpuscle in the plane between the internal anal sphincter and the external anal sphincter and in the presacral space, globular ending in the presacral space, and free nerve ending in the epithelium of the anal canal and in the perianal skin. It was found that there were significantly fewer muscle spindles in the puborectalis and many fewer Pacinian corpuscles and globular endings in the presacral space of high and intermediate deformities than normal. No spindle was found in the external sphincteric muscles of the deformities. On the other hand, the Pacinian corpuscles and the globular endings of high and intermediate deformities lagged behind normal in development. The densities of the nerve bundles in the subepidermis and the nerve fibers in the dermis of perineal region in high and intermediate deformities were much lower than normal, and the decrease in density corresponded to the levels of the rectal pouch. The observation showed that the agenesis of sensory nerve endings in the puborectalis and the anal region was one of the most significant pathological features in high and intermediate types of anorectal anomalies, and might be responsible for the abnormalities of the reflex of the anal sphincter and the anal sensation in such patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Anal Canal↗
PubMed1990

A new approach to the treatment of malignant effusion.

Lymphocytes isolated from malignant effusion were induced to become LAK cells after in vitro culture with rIL-2. 28 patients with malignant effusion were treated by i.p. or intrapleural administration of autologous LAK cells combined with rIL-2 or by rIL-2 alone. The effusion disappeared in 13 patients and significantly decreased in another 13. Two patients did not respond to the treatment. Tumor cells in effusion disappeared or significantly decreased and lymphocytes significantly increased in all responses. Except for transient fever in 9 patients, no serious side effects were found.

Adult↗
PubMed1990

[Asphyxiating thoracic dystrophy: a case report].

Asphyxiating thoracic dystrophy (ATD) is a rare case of autosomal recessive disease. We report a case of full term female infant, who was noted to have small chest cage with severe respiratory distress soon after birth. On physical examination. The chest wall was fixed and small with the narrowest circumference about 29 cm in size, general cyanosis and distended abdomen were noted, there was a umbilical hernia around 1 cm in diameter. Otherwise, no other gross anomalies were found. Radiologic studies revealed short and horizontal ribs, small lung volume but depressed diaphragm, the clavicles and the spine were normal. The abdomen and long bone series all showed negative findings. The patient died of respiratory failure at 18 hours after birth. Autopsy was documented as a case of ATD. According to family history, there was one sibling die in the similar condition, although no autopsy available. Because the disease is transmitted as autosomal recessive trait, so 25% of next sibling will get the same condition. Therefore genetic consulting is necessary.

Asphyxia Neonatorum↗
PubMed1990

[Intraocular lens implantation at Kaohsiung Medical College].

Between March 1984 and December 1987, 993 cataractous eyes in 884 patients (462 males, 422 females) were operated on using intraocular lens implantation at the Kaohsiung Medical College Hospital. The age of the patients ranged from half year to 93 years, with an average of 61.9 years. Primary lens implantation was performed in 98.4% of the cases, secondary implantation in 1.6% of the cases. There were 6 cases were done by using the triple procedure (combined keratoplasty with cataract extraction and intraocular lens implantation). Among these 742 eyes followed-up for from one to 43 months, final vision could be corrected to 6/12 or better in 63.5% of the cases. While 64.4% of the cases of post-operation cylinder were less than 2 diopters, the final refraction showed that the spherical equivalent diopters were within 2 diopters in 61.7% of the cases. Complications in the anterior chamber lens group included pupillary changes (21.2%), pseudophakic bullous keratopathy or decompensation (13.5%), lens subluxation or dislocation (13.5%) and cystoid macular edema (5.8%). Complications in the posterior chamber lens group included pupillary changes (16.2%), posterior capsular thickening (3.2%), anterior or posterior synechiae (2.7%) and lens subluxation or dislocation (2.8%).

Adolescent↗