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C C Liang

Publications and source records attributed to C C Liang.

86 records · Page 5Linked to original sources
PubMed1977

Bradycardia in thiamin deficiency and the role of glyoxylate.

1. Method of recording the heart rate in rats is described. 2. It was found that during the course of developing thiamin deficiency, the heart rate of rats dropped from 448 to 220 beats/min. (There was no difference between male and female rats.) 3. A number of metabolic products were injected into the normal rats and only glyoxylate was shown to cause a significant drop in heart rate. 4. Graded amounts of Na-glyoxylate were injected peritoneally into the normal rats and blood samples were taken at intervals to test the amount of glyoxylate present. It was found that peak concentration appeared 6 min after injection and thereafter declined or disappeared, depending on the amount of glyoxylate administered. 5. It was found that glyoxylate accumulates in the body of thiamin-deficient rats and in the pair-fed rats reared on restricted diet for a long period. 6. Drop in heart rate depended on the appearance of glyoxylic acid present in the blood rather than on the reduction of body weight.

Animals↗
PubMed1975

Metabolic changes in rats during developing thiamin deficiency.

Determinations of rectal temperature, blood glucose, plasma free fatty acids, liver acetyl-CoA and carcass fat of thiamin-deficient rats indicated that during the ensuing anorexia they metabolized their fat reserves more rapidly than did pair-fed normal controls. Their lower metabolic rate indicates that the reserves mobilized are utilized inefficiently.

Acetyl Coenzyme A↗
PubMed1972

Re-investigation of the effect of adrenaline and noradrenaline on renal function in situ.

1. Adrenaline or noradrenaline in single doses (0.01-0.10 mug/kg) or by continuous infusion (0.3-3.0 mug.kg(-1) min(-1)) into anaesthetized dogs has been administered by different routes. The changes in femoral arterial B.P., hepatic portal venous pressure, renal venous pressure, intrarenal venous pressure, kidney volume, renal plasma flow (RPF), glomerular filtration rate, urine flow and plasma protein concentration have been followed. The effects varied with route of administration, with dose and time.2. Direct injection of single doses of these drugs (</= 0.02 mug/kg) into the renal artery reduced RPF and urine flow without affecting the systemic B.P. or hepatic portal venous pressure.3. When the catecholamines were administered in single small doses (</= 0.02 mug/kg), I.M. or S.C. or via the hepatic or common carotid arteries, only a slight effect on systemic B.P. was observed. There was little effect on hepatic portal venous pressure, and no diuresis was observed.4. Single injection of these drugs (</= 0.02 mug/kg) into the mesenteric artery caused an immediate fall of hepatic portal venous pressure without a direct effect on the kidney. A subsequent rise in hepatic portal venous pressure was associated with an increase in urine flow.5. Administration of these drugs (0.01-0.10 mug/kg) into the femoral vein, inferior vena cava or internal jugular vein caused a great rise in systemic B.P., a decrease in hepatic portal venous pressure and an antidiuresis, but this was usually followed by a rise of hepatic portal venous pressure and by an associated diuresis, as systemic B.P. returned to normal values.6. The total and segmental renal vascular resistance were calculated from parameters measured during ureteral occlusion. The primary effect of the catecholamines was to increase the resistance in all renal vascular segments and produce antidiuresis; subsequently a drastic drop of all segmental resistances occurred and this was accompanied by a diuresis.7. After block of the alpha-adrenergic receptors by dibenzyline or ergotamine, manipulations which increased the hepatic portal venous pressure could still evoke an immediate reflex diuresis.8. Since the primary renal effect of catecholamines is a vasoconstriction and antidiuresis, it seems that the subsequent reduction of the renal vascular resistance and the associated diuresis is caused by some other mechanism.9. It is concluded that the complex effects of catecholamine on renal function represent the resultant of direct intrarenal together with indirect extrarenal actions and that the relative significance of these various actions depends on dose, time and the route of administration.

Animals↗
PubMed1971

Formation of malate from glyoxylate in animal tissues.

1. Incubation of rat liver homogenate with [1-(14)C]glyoxylate, ATP and acetate shows a rapid sequential incorporation of radioactivity into malate, oxaloacetate and citrate. 2. In liver from normal rats the rate of the formation of each substance in question is higher than that in liver from thiamin-deficient rats. 3. The net accumulation of malate is greater with liver from thiamin-deficient rats. Its further metabolism is retarded, it is suggested, by inhibitors formed by a condensation of glyoxylate and oxaloacetate.

Acetates↗
PubMed1971

The influence of hepatic portal circulation on urine flow.

1. A study of the effect of changes in the hepatic portal venous pressure (HPVP) on the rate of urine flow in dogs has been made. Normally this pressure varies between 3.7 and 14.9 cm H(2)O. It can be raised or lowered by varying the method of manipulation of the visceral organs.2. When the HPVP was raised within 15 cm H(2)O above the premanipulation level it caused an increase in urine flow to 2-3 times the normal levels within 2-5 sec. If the HPVP was raised to more than 15 cm H(2)O above the pre-manipulation levels it resulted in a period of antidiuresis. The urine flow returned rapidly to normal level immediately after the pressure was released.3. The kidney volume increased when an induced diuresis occurred and decreased when an antidiuresis occurred.4. The urine chloride concentration decreased during diuresis, but total chloride excretion increased. Total chloride excretion was reduced when an antidiuresis occurred.5. Topical application of local anaesthetics at the hilus of the kidney and on the renal nervous plexus abolished the response. This and other evidence indicate that this effect on urine flow is a result of nervous reflex activity, probably involving the sympathetic but not the vagus.6. The receptive area lies in the mesentery between the mesenteric capillaries and the main portal vein.

Anesthesia, Local↗
PubMedDate not supplied

Targeted correction of the point mutations of beta-thalassemia and targeted mutagenesis of the nucleotide associated with HPFH by RNA/DNA oligonucleotides: potential for beta-thalassemia gene therapy.

An RNA/DNA chimeric oligonucleotide was found to be effective in the targeted correction of point mutations in Escherichia coli, plant, and mammalian genomes. This strategy, named chimeraplasty, has the potential for gene therapy of many genetic diseases caused by point mutations. beta-Thalassemia is a very common human genetic disease and in most cases it is caused by point mutations. To test whether the chimeraplasty can be used to correct the point mutations responsible for beta-thalassemia, we introduced one mutated beta-globin gene, betaE, into MEL cells and successfully corrected the point mutation of the betaE gene with the highest correction efficiency of 1.9%. Furthermore, a targeted -202 C-->G mutation of the Ggamma-globin gene, which is associated with the elevated Ggamma-globin gene expression in the adult stage, was introduced into HeLa and CMK cells by an RNA/DNA oligonucleotide. These results indicated that the chimeraplasty has potential for human beta-thalassemia gene therapy.

Animals↗
PubMedDate not supplied

Prospects of chimeric RNA-DNA oligonucleotides in gene therapy.

A strategy called targeted gene repair was developed to facilitate the process of gene therapy using a chimeric RNA-DNA oligonucleotide. Experiments demonstrated the feasibility of using the chimeric oligonucleotide to introduce point conversion in genes in vitro and in vivo. However, barriers exist in the low and/or inconstant frequency of gene repair. To overcome this difficulty, three main aspects should be considered. One is designing a more effective structure of the oligonucleotide. Trials have included lengthening the homologous region, displacing the mismatch on the chimeric strand and inventing a novel thioate-modified single-stranded DNA, which was demonstrated to be more active than the primary chimera in cell-free extracts. The second aspect is optimizing the delivery system. Producing synthetic carriers for efficient and specific transfection is demanding, especially for treatment in vivo where targeting is difficult. The third and most important aspect lies in the elucidation of the mechanism of the strategy. Investigation of the mechanism of strand exchange between the oligonucleotide molecule and double-stranded DNA in prokaryotes may greatly help to understand the mechanism of gene repair in eukaryotes. The development of this strategy holds great potential for the treatment of genetic defects and other purposes.

Animals↗
PubMedDate not supplied

A possible sympathetic cholinergic mechanism in the renal reflex elicited by stimulation of abdominal viscera in the dog.

1. Isolated blood-bathed tissues which were superfused with renal venous blood during various manipulations of the visceral organs of dogs showed no detectable pharmacologically active substances, except a noradrenaline-like substance which was liberated under some conditions of manipulation. 2. An acetylcholine-like substance was liberated into renal venous blood during experimental manipulation of visceral organs in dogs during infusion of physostigmine; the acetylcholine activity was detected with the dorsal muscle of the leech. 3. The amount of liberated acetylcholine-like substance depended on the strength of visceral stimulation as judged by the changes in the hepatic portal venous pressure. Strong reflex stimulation produced the release not only of acetylcholine but also of noradrenaline. 4. Physostigmine augmented and prolonged the reflexly induced renal vasodilator and diuretic responses, and these were abolished by atropine. It was suggested that the reflex involves a cholinergic nervous mechanism. 5. In some dogs there was a high output of acetylcholine from the kidney during visceral stimulation, and this was accompanied by a decrease in urine flow. The reason was not known. 6. Prostaglandin E1 administered into the renal artery produced similar vasodilator and diuretic responses to acetylcholine, but the onset of the effects were slower and they persisted longer than those produced by acetylcholine.

Acetylcholine↗
PubMedDate not supplied

Scar endometriosis.

BACKGROUND: Scar endometriosis may develop after pelvic operations, such as cesarean section, tubal ligation, hysterotomy and hysterectomy. This prompted us to demonstrate the proper diagnosis; management and prophylactic procedure of scar endometriosis. METHODS: Twelve patients with scar endometriosis were diagnosed by clinical symptoms and signs, including a painful scar mass related to the menstrual cycle and cyclic bleeding from scars. Preoperative ultrasound needle aspiration cytology was arranged in three patients without painful mass. The management comprised complete surgical excision and selective medical treatment. Postoperative follow-up was scheduled at six-month intervals. RESULTS: Except for two patients who complained of scar pain but no palpable mass during menstruation, there was no evidence of recurrence in the other 10 patients. CONCLUSIONS: Diagnosis of scar endometriosis should involve detailed history taking and pelvic examination. Concerning the role of needle aspiration cytology, it still remains controversial. Several prophylactic procedures have been presented to prevent decidual contamination of the wound. Complete surgical excision including the adjacent fascia or skin is the proper treatment of scar endometriosis.

Adult↗