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Biomedical subjects

H M Liu

Publications and source records attributed to H M Liu.

At least 145 records · Page 8Linked to original sources
PubMed1985

Arterialized capillary blood gases and acid-base studies in normal individuals from 29 days to 24 years of age.

Studies of arterialized capillary blood gases and acid-base values were performed on 712 normal persons who were between the ages of 29 days and 24 years. The results were divided for clinical use into six groups by age; linear regression lines were constructed for better understanding of the development of blood gas levels and the acid-base balance. The blood pH essentially remained unchanged throughout the study period. The oxygen and carbon dioxide pressures, base excess of extracellular fluid, and buffer base and bicarbonate levels are lower in infants than in children and adults; adult values are reached at approximately 7 to 12 years of age. The probable explanation for the lower values in infants is discussed. The effects of crying on the composition of blood gases are mentioned.

Acid-Base Equilibrium↗
PubMed1985

[Cisplatin for malignant lymphoma--preliminary observation on 43 patients].

This paper reports the treatment results of cisplatin in 43 cases of malignant lymphoma. All were proved by pathology, cytology or X-ray and were non-resectable, disseminated advanced or refractory to routine anticancer drugs. The total dose of each course of cisplatin was usually 100-150 mg (2 mg/kg). One fifth or a tenth part of the dose was given with normal saline intravenously once a day. Complete remission rate was 9%, partial remission rate was 28%. Lymphosarcoma and reticulum cell sarcoma gave better results. During the treatment, anorexia, nausea and vomiting were common. Mild or moderate reduction of WBC and platelet was usually observed in the partial responsive cases but the depression on the bone marrow was relative mild. Cisplatin therapy did not cause marked renal dysfunction which was probably due to the hydration instituted. The anticancer action of cisplatin is similar to that of the alkylating agents but the participation of immunologic mechanism may also play a role.

Adult↗
PubMed1982

Isolation and characterization of a recombinant plasmid carrying a functional part of the Bacillus subtilis spoIIA locus.

Plasmid pHM2 consists of a 3.3 kb insert of Bacillus subtilis DNA in the chimeric plasmid pHV33, and can replicate in Escherichia coli and B. subtilis. In B. subtilis, pHM2 complements the defects resulting from mutations spo-42, spo-50, spo-69 and sas-1 in the spoIIA locus. This complementation can occur in recE4 strains where recombination of the plasmid with the chromosome is prevented, and the chromosome retains the mutant allele. Thus the plasmid carries a functional part of the spoIIA locus; it does not contain the complete locus as it cannot complement several other spoIIA mutations. It is likely that the locus is complex, containing at least two genes.

Bacillus subtilis↗
PubMed1982

Facile in vivo transfer of mutations between the Bacillus subtilis chromosome and a plasmid harbouring homologous DNA.

Transformation of Bacillus subtilis strains carrying the point mutations spoIIA42 or spoIIA69 by a plasmid, pHM2, carrying the spoIIA+ allele gave occasional recombinants in which the plasmid had acquired the chromosomal mutation. Transformation of a spo+ strain by these derivative plasmids gave occasional recombinants in which the chromosome of the recipient had acquired the plasmid-borne spoIIA mutation. Both types of behaviour were recE+-dependent. Mutations spoIIA42 and spoIIA69 fell into a single complementation group.

Alleles↗
PubMed1981

Vasopressin release by nicotine in the cat.

Our goal in this study was to examine where nicotine acted on the neurohypophysial release of arginine vasopressin (AVP). In the chamber-isolated, unanesthetized cat, an IV infusion of nicotine (25--50 micrograms/kg/min for 10 min) produced a 54-fold rise in plasma AVP (65 +/- 12.5 microU/ml) and a behavioral sequence of restlessness, ear twitching, salivation, chewing and retching. Chloralose anesthesia and acute surgical preparation increased plasma AVP (9.4 +/- 3.8 microU/ml) 4-times the control level in the unanesthetized state (2.4 +/- 0.1 microU/ml). In the anesthetized cat, an IV infusion of nicotine produced a 140-fold rise in plasma AVP (802.7 +/- 289.0 microU/ml) and a biphasic response in mean arterial blood pressure (MABP) which rose to 32% above control in the first 5 min and fell to 25% below control during the last 5 min. Bilateral surgical section of the carotid sinus and vagus nerves increased plasma AVP (47.6 +/- 25.8 microU/ml) to 5-times the control level in the anesthetized state (9.4 +/- 3.8 microU/ml). In the anesthetized, baroreceptor-denervated cat, an IV infusion of nicotine produced a 3-fold rise in plasma AVP (141.5 +/- 31.3 microU/ml) and a biphasic MABP response. Hypophysectomy abolished the nicotine-induced rise in AVP but did not modify the biphasic MABP response. These data suggest that in the cat nicotine releases AVP from the neurohypophysis by multiple sites of action within the receptive fields of te carotid sinus and vagus nerves and at unknown loci within the central nervous system.

Animals↗
PubMed1981

Osmotic regulation of vasopressin in the cat.

This study examines the effects of blood osmolality on the release of arginine vasopressin (AVP) in the cat. Prior to the beginning of the experiments, the chamber-isolated, unanesthetized cat, allowed water ad libitum had a constant plasma osmolality averaging 320 +/- 2 (SE) mosmol/kg and a constant plasma AVP averaging 3.4 +/- 0.7 microU/ml. Water loading decreased plasma osmolality to 312 +/- 2 mosmol/kg and lowered plasma AVP to 1.3 +/- 0.2 microU/ml. As dehydration occurred during fluid restriction, the plasma osmolality increased and plasma AVP rose to 8 times the base line after 2 days. The rise in plasma AVP correlated linearly with the rise in plasma osmolality (r = 0.81; P less than 0.01). The cat's osmotic-vasopressin relationships are unique among mammals, revealing an elevated osmotic "set point" (threshold) and with regression analysis an increased "gain" or "'sensitivity" (increased slope of the regression line). We speculate that these unusual osmotic-AVP relationships may be related to some specialized features of the cat, such as hypothalamic anatomy or cerebral arterial blood supply.

Animals↗
PubMed1978

Methotrexate encephalopathy. A neuropathologic study.

The present report is a neuropathologic study of three patients who died from a severe form of necrotizing encephalopathy following intrathecal methotrexate therapy and craniospinal irradiation for acute lymphoblastic leukemia. During the early phase the lesion presented as multifocal coalescing areas of coagulation necrosis in the deep white matter. In the diseased areas the myelin was lost and the axons were severely swollen and fragmented. During the late stage the white matter was reduced to a thin gliotic calcified layer. The pathogenesis of this lesion is unclear, but the preferential involvement of the white matter with sparing of the cortical gray matter and basal ganglia makes it unlikely that direct chemical injury is the cause. The distribution of the lesion suggests a vascular disturbance due to endothelial injury caused by interaction of the methotrexate with tissue infiltrated by leukemic cells and altered by irradiation.

Brain↗
PubMed1978

Central hypoventilation syndrome: experience with bilateral phrenic nerve pacing in 3 neonates.

Successful long-term phrenic nerve pacing has been reported in adults with acquired central hypoventilation syndrome. This report summarizes our experience with phrenic nerve pacing in 3 infants with congenital central hypoventilation syndrome. The electrodes were implanted in the lower thoracic portion of each phrenic nerve. In all patients. bilateral simultaneous pacing was required to maintain an adequate arterial PO2, tidal volume, and minute ventilation during quiet sleep. Case 1 died of problems primarily related to the severe cor pulmonale that had been present before pacemaker insertion; at autopsy, the pacemaker system was intact and there were no significant phrenic nerve abnormalities. Case 2 later developed failure of awake ventilatory control and died because of extensive phrenic nerve damage incurred by 19 days of continuous pacing. Case 3 has received quiet sleep pacemaker support since September 1977 and has been able to maintain normal quiet sleep ventilation in this manner. Phrenic nerve pacing can be successful in infants as long as continuous pacing is not required. Bilateral simultaneous pacing appears to be an appropriate alternative to home-based intermittent positive-pressure breathing for long-term management of children with central hypoventilation syndrome.

Electric Stimulation↗