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Biomedical subjects

X P Zhou

Publications and source records attributed to X P Zhou.

14 recordsLinked to original sources
PubMed1996

Resection of meningiomas with implantable microwave coagulation.

Implantable microwave coagulation was used to perform resection on 62 patients that had intracranial meningiomas. When 20-60 W microwave power was applied for 15 s, the temperature at the center of the tumor tissue was 43-63 degrees C; 30 mm from the center, the temperature was under 40 degrees C. Histological changes in the center of the tumor showed coagulative necrosis, diminished nuclei, and obliterated blood vessels. The changes at 10-20 mm from the center of the tumor showed coagulative necrosis and degeneration and, 30-50 mm from the center of the tumor, showed normal cell morphology after microwave coagulation. The thermal field in brain tumor has an effective diameter of about 40 mm. No side effects on the normal brain tissues were observed. The amount of blood loss during the operation was minimal while the meningioma was coagulated, especially when the meningioma was located at the skull base or in the parasagittal or cerebral convexity region. After microwave coagulation, the entire tumor could easily be removed. Among the 62 surgically treated cases, gross total tumor excision was 85 percent. No postoperative complications occurred after microwave coagulation, and there was no operative mortality in the series. We believe that this new technique has the advantage of simplicity, less blood loss, and smooth postoperative procedures. Hemostatic effects during the operation are satisfactory, and blood transfusion can be reduced by 50-60 percent.

Adult↗
PubMed1996

Prevention of early glomerulopathy with tolrestat in the streptozotocin-induced diabetic rat.

Hyperglycemia is of central importance in the pathogenesis of the complications of diabetes mellitus. Glucose activation of the polyol pathway may lead to renal arteriolar smooth muscle and glomerular mesangial cell hypocontractility. In the streptozotocin-induced diabetic rat, the effect of the aldose reductase inhibitor, tolrestat, in preventing glomerular hyperfiltration, renal hypertrophy, extracellular matrix accumulation, and mesangial cell hypocontractility was addressed. Streptozotocin-induced diabetic rats were followed for 12 weeks and half received tolrestat (25 mg/kg per day). Increased glomerular filtration rate was prevented by tolrestat (3.1 +/- 0.3 vs. 1.8 +/- 0.2 mL/min, diabetes vs. diabetes + tolrestat, p < 0.01), in part by reduction of the filtration fraction (0.39 +/- 0.03 vs. 0.29 +/- 0.01, diabetes vs. diabetes + tolrestat, p < 0.01). Tolrestat prevented the raised albumin excretion rates (3594 +/- 1154 vs. 713 +/- 161 mg/24 h, diabetes vs. diabetes + tolrestat, p < 0.01). Endothelin-1-induced contraction of isolated glomeruli was normal in tolrestat-treated diabetic animals compared with the hypocontractile diabetic glomeruli. Tolrestat prevented glomerular hypertrophy (1.86 +/- 0.10 vs. 1.49 +/- 0.03 microns 2 x 10(5), diabetes vs. diabetes + tolrestat, p < 0.001) and attenuated the accumulation of basement-membrane-like material (50.2 +/- 0.4% vs. 46.4 +/- 0.8%, diabetes vs. diabetes+tolrestat, p < 0.001). Fractional mesangial expansion was unchanged in tolrestat-treated diabetic rats compared with untreated animals. Tolrestat prevents the functional changes of glomerular hyperfiltration, mesangial cell hypocontractility, and increased glomerular permeability to albumin. Polyol accumulation may have differential effects on glomerular growth and extracellular matrix accumulation in early diabetic nephropathy.

Ampholyte Mixtures↗
PubMed1996

Modulatory effects of gonadorelin on GABA-induced depolarization and GABA-activated current in rat spinal ganglion neurons.

AIM: To explore the modulatory effects of gonadorelin on GABA-induced depolarization and GABA-activated current in membrane of rat primary sensory neurons. METHODS: Intracellular recordings and whole-cell patch clamp techniques were performed on neurons in rat spinal ganglia (SG) preparation and neurons freshly isolated from rat SG, respectively. Drugs were applied by superfusion and/or by bath application. RESULTS: In the majority of neurons GABA (10 mumol.L-1 -1 mmol.L-1) induced a depolarization, which was blocked by bicucullin (100 mumol.L-1). Pretreatment with gonadorelin (50 mumol.L-1) decreased the GABA-induced depolarization by 79 +/- 22% (n = 29), while gonadorelin elicited no effect or slight depolarization alone. In 6 of 11 cells, GABA-activated currents were also inhibited by pretreatment with gonadorelin (50 mumol.L-1), while in 5 of 11 cells, there was no change or a slight potentiation. CONCLUSION: Gonadorelin exerts an inhibitory effect on GABA-induced depolarization and GABA-activated current in the primary sensory neurons.

Animals↗
PubMed1994

[Modulatory effects of substance P on the membrane responses mediated by GABAA and GABAB receptors in DRG neurons].

Intracellular recordings were performed on the neurons of young rat DRG to study the modulatory effects of SP on the responses mediated by GABAA and GABAB receptors. In the majority of the neurons (20/30) the GABA induced depolarization was suppressed to 50.8 +/- 20.2% by preapplication of SP (5 x 10(-6)-4 x 10(-5) mol/L), which applied alone had no effect or only caused a slight depolarization. In addition, SP could increase APD50 by 28.7 +/- 9.1% in many neurons (10/18), and the baclofen-induced shortening of 20.6 +/- 2.9% in APD50 could abolished (4/12) or even reverse to a lengthening of 19.3 +/- 8.9% in APD50 (8/12) by the preapplication of SP. Moreover, it was found that the activation of GABAB receptors could inhibit the succeeding response mediated by GABAA receptors. Since the soma of the DRG neuron is generally considered as an accessible model for the primary afferent terminals, the results suggest that SP which is released in the dorsal horn during nociceptive stimulation can antagonize the responses mediated by GABAA and GABAB receptors.

Action Potentials↗
PubMed1994

[Effect of jiutuo II injection on shock model of superior mesenteric artery occlusion in rabbit].

Tang's SMAO method was adopted to produce shock model to observe the efficacy of the Jiutuo II(JTII) intravenously given. It was found that JTII could normalize the BP rapidly, which were superior to that of Dopamine and NS groups (P < 0.05, P < 0.01). At the same time, it could decrease mortality rate, comparing with Dopamine and NS the difference was significant (P < 0.05, P < 0.01); and it could also inhibit the formation of lipid peroxides (LPO). The contents of LPO in heart, liver, kidney of shock rabbit were obviously lower than that of Dopamine and NS groups (P < 0.05, P < 0.01). The electron microscopy indicated that the drug could relieve the injury of mitochondria and lysosome in the tissues of heart, liver and kidney and protect the cellular ultrastructure of cardinal viscera. This study suggests that the JTII had good efficacy in treating the shock rabbit caused by SMAO method.

Animals↗
PubMed1993

Dependence of cardiac filling pressure on cardiac output during rest and dynamic exercise in dogs.

At rest, central venous pressure (CVP) falls when cardiac output (CO) rises. This can be attributed to flow-dependent redistribution of blood volume from central to peripheral blood vessels. In contrast, CVP rises during dynamic exercise despite a rise in CO. Therefore peripheral circulatory changes during exercise must counteract the factors that lower CVP when CO rises during rest. Our objectives were to determine the importance of blood flow, the muscle pump, and reflexes on changes in ventricular filling pressure during dynamic exercise. In seven dogs with a surgically produced atrioventricular (AV) block, normal relationships between CO and CVP were established by AV-linked pacing (normal heart rates) during rest and exercise. Cardiac output was altered during rest and treadmill exercise (4 miles/h at 0, 10, or 20% grade) by changing ventricular pacing rate to establish curves relating delta CVP to delta CO. These curves were displaced rightward (higher CO) and upward (higher CVP) by exercise because of the muscle pump. Changing CO by pacing during rest and exercise revealed a constant slope for delta CVP/delta CO of -2.7 mmHg.l-1.min-1. Blockade of reflex vasoconstriction and venoconstriction with hexamethonium at rest and during mild exercise (to isolate effects of the muscle pump) did not alter these slopes or the displacement of the curves by exercise, although CVP was 4.3 mmHg lower at a given CO after blockade.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Streptozotocin induced cardiomyopathy in diabetic rats.

Microscopic quantitative cardiomyopathy was previously reported in spontaneous diabetic biobreeding (BB) rats, but the nature of the lesions remains obscure. To further study the specificity of cardiomyopathy in streptozotocin-diabetic rats and discuss the existence of diabetic heart disease, we compared 40 streptozotocin-diabetic rats (D group) with 40 normal control rats (C group) at various durations in plasma glucose, fructosamine, plasma lipid, left ventricular enzyme contents and alterations of myocardial cells and coronary artery tree under electron and light microscope respectively. In 4 weeks, D rats showed myocardial mitochondrial swelling and degeneration, whereas at 8 weeks, myocardial enzyme contents markedly decreased, and myocardial lesions were more conspicuous with disruption of myocardial cells, formation of myocardial contraction bands, dilatation of intercalated discs, deposition of glycogen granules, etc. At 11 weeks, microscopic changes were essentially similar, whereas the decrease of enzyme contents became more conspicuous. During the 11 weeks, persistent and marked hyperglycemia and elevation of fructosamine were observed, however, no abnormalities were found along the coronary artery tree in the D rats. The results indicated that cardiomyopathy is diabetes specific, and exists independently as one of the three important components of diabetic heart disease.

Animals↗
PubMed1992

[Relationship between neuronal activities of the guinea-pig inferior mesenteric ganglion neurons and muscular contraction of the colon in vitro].

A perfused inferior mesenteric ganglion (IMG)-colon preparation was prepared from the guinea-pig for intracellular recording of IMG neurons and for simultaneously recording the muscular contraction. It was found that: (1) At zero preloaded tension of colon, the spontaneous fast excitatory post-synaptic potentials (f-EPSPs) could be recorded in about 50% sampled neurons. These f-EPSPs were abolished by either severing the colonic nerve or superfusing IMG with d-tubocurarine (d-TC, 50 mumol/L). (2) The contraction of circular but not longitudinal muscle was augmented and slowed down by superfusing IMG with d-TC or low Ca/high Mg solution. (3) A train stimulation of the preganglionic nerves initiated a volley of f-EPSPs or orthodromic discharges, in the IMG neurons and a quick relaxation of the longitudinal muscle with a latency of between 0.1 s and 0.2 s. The responses of the neuron and the muscle could be eliminated by superfusing IMG with d-TC. Multiple irregular responses of the circular muscle of the colon to the train stimulation could also be found. The results suggest that the IMG neurons participate in the cholinergic afferents and colo-colonic reflex mediated by cholinoceptors. The output of the reflex mainly inhibited the circular muscle contraction of the colon.

Action Potentials↗
PubMed1991

[Effect of adrenal cortical hormones on the expression of atrial natriuretic peptide (ANP) gene in vivo].

Experiments were conducted in intact and adrenalectomized female Wistar rats given dexamethasone, deoxycorticosterone or both, and atria total RNA was extracted with cold phenol method and hybridized to rat ANP-cDNA probe labeled with alpha-32P. The ANP gene transcripts in intact rats receiving dexamethasone and in adrenalectomized rats receiving dexamethasone and deoxycorticosterone increased by 2-fold, while there were no significant changes in the other groups. The results suggest that glucocorticoids enhance ANP gene expression, an effect relying on the presence of mineralocorticoids which given alone does not give rise to ANP gene expression enhancement.

Animals↗
PubMed1990

Dynamic observation on thyroid function in severe head injury.

The dynamic changes of thyroid hormone levels in patients with severe head injury were observed. The results showed that the serum thyroid hormone levels changed rapidly within several hours after the injury and the mean levels of serum total T3 and T4 (TT3, TT4) decreased while high reverse triiodothyronine (rT3) increased significantly. Serum TT3, TT4 and rT3 levels returned to normal gradually in 2 to 3 weeks after the injury in the surviving group, whereas serum total T4 gradually declined and rT3 steadily increased in the fatal group. The mean levels of serum TSH remained unchanged in both groups. Therefore, the use of the levels of serum thyroid hormones as adjuvant indices can be helpful in making pertinent judgements of the severity and prognosis of severe head injuries.

Adult↗
PubMed1990

Electronmicroscopic observation on chronic cardiopathy in spontaneous diabetic biobreeding rats.

The ultrastructural changes of chronic cardiopathy in diabetic biobreeding rats were observed electronmicroscopically. The thickness of the myocardial capillary basement membrane (CBM) and volume fraction of myofilaments in the myocardium were quantitatively measured with a video interactive display system III (VIDS-III). The effect of metabolic control on chronic diabetic cardiopathy was also investigated.

Actin Cytoskeleton↗
PubMed1987

Blindness from intracranial tumors: a clinical analysis of 60 cases.

We analyzed the cause of blindness in 60 people with intracranial tumors. Twenty-three (38.3%) had binocular blindness, thirty-seven (61.2%) had monocular blindness. The most common tumors producing blindness were pituitary chromophobe adenomas and craniopharyngiomas. Blindness in this series resulted usually from intracranial tumors, which directly or indirectly involved the optic nerve or optic chiasma. These tumors were sometimes misdiagnosed when these patients were first examined by physicians. Specific ophthalmic examinations should permit the diagnosis to be made earlier.

Adolescent↗