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Biomedical subjects

C L Huang

Publications and source records attributed to C L Huang.

At least 109 records · Page 6Linked to original sources
PubMed1996

Correlation of KAI1/CD82 gene expression with good prognosis in patients with non-small cell lung cancer.

As part of our evaluation of members of the transmembrane 4 super-family as possible prognostic predictors, we performed a retrospective study on the expression of the recently identified KAI1 gene by tumors of the lung. This gene, which is identical to CD82, suppresses tumor metastasis of prostate cancer, and its decreased expression may be involved in malignant progression. We used reverse transcription-PCR to analyze tumor tissues from 151 lung cancer patients; 74 tumors were stage I, 17 were stage II, and 60 were stage III. Our results indicate that while 35 patients had tumors in which the KAI1/CD82 gene was conserved (positive), 116 patients had tumors with reduced gene expression (negative). The overall survival rate of patients with KAI1/CD82-positive tumors was significantly higher than that of patients with KAI1/CD82-negative tumors (77.4% versus 38.5%; P=0.002). Furthermore, the overall survival rate of patients with KAI1/CD82-positive adenocarcinoma was also much higher than that of individuals whose adenocarcinoma had reduced KAI1/CD82 expression (73.4% versus 27.1%;P=0.009). Multivariate analysis with the Cox regression model indicated that KAII/CD82 positivity correlated best with the overall survival rate, except for lymph node status. Our data suggest that high KAII/CD82 gene expression by tumors of the lung may be associated with a good prognosis. These findings complement our earlier studies on MRP-1/CD9, another member of the transmembrane 4 superfamily, whose reduced expression in non-small cell lung cancer appears to be a factor of poor prognosis. This set of observations suggests that assessment of the expression status of KAI1/CD82 and MRP-1/CD9 by tumors may provide prognostic information on the clinical behavior of lung cancer.

Age Factors↗
PubMed1996

Antenatal management of alloimmune thrombocytopenia with intravenous gamma-globulin: a randomized trial of the addition of low-dose steroid to intravenous gamma-globulin.

OBJECTIVES: Our purposes were to investigate maternal infusions of intravenous gamma-globulin, to prevent intracranial hemorrhage, and to determine whether 1.5 mg dexamethasone and 60 mg prednisone per day add to the effect of intravenous gamma-globulin. STUDY DESIGN: Fifty-four women with alloimmune thrombocytopenia and thrombocytopenic fetuses were randomized to intravenous gamma-globulin 1 gm/kg per week with or without dexamethasone. Nonresponders after 4 to 6 weeks received continued intravenous gamma-globulin plus 60 mg of prednisone per day ("salvage"). RESULTS: Dexamethasone did not add to the effect of intravenous gamma-globulin. Overall, there was a mean platelet increase from the first to the second fetal blood sampling of 36,000/microliters (n = 47) and from the first fetal blood sampling to birth of 69,000/microliters (n = 54). A total of 62% to 85% of fetuses responded. There were no intracranial hemorrhages. "Salvage" increased the platelet count in 5 of 10 nonresponders to intravenous gamma-globulin. CONCLUSION: Intravenous gamma-globulin treatment is appropriate for thrombocytopenic fetuses with alloimmune thrombocytopenia before use of weekly in utero platelet transfusions, even in severe thrombocytopenia.

Cerebral Hemorrhage↗
PubMed1996

Acquired generalized hypohidrosis/anhidrosis with subclinical Sjögren's syndrome: report of a case with diffuse syringolymphoid hyperplasia and lymphocytic sialadenitis.

The pathogenesis and the underlying pathologic changes of acquired generalized hypohidrosis/anhidrosis (AGHA) are largely unknown. We studied a case of AGHA in a young woman suffering from heat intolerance and progressive loss of sweating. Pathologic study of affected skin revealed unique syringolymphoid hyperplasia with T cell infiltration, suggesting a T cell-mediated autoimmune disease. The patient also had subclinical Sjögren's syndrome and diffuse hair loss. The pathogenesis of the latter two conditions is believed to be related to the patient's AGHA.

Adult↗
PubMed1996

Neurocutaneous melanosis: clinical features of large congenital melanocytic nevi in patients with manifest central nervous system melanosis.

BACKGROUND: Patients with a large congenital melanocytic nevus (LCMN) may have associated leptomeningeal melanocytosis with or without central nervous system (CNS) melanomas. These patients are considered to have neurocutaneous melanosis, a disorder that, when symptomatic or otherwise manifest neurologically, carries a poor prognosis even in the absence of malignancy. OBJECTIVE: Our purpose was to identify typical clinical features in patients who have manifest CNS melanosis in association with LCMN. METHODS: The records of 117 patients with LCMN in the New York University Registry of LCMN and the reports of 172 cases of LCMN in the world literature were included for features that might signal a high risk for the development of manifest CNS involvement. RESULTS: Of the 289 patients with LCMN, 33 had manifest CNS melanosis. In all 33 in whom symptomatic neurocutaneous melanosis was diagnosed, the LCMNs were present in a posterior axial location on the head, neck, back, and/or buttocks. "Satellite" nevi were known to be present in 31 of the 33 patients. CONCLUSION: Patients with LCMN in a posterior axial location, especially when associated with "satellite" melanocytic nevi, are at greater risk for the development of manifest neurocutaneous melanosis than patients with LCMN limited to the extremities or those who are lacking satellite nevi.

Adolescent↗
PubMed1996

Kinetic isoforms of intramembrane charge in intact amphibian striated muscle.

The effects of the ryanodine receptor (RyR) antagonists ryanodine and daunorubicin on the kinetic and steady-state properties of intramembrane charge were investigated in intact voltage-clamped frog skeletal muscle fibers under conditions that minimized time-dependent ionic currents. A hypothesis that RyR gating is allosterically coupled to configurational changes in dihydropyridine receptors (DHPRs) would predict that such interactions are reciprocal and that RyR modification should influence intramembrane charge. Both agents indeed modified the time course of charging transients at 100-200-microM concentrations. They independently abolished the delayed charging phases shown by q gamma currents, even in fibers held at fully polarized, -90-mV holding potentials; such waveforms are especially prominent in extracellular solutions containing gluconate. Charge movements consistently became exponential decays to stable baselines in the absence of intervening inward or other time-dependent currents. The steady-state charge transfers nevertheless remained equal through the ON and the OFF parts of test voltage steps. The charge-voltage function, Q(VT), shifted by approximately +10 mV, particularly through those test potentials at which delayed q gamma currents normally took place but retained steepness factors (k approximately 8.0 to 10.6 mV) that indicated persistent, steeply voltage-dependent q gamma contributions. Furthermore, both RyR antagonists preserved the total charge, and its variation with holding potential, Qmax (VH), which also retained similarly high voltage sensitivities (k approximately 7.0 to 9.0 mV). RyR antagonists also preserved the separate identities of q gamma and q beta species, whether defined by their steady-state voltage dependence or inactivation or pharmacological properties. Thus, tetracaine (2 mM) reduced the available steady-state charge movement and gave shallow Q(VT) (k approximately 14 to 16 mV) and Qmax (VH) (k approximately 14 to 17 mV) curves characteristic of q beta charge. These features persisted with exposure to test agent. Finally, q gamma charge movements showed steep voltage dependences with both activation (k approximately 4.0 to 6.5 mV) and inactivation characteristics (k approximately 4.3 to 6.6 mV) distinct from those shown by the remaining q beta charge, whether isolated through differential tetracaine sensitivities, or the full approximation of charge-voltage data to the sum of two Boltzmann distributions. RyR modification thus specifically alters q gamma kinetics while preserving the separate identities of steady-state q beta and q gamma charge. These findings permit a mechanism by which transverse tubular voltage provides the primary driving force for configurational changes in DHPRs, which might produce q gamma charge movement. However, they attribute its kinetic complexities to the reciprocal allosteric coupling by which DHPR voltage sensors and RyR-Ca2+ release channels might interact even though these receptors reside in electrically distinct membranes. RyR modification then would still permit tubular voltage change to drive net q gamma charge transfer but would transform its complex waveforms into simple exponential decays.

Animals↗
PubMed1996

Nitric oxide as a mediator of cocaine-induced penile erection in the rat.

1. The effect of local application of cocaine to the corpus cavernosum on intracavernous pressure (ICP), an experimental index for penile erection, was examined in Sprague-Dawley rats anaesthetized with chloral hydrate. The potential involvement of dopamine, noradrenaline or nitric oxide as the chemical mediator in this process, and the pharmacological action of cocaine as a local anaesthetic in the induced increase in ICP, were also investigated. 2. Intracavernous (i.c.) administration of cocaine (40, 80 or 160 micrograms) to the corpus cavernosum resulted in a dose-related increase in both amplitude and duration of ICP. 3. The elevation of ICP induced by cocaine (160 micrograms, i.c.) was not significantly influenced by prior injection into the corpus cavernosum of either the D1 or D2 dopamine receptor antagonist, R-(+)-SCH 22390 (250 pmol) or (-)-sulpiride (250 pmol). 4. Similarly, penile erection promoted by cocaine (160 micrograms, i.c.) was not appreciably affected by i.c. pretreatment with the alpha 1-, alpha 2-, or beta-adrenoceptor antagonist, prazosin (50 pmol), yohimbine (50 pmol) or propranolol (5 nmol). 5. Whereas lignocaine (4 mumol, i.c.) depressed penile erection induced by papaverine (400 micrograms, i.c.), local application of cocaine (160 micrograms) into the corpus cavernosum still elicited significant elevation in ICP in the presence of lignocaine or papaverine. 6. The increase in ICP induced by cocaine (160 micrograms, i.c.) was attenuated dose-dependently by prior cavernosal administration of the NO synthase inhibitor, N omega-nitro-L -arginine methyl ester (L-NAME, 0.5, 1 or 5 pmol) or NG-monomethyl-L-arginine (L-NMMA, 2.5, 5 or 10 pmol). The blunting effect of L-NAME or L-NMMA was reversed by co-administration of the NO precursor, L-arginine (1 nmol, i.c.). 7. Pretreatment by local application into the corpus cavernosum of methylene blue (2.5 mumol), an inhibitor of cytosolic guanylyl cyclase, antagonized cocaine-induced penile erection. 8. Direct i.c. administration of a NO donor, nitroglycerin (10 or 20 nmol), mimicked the local action of cocaine by promoting a significant increase in ICP. 9. It is concluded that cocaine may induce penile erection by increasing ICP via a local action on the corpus cavernosum. This process did not appear to involve either dopamine or noradrenaline as the chemical mediator, nor the pharmacological action of cocaine as a local anaesthetic. On the other hand, it is likely that initiation and maintenance of penile erection elicited by cavernosal application of cocaine engaged an active participation of NO and subsequent activation of guanylyl cyclase in the corpus cavernosum.

Anesthetics, Local↗
PubMed1996

Extracellularly applied ruthenium red and cADP ribose elevate cytosolic Ca2+ in isolated rat osteoclasts.

We demonstrated recently that the divalent cation-sensing receptor on the osteoclast, the Ca2+ receptor (CaR), is a functional component of a cell surface-expressed ryanodine receptor-like molecule (RyR). The objective of the present study was to further characterize this putative RyR by use of the two well-known cell-impermeant RyR modulators, ruthenium red and adenosine 3',5'-cyclic diphosphate ribose (cADPr). We found that, when applied extracellularly, ruthenium red (5 x 10(-8)-10(-4) M) and cADPr (5 x 10(-6) M) triggered an elevation of cytosolic [Ca2+]. Depolarization of the cell membrane by the application of 0.1 M K+ in the presence of 5 x 10(-6) M. valinomycin resulted in a concentration-dependent increase in the magnitude of the cytosolic Ca2+ response to extracellular ruthenium red (5 x 10(-9) and 5 x 10(-5) M), a phenomenon that was not seen when osteoclasts were hyperpolarized using 5 x 10(-3) M K+ with 5 x 10(-6) M valinomycin. In the presence of an intact nonleaky cell membrane, these results would favor a plasma membrane locus of action for the two modulators. Furthermore, pretreatment of osteoclasts with either modulator resulted in a markedly attenuated cytosolic Ca2+ transient elicited in response to the CaR agonist Ni2+, thus confirming an interaction between the cADPr- and ruthenium red-sensitive sites and the osteoclast CaR. The inhibition of the cytosolic Ca2+ response to Ni2+ induced by ruthenium red remained unchanged in the face of membrane potential changes. Finally, the cytosolic Ca2+ response to caffeine (5 x 10(-4) M), another RyR modulator, was also strongly attenuated by pretreatment with 5 x 10(-9) M ruthenium red. We conclude that ruthenium red and cADPr act on plasma membrane-resident sites and that both these sites interact with the process of divalent cation sensing.

Adenosine Diphosphate Ribose↗
PubMed1996

Prophylaxis against acid aspiration in regional anesthesia for elective cesarean section: a comparison between oral single-dose ranitidine, famotidine and omeprazole assessed with fiberoptic gastric aspiration.

BACKGROUND: Acid aspiration syndrome is still an important cause which contributes to maternal mortality in obstetric anesthesia. In this study, we compared famotidine, ranitidine, omeprazole with placebo for prophylaxis against aspiration pneumonitis in elective Cesarean section under regional anesthesia. METHODS: One hundred and sixty patients undergoing elective Cesarean section under spinal anesthesia were allocated randomly into four groups: Group P (n = 40) received placebo only; Group F (n = 40) received famotidine 40 mg Group R (n = 40) received ranitidine 300 mg; and Group O (n = 40) received omeprazole 40 mg. All drugs were given orally at least three hours before the patients entering the operating room. Gastric content was directly aspirated and measured respectively with a flexible fiberoscope under visualization and by a pH meter after delivery. RESULTS: Although these three drugs (F, R, and O) were all effective in controlling the secretion of gastric acid, from gastric analysis it was demonstrated that famotidine and ranitidine could be more defective to neutralize acidity than omeprazole (p < 0.05). Percentages of patients with pH < or = 2.5 in Groups P, F, R, and O were respectively 88%, 10%, 8%, and 21%, showing that the innate pH of gastric juice was far lower than expected. Patients receiving omeprazole in single oral dose regimen retained a greater gastric volume (> or = 0.4 ml/kg) than those who received famotidine or ranitidine (p < 0.005). From the criteria defining the patients "at risk" (pH < or = 2.5 and gastric volume > or = 0.4 ml/kg), it is speculated that all these three regimens could potentially reduce the incidence of patients with calculated risk. CONCLUSIONS: Our data demonstrated that parturients under regional anesthesia were at a higher risk of aspiration pneumonitis than generally thought. Single dose of ranitidine or famotidine administered orally three hours before surgery provided a more effective means to control and neutralize gastric secretion than omeprazole in parturients.

Administration, Oral↗
PubMed1996

[Studies on a new type of all-solid-state atropine ion-selective electrode].

Using urea-formaldehyde resin as frame material and KCl powder as active component, a Ag/AgCl solid state electrode was prepared. Then, using the prepared Ag/AgCl solid state electrode as substrate and atropine tetraphenylborate ion-pair complex as active component, a new type of all-solid-state atropine ion-selective electrode was constructed. The properties of this electrode were studied in detail. The results indicate that the electrode showed good stability and can be used for potentiometric determination of atropine in pharmaceutical preparations.

Atropine↗
PubMed1995

Reduced motility related protein-1 (MRP-1/CD9) gene expression as a factor of poor prognosis in non-small cell lung cancer.

Motility related protein-1 (MRP-1) is a transmembrane glycoprotein that is identical to the CD9 antigen. In previous studies, we showed that various types of cultured tumor cells transfected with MRP-1/CD9 cDNA have low motility and diminished metastatic potential to the lung. More recently we used immunohistochemical procedures, immunoblotting, and reverse transcription-PCR to demonstrate that the level of MRP-1/CD9 expression was inversely related to the clinical stage of a given carcinoma of the breast. In addition, we found that the primary tumors of almost 50% of the patients had higher MRP-1/CD9 levels than their respective metastatic lymph nodes. In consideration of these findings, we have now applied reverse transcription-PCR to determine MRP-1/CD9 gene expression in lung cancer. We analyzed tumor tissues of 109 patients: 49 tumors were stage I; 15 were stage II; and 45 were stage III. We found that 67 patients had MRP-1/CD9-positive tumors, and that gene expression was reduced in the tumors of the remaining 42 individuals. The overall rate of survival was strikingly higher among patients with positive tumors than in those whose tumors had reduced gene expression (62.3 versus 34.9%; P < 0.001). This also pertained to patients with adenocarcinomas of the lung (55.4 versus 26.0%; P < 0.001). Multivariate analysis with the Cox regression model indicated that MRP-1/CD9 positivity correlated better with overall survival rate than did other variables, except lymph node status. Our data suggest that low MRP-1/CD9 expression by tumors of the lung may be associated with poor prognosis. It is conceivable that testing for MRP-1/CD9 may identify node-negative lung cancer patients and patients with adenocarcinomas who are at high risk for early disease recurrence.

Antigens, CD↗
PubMed1995

Motility related protein 1 (MRP-1/CD9) expression: inverse correlation with metastases in breast cancer.

In our previous studies we showed that motility related protein 1 (MRP-1) is a glycoprotein recognized by mAb M31-15, and that the sequence of MRP-1 is identical to that of CD9, a WBC differentiation antigen. Transfection of MRP-1/CD9 cDNA into cultured nonhematopoietic cells suppresses cell motility. The extent of suppression is directly related to the level of MRP-1/CD9 expression. In addition, the metastatic potential of MRP-1/CD9-transfected melanoma BL6 cells is lower than that of control BL6 cells. To determine whether these experimental results are of relevance with respect to actual human tumors, we investigated MRP-1/CD9 expression in 143 invasive ductal carcinomas of the breast. Of 97 patients with MRP-1/CD9-positive tumors, only 36 (37.1%) had lymph node involvement. In contrast, 21 of 39 (53.8%) patients whose tumors had reduced MRP-1/CD9 immunoreactivity and 5 of 7 patients whose primary carcinomas were not stained by the anti-MRP-1/CD9 MAb had lymph node metastases. The comparison of protein expression by 62 primary tumors and their respective metastatic lymph nodes revealed that in almost 50% of the cases, the latter had lower MRP-1/CD9 levels than the former. Moreover, reverse transcriptase-PCR-based analysis disclosed that MRP-1/CD9 gene expression in the metastatic lymph nodes of 17 of 32 patients was strikingly lower than in the primary invasive ductal carcinomas. Gene overexpression was not observed in any of the samples studied. Our data suggest that low MRP-1/CD9 expression may be associated with the metastatic potential of certain human tumors.

Adult↗
PubMed1995

Effect of membrane potential on surface Ca2+ receptor activation in rat osteoclasts.

Osteoclasts are known to possess a divalent cation-sensitive receptor, the Ca2+ receptor (CaR). The latter monitors changes in the local Ca2+ concentration generated as a result of hydroxyapatite dissolution. CaR activation elevates cytosolic [Ca2+] and thereby inhibits osteoclastic bone resorption. Recent studies have used Ni2+ as a surrogate CaR agonist to elicit changes in cytosolic [Ca2+]. This article examines the effects of membrane potential changes on the kinetics of the cytosolic [Ca2+] signal resulting from such Ni(2+)-induced CaR activation. Membrane potential was altered through variations in the extracellular [K] in combination with applications of the K+ ionophore, valinomycin. Membrane potential changes were confirmed by independent electrophysiological patch clamp studies of whole osteoclasts. The application of valinomycin produced a distinct, sustained elevation of cytosolic [Ca2+] in single fura 2-loaded cells, a "primary" response. This response was independent of valinomycin concentration (between 5 nM to 5 microM) and persisted in Ca(2+)-free, EGTA-containing solutions. It also persisted both in high (105 mM) and low (5 mM) extracellular [K+]. A gradual "secondary" elevation of cytosolic [Ca2+] then followed with the continued application of valinomycin, but this was eliminated by sequestering the extracellular [Ca2+] or by increasing extracellular [K+] from 5 to 105 mM. In a separate set of experiments, the presence of 5 microM [valinomycin]-([K+] = 5 mM) prolonged the cytosolic [Ca2+] signal elicited by 50 microM-[Ni2+] application. These prolonged kinetics persisted in low extracellular [Ca2+] (zero-added Ca2+), but reverted to a rapid time-course in the presence of 105 mM-[K+] or at higher [Ni2+] (500 microM and 5 mM). The experiments thus indicate that membrane voltage modifies the kinetics of CaR activation by Ni2+ and therefore suggests that the CaR is an integral protein in the osteoclast surface membrane.

Animals↗
PubMed1995

The afterdepolarization in Rana temporaria muscle fibres following osmotic shock.

Rana temporaria sartorius muscle fibres were exposed to varied sequences of solution and temperature changes that have been employed hitherto in procedures that sought to decouple the transverse tubules from the surface membrane. The incidence of such detubulation was assessed in large numbers of fibres through demonstrating a loss or otherwise of the after-depolarization that normally reflects successful tubular propagation of the surface action potential. This criterion yielded assessments of the existing detubulation techniques in agreement with earlier results. The experiments then developed an improved detubulation procedure that required only brief (15 min) exposures to glycerol, its replacement in a single step by a Ca2+/Mg(2+)-Ringer solution for 30 min, and rapid cooling from room temperature (19-21 degrees C) to 6-10 degrees C prior to final restoration of the normal Ringer solution. This sequence of steps yielded an optimal incidence (98%) of detubulation in viable surface fibres that were amenable to electrophysiological studies. Studies that systematically modified the detubulation procedure demonstrated that the omission of any one step in the protocol significantly reduced the incidence of detubulation with or without accompanying deteriorations in fibre resting potentials. Successful detubulation accordingly required an initial exposure to an optimal glycerol concentration that lasted for a minimal duration and for its abrupt withdrawal. Inclusion of a cooling step within 30 min after glycerol withdrawal was coincident with, and critical to, optimal tubular isolation. Thus, cooling steps that either preceded, or that followed the glycerol withdrawal step by more than 60 min, resulted in a sharp reduction in the incidence of detubulation. Similarly, a critical period of exposure to Ca2+/Mg2+ Ringer solution also promoted detubulation without compromising the recovery of stable and satisfactory resting potentials. The findings reported here remain consistent with a primarily osmotic mechanism for detubulation. However, they demonstrated additional and important influences of temperature and of divalent cation concentration on the extent of tubular detachment when such factors were modified during the time course of the expected volume changes that followed each adjustment in osmotic condition.

Action Potentials↗
PubMed1995

Systemic artery-to-pulmonary artery shunt after using an omental pedicle flap.

A 66-year-old man was hospitalized because of hemoptysis. Four years earlier, he had undergone an operation involving the use of an omental pedicle flap that was supplied by the right gastroepiploic artery for the treatment of empyema. Arteriography revealed that the right gastroepiploic artery communicated with the periphery of the right pulmonary artery. The right gastroepiploic artery was divided surgically.

Abdominal Muscles↗
PubMed1995

Clear cell papulosis: report of three cases of a newly recognized disease.

BACKGROUND: Clear cell papulosis is a newly described disease. Since the first report in 1987, no other cases have been reported. OBJECTIVE: Our purpose was to describe three more newly identified cases that further characterize this disease. METHODS: Formalin-fixed and paraffin-embedded biopsy specimens were used for histochemical and immunohistochemical studies. RESULTS: The three patients included two boys and, for the first time, a girl. All three had multiple white papules on the lower part of the abdomen, with or without scattered lesions along the milk lines bilaterally. The main histopathologic finding was the presence of clear cells scattered mainly among the basal cells of the acanthotic epidermis. The clear cells were variably stained by mucicarmine, colloidal iron, alcian blue (pH 2.5), periodic acid-Schiff, the anticytokeratin antibody AE1, carcinoembryonic antigen, epithelial membrane antigen, and gross cystic disease fluid protein-15. CONCLUSION: Clear cell papulosis is a unique clinicopathologic entity. The clear cells were confirmed to be sweat gland secretory cells by their positive immunostaining with gross cystic disease fluid protein-15. The latter was also present in eccrine sweat gland coil cells. However, whether the clear cells were eccrine or apocrine secretory cells could not be determined.

Biopsy↗
PubMed1995

Evidence that direct binding of G beta gamma to the GIRK1 G protein-gated inwardly rectifying K+ channel is important for channel activation.

Activation of G protein-gated K+ channels by G protein-coupled receptors contributes to parasympathetic regulation of heart rate in the atrium and inhibitory postsynaptic potentials in the peripheral and central nervous system. Having found that G beta gamma activates the cloned GIRK1 channel, we now report evidence for direct binding of G beta gamma to both the N-terminal hydrophilic domain and amino acids 273-462 of the C-terminal domain of GIRK1. These direct interactions are physiologically important because synthetic peptides derived from either domain reduce the G beta gamma binding as well as the G beta gamma activation of the channel. Moreover, the N-terminal domain may also bind trimeric G alpha beta gamma, raising the possibility that physical association of G protein-coupled receptors, G proteins, and K+ channels partially accounts for their compartmentalization and hence rapid and specific channel activation by receptors.

Amino Acid Sequence↗
PubMed1995

The effect of cerebrospinal fluid dilution of isobaric 0.5% bupivacaine used for spinal anaesthesia.

A prospective study was conducted to see the effect on spinal anaesthesia of the dilution of isobaric 0.5% bupivacaine with cerebrospinal fluid. Sixty patients were randomly allocated to three groups. In group 1, patients received 3 ml isobaric 0.5% bupivacaine intrathecally without aspirating cerebrospinal fluid. In groups 2 and 3, cerebrospinal fluid 1 ml and 2 ml was aspirated respectively and mixed with 3 ml isobaric 0.5% bupivacaine. A total volume of 4 ml in group 2 and 5 ml in group 3 was administered. Thus, the volume of cerebrospinal fluid remained unchanged. Pinprick analgesia and motor block was evaluated from induction until recovery. No differences in onset time, duration and 'two segments regression' were noticed. The only statistical difference was the time to reach complete motor block, which was shorter in group 1 as compared to groups 2 and 3 (6.9 SD 1.4 min versus 11.3 SD 3.0 and 13.5 SD 3.9 min respectively). The mean value of maximum decrease in systolic blood pressure was small, being less than 15% of the pre-operative value for each group. In conclusion, the effect of diluting isobaric 0.5% bupivacaine with cerebrospinal fluid, 1 ml and 2 ml, is minimal and it is an unnecessary procedure with limited clinical effect.

Adult↗