Volume 110  ·   Issue 12  ·  1997

Purpose To review the spatiotemporal behaviours of central otolith neurons in decerebrate animals. Data sources Laboratory of Neurophysiology, Department of Physiology, Faculty of Medicine, The University of Hong Kong. Data extraction Results of key research findings from 1992 to 1997. Results With constant velocity colckwise (CW) and counterclockwise (CCW) off-vertical axis rotations as stimuli to the otolith organs, neurons in the vestibular nuclei and medullary reticular formation showed characteristic spatiotemporal behavious. One-dimensional neurons showed symmetric and stable bidirectional response sensitivities (δ) to change in velocity while two-dimensional neurons showed asymmetric and variable δ to velocity. This CW-CCW asymmetry to bidirectional rotations may provide directional coding in the modulation of neural signals. Vestibular nuclear neurons also displayed distinct spontaneous discharge patterns at the stationary and earth-horizontal position, indicating that one- and two-dimensional neurons belong to physiologically distinct etities. These spatiotemporal behavious of the vestibular nuclear neurons were also shown to be precisely controlled by imputs from the vestibulocerebellum and/or bilateral otoliths. In both the vestibular nucleus and the reticular formation, the best response orientations of one-dimensional neurons and the orientations of the maximum response vector of two-dimensional neurons were found to point in all directions close to the horizontal plane, indicating that all head orientations on this plane are encoded across an ensemble of neurons. Conclusions Otolith-evoked behaviours of the one-dimensional and two-dimensional neurons constitute an important element for the recognition of the direction and orientation of head motion in space.

OBJECTIVE To identify aspects of the health of Chinese women throughout their lifespan which may paradoxically be threatened by modernization and to suggest relevant interventions through medical practice, education and research to meet these challenges. DATA SOURCES Six risk areas were selected as examples: infant sex ratios; tobacco use by girls; respiratory illness plus anemia; psychosocial stress; osteoporosis; and dementia. Articles and other databases, through article citations, and through consultations with Chinese medical professionals. DATA SELECTION Studies were selected which described clinical investigations, health care policy, or conditions of women in the People's Republic of China (PRC). Preference (but not exclusivity) was given to articles in internationally available publications, in English, and to authors working in the PRC. DATA EXTRACTION Study quality, specific descriptive information concerning population, samples, and outcome measures were evaluated. DATA SYNTHESIS Data documenting the present and future significance of these health threats are described, and current and potential interventions to address these problems through medical practice, education and research are outlined. CONCLUSIONS Important issues in women's health are currently recognized in the PRC; problems occur in assigning priorities in the face of a large population and limited resources. The Chinese medical community plays a central role in developing and carrying out interventions to protect and promote women's health.

OBJECTIVE To investigate the vascular smooth muscle cell (SMC) growth suppression by recombinant adenovirus vector expressing a retinoblastoma (Rb) protein and to explore a gene therapy approach for vascular proliferative disorders including atherosclerosis and artery restenosis. METHODS A replication-deficient adenovirus vector encoding a wild-type Rb and AdCMVRb, was constructed and transfected into cultured rabbit aortic SMC. The efficiency of gene transfection and expression was detected by immunochemical staining and polymerase chain reaction. The role of Rb in regulating vascular SMC proliferation was observed by cell-counting, [ 3H] thymidine incorporation, and flow cytometry. RESULTS Wild-type Rb gene transfected effectively into the cultured SMC with AdCMVRb can suppress growth factor-stimulated cell proliferation through regulation of DNA synthesis and cell cycle progression. CONCLUSIONS The RESULTS demonstrate the potential of adenovirus-mediated Rb gene therapy for atherosclerosis and artery restenosis after balloon angioplasty.

OBJECTIVE To investigate the embryonic development of lamina cribrosa of human eyes. METHODS The lamina cribrosa of 291 eyes were studied including 260 eyes taken from embryos and fetus of 7 weeks to full term and 31 eyes from infants under 1 year of age by using light microscopy (LMS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). RESULTS From observations, it was found that the development of the lamina cribrosa was lagged behind the development of the optic nerve. CONCLUSIONS In eyes taken from embryos or fetus less than 4 months of pregnancy, only ectodermal primordium of the lamina cribrosa could be seen. The initial scleral part of the lamina cribrosa began its formation in the 5th month of fetus. The fibrous tissue originating from the choroid and optic nerve sheath contributed to the formation of the lamina cribrosa in the 8th month fetus. At this time, the morphology of the lamina cribrosa is similar to that of an adult, however the thickness of the structure is still getting increased up to one year after birth.

OBJECTIVE To assess a method of antepartum diagnosis of cephalopelvic disproportion by comparing the diameters of fetal head with those of the maternal midpelvis. METHODS Transvaginal ultrasound pelvimetry was performed on 190 healthy primigravidas with cephalic presentation at 28-35 weeks of gestation, and the fetal heads were measured within one week before delivery. The cephalopelvic indices of diameter, circumference and area were calculated and compared. RESULTS The index exhibiting the highest degree of accuracy (77.9%) was the cephalopelvic index of diameter (CID) defined as the difference between the mean diameter of the midpelvis and the fetal biparietal diameter (BPD). Eighty-three percent of the cases with CID less than 15.8 mm needed operative delivery, and 76.2% of the cases with CID more than 15.8 mm underwent vaginal delivery. CONCLUSIONS The CID may be used to identify cephalopelvic disproportion before the labor and help obstetricians choose the most appropriate form of delivery in an uncomplicated vertex presentation.

OBJECTIVE To review the clinical characteristics and outcomes of critically ill obstetrical patients and to determine the outcome predictability using the Acute Physiology and Chronic Health Evaluation (APACHE) II scoring system. METHODS A retrospective data collection of all obstetrical patients (n=49) admitted for more than 24 hours to the Intensive Care Unit at Kwong Wah Hospital from 1988 to 1995 was conducted. Demographics, obstetric data, preexistent medical problems, diagnosis, days staying in the ICU and ICU related data were recorded for each patient. RESULTS Obstetric admissions to ICU during the study period represented 0.12% of all deliveries during this period. There was a predominance of postpartum admissions and obstetric diagnosis responsible for the patients' critical illness. Massive postpartum haemorrhage was the single most common cause of ICU admission, representing 53.0% of all patients. Preeclampsia and eclampsia (14.3%), anaesthesia related complications (14.3%), and medical diseases complicating pregnancy (14.3%) were the other common disease categories for ICU admission. Two cases (4.1%) of surgical disease complicating pregnancy were admitted. The maternal mortality rate was 5.1 deaths per 100,000 total births, or 2 maternal deaths in 39,354 total deliveries in this study period. All deaths were due to nonobstetric causes. The perinatal mortality rate was 10.0% (5 cases) in this study group. CONCLUSIONS When applying the Acute Physiology and Chronic Health Evaluation (APACHE) II scoring system in predicting the final outcome in this group of obstetric patients, we found that our obstetric patients requiring intensive care had a better outcome than predicted, as expressed by a low mortality ratio (0.25).

OBJECTIVE To study the effect of endotoxin on the alteration of the transcription, expression and cellular location of endothelin-1 (ET-1) mRNA in the hepatic tissue. METHODS Wistar rats were divided into control and endotoxic group. The rats in the control group were injected with saline, and those in the endotoxic group with endotoxin at a dose of 10 mg·kg-1 body wt. ET-1 hepatic homogenate was assayed by radioimmunoassay at 3, 6, 9, 12 and 24 h after endotoxin administration. Dot blot was used to identify and quantify ET-1 mRNA of the hepatic tissue. Hybridization of ET-1 of the hepatic tissue was proceeded at 3, 6, 12 and 24 h after endotoxin administration. RESULTS ET-1 concentrations and the level of ET-1 mRNA increased rapidly and reached the peak at 6 h, and remained high at 24 h after endotoxin administration. By in situ hybridization, ET-1 mRNA was found in hepatic sinusoids, endothelial cells of portal vein and kupffer cells. CONCLUSIONS Endotoxin may be the principal stimulating factor for expression of ET-1 mRNA in hepatic tissue. Endotoxin may affect transcription and translation level of ET-1, leading to increase of the synthesis and release of ET-1. The hepatic vascular endothelial cells, hepatic sinusoids and Kupffer cells all synthesize and release ET-1.

OBJECTIVE To evaluate the effect of transforming growth factor-β/bone morphogenetic protein (TGF-β/BMP) composite on the healing of large segmental bone defects and to discuss the interaction between TGF-β and BMP during bone repair. METHODS A 1.5 cm segmental defect was made in the mid-upper part of the radial shaft of 48 adult rabbits. The defects were filled with implants of TGF-β/carrier, BMP/carrier or TGF-β/BMP/carrier separately. 120 micrograms of purified bovine TGF-β and 12 mg of BMP were used in the composite. The defects were examined radiographically and histologically at 4, 8, 12 and 16 weeks post-operation. RESULTS In the group filled with TGF-β/BMP composite, the defect areas were bridged at 4 weeks, with callus of uniform radiodensity. Cortices of the cut ends were obscured by new bone. By 16 weeks post-operation, the defects were bridged by uniform new bone and the cut ends of the cortex could not be seen in all groups. In group of BMP/carrier, the defects were filled with more irregular woven bone callus than in other two groups. TGF-β/BMP implanted defects in animals killed at 16 weeks showed histologically new lamella and woven bone that was formed in continuity with the cut ends of the cortex. Medullar canal was recanalized and contained marrow elements with normal appearance. CONCLUSIONS These data demonstrate not only the synergistic action between TGF-β and BMP in the process of bone healing, but also a better effect of TGF-β/BMP composite than single TGF-β or BMP on bone repair, especially in the early stage of bone repair process.

OBJECTIVE To examine the kinetics of plasma tumor necrosis factor α (TNFα), interleukin-6 (IL-6) and interleukin-8 (IL-8) in patients with severe trauma and to discuss their relationship with organ damage and endotoxemia. METHODS Seventeen patients (10 men and 7 women) with severe trauma were selected in this study. Their mean age was 37.9±11.9 years. All patients were divided into two groups according to injury severity score (ISS): group I with ISS from 16-25 (18.8±2.9, n=10) and group II with ISS more than 25 (34.3±8.3, n=7). Ten young healthy volunteers (6 men and 4 women) were used as controls. Plasma TNFα and IL-8 levels were assayed with enzyme-linked immunosorbent assay. IL-6 activity in the plasma was determined by bioassay with IL-6-dependent cell-line 7TD1. Limulus amebocyte lysate chromogenic test was used for plasma endotoxin assay. RESULTS Plasma cytokine levels in patients with trauma had a successively significant increase. Plasma TNF level increased earlier. Increases in plasma IL-6 and IL-8 occurred later. All the increases were significantly correlated with the severity of trauma and organ damage after trauma. In addition, obvious endotoxemia occurred at the early stage of trauma and was significantly correlated with the severity of trauma and the levels of plasma TNFα, IL-6 and IL-8. CONCLUSIONS Release of TNFα, IL-6 and IL-8 can be significantly increased in patients with severe trauma. The increase may be related to massive endotoxin translocation and may play an important role in the development of organ damage after trauma.

OBJECTIVE To evaluate the characteristics of P-glycoprotein (P-gp) expression of acute non-lymphocytic leukemia (ANLL) at different status and the prognostic and biological features in ANLL at diagnosis. METHODS Monoclonal antibody UIC2 and indirect immunofluorescence assay by flow cytometry were used to determine P-gp expression of 169 patients with ANLL, including 152 previously untreated, 7 refractory and 10 at remission. RESULTS P-gp was expressed in 28.9% of the previously untreated ANLL cases and P-gp was lower than that in 71.4% of the refractory cases (P<0.05). No P-gp expression was found in the patients at remission. For previously untreated AN-LL, P-gp was highly expressed in hybrid acute leukemia (66.7%) and acute monoblastic leukemia (47.4%). P-gp expression was highly associated with surface markers [cluster of differentiation (CD) 34, CD7, CD14, CD42b and CD61] and unfavorable cytogenetic abnormalities. About 23% of P-gp+ ANLL obtained complete remission, which was significantly lower than that (76%) in P-gp-cases. CONCLUSIONS P-gp expression is higher in refractory ANLL cases than that in cases at diagnosis or at remission. P-gp is an index of poor prognosis in adults with ANLL. P-gp+ ANLL cases have unique clinical and biological characteristics.

OBJECTIVE To assess renal function in patients with obstructive sleep apnea syndrome (OSAS) during two nights when they were untreated and treated with continuous positive airway pressure (CPAP). METHODS Tubular function was estimated on the basis of the renal lithium clearance and its derived formulae, urinary osmolality, osmolal clearance and free water clearance; while glomerular function was evaluated by endogenous creatinine clearance. Twenty patients with OSAS and sixteen normal controls were studied. RESULTS The untreated patients with OSAS had significantly lower fractional proximal tubular sodium reabsorption (59.1%±7.1%, P<0.001 vs controls), lower fractional distal tubular sodium reabsorption (93.8%±1.7%, P<0.05 vs controls) and urinary osmolality (573.0±107.9 mosm·kg-1, P<0.05 vs controls). The absolute distal tubular reabsorption rate of sodium and osmolal clearance in the untreated patients were higher 47.0±26.0 mmol·L-1 and 25.0±4.1 ml·L-1; P<0.01 and P<0.05 respectively vs controls). During CPAP-treated nights all abnormal renal function indexes in the OSAS patients restored to normal control values (P>0.05). CONCLUSIONS The natriuresis and diuresis of OSAS patients were due to the decrease in proximal and distal tubular sodium reabsorption and in tubular concentration ability during their nocturnal sleep and were returned to normal by CPAP therapy.

OBJECTIVE To compare the effect of ouabain on the blood pressure of rats with that of digoxin to find the evidences of the relationship between endogenous ouabain (EO) and development of hypertension. METHODS Sprague-Dawley rats, which were divided into 3 groups, were infused with ouabain (23.75 μg·kg-1/day, i.p.), digoxin (36.84 μg·kg-1/day, i.p.) and normal saline (NS) once a day respectively. Systolic blood pressure and body weight were recorded weekly. Five weeks later, rats of ouabain group were randomly assigned to three infusion subgroups: Oc group, continued with ouabain infusion; Od group, added digoxin (73.68 μg·kg-1/day, i.p.) and Os group, stopped administration of ouabain. Another week later, direct blood pressure was recorded in aorta. Systolic and diastolic cardiac function, plasma renin activity and aldosterone levels of all the rats were measured. RESULTS After a latent period of one week, blood pressure of Ouabain group increased significantly [95.4±11.8 mmHg (1 mmHg=0.133 kPa) at the beginning of the experiment vs 122.5±16.9 mmHg at the end of week 6, P<0.05] with normal plasma renin activity and higher aldosterone (1.28±0.45 ng/ml vs 0.69±0.27 ng/ml, P<0.05). The blood pressure decreased after either withdrawal of ouabain or addition of digoxin (116.3±14.4 mmHg vs 100±10.7 mmHg, P<0.05; 123.9±13.9 vs 103.3±10.5 mmHg, P<0.05, respectively). No difference of blood pressure was found between the digoxin and NS group. CONCLUSIONS Our results suggested that EO might be one of the causes of the development of hypertension. Aldosterone might play some role in the mechanism of ouabain-induced hypertension. Digoxin can not induce hypertension. There is a great difference between the effect of ouabain and digoxin on the blood pressure. Moreover, digoxin can reverse the hypertension induced by ouabain.