[New method for preparing oridonin by column chromatography]

Compared with the traditional methods, the separation and preparation of oridonin by column chromatography have the advantages of fast speed, harmlessness and non-pollution of solvent, safety, economy and easily obtained, etc. After re-crystallizing the oridonin content is determined by TLC scanning to be as high as 97.03%.

Neuronal and glial apoptosis after traumatic spinal cord injury

Cell death was examined by studying the spinal cords of rats subjected to traumatic insults of mild to moderate severity. Within minutes after mild weight drop impact (a 10 gm weight falling 6.25 mm), neurons in the immediate impact area showed a loss of cytoplasmic Nissl substances. Over the next 7 d, this lesion area expanded and cavitated. Terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate-biotin nick end labeling (TUNEL)-positive neurons were noted primarily restricted to the gross lesion area 4-24 hr after injury, with a maximum presence at 8 hr after injury. TUNEL-positive glia were present at all stages studied between 4 hr and 14 d, with a maximum presence within the lesion area 24 hr after injury. However 7 d after injury, a second wave of TUNEL-positive glial cells was noted in the white matter peripheral to the lesion and extending at least several millimeters away from the lesion center. The suggestion of apoptosis was supported by electron microscopy, as well as by nuclear staining with Hoechst 33342 dye, and by examination of DNA prepared from the lesion site. Furthermore, repeated intraperitoneal injections of cycloheximide, beginning immediately after a 12.5 mm weight drop insult, produced a substantial reduction in histological evidence of cord damage and in motor dysfunction assessed 4 weeks later. Present data support the hypothesis that apoptosis dependent on active protein synthesis contributes to the neuronal and glial cell death, as well as to the neurological dysfunction, induced by mild-to-moderate severity traumatic insults to the rat spinal cord.

Characterization of immobilization of an enzyme in a modified Y zeolite matrix and its application to an amperometric glucose biosensor

A new approach to construct an amperometric biosensor is described. Without using bovine serum albumin-glutaraldehyde, glucose oxidase (GOx) was immobilized on a dealuminized Y zeolite (DAY)-modified platinum electrode to construct a glucose sensor. The large specific surface area of the zeolite substrate resulted in high enzyme loading. The immobilized GOx in this manner was stable and could maintain its high activity for at least 3 months. The interactions between the zeolite and the enzyme were investigated by means of Fourier transform infrared spectra, and the pore distribution and the surface acid property of DAY were preliminarily studied. The results showed that the hydrophilic property and the existing mesopores of DAY played important roles in the enzyme immobilization. This resulting biosensor exhibited good reproducibility and selectivity, owing to the uniform pore structure and unique ion-exchange property of the zeolite. The biosensor responded rapidly to glucose in the linear range from 2.0 x 10(-6) to 3.0 x 10(-3) M, with a detection limit of 0.5 microM.

[Relationship of C-erbB-2 oncogene overexpression to estrogen progesterone receptors in brease cancer and its prognostic significance]

In order to understand the relationship of C-erbB-2 oncogene overexpression to ER and PR in breast cancer and its prognostic significance, we examined overexpression of C-erbB-2 oncogene in 106 breast carcinomas by using immunohistochemical techniques (LSAB). The results showed that the positive rate of C-erbB-2 overexpression was 63.21% (67/106). The overexpression of C-erbB-2 oncogene related negatively with survival. 81.63% of the cases with overexpression of C-erbB-2 oncogene survived < or = 5 years and 34.29% survived > 10 years. There were significant associations of C-erbB-2 overexpression with advance clinical stage, high histological grade, and positive axillary node status in breast cancers. Negative relationship between hormone receptors and C-erbB-2 oncogene. All of these findings suggested that overexpression of C-erbB-2 oncogene might be an important prognostic factor and the detection of C-erbB-2 oncogene might be arranged as a regular pathological examination in the cases of breast cancer.

[Determination of oridonin in Rabdosia rubescens by TLC-scanning method]

We have determingd the content of oridonin in Rabdosia rubescens Hemsl by TLC-scenning method. This method is proved to be simple, fast, precise and sensitive, and the result is stable, repetition property is good. Its rate of recovery is as high as 98.03 percent.

Assessment of vertebral body motion during spine surgery

STUDY DESIGN

In vitro and in vivo assessment of the accuracy of devices proposed for tracking spine motion during surgery; in vivo assessment of vertebral motion during spine surgery.

OBJECTIVES

1) To quantify the accuracy of newly designed vertebral body trackers; 2) to demonstrate the feasibility of tracking vertebral motion in a cadaveric model; and 3) to quantify the vertebral motion that occurs during spinal surgery.

SUMMARY OF BACKGROUND DATA

Computer techniques are beginning to be applied to spine surgery. Validation of accuracy of methods of spinal tracking has not been reported. No information exists on the amount of vertebral motion that occurs during surgery. Because the new techniques require accurate positional information for the vertebral body, it is important to understand and evaluate methods of tracking vertebrae.

METHODS

An optical tracking system (Northern Digital, Waterloo, Ontario, Canada) was used to track custom-designed trackers. The reliability and accuracy of the trackers were evaluated in vitro. The proposed tracking methodology for human testing was performed using a cadaveric model, and after successful completion, human testing was done in the operating room to evaluate the motion of two vertebral bodies during exposure for instrumentation of the lumbar spine. This technique was used to evaluate the custom designed trackers effectiveness for tracking vertebral bodies for pedicle screw insertion.

RESULTS

The trackers developed were accurate and capable of tracking the motion of the spine. Measured motion of L3 and L4 during breathing was 1.3 mm, peak to peak. Maximal intraoperative motion of the vertebral bodies was 12.3 mm during maneuvers simulating dissection of soft tissue and targeting of spinal pedicles.

CONCLUSIONS

Significant motion occurs in lumbar vertebral bodies during surgery. Breathing motion alone is up to 1.3 mm, and surgeon-induced motion up to 10 times greater. Vertebral body trackers for use with an optical position sensor were capable of measuring this motion.

Spatial distribution of larval Ixodes scapularis (Acari:Ixodidae) on Peromyscus leucopus and Microtus pennsylvanicus at two island sites

Larval blacklegged ticks, Ixodes scapularis, were collected from white-footed mice. Peromyscus leucopus, on Prudence Island (where Microtus pennsylvanicus were not captured) and from meadow voles. M. pennsylvanicus, on Patience Island (where P. leucopus was absent) in Narragansett Bay, Rhode Island from June to October 1992. Ixodes scapularis larvae were also collected by flagging in the vicinity of host captures. On both islands, the relative density of larvae changed from July to September in samples from hosts, but not in flagging samples. Consequently, different sampling techniques can give different assessments of tick populations. Larvae were highly aggregated on both of the host species throughout the sampling period. As the mean relative density of larvae increased in the environment (based on flagging samples), larvae on the hosts became more dense and more crowded. Increased densities of larvae in the environment were not correlated with increased patchiness in the distribution of larvae among host animals on either island. Changes in the spatial distribution of larval I. scapularis on each host species had similar trends as larval densities and distributions within the environment. These results suggest that M. pennsylvanicus can serve as an alternative host for immature I. scapularis in a P. leucopus-free environment and have similar distributional characteristics.

Neurologic evaluation of infant and adult rats before and after sciatic nerve blockade

BACKGROUND

Only limited data exist comparing differences in sensory function and responses to neural blockade in infant and adult rats. Therefore, the authors sought (1) to compare baseline thermal, proprioceptive, and postural responses in infant, adolescent, and adult rats; and (2) to compare the effects of sciatic nerve blockade on thermal, proprioceptive, and postural responses in infant, adolescent, and adult rats.

METHODS

Infant, adolescent, and adult rats were evaluated for proprioceptive, thermal, and mechanical nociceptive and motor function before and after sciatic blockade using a detailed neurologic examination.

RESULTS

Mechanical and thermal nociception were present in all rats, starting from age 1 day. The withdrawal reflex latency to pinch was rapid at all ages, whereas that reaction to thermal stimulus depended on both age and temperature. In contrast, the tactile placing response and hopping response were absent at birth and developed completely during the first 10 days of life. The extensor postural thrust was absent in the first 2 weeks of life and developed variably during the first 50 days of life. Sciatic blockade duration is shorter in infant rats than in adult rats receiving the same dose per kilogram. A brief halothane general anesthetic at the time of sciatic injection in infant or adult rats does not alter the duration of blockade.

CONCLUSIONS

Infant rats show increased sensitivity to noxious thermal stimuli and similar response to deep mechanical stimuli compared with adult rats. Their proprioceptive and motor responses develop during the first 2 weeks of life. When doses are scaled by body weight, block duration is shorter in infant than in adult rats.

Identification of a candidate tumour suppressor gene, MMAC1, at chromosome 10q23.3 that is mutated in multiple advanced cancers

Deletions involving regions of chromosome 10 occur in the vast majority (> 90%) of human glioblastoma multiformes. A region at chromosome 10q23-24 was implicated to contain a tumour suppressor gene and the identification of homozygous deletions in four glioma cell lines further refined the location. We have identified a gene, designated MMAC1, that spans these deletions and encodes a widely expressed 5.5-kb mRNA. The predicted MMAC1 protein contains sequence motifs with significant homology to the catalytic domain of protein phosphatases and to the cytoskeletal proteins, tensin and auxilin. MMAC1 coding-region mutations were observed in a number of glioma, prostate, kidney and breast carcinoma cell lines or tumour specimens. Our results identify a strong candidate tumour suppressor gene at chromosome 10q23.3, whose loss of function appears to be associated with the oncogenesis of multiple human cancers.

Cytokine pattern in relation to disease progression in human immunodeficiency virus-infected children

Cytokine mRNA expression and stimulus-induced cytokines were examined in peripheral blood mononuclear cells in 62 human immunodeficiency virus (HIV)-infected children and uninfected controls. Compared with that in controls, constitutive mRNA expression in patients was increased for tumor necrosis factor (TNF)-alpha, interferon (IFN)-gamma, and interleukin (IL)-10 and decreased for IL-12; it was undetectable for IL-2 and IL-4 in both patients and controls. Stimulus-induced secretion of TNF-alpha, IFN-gamma, IL-12, and IL-4 was less than that in controls; IL-10 secretion was similar. There was no increase in stimulus-induced or constitutive IL-4 or IL-10 in children with severe immunologic deficit compared with controls. A higher stimulus-induced IL-10 secretion and a lower constitutive TNF-alpha mRNA were associated with a slower rate of disease progression, and TNF-alpha mRNA expression correlated with lower plasma HIV RNA. Thus, constitutive cytokine mRNA expression differs from stimulus-induced cytokine responses. The dominant defect in HIV-infected children appears to be one of reduced type 1 cytokines, predominantly IL-2.

[Changes in brain monoamine neurotransmitter in iron deficiency nonanemic rats]

An iron deficiency nonanemic rat model was established by feeding with low-iron diet (11.9 mg/kg) to study if there exists biochemical abnormality in brain tissues. Iron contents of the brain, activities of monoamine oxidase (MAO) in the corpus striatum, and the contents of monoamine neurotransmitter and its metabolite in the cerebral cortex and hippocampus were determined by DCP-AES technique, enzyme histochemical method, and high performance liquid chromatography with electrochemical detection (HPLC-ECD), respectively. Results showed that iron contents and activities of MAO in brain tissues of iron deficiency nonanemic rats reduced significantly, and contents of norepinephrine (NE) and 5-hydroxytryptamine (5-HT) in cerebral cortex were significantly higher than those of controls, while 5-hydroxydroxytryptamine acid (5-HIAA) metabolite of 5-HT in the hippocampus was lower than that of controls. It indicated that there existed metabolic abnormality of monoamine neurotransmitter in the brain tissues of iron deficiency nonanemic rats. Also, this study laid a biochemical basis for abnormal mental and behavioral development caused by iron deficiency.

Experimental Babesia microti infection in golden hamsters: immunoglobulin G response and recovery from severe hemolytic anemia

We described the parasitemia, hematologic changes, and immunity developed by golden hamsters during 8 wk of infection with Babesia microti following experimental inoculation. All 8 hamsters used in this study were readily infected. Animals attained peak parasitemias asynchronously but within a 2-wk period. Most of the animals reached their peak parasitemia by 4 wk postinoculation, attaining a mean +/- SD of 21.9 +/- 9.4% infected erythrocytes (range = 20-35%). Red blood cell count, packed cell volume, and hemoglobin level were used to monitor the course of the hemolytic anemia experienced by infected hamsters. All 3 measures corresponded inversely to the parasitemia; significant hematologic changes (P = 0.0001) were observed during the 8 wk of monitoring. Although all hamsters suffered from severe hemolytic anemia, they also recovered within the same period. Golden hamsters developed a detectable anti-B. microti IgG response by 2 wk postinoculation. Individual animals typically attained peak antibody levels (> or = 1:8, 192) 1 wk after the peak parasitemia. Hamsters retained a high IgG titer (> or = 1:4,096), although parasitemias fell dramatically, fluctuating thereafter at low levels (< 5%).

HIV-1 gp160 induces transforming growth factor-beta production in human PBMC

Transforming growth factor-beta (TGF-beta) is a multifunctional cytokine secreted by many mononuclear cells in peripheral blood (PBMC) and has diverse effects on cellular and humoral immunity. Increased TGF-beta mRNA expression has been reported in PBMC of HIV-infected patients, but the mechanism by which HIV induces TGF-beta secretion is unknown. In this study, we observed that HIV gp160 could induce significant TGF-beta secretion and TGF-beta mRNA expression in PBMC from HIV-seronegative healthy donors. The cellular source of TGF-beta was attributed to non-T cells, presumably monocytes. Specificity of secreted TGF-beta was confirmed by the addition of anti-TGF-beta mAb which abrogated the proliferative response of CCL-64 cells by gp160-treated culture supernatants. Soluble CD4 blocked the gp160-induced TGF-beta production, suggesting that CD4-gp160 interaction is required to induce TGF-beta production. Our results suggest that HIV-1 gp160 may contribute to the immune defects in HIV infection by inducing TGF-beta secretion.

Entomological correlates of Babesia microti prevalence in an area where Ixodes scapularis (Acari:Ixodidae) is endemic

Zoonotic prevalence of Babesia microti Franca piroplasms infecting white-footed mice, Peromyscus leucopus Rafinesque, was determined at 34 sites in Rhode Island where nymphal blacklegged tick, Ixodes scapularis Say, densities ranged from low to hyperabundant (1.7-525.3 nymphs per hour of flagging). Babesia was only detected at sites where tick abundance was moderate to high (> 20 nymphs per hour of flagging) and appeared to exhibit a clumped distribution. Where B. microti was detected, the mean number of nymphal ticks collected per hour of flagging was 229.2 compared with a mean of 40.1 at sites where Babesia was not detected. By combining the spatial occurrence of Babesia with a tick density database in a geographic information system, it may be possible to predict the pattern of zoonotic and human infection with B. microti.

Small versus large diameter closed-section femoral nails for the treatment of femoral shaft fractures: is there a difference?

A retrospective series of 99 femoral shaft fractures treated by small diameter (10 and 11 mm) and large diameter (> 11 mm) closed section femoral nails from November 1989 to September 1993 was analyzed. No significant differences in the parameters of bony union and time to full weight bearing were seen between the two groups nor were there significant differences between the rate of secondary procedures. There were no broken nails in either group and there was no difference in the overall respiratory complication rate.

CONCLUSION

No statistically significant differences existed between the small and large diameter groups except for the mean age and mean follow-up period. Small diameter nails can be used safely without the risk of nail breakage.

Biomechanical analysis of hemipelvic deformation after corticospongious bone graft harvest from the posterior iliac crest

STUDY DESIGN

The stiffness of the hemipelvis during simulated physiologic loading and the bone deformation in the remaining posterior ilium after the harvest of increasing sizes of corticospongious bone graft were compared with values in intact bone.

OBJECTIVES

To quantify the biomechanical effects of the removal of bone grafts from the posterior ilium and to relate the size of graft removed to the stiffness of the hemipelvis and deformation of the remaining bone.

SUMMARY OF BACKGROUND DATA

Bone fractures and pelvic instability have been reported to complicate graft harvest from the posterior iliac crest. There is no quantitative data relating graft size to the mechanical properties of the remaining ilium.

METHODS

Seven cadaveric hemipelves were loaded with a materials testing machine through the superior sacrum while supported at the acetabulum and stabilized with a cable fixed to the ilium. Force and displacement histories and deformation in the greater sciatic notch were recorded for the intact bone and after removal of corticospongious bone graft in 1.5-cm increments from the posterior iliac crest.

RESULTS

If the length of the removed corticospongious bone graft exceeded 3.0 cm, the stiffness of the posterior pelvic ring decreased, and deformation in the remaining bone increased substantially.

CONCLUSIONS

Removal or bone graft in excess of 3 cm from the posterior ilium increases the risk of iatrogenic fatigue fracture.

Additive neuroprotective effects of dextrorphan and cycloheximide in rats subjected to transient focal cerebral ischemia

Previous studies have implicated both excitotoxicity and apoptosis in the pathogenesis of cerebral infarction induced by focal ischemic insults. Here we tested the possibility that the NMDA antagonist, dextrorphan, and the protein synthesis inhibitor, cycloheximide, would produce additive protective effects in a rodent model of focal ischemia-reperfusion. Transient focal cerebral ischemia was induced by a 90 min period of ligation of the right middle cerebral artery and both common carotid arteries. Administration of either 30 mg/kg dextrorphan or 0.5 mg/kg cycloheximide, given i.p. 15 min before ischemia, reduced infarct volume by about 65%. When optimal concentrations of each drug were given together, infarct volume was reduced by 87% as measured 14 days later. These observations support the idea that both excitotoxicity, and apoptosis dependent on new protein synthesis, contribute to cerebral infarction after transient focal ischemia in the rat.

Dextrorphan reduces infarct volume, vascular injury, and brain edema after ischemic brain injury

Focal cerebral ischemia confined to the cerebral cortex in the right middle cerebral artery (MCA) territory was induced by temporary ligation of the MCA and both common carotid arteries (CCAs). Reperfusion was initiated by releasing all three arterial occlusions after 90 min of ischemia. Infarct volume was morphometrically measured after triphenyltetrazolium chloride staining 24 h postischemia. Blood-brain barrier breakdown was assessed 4 h postischemia by measuring vascular permeability to fluorescein isothiocyanate-conjugated dextran (FITC-D), a macromolecule tracer. Ischemic brain edema was measured based on percent water content, 24 h postischemia. Dextrorphan (DX) 20-10 mg/kg given ip 15 min before ischemia reduced infarct volume in a dose-dependent manner with an apparent U-shaped dose-response curve; best protection was observed at 30 mg/kg. Posttreatment at 30 min, but not 60 min, was still effective. DX (30 mg/kg, given 15 min before ischemia) also reduced the postischemic increase in vascular permeability and brain edema in the right MCA cortex. Results from this study support the idea that NMDA receptor activation contributes to blood-brain barrier breakdown and brain edema after ischemic insults