Hypoxic ventilatory response after rocuronium-induced partial neuromuscular blockade in men with obstructive sleep apnoea

Obstructive sleep apnoea and residual neuromuscular blockade are, independently, known to be risk factors for respiratory complications after major surgery. Residual effects of neuromuscular blocking agents are known to reduce the hypoxic ventilatory response in healthy volunteers. Patients with obstructive sleep apnoea have impaired control of breathing, but it is not known to what extent neuromuscular blocking agents interfere with the regulation of breathing in such patients. In a physiological study in 10 unsedated men with untreated obstructive sleep apnoea, we wished to examine if partial neuromuscular blockade had an effect on hypoxic ventilatory response (isocapnic hypoxia to oxygen saturation of 80%) and hypercapnic ventilatory response (normoxic inspired carbon dioxide 5%). The hypoxic ventilatory response was reduced by 32% (p = 0.016) during residual neuromuscular block (rocuronium to train-of-four ratio 0.7), but the hypercapnic ventilatory response was unaffected. We conclude that neuromuscular blockade specifically depresses peripheral chemosensitivity, and not respiratory muscle function since the hypercapnic ventilatory response was unaffected.     

Cloxacillin concentrations in serum,subcutaneous fat,and muscle in patients with chronic critical limb ischemia

Background

Patients suffering from critical limb ischemia (CLI) have poor wound healing in the ankle and foot areas. Secondary wound infections are frequent and often treated with prolonged courses of antibiotics.

Purpose

This study set out to investigate to what extent the unbound fraction of 4 g of cloxacillin i.v. reaches its target organ in poorly vascularized tissues, i.e., the calf and foot of patients suffering from CLI.

Methods

Cloxacillin concentrations were measured by HPLC in serum and in microdialysis samples from skin and muscle of the lower part of the calf and as reference subcutaneously at the pectoral level in eight patients suffering from CLI (four males, four females, mean age 78 years, range 66–85 years) and in three healthy controls (two females, one male, mean age 67, range 66–68 years).

Results

In patients suffering from CLI, the tissue penetration of cloxacillin after a single 4 g dose was comparable to that of healthy controls, despite impaired blood circulation.

Conclusions

The reduced blood flow in the peripheral vessels of the CLI patients presented here apparently is not the rate-limiting factor for delivery or tissue penetration of cloxacillin.     

Rapid prenatal diagnosis of beta thalassemia using DNA amplification and nonradioactive probes

We used in vitro DNA amplification by the polymerase chain reaction and nonradioactive probes for prenatal diagnosis of beta thalassemia in Chinese from the Guangdong province. Exact molecular diagnoses were made in all 20 fetuses studied over a 6-month period. We conclude that this method of prenatal diagnosis for beta thalassemia is a viable approach in many parts of the world where this disease is common.     

Response to 2'-deoxycoformycin after failure of interferon-alpha in nonsplenectomized patients with hairy cell leukemia

Two patients with hairy cell leukemia with massive splenomegaly and severe pancytopenia were treated with recombinant alpha-A interferon (IFN-alpha-2a). There was no significant response to a trial of IFN- alpha-2a (11 and 20 weeks) with respect to blood counts or spleen size. Subsequent treatment with 2'-deoxycoformycin (dCF) for 8 consecutive weeks (4 mg/m2/wk) resulted in normalization of spleen size and a normalization of peripheral blood counts and bone marrow in one patient. The second patient demonstrated a reduction in spleen size and improved blood counts following 9 weeks of dCF therapy but eventually became refractory. This demonstrates that dCF is non-cross-resistant with interferon and confirms the efficacy of dCF in nonsplenectomized patients.     

The incidence of a first major osteoporotic fracture in Iceland and implications for FRAX

Summary

Based on an extensive cohort study over 25 years, the present study supports the assumption that major osteoporotic fractures can be reasonably predicted from hip fracture rates.

Introduction

The construct for FRAX models depends on algorithms to adjust for double counting of fracture outcomes in some models and in others, to estimate the incidence of a major fracture from hip fracture rates. The aim of the present study was to test the validity of these algorithms in a large prospective cohort.

Methods

The incidence of hip, clinical spine, distal forearm, and humerus fracture was determined in the prospective and ongoing population-based Reykjavik Study with follow up of 257,001 person-years. The incidence of a first major fracture was compared with the correction factors used in FRAX to adjust the incidence of several fracture outcomes for double counting. In addition, the incidence of a major osteoporotic fracture estimated from the Icelandic hip fracture rates was compared with the Malmo ratios used in FRAX.

Results

The adjustments necessary to account for multiple fracture outcomes were similar to those previously derived from Sweden. Additionally, incidence of a first major osteoporotic fracture was similar to that derived for FRAX models.

Conclusion

The findings of the present study support the algorithms used in FRAX to estimate the incidence of a first major fracture and the predictive value of hip fracture for other major fractures.     

Studies on the effect of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) on central catecholamine neurons in C57BL/6 mice. Comparison with three other strains of mice

The effect of the parkinsonism-inducing neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) on central catecholamine neurons in C57BL/6 mice has been studied employing neuro- and histochemical techniques. The number of dopamine (DA) cell bodies in substantia nigra pars compacta (SNC) was reduced by 70% in MPTP-treated C57BL/6 mice, as demonstrated both by tyrosine hydroxylase (TH) immunohistochemistry and conventional histology (Cresyl violet staining) and an almost complete loss of DA fibers in striatum was also found. A detailed analysis of the effects of MPTP on endogenous catecholamine levels in various brain regions revealed that MPTP caused a severe reduction of endogenous DA in substantia nigra and striatum (35 and 5% of control) which was accompanied by an increase in the 3,4-dihydroxyphenylacetic acid (DOPAC)/DA ratio. There was also a decrease of DA in nucleus accumbens and the olfactory tubercle to 41 and 44% of control, respectively, without any significant change in the DOPAC/DA ratio and density of TH-positive fibers. Small but significant decreases of the noradrenaline (NA) levels in septum, entorhinal cortex and frontal cortex were seen, although the uptake of [3H]NA in frontal cortex was not significantly changed. Minor MPTP-induced decreases of the serotonin levels in frontal cortex, occipital cortex and spinal cord were also seen. The MPTP treatment also induced a 55% increase of adrenaline levels in hypothalamus, while no changes were seen in pons-medulla and spinal cord. Comparing this with 3 other strains of mice, the MPTP-induced reduction of endogenous DA in striatum was most pronounced in C57BL/6, less in N.M.R.I. and CBA/Ca mice, and least in Swiss-Webster. Concerning the effect of MPTP on cortical NA levels, the same relation was at hand except for C57BL/6, where, as mentioned, the effect was merely detectable. No reduction of DA perikarya in SNC was seen in Swiss-Webster mice. These findings show that in mice major differences exist in sensitivity of catecholamine neurons to MPTP between different strains. The data show that MPTP can produce an almost complete, permanent and relatively selective degeneration of the nigrostriatal DA neurons in C57BL/6 mice similar to that seen in primates. This strain may therefore serve as a useful model for studies on various aspects of MPTP-induced parkinsonism.     

牙列缺损的计算机三维建模

目的 建立牙列缺损的计算机三维模型。方法 采用表面绘制法,依据CT扫描头颅骨标本获得的二维断层图像数据在3D Studio Max中沿牙体长轴放样、微调并赋以材质,得到牙列缺损的计算机三维模型。结果 能在计算机中方便快速地模拟任意类型的牙列缺损,并可全方位地旋转、放大和缩小。结论 提供了一种牙列缺损三维建模的新方法,有利于三维义齿专家系统的开发和计算机辅助教学。