Responses to questions by medical students about family practice

Medical students frequently have questions about the specialty of family practice. Responses to 30 questions commonly asked about family practice are presented with a review of recent literature. These responses may assist medical students and their advisors in considering the choice of family practice as a career.     

Allele-specific differential expression of a common adiponectin gene polymorphism related to obesity

Adiponectin gene polymorphisms have recently been reported to be associated with obesity, insulin sensitivity, and the risk of type 2 diabetes. We examined a T94G polymorphism of the adiponectin gene in 245 ostensibly normal nondiabetic subjects. The G allele frequency was lower among subjects with higher BMI (> or =27) than in those with lower BMI. BMI was inversely correlated with the dose of G allele. Multivariate linear regression analyses showed that the adiponectin genotypes were significantly related to BMI after adjusting for age and gender. The dose of the G allele was associated with a reduction of approximately 1.12 kg/m(2) in BMI. We further found that the relative mRNA levels of G allele were consistently higher than those of T allele in the omental adipose tissue from 21 heterozygous subjects. Finally, we observed that the expression levels of adiponectin affected insulin-stimulated glucose uptake in differentiated 3T3-L1 adipocytes. In conclusion, the allele-specific differential expression of this common polymorphism could be responsible for its biological effects observed in this and the other studies.     

IMMUNOHISTOCHEMICAL DISTRIBUTION OF CANNABINOID CB 1 RECEPTOR IN THE RAT CENTRAL NERVOUS SYSTEM

IMMUNOHISTOCHEMICAL DISTRIBUTION OF CANNABINOID CB 1 RECEPTOR IN THE RAT CENTRAL NERVOUS SYSTEM@邹冈     

Suppression of noxious stimulus-evoked expression of Fos protein-like immunoreactivity in rat spinal cord by a selective cannabinoid agonist

In rats, cannabinoids inhibit behavioral responses to noxious stimulation with a potency and efficacy similar to that of morphine. However, because cannabinoids depress motor function, it has not been possible to state beyond any doubt that these effects were related to a dampening of noxious sensory input. Therefore, c-fos immunocytochemistry was used to explore the possibility that cannabinoids reduce behavioral responses to noxious stimuli by decreasing spinal processing of nociceptive inputs. Rats received systemic injections of the potent and selective cannabinoid agonist WIN 55,212-2, the receptor-inactive enantiomer WIN 55,212-3 or vehicle prior to observations in a model of tonic pain, the formalin test. As demonstrated previously, plantar injections of formalin led to lifting and licking of the injected paw, with two peaks of activity occurring at 5 and 30 min after injection. The cannabinoid agonist suppressed these pain responses and produced a reduction in mobility. Immunocytochemical processing of sections with an antibody to the Fos protein revealed that the cannabinoid markedly suppressed pain-evoked c-fos expression in the superficial and neck regions of the spinal dorsal horn, but not in the nucleus proprius. Decreased expression of c-fos also occurred in the ventral horn. The specificity of this effect and its probable mediation by cannabinoid receptors are suggested by three findings: (i) the suppression by the drug of both behavioral and immunocytochemical responses to pain was dose-dependent; (ii) neither the behavioral nor the immunocytochemical response to the noxious stimulus was significantly affected by the receptor-inactive enantiomer of the agonist; (iii) animals rendered tolerant to cannabinoids by repeated injections of the agonist showed reduced responses to the drug. These findings suggest that cannabinoids inhibit the spinal processing of nociceptive stimuli and support the notion that endogenous cannabinoids may act naturally to modify pain trnasmission within the central nervous system.     

大麻酚类受体—1在脊髓,背角,背根神经节和周围神经的分布

AIM: The localization of CB1 receptors in the spinal cord, spinal roots, dorsal root ganglion (DRG), and peripheral nerve of the rat was determined. METHODS: We studied the distribution of CB1 cannabinoid receptors by immunohistochemistry using an antibody raised against the N-terminal of the receptor. RESULTS: The spinal cord showed numerous transverse fibers labelled for CB1 receptors throughout and concentrated in the dorsal horn. Lightly-stained cells were observed throughout the spinal cord gray matter. The DRG also showed cells and fibers labelled for CB1 receptors. Labelled fibers were observed in both dorsal and ventral roots as well as in peripheral nerves. CONCLUSION: The presence of CB1 receptors in the DRG, the dorsal root, and the dorsal horn is in accordance with the analgesic effects of cannabinoids. The presence of labelled cells and fibers in the ventral horn and ventral root provides a substrate for cannabinoid-induced muscle relaxant and antispastic effects.     

Clinical application of NMP22 and urinary cytology in patients with hematuria or a history of urothelial carcinoma

For evaluation of the clinical application of immunoassay for nuclear matrix protein 22 (NMP22 immunoassay) and urinary cytology for early diagnosis and detection of bladder cancer in patients with hematuria and/or a previous history of bladder cancer, 209 urine samples obtained from 137 patients presenting episodes of hematuria or a history of bladder cancer were assayed for NMP22 levels and/or prepared for cytology examination. Biopsy was performed when any visible tumor was identified during cystoscopy examination. The median NMP22 concentrations measured in samples taken from patients with active bladder cancer, from patients with a history of bladder cancer but no active disease, from patients with hematuria, and from healthy volunteers were 18.95, 5.45, 6.39, and 3.75 U/ml, respectively. The urinary NMP22 level recorded for patients with urothelial carcinoma was significantly higher than that noted for individuals without active disease. The sensitivity of the NMP22 assay and of urinary cytology in diagnosing bladder cancer was 69% and 67%, respectively. In contrast, the specificity of these two diagnostic modalities reached 72% and 93%, respectively. The NMP22 assay is slightly more sensitive but less specific than urinary cytology in detecting bladder cancer. This study indicates that determination of urinary NMP22 levels is a useful and noninvasive tool for the detection of bladder cancer because of its high sensitivity. The urinary NMP22 assay may be used as a first-line routine screening method; however, it cannot replace the use of urinary cytology because of its lower specificity.     

Role of the superior colliculus in the motor effects of cannabinoids and dopamine

We studied the cellular distribution of CB1 cannabinoid receptors in the superior colliculus of the rat using an antibody raised against the N-terminal of the receptor. The effect of unilateral cannabinoid receptor stimulation in the intermediate layers of the superior colliculus on rotational behavior in rats was also explored. The antibody against CB1 receptors outlined the crossed descending system of the superior colliculus (predorsal bundle output system) as well as the collicular commisure. The potent cannabinoid agonist CP55,940 (5 microgram/0.25 microliter) induced strong contralateral turning when microinjected unilaterally into the lateral intermediate layers of the superior colliculus. The levels of turning obtained with the intracollicular administration of the cannabinoid were comparable to the highest levels obtained with dopamine agonists in the basal ganglia. The D(2) dopamine agonist quinpirole or the D(1) dopamine agonist SKF82958 reversed this contralateral rotation but failed to affect motor behavior on their own. A new motor pathway for cannabinoids is discussed.     

Failures of Cu-Cu Joints under Temperature Cycling Tests

In this study, the failure mechanisms of Cu-Cu joints under thermal cycling were investigated. Two structures of dielectrics (PBO/underfill/PBO and SiO₂) were employed to seal the joints. Stress gradients induced in the joints with the different dielectrics were simulated using a finite element method (FEM) and correlated with experimental observations. We found that interfacial voids were forced to move in the direction from high stress regions to low stress ones. The locations of migrated voids varied with the dielectric structures. Under thermal cycling, such voids were likely to move forward to the regions with a small stress change. They relocated and merged with their neighboring voids to lower the interfacial energy.