大脑后动脉交通前段及其内穿支研究

本文介绍Willis动脉环后半环大脑后动脉及其内穿支的显微解剖,大脑后动脉交通前段内穿支是脑深部的重要供血血管之一,100％的病例双侧具有该血管。     

Localized proton magnetic resonance spectroscopy of a cerebellar tumor in a two-year-old child

Noninvasive localized proton magnetic resonance spectroscopy (MRS) was used for differential diagnosis of a focal brain lesion in a 2.5-year-old girl. The clinical signs were a mild head tilt and neck pain. Magnetic resonance imaging (MRI) revealed a lesion in the right hemisphere of the cerebellum, but its nature remained obscure. In this lesion quantitative determinations of cerebral metabolites by fully relaxed, short-echo-time proton MRS revealed markedly lowered N-acetylaspartate (NAA) and pronounced elevations of choline-containing compounds (Cho) and myo-inositol (Ins), whereas metabolite concentrations in cortical gray matter and white matter were within normal ranges. The metabolite pattern of the lesion indicated loss of vital neuroaxonal tissue (low NAA) and enhanced glial proliferation (high Cho and Ins), which, together with the MRI morphology, suggested a brain tumor. The diagnosis was established by neurosurgical exploration and total extirpation of the tumor. Histology confirmed an astrocytoma (WHO II). After 2 weeks' recovery the child was discharged with no neurological signs.     

Excessive zinc ingestion. A reversible cause of sideroblastic anemia and bone marrow depression

Two patients with sideroblastic anemia secondary to zinc-induced copper deficiency absorbed excess zinc secondary to oral ingestion. The source of excess zinc was a zinc supplement in one case; in the other, ingested coins. In each case, the sideroblastic anemia was corrected promptly after removal of the source of excess zinc. These two cases emphasize the importance of recognizing this clinical entity, since the myelodysplastic features are completely reversible.     

Intracranial tumors of the first year of life

The introduction of new diagnostic tools for neuroimaging has resulted in the early recognition of congenital brain tumors. In the present report we describe a personal series of 39 children and an International Multicenter Series of 876 children with brain tumors, in whom the diagnosis was obtained during the first 12 months of life. Most of the tumors were located within the supratentorial compartment. In spite of a relatively high operative mortality, surgery still appears to be the more effective therapy. Radiotherapy in this age group is of a scarce value, due to the vulnerability of the infantile brain. At the present time, chemotherapy still plays a controversial role.     

Receptor-dependent regulation of the concentration of Ca2+ in the cytoplasm of thrombocytes in hypertensive patients

Platelet activation factor (PAF)-, ADP and vasopressin-induced increments of platelet Ca2+ concentration were measured by quin-2 in 64 patients with essential hypertension and 16 normal donors. Basal concentration of free Ca2+ was 87 +/- 4 nM in donors, 106 +/- 5 nM in patients with labile hypertension (LH) and 122 +/- 6 nM in those with stable hypertension (SH) (p less than 0.01). PAF, ADP and vasopressin, added to platelets, increased [Ca]in by 448 +/- 58, 397 +/- 66, and 277 +/- 50 nM, respectively, in the donors, by 473 +/- 57, 479 +/- 54 and 195 +/- 32 nM, in LH patients, and by 607 +/- 85, 584 +/- 73 and 245 +/- 41 nM in SH patients. There were no significant variations between the three samples, using the ANOVA test. In 20 patients, whose both parents had essential hypertension, [Ca]in increment was 738 +/- 8 nM for PAF, 682 +/- 90 nM for ADP, and 320 +/- 61 nM for vasopressin. In 19 patients, who admitted to no essential hypertension in the family, these parameters were significantly lower: 310 +/- 40 nM for PAF, 389 +/- 61 nM for ADP, and 147 +/- 26 nM for vasopressin. The demonstrated changes may be making an important contribution to the maintenance of elevated vascular tone and provide an evidence in favor of a genetically-predetermined EH variety.     

Keloids

Keloids are benign fibrous growths that result from an abnormal connective tissue response in certain predisposed individuals. Blacks form keloids more often than whites; however, the reason for this racial difference is not known. Trauma, foreign-body reactions, infections, and endocrine dysfunction have all been proposed as precipitating factors. Keloids are found most commonly on the ear lobes, shoulders, upper back, and midchest. They extend past the area of trauma and once present tend to remain stable. Although sometimes pruritic, painful, or tender, they are usually asymptomatic. Histologically, keloids are characterized by thick collagen bundles, abundant mucinous ground substance, few fibroblasts, and few if any foreign-body reactions. Although there have been many therapeutic modalities, most have had limited success. The most commonly used therapeutic approach is a combination of cryotherapy, intralesional steroid injections, surgical excision, and pressure devices.     

Confounders contributing to the reported associations of coffee or caffeine with disease

The role of caffeine or coffee in causing or promoting the incidence of serious disease is equivocal. Two design factors may account for the discrepancies in reported findings on the effects of coffee drinking: (a) imprecision of measurement and (b) confounding variables. A study of 2,714 white U.S. adults disclosed that, of 32 risk factors analyzed by linear and logistic regression, only sex and cigarette smoking were found to be important potential confounders of caffeine and coffee intake. Partial R2 values of the other 30 risk factors were relatively small and were inconsistent for each sex. It is unlikely that any of these factors could explain any of the reported associations between caffeine or coffee consumption and certain diseases. However, certain weak associations with caffeine or coffee intake should be included in the study design when they are known to be risk factors of a disease under investigation. These factors for men are dietary fat intake, vitamin C intake, and body mass index; and for women are vitamin use, alcohol intake, stress, and perceived health status.