Structural periodicity in human articular cartilage: comparison between magnetic resonance imaging and histological findings.

OBJECTIVE: To relate the vertical striations visualized in the deeper layers of articular cartilage by Magnetic Resonance Imaging (MRI) to histological features. METHODS: Two knee joints recovered at post-mortem from males in their seventies with no history or visual evidence of joint disease were examined. MR images were obtained in a 4.7 T 400 mm-bore magnet, after which the knees were fixed, sectioned, and examined histologically. RESULTS: High resolution MR showed vertical high/low signal striations with a two to three-fold variation in signal intensity and a periodicity of 0.56 (+/-0.16 mm), most prominent in weight bearing areas. Histological sections revealed alternating light and dark staining areas with a periodicity of 1.01+/-0.54 mm in the lower zones of the cartilage, some, but not all of which clearly represented folding. Given that MR will only visualize vertical structures in cartilage aligned at 90 degrees, whereas histology will cut them at varying angles, it is likely that the vertical structures seen by each modality correspond, and that they represent structural heterogeneity in cartilage; perhaps the presence of plates of high collagen and proteoglycan content. CONCLUSION: The vertical striations seen routinely in the deep zones of hyaline articular cartilage on histological sections are not artefactual; they are likely to represent structural heterogeneity due to the presence of areas of high collagen and high proteoglycan content that exist in weight-bearing areas. This structural heterogeneity may be of great importance to the integrity and function of the cartilage.     

A Pro51Ser mutation in the COCH gene is associated with late onset autosomal dominant progressive sensorineural hearing loss with vestibular defects

We analysed a Dutch family with autosomal dominant non-syndromic progressive sensorineural hearing loss and mapped the underlying gene defect by genetic linkage analysis to a 11.0 cM region overlapping the DFNA9 interval on chromosome 14q12-q13. Clinically, the Dutch family differs from the original DFNA9 family by a later age at onset and a more clearly established vestibular impairment. A gene that is highly and specifically expressed in the human fetal cochlea and vestibule, COCH (previously described as Coch5B2 ), was mapped to the DFNA9 critical region. Sequence analysis revealed a 208C-->T mutation in the COCH gene, resulting in a Pro51Ser substitution in the predicted protein in all affected individuals of the family but not in unaffected family members and 200 control individuals. The same mutation was also identified in three apparently unrelated families with a similar phenotype, suggesting the presence of a Dutch founder mutation. The function of COCH is unknown but several characteristics of the protein point to a structural role in the extracellular matrix. The mutant serine at position 51 is situated between cysteines and possibly interferes with proper COCH protein folding or its interaction with extracellular matrix proteins.      

Noma: public health problem in Senegal and epidemilogical surveillance

Noma or cancrum oris is currently a real public health problem for developing countries. In Senegal, awareness of the disease has led the country to be included in the noma programme initiated by the WHO as early as 1994. The objectives are to evaluate the incidence of necrotizing ulcerative gingivitis (NUG) among children, to evaluate the prevalence of noma and infantile diseases, and to promote prevention strategies among vulnerable populations. Data processing was carried out in two phases: manual processing consisted of checking the questionnaires by nurses, and computer processing started as early as the first collection of data. Noma occurs owing to fever and similar cases. Successfully fighting against malnutrition would allow us to reduce the noma rate.     

The World Health Organization initiative on noma

Oro-facial noma is a worldwide scourge in a context where the World Health Report 1998 gives a global incidence of 140,000 cases, a prevalence in 1997 of 770,000 persons surviving with heavy sequelae. The background and the five steps of the WHO oral health programme to control noma including: (i) ensuring training and awareness on early diagnosis and treatment for each public health structure, (ii) raising awareness and informing populations, (iii) promoting epidemiological research, (iv) promoting aetiological research, (v) setting up an African regional centre for the treatment of after-effects, are developed in this paper.     

Problem-solving counseling for caregivers of the cognitively impaired: effective for whom?

BACKGROUND: Individualized problem-solving counseling for caregivers of cognitively impaired relatives is thought to help caregivers cope with the stress and burden of caregiving. Few studies have shown the effectiveness of counseling for these caregivers. OBJECTIVES: To determine the effectiveness of individualized problem-solving counseling by nurses for caregivers and the expenditures of health care utilization. METHOD: Caregivers (n = 77) of the cognitively impaired living at home were randomized to receive nurse counseling or not. Psychosocial adjustment to their relative's illness, psychological distress, burden, coping skills, and expenditures were measured after 6 months and 1 year. RESULTS: Although on average, all caregivers receiving nurse counseling indicated no improvement in psychosocial adjustment to their relative's illness, psychological distress, or caregiver burden, they found counseling very helpful and it was effective for a subgroup of caregivers. Those with poor logical analysis coping skills at baseline had decreased psychological distress (F(1,53) = 9.7, p = .003) and improved psychosocial adjustment (F(1,53) = 4.7, p = .035) after 1 year. Caregivers in control and counseling groups whose relatives entered a nursing home improved their psychosocial adjustment 23% on average whereas those continuing to live in the community decreased by 8%. Almost half as many relatives entered nursing homes in the counseling group (n = 9 vs. n = 5) but these compared to control group relatives had greater annualized per person expenditures for health and social services (Cdn$23,437 vs. Cdn$15,151). CONCLUSIONS: Caregivers found nurse counseling most helpful. Those indicating infrequent use of logical analysis coping skills showed benefits.     

Increased risk of allergy in children due to formaldehyde exposure in homes

BACKGROUND: Formaldehyde levels were measured in 80 houses in the Latrobe Valley, Victoria, Australia. An association between exposure to formaldehyde and sensitization to common aeroallergens has been suggested from animal trials, but no epidemiologic studies have tested this hypothesis. METHODS: A total of 148 children 7-14 years of age were included in the study, 53 of whom were asthmatic. Formaldehyde measurements were performed on four occasions between March 1994 and February 1995 with passive samplers. A respiratory questionnaire was completed, and skin prick tests were performed. RESULTS: The median indoor formaldehyde level was 15.8 microg/ m3(12.6ppb), with a maximum of 139 microg/m3 (111 ppb). There was an association between formaldehyde exposure and atopy, and the adjusted odds ratio was 1.40 (0.98-2.00, 95% CI) with an increase in bedroom formaldehyde levels of 10 microg/m3. Furthermore, more severe allergic sensitization was demonstrated with increasing formaldehyde exposure. On the other hand, there was no significant increase in the adjusted risk of asthma or respiratory symptoms with formaldehyde exposure. However, among children suffering from respiratory symptoms, more frequent symptoms were noted in those exposed to higher formaldehyde levels. CONCLUSIONS: Low-level exposure to indoor formaldehyde may increase the risk of allergic sensitization to common aeroallergens in children.     

O等位基因引起ABO基因型与表现型定型差异

保证输血时血清学方面的安全,首要的是对受血者与献血者ABO血型定型,血清学检查通常分两个步骤.正定型通常使用鼠源单克隆抗体检测红细胞表面是否存在A或B抗原.互补的实验即反定型,利用当红细胞上缺乏A或B抗原时,人群可天然产生相对应的抗体的原理,检测血清中是否存在抗-A或者抗-B抗体.确定了受血者红细胞表面的ABO抗原以及血浆中的抗体,便能确定血型,为其提供相合的血液.