Anatomy of the mastoid triangle and morphometric sex differences

OBJECTIVE OF THE STUDY

This study aimed to quantify the area of the mastoid triangle (MT) and assess potential morphometric differences between males and females.

PATIENTS

The sample consisted of 244 dry human skulls, with biological sex known based on genetic analysis, collected from a medicolegal osteological database from Central-Western Brazil.

MATERIALS AND METHODS

The study was observational, analytical, and cross-sectional. The skulls were analyzed using Heron's equation to calculate the area of the MT. The landmarks connecting each of the sides of the triangle were: Porion (Po)>Mastoidale (Ma)>Asterion (Ast). Morphometric references were calculated and compared based on sex.

RESULTS

The area of the MT was nearly 14% larger in males compared to females (p<0.05). The mean MT area for the right and left sides of males were 684.11±93.25mm² and 668.94±111.95mm², respectively. In females, the mean MT for the right and left sides were 588.93±91.09mm² and 582.88±102.98mm², respectively. Right and left side measurements were significantly different (p<0.05), except for Po-Ast (p=0.232).

CONCLUSION

Morphometric features regarding the MT were slightly different between males and females. Application of the MT as a dimorphic tool should be adjuvant. Moreover, this tool should be considered carefully, especially because the sex-based differences were statistically significant, but discrete between males and females.

Neurophysiological, behavioral and morphological abnormalities in the Fabry knockout mice

Fabry disease (OMIM 301500) is a rare X-linked recessive disorder caused by mutations in the alpha-galactosidase gene (GLA). Loss of alpha-galactosidase (alpha-Gal) activity leads to the abnormal accumulation of glycosphingolipids in lysosomes predominantly of vascular endothelial cells. Clinically the disorder presents with angiokeratomas, clouding of the cornea, and renal, cardiac, and cerebrovascular complications. In addition, there is an increased incidence of neuropathic pain in Fabry patients. In this study, we investigated the implications of loss of alpha-galactosidase A activity on sensorimotor function and peripheral nervous system. Similar to the described in Fabry disease patients, the sensorimotor assessment of Fabry mice revealed diminished locomotor activity and warm hypoalgesia as assessed in the hot-plate. Moreover Fabry mice displayed alterations both in balance and co-ordination. By histological analysis, the cyto-architecture of Fabry mice sciatic nerves showed an increase in mean cross-sectional area accompanied by a decrease in the density of non-myelinated fibers as well as a trend for a decreased number of small myelinated fibers, a well established feature of Fabry disease. A relative preservation of large myelinated fibers and nerve conduction velocity measurements was observed. Our findings demonstrate for the first time that Fabry knockout mice have Gb3 accumulation in the peripheral nervous system, alterations in sensorimotor function, hypoalgesia and no impairment of motor nerve conduction.

Methamphetamine exacerbates the toxic effect of kainic acid in the adult rat retina

The recreational use of the psychoactive drug, methamphetamine has increased markedly over the last three decades. It has long been known that this drug has detrimental effects upon the mammalian brain monoaminergic system, but the long- or short-term effects on the retina, a neurological extension of the central nervous system, have received little attention. The aim of this study was, therefore, to determine whether intraocular injection of methamphetamine (MA) is toxic to the healthy adult rat retina and to analyse its effects on the compromised retina after an injection of the ionotropic glutamate receptor agonist, kainate, which is known to cause retinal neuropathology. The equivalent of 1 mM (in the vitreous humour) MA and/or kainate (40 microM) were injected intravitreally. Flash electroretinograms (ERGs) were recorded before and 2 and 4 days after treatment. Five days after treatment, animals were killed and the retinas analysed either for the immunohistochemical localisation of various antigens or for electrophoresis/Western blotting. Some animals were kept for 19 days after treatment and the retinas analysed for tyrosine hydroxylase immunoreactivity. No differences could be found between vehicle- and MA-treated retinas with respect to the nature or localisation of either tyrosine hydroxylase immunoreactivity after 5 or 19 days or other antigens after 5 days. Moreover, the normal ERG and GFAP and calretinin protein antigens were unaffected by MA. Kainate treatment, however, caused a change in the ERGs after 2 and 4 days, an alteration in every antigen localised by immunohistochemistry and an increase in the retinal levels of calretinin and GFAP proteins. Significantly, the changes seen in the b-wave amplitude and implicit time of the ERG after 4 days and the increased level of GFAP protein after 5 days following kainate treatment were enhanced when MA was co-injected. Intravitreal injection of methamphetamine had no detectable detrimental effect on the normal adult rat retina but exacerbated the damaging effects of kainic acid. Such data suggest that a neurotoxic effect of MA may be more obviously illustrated when the tissue is already compromised as occurs in, for example, ischemia.

Validation of national algorithms for the diagnosis of sexually transmitted diseases in Brazil: results from a multicentre study

OBJECTIVE

To validate STD flow charts for the management of genital discharge and genital ulcer currently recommended by the National STD Control Programme in Brazil.

METHODS

A study was conducted in five Brazilian STD clinics from January to June 1995. After an interview, a clinical examination was performed by a physician, who recorded a presumptive diagnosis, based on his/her clinical experience. This diagnosis was compared with a gold standard laboratory diagnosis in order to calculate sensitivity, specificity, and positive predictive value of the clinical diagnosis. The validity of the simulated national flow charts was assessed using the same method.

RESULTS

A total of 607 men and 348 women participated in the study. Gonorrhoea was the aetiology most frequently detected in men with urethral discharge. The sensitivity of the clinical diagnosis was far lower than the sensitivity fo the national flow chart, using the syndromic approach, for both gonococcal and chlamydial urethritis. Adding a simple laboratory test (Gram stain) to the national flow chart increased the specificity and positive predictive value for gonorrhoea. Among the women with vaginal discharge, a cervical infection was detected in 17%, a vaginal infection in 74%, and mixed infection in 9%. The sensitivity of the diagnosis for cervical infection increased from 16% (clinical aetiological approach) to 54% (when adding a syndromic approach) and to 68% when adding a risk assessment, as in the national flow charts. The cure or improved rate of genital ulcers was 96% after 1 week.

CONCLUSIONS

The results of the study will help to convince policy makers and those involved in training healthcare workers in Brazil of the public health advantages of the syndromic approach, as an essential part of STD/HIV control activities.

Resources needed to culture Chlamydia trachomatis in laboratories of clinics for sexually transmitted diseases

Genital infections with Chlamydia trachomatis may be more prevalent than infection with Neisseria gonorrhoeae and may have serious sequelae such as epididymitis and pelvic inflammatory disease in adults and conjunctivitis and pneumonia in neonates. A culture of the organism is the most sensitive and specific means for detecting C. trachomatis in the genital tract, yet this procedure is available only in specialized centers and universities. Establishment of a chlamydia laboratory as part of a clinic for sexually transmitted diseases (STD) requires major technical and financial resources. Technical resources include the expertise of technicians as well as specialized equipment, glassware, and reagents. The current (August, 1981) minimal cost of performing a chlamydial culture is estimated to be $14.69.