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Biomedical subjects

M Hirsch

Publications and source records attributed to M Hirsch.

At least 127 records · Page 7Linked to original sources
PubMed1985

Spermarche--the age of onset of sperm emission.

Gonad maturation in boys is not characterized by a critical visible event such as menarche in girls. Establishing spermatogenesis by masturbation in maturing boys may be considered inappropriate. In order to estimate the median age of spermarche, a group of 155 normal schoolboys were examined twice (ages 12 and 13 years) for the occurrence of sperm in the first voided morning urine. The boys were requested to bring a daily sample for 10 consecutive days. Over 90% brought at least two samples and 50% brought 5-10 samples. The rate of boys with spermaturia at each age was calculated by the life-table method to adjust for the varying number of samples. New spermaturia was detected with each additional sample in the boys who brought in a greater number of samples. The urine examination carried a considerable false negative rate; even in boys who brought five or more samples, over 40% of boys positive at age 12 were negative at age 13. The rate of spermaturia at age 12 years was 37.5%, and at age 13 it was 68.9%. Our previous report showed the rate at age 11 years to be less than 1%. Because of an uncertain number of false negatives, these are probably under estimates of the true rate of spermatogenesis. The occurrence of spermarche was significantly associated with maturation of secondary sex characteristics.

Actuarial Analysis↗
PubMed1985

Intercellular junctions in the developing rat corneal endothelium.

The surface events which occur during the morphogenesis of the corneal endothelium were studied in the rat with special attention to intercellular contacts, using scanning and transmission electron microscopy, and freeze-fracture technique. Confluency was reached at the 16th-17th day of fetal development. As soon as adjacent cells make contact, marginal interdigitated finger-like processes developed and apical cell junctions appeared, namely tight and gap junctions. Tight junction networks progressively developed, girdling the apical side of lateral membranes, nevertheless, they remained very irregular in their apicobasal thicknesses. At every stage studied, neutralized lanthanum used as an ultrastructural tracer was seen filling the intercellular clefts and junction domains. Hence, the apical junctions do not constitute an impermeable barrier to this tracer in the developing corneal endothelium.

Animals↗
PubMed1985

The structure of tight junctions in the ciliary epithelium.

The tight junctions of the ciliary epithelium act as a barrier preventing the passage of blood borne macromolecules into the posterior chamber. The use of the freeze-fracture technique has led to a good knowledge of their morphological pattern in various species. However, in order to attempt a correlation of the morphology of the tight junctions with their physiological properties, their intimate substructure must be considered. As in other glutaraldehyde-fixed epithelia, the tight junctions appear as networks (variable in their apico-basal thickness) of more or less discontinuous P-face ridges and as complementary E-face furrows in which some particles or short bars are found. The significance of the discontinuities of ridges has been analysed. The continuity of the junctional fibrils was evident as assessed both by quantitative measurements as well as morphological examination of complementary fracture faces. In addition, the absence of loss of junctional material showed that the integrity of the junction was preserved during the freeze-fracture process, even in conditions where an increase in "transfer" of junctional elements was experimentally induced. Most of all, a "pore system" due to visualizable gaps in the fibrils is not tenable for the ciliary epithelium. Furthermore, the analysis of transition steps at the level of membrane "fusion" showed that the tight junctions of the ciliary epithelium must now be considered as formed by two slightly offset fibrils, one per adjacent plasma membrane.

Animals↗
PubMed1984

Giant cerebral Echinococcus cyst with galactorrhea and amenorrhea.

A case of giant left-sided frontal cerebral Echinococcus cyst causing headaches, galactorrhea--amenorrhea, secondary sterility, and gain in weight in an adult female patient is reported. The operative removal of this huge cyst led to complete neurological and endocrinologic recovery.

Adult↗
PubMed1984

Preservation of the structural integrity of tight junctions during the freeze-fracture of ciliary epithelium.

It has recently been reported that losses of tight junction material could result from the freeze-fracture process. To verify this assumption, we tried to increase the possibility, if any, of losses of junction material, by inducing an important fragmentation of junctional fibrils by bathing ciliary epithelium in a 0.5M sucrose solution before glutaraldehyde fixation and freeze-fracturing at -160 degrees C. In spite of a significant redistribution of junctional material on both fracture faces, careful examination of complementary replicas and measurements of junction elements and interruption lengths showed that no loss of junctional material occurred in this tissue. The influence of physical parameters (i.e. temperature) on the preservation of the structural integrity of the tight junction during fracturing is now a problem to be considered.

Animals↗
PubMed1984

Prone computed tomography metrizamide myelography: a technique for improved diagnosis of lumbar disc herniation.

Computed tomography metrizamide myelography of the lumbar spine in the prone position is advocated for better visualisation of the thecal sac-disc annulus interface. This method allows a more precise diagnosis of disc herniation. Therefore, it is suggested that this technique should routinely be performed prone. In cases where suspended respiration in the prone position is difficult, the same result may be achieved by patient movement before scanning in the supine position.

Humans↗
PubMed1984

Evaluation of the morphology of sperm in urine of adolescent boys.

The morphology of spermatozoa in the first morning void of boys aged 12-16 years was evaluated. The results suggest that the number of cells having normal morphology increases with advancing age. Thus, the percentage of boys with greater than 45% normal sperm was 26% at the age of 12-13, increasing to 51% at the age of 15-16.

Adolescent↗
PubMed1984

Congenital dislocation of the hip and computerised axial tomography.

CT scans of 18 hips with typical congenital dislocation have been studied in 16 children. These show that the common position of dislocation is lateral, superior and slightly anterior, and that a "false acetabulum" can be distinguished even in young children. A defect in the posterior ischium causing distortion of the acetabulum was also present in most cases. The cartilage and the acetabular contents were well shown. Positions of reduction and the anteversion of the acetabulum and the femoral neck were studied. Hypotheses are presented on the mode of dislocation and on the cause of the pathological changes.

Acetabulum↗
PubMed1984

Endocrine profile in patients with Klinefelter's syndrome.

Twenty-seven patients with Klinefelter's Syndrome, aged 19-38 years were divided according to the basal testosterone (T) levels into sub-eugonadal (less than or equal to 3 ng/ml) and eugonadal (greater than 3ng/ml) groups. The pretreatment T level was 3.21 +/- 1.59 ng/ml. The LH and FSH levels, 14.54 +/- 6.68 mIU/ml and 21.51 +/- 10.74 mIU/ml respectively, were above the upper eugonadal range. Short-term hCG treatment stimulated T production significantly and a further increase was observed following long-term hCG treatment. In patients with sub-eugonadal levels of basal T, a greater relative increment of the T level was observed following the hCG stimulation but not in the absolute T increase. Thus, the assumption that in Klinefelter's patients, the low basal T levels and the relative refractoriness to hCG stimulation are secondary to chronic exposure to elevated LH levels, could not be supported. Higher FSH levels were associated with elevated plasma T levels (p less than 0.025). No such association was established with the LH.

Adult↗
PubMed1984

Brain sarcoma of meningeal origin after cranial irradiation in childhood acute lymphocytic leukemia. Case report.

The authors report their experience with an unusual case of intracerebral sarcoma of meningeal cell origin in an 8 1/2-year-old girl. This tumor occurred 6 1/2 years after cranial irradiation at relatively low dosage (2200 rads) had been delivered to the head in the course of a multimodality treatment for acute lymphocytic leukemia. The tumor recurred approximately 10 months after the first surgical intervention. Macroscopic total excision of the recurrent growth followed by whole-brain irradiation (4500 rads) failed to eradicate it completely and local recurrence prompted reoperation 18 months later. This complication of treatment in long-term childhood leukemia survivors is briefly discussed, as well as the pathology of meningeal sarcomas.

Brain Neoplasms↗
PubMed1984

CT pneumomeatography in the diagnosis of small acoustic neuromas.

The introduction of a small quantity of air by lumbar puncture in the lateral decubitus position followed by high-resolution computerized tomography (CT) scanning is a simple method allowing optimal visualization of the cerebellopontine angle cistern and the internal auditory meatus. Our experience with 37 CT pneumomeatographies in 22 patients who had clinical and audiometric findings suggestive of retrocochlear lesions is presented. Thirty-two examinations were normal, and 5 revealed small acoustic neuromas. In all cases, conventional X-rays, multidirectional tomography and contrast CT were nonconclusive. We advocate that CT pneumomeatography be the procedure of choice in the diagnosis of purely intracanalicular or very small extracanalicular acoustic neuromas.

Aged↗
PubMed1984

Lipoma of the esophagus.

Lipomas of the esophagus are relatively rare, but are of clinical interest since they may produce significant clinical symptoms that must be differentiated from malignant conditions. A case of esophageal lipoma is reported. The pliable, pedunculated esophageal tumor, which changes shape radiologically and has minimal clinical symptomatology, are the hallmarks for a correct diagnosis.

Diagnosis, Differential↗
PubMed1983

Systemic-pulmonary arteriovenous fistula of traumatic origin: a case report.

Arteriovenous fistulas between the systemic circulation and the pulmonary artery are extremely rare. Continuous precordial murmur is the usual clinical sign while unilateral rib notching may be the only radiologic manifestation of this condition. Selective angiographic investigation is necessary to localize the site of such an arteriovenous (AV) fistula before surgery is performed. In a review of the literature of 15 published cases, the majority were of congenital origin, with four of these systemic-pulmonary AV fistulas of traumatic origin, of which one occurred after insertion of an intercostal catheter. We describe one case of traumatic origin 9 years after percutaneous thoracic drainage for spontaneous pneumothorax, in which transcatheter embolic occlusion of the feeding arteries of an AV fistula was attempted. The advantages and the disadvantages of the nonsurgical and surgical therapeutic approaches are discussed.

Adult↗