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Biomedical subjects

A M Jequier

Publications and source records attributed to A M Jequier.

At least 19 recordsLinked to original sources
PubMed2001

Differentially expressed DNA sequences following recovery from unilateral testicular torsion in rat.

The molecular response during recovery from torsion-induced stress in the testis is diverse with a variety of mechanisms. In this study, using unilateral testicular torsion in rat as a model, we used subtractive hybridisation to identify differentially expressed DNA sequences in the torsioned and control testes. Three genes were identified as being down regulated in the torsioned testis compared with controls: Control Testis genes 1, 2 and 3 (CT1, CT2 and CT3). Two genes were up regulated in the torsioned testes: Torsioned Testes genes 1 and 2 (TT1 and TT2). Differential expression was confirmed by Reverse Northern blot analysis. An homology search revealed that CT1 had 88% homology with rat metallothionein cDNA; CT2 had 81% homology with rat cell surface antigen in MHC class I, but no homology could be found for CT3. TT1 had 92% identity with rat Rieske iron-sulphur protein mRNA whereas TT2 had 73% identity with a human clone of unknown function (RP 11-252D22). These results indicate that changes in gene expression occur following torsion induced stress, and that identification of differentially expressed genes may provide insights into the mechanisms of cellular tissue damage in this model.

Animals↗
PubMed2000

Torsion-induced injury in rat testes does not affect mitochondrial respiration or the accumulation of mitochondrial mutations.

Male rats were subjected to 1 h testicular torsion of the spermatic cord or 1 h torsion followed by detorsion and recovery up to 4 weeks. The extent of tissue damage was evaluated by a testicular biopsy score count and mitochondrial function. Torsion for 1 h followed by detorsion induced significant morphological damage, which became more severe with longer periods of recovery. This morphological damage could not be correlated with mitochondrial damage as assessed by measuring the 4834 bp mitochondrial DNA 'common deletion' using a quantitative competitive polymerase chain reaction (PCR) assay. Mitochondrial respiratory chain activity, as measured by mitochondrial oxygen consumption using an oxygen electrode, did not vary between the treated animals and the controls. We conclude that the common mitochondrial DNA deletion and oxygen consumption are not good indicators of testicular damage induced by torsion.

Animals↗
PubMed1999

Single-step method for the determination of the amount of the common deletion in mitochondrial DNA.

A fluorescent-based quantitative PCR assay to measure the percentage of the common deletion in rat mitochondria is reported. The amount of the common deletion is measured relative to the amount of total mitochondrial (mt)DNA. The use of a heterologous competitor construct allows the reaction to be monitored to ensure that exponential accumulation of products occurs. The use of fluorescence-labeled primers provides a safe and sensitive means to quantify products without any adjustment for size. This assay will allow the quantitative determination of the common deletion with one dilution range.

Animals↗
PubMed1998

Semen levels of mitochondrial DNA deletions in men attending an infertility clinic do not correlate with phenotype.

In view of previous reports associating mitochondrial DNA deletions with male reproductive disorders, levels of the 'common' 4977 bp mitochondrial DNA deletion were evaluated semi-quantitatively in 64 men, without prior knowledge of the clinical diagnosis. Significant levels of deletions were detected in 34/64 men (53%) but 29 of these (45%) had a normal semen profile and were phenotypically normal. No deletions were detected in 30 men, of whom 21 were normospermic, six were oligozoospermic and three were azoospermic. It is concluded that although mitochondrial DNA deletions within the testis may be associated with primary testicular disease, no correlation with semen quality was evident in this study, thus limiting its potential use as a diagnostic test.

DNA, Mitochondrial↗
PubMed1998

Vasectomy related infertility: a major and costly medical problem.

Of a group of 860 men who attended a private infertility clinic in Western Australia, 80 (9.3%) presented with vasectomy-related infertility. Of these men, 73 (91%) requested treatment due to re-marriage. The median age of the men was 42.5 years and their present partners were approximately 10 years younger. The median vasectomy interval in the men in this study was 9 years. Treatment of vasectomy-related infertility included vasectomy reversal procedures, donor insemination and both in-vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI). It is suggested that care must be taken in counselling such patients prior to a vasectomy. The cryopreservation of semen prior to vasectomy would also make much of this type of infertility treatment unnecessary.

Adult↗
PubMed1997

Clinical assessment of male infertility in the era of intracytoplasmic sperm injection.

This communication outlines the major causes of infertility in the male and, where indicated, the application of in vitro fertilization and intracytoplasmic sperm injection in their treatment. It also points out that there are many types of infertility in the male where other methods of treatment are also successful and where reproductive technology is unnecessary.

Ejaculation↗
PubMed1996

Mitotic chromosomal anomalies among 1210 infertile men.

Detailed medical and clinical examinations were carried out on 1608 men attending an infertility clinic to determine if any of those exhibiting abnormal semenograms also had any other readily identifiable clinical condition. In all, 1210 men showed abnormal semenograms according to World Health Organization criteria. Karyotyping of the white blood cells in these 1210 men revealed 44 (3.6%) individuals with either autosomal or sex chromosomal aberrations. However, no single characteristic feature of their semenogram or clinical condition was of any diagnostic value to predict the existence of a chromosomal anomaly.

Chromosome Aberrations↗
PubMed1995

Relationship between testicular morphology and sperm production following ischaemia in the ram.

Arteriosclerosis was induced in the internal spermatic artery of rams to determine if this condition is implicated in the aetiology of testicular pathology which causes male infertility. Data were collected on sperm concentration and motility for 56 days following surgery to provide an index of testicular function. Testes were then weighed and a testicular biopsy score count was performed on histological sections to assess spermatogenic potential of seminiferous tubules. Vascular disturbance caused focal damage of the seminiferous epithelium, similar to that seen among infertile men, and a reduction in ejaculate volume, sperm concentration and sperm motility. Sperm concentration decreased following ischaemia yet was maintained to some degree by a germ-cell depleted spermatogenic epithelium. Normal testicular morphology was maintained above a testis weight of about 120 g (for an individual testis), but below this threshold spermatogenesis was severely impaired. In conclusion, these data have provided information on the relationship between testicular morphology and function following ischaemia in the ram. Furthermore, the morphological changes induced in the testis were similar to those seen among infertile men and, by their focal nature, could explain the distinction between oligozoospermia and azoospermia in men exhibiting spermatogenic arrest.

Animals↗
PubMed1995

Effects of ischaemia on the caput epididymis and its relationship to higher epididymal obstruction: a qualitative study in the ram.

The objective of this study was to determine if localized ischaemia of the caput epididymis in the ram causes morphological changes similar to those characteristic of higher epididymal obstruction in humans. This was tested by performing unilateral occlusion of the superior epididymal artery in 10 rams. At the end of 4 (n = 5) or 28 weeks (n = 4), rams were castrated and the testes and epididymides were weighed. Analysis of histological sections at the light microscope level provided quantitative data on lumen diameter and epithelial cell height of the efferent ducts. Qualitative analysis and specific histochemical stains for identification of lipofuscin pigment provided further information on tissue changes. Electron microscopy was performed on the efferent ducts to assess ultrastructural changes. The results revealed that localized ischaemia of the proximal epididymis caused a dramatic change in tubule calibre of the efferent ducts and initial segment resulting in obstruction of the distal lumina. These changes were more severe following 28 weeks of arterial occlusion. The epithelial cells of the proximal region showed an increase in the number of lysosomes and they became active in phagocytosis of spermatozoa. Lipofuscin pigment accumulated within the epithelial cells and also in macrophage-like cells that had invaded the lumina, interstitium and intra-epithelial regions of the ducts. On the basis of these observations we conclude that the tissue changes which occur in the ram epididymis as a result of localized ischaemia show a striking similarity to those seen in men exhibiting higher epididymal obstruction. This suggests the possible implication of vascular disorders in the aetiology of obstructive azoospermia in men.

Animals↗
PubMed1994

Testicular morphology and androgen profiles following testicular ischaemia in rams.

Arteriosclerotic changes were induced in the internal spermatic artery of rams to determine whether there is a link between this condition and some pathological conditions of the testes, similar to those that cause infertility in men. Eight weeks after the induction of testicular ischaemia, blood plasma was collected simultaneously from the jugular and spermatic veins after an LH injection (10 micrograms) and assayed for testosterone. The rams were then castrated and sections of the testis, ductuli efferentes and spermatic cord were examined quantitatively and qualitatively. Vascular disturbance decreased the percentage of normal spermatogenic epithelium (P < 0.01) and the diameter of the seminiferous tubules (P < 0.001). These effects were accompanied by an increase in the percentage of the interstitial region within the testis (P < 0.05). Macrophages, lymphocytes and other inflammatory cells became numerous in the interstitium as damage to the seminiferous epithelium progressed. The most striking feature of the ischaemic testis was the focal damage of the spermatogenic epithelium, that is, sections of the same testis exhibited both normal and germ cell-depleted seminiferous tubules. Concentrations of testosterone in peripheral plasma were not significantly altered by either unilateral or bilateral testicular ischaemia; however, the concentration of testosterone was higher in the experimental spermatic vein than in the contralateral spermatic vein (P < 0.05) as was the ratio of LH:testosterone (P < 0.05). Unilateral vascular disturbance of the testis did not cause damage in the contralateral testis. The ductuli efferentes of these rams also showed structural changes as a result of vascular disturbance.(ABSTRACT TRUNCATED AT 250 WORDS)

Androgens↗
PubMed1993

Primary testicular disease presenting as azoospermia or oligozoospermia in an infertility clinic.

A group of 173 patients who made up 23% of a population of patients attending a male infertility clinic with primary testicular disease were examined; 63 patients (36%) were azoospermic and 110 (64%) were oligozoospermic. Their aetiology and clinical features are described, together with the endocrine findings, white blood cell karyotypes and, where available, the histology seen on a testicular biopsy. The relationship of these lesions with the presence or absence of a varicocele is discussed.

Adult↗