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Biomedical subjects

K Kula

Publications and source records attributed to K Kula.

At least 55 records · Page 3Linked to original sources
PubMed1983

In vitro effect of APF gel on three composite resins.

A laboratory study was conducted to determine effects of 1.23% APF gel on three composite resins. All composite resins immersed in APF gel lost significantly more weight than did their controls with significantly different weight losses among the APF-treated composites. Surfaces of all resins exposed to APF gel, as viewed in SEM's, exhibited degradation of filler particles.

Acidulated Phosphate Fluoride↗
PubMed1980

Somatic and germinal cells' interrelationship in the course of seminiferous tubule maturation in man.

Certain successive phases of seminiferous tubule maturation were observed in a transsection of a Leydig cell adenoma-bearing testis of a boy with precocious puberty. Massively accumulated Leydig cells may stimulate the maturation of Sertoli cells, as indicated by progressive replacement of Sertoli cell precursors by mature Sertoli cells at a distance closer to the adenoma. On the other hand, tubules less advanced in maturation contained a higher number of somatic cells than those more advanced in maturation. Leydig-cell-dependent maturation of Sertoli cells may be in competition with Certoli cell multiplication, or numerous undifferentiated somatic cells may undergo a natural elimination in the course of tubular maturation. An inverse relation between the number of Sertoli cell precursors and the number of meiotic spermatocytes suggests that quantitative reduction of Sertoli cell precursors may be important for the intratubular milieu necessary for the onset of the first meiosis in man.

Child↗
PubMed1979

Serum immunoglobulins IgG and IgM in the seminal plasma of men with normospermia, oligozoospermia, and azoospermia.

The seminal plasma of eight males with normospermia, seven with oligozoospermia, and eight with azoospermia was examined for the presence of IgG and IgM by means of double-gel immunodiffusion. IgG was present in every seminal plasma sample. The highest titers of IgG were found in azoospermic and normospermic samples, but the lowest IgG titers were seen only in normospermic samples. IgM was detected only in some cases, mainly in the azoospermic group. Testicular biopsy was performed in all the azoospermic patients, but IgM was found only in the cases demonstrating spermatogenic arrest and was not found in the cases with complete spermatogenesis. It is concluded that the IgM present in the seminal plasma was of testicular origin and was associated with injury of the male genital system.

Adult↗
PubMedDate not supplied

The influence of human menopausal gonadotropin, natrium fluoride and cyproterone acetate on the spermatogenesis in immature rats.

Human menopausal gonadotropin (HMG), natrium fluoride (NaF) and cyproterone acetate (CYA) were applied to immature male rats between the 26th and 32nd day of life and histological examination was performed in testes of 33rd-day-old rats. HMG treatment alone slightly influenced the spermatid completion process, while NaF evidently increased frequency of occurrence of various seminiferous tubules containing spermatids. CYA alone damaged the spermatid completion process (especially the cap-phase of spermiogenesis), produced a degeneration of meiotic spermatocytes, and decreased the tubular diameter. Those changes were prevented by addition of HMG to the CYA treated animals. The results suggest a possible regulatory role of FSH at the end of the first meiosis, and, also, in the progression of spermiogenesis. The mechanism of action of NaF may be hypothetical, but it probably consists of direct action on the seminiferous epithelium level.

Animals↗
PubMedDate not supplied

Synthesis of testosterone and 5 alpha-reduced androgens during initiation of spermatogenesis in the rat.

Numerous investigators demonstrated increased 5 alpha-reductase activity in testes of developing rats. The rapid in vitro metabolism of progesterone to 5 alpha-reduced androgens occurs at certain stages of testicular development. This was considered evidence for the conclusion that testosterone is primarily an intermediate rather than the final product in testes of immature rats. However, a discrepancy is noted when developmental patterns of circulating or intratesticular levels of androgens are compared with the patterns of accumulation of metabolites of progesterone in vitro. In blood and testicular tissue of 17-20 day old rats a testosterone peak has been reported, while in the in vitro studies such peak was not observed. In this study radiolabelled pregnenolone was utilized in vitro as a substrate, and a pattern of androgen formation similar to that observed in the in vivo studies was noted. A peak of androgen formation (testosterone and 5 alpha-androstanediol) was observed used prior to completion of the meiotic prophase. However, when testosterone was utilized as the substrate, no correlation between 5 alpha-reduction and completion of the meiotic prophase was detected. This suggests that the rise in testosterone may be associated with completion of the meiotic prophase. Investigation of the androgen metabolic pathways revealed the following age-related patterns: no change in 17 beta-hydroxysteroid dehydrogenase, activation of 5 alpha-reductase at 12 days of age, and activation of 3 alpha-hydroxysteroid dehydrogenase between 14 and 18 days of age.(ABSTRACT TRUNCATED AT 250 WORDS)

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMedDate not supplied

Hyperactivation of early steps of spermatogenesis compromises meiotic insufficiency in men with hypergonadotropism. A possible quantitative assay for high FSH/low testosterone availabilities.

It has been shown previously that blood plasma elevation of FSH is associated with an impaired function of the seminiferous tubules. In the study presented here quantitative analysis of the seminiferous epithelium was performed in testicular biopsies of men with qualitatively complete spermatogenesis and hypergonadotropism (HG group, n = 6) or normogonadotropism (NG group, n = 9). Hormonal determinations were performed also in eight men with Sertoli cells only (SCO group). Plasma levels of gonadotropins found in HG were comparable with those found in SCO, while mean plasma testosterone levels in these patients were significantly lower than in SCO or NG. A significant decrease in the mean number of spermatids was present in HG, while the mean numbers of B spermatogonia (0.6 +/- 0.2) and preleptotene spermatocytes (0.6 +/- 0.1) were significantly elevated in comparison with NG (0.4 +/- 0.1 and 0.3 +/- 0.2, respectively). In all men with HG a GnRH test (100 micrograms i.v.) was performed and the relative increase of plasma FSH (maximum/basal level) correlated positively with the number of A-pale (r = 0.85, P less than 0.05) and B spermatogonia (r = 0.81, P less than 0.05). In NG group basal levels of FSH correlated with A-pale (r = 0.90, P less than 0.001) and B spermatogonia (r = 0.59). It seems that FSH plays a role to maintain the number and the differentiation rate of spermatogonia in men and is responsible for the hyperactivation of spermatogonia when secreted in excess. Hyperactivation of spermatogonia probably develops to compensate quantitative decrease in gamete production.(ABSTRACT TRUNCATED AT 250 WORDS)

Follicle Stimulating Hormone↗
PubMedDate not supplied

In vitro effect of topical fluorides on sealant materials.

The purpose of this study was to determine by visual inspection and by scanning electron microscopy (SEM) whether commercially available, topical, acidulated phosphate fluoride (APF) and neutral sodium fluoride (NaF) agents cause surface roughening of five sealant materials: two unfilled resins, two filled resins, and one glass-ionomer material. In addition, the effect of treatment with 1.23% APF and sonification on weight of an unfilled and a filled sealant was compared to treatment with controls. Unfilled sealants exhibited no surface changes visually or on micrographs following any treatment. Filled sealants and the glass-ionomer sealant exhibited visually apparent changes depending on the treatment. SEM inspection of filled sealants with visually apparent changes showed loss of filler particles whereas the glass-ionomer sealant exhibited apparent destruction both of the matrix and the filler particle. No significant differences in weight were found between sonicated and unsonicated specimens. However, significant loss of weight was found with filled sealant specimens, but not unfilled sealant specimens, treated with 1.23% APF gel as compared with the specimens treated with water. The results of this in vitro study indicate that preventive therapies that combine use of topical fluorides and sealants may cause deterioration of filled sealants and glass-ionomer sealant material, but not unfilled sealants.

Acidulated Phosphate Fluoride↗
PubMedDate not supplied

Craniofacial features associated with amelogenesis imperfecta.

Craniofacial alterations occur with increased frequency in patients with amelogenesis imperfecta (AI). The purpose of this study was to characterize the craniofacial features associated with AI in families from the US. Twenty-seven people with AI and 14 unaffected family members from nine separate kindreds were evaluated. The diagnosis was established by history, clinical, and radiographic examination, and histological and or biochemical analysis of enamel. The kindreds were generally classified as hypoplastic AI (HPAI), hypocalcified AI (HCAI), or hypomaturation AI (HMAI) and then further subclassified based on phenotype and mode of inheritance. Linear and angular cephalometric measures were converted to z-scores using gender/age matched values from the Bolton and Behrent's standards. Statistical analyses included t-tests and ANOVA accepting P < or = 0.05 as significant. The vertical dimension of the lower face was significantly increased (ANSMe; P = 0.001), especially in affected individuals compared with unaffected relatives, in all kindreds with HCAI and HMAI but in only one kindred with autosomal recessive rough AI. Clinically, an anterior open bite (overbite < 0 mm) was observed in 26% of all dentate individuals with AI and none of their unaffected relatives. Skeletal morphology was highly variable depending on the AI type and kindred. While this study shows an association of altered craniofacial morphology with certain AI kindreds, the relationship of the AI genotype to the observed malocclusions remains to be defined.

Adolescent↗
PubMedDate not supplied

[Sex steroids versus lipid profile and the degree of coronary artery stenosis in men with angiographically documented coronary artery disease].

The aim of the study was to assess the correlations between the levels of sex hormones and blood lipid profile as well as indexes of coronary artery stenosis in men with angiographically documented coronary artery disease. 111 men, aged 36-73 yrs (av. 55) were studied. In all the patients levels of testosterone (T), dehydroepiandrosterone sulfate (DHEA-S), estradiol (E), SHBG, LH and FSH were measured. The level of bioavailable testosterone (BT) was calculated knowing SHBG level. Total cholesterol (TCh), HDL-cholesterol, LDL-cholesterol and triglycerides (TG) levels were estimated as well as the degree of coronary artery stenosis was estimated by means of modified indexes. For statistics R-Spearman test was used. Summing coronary stenosis index correlated significantly with T-Ch and LDL-Ch levels. Positive correlation was found between blood level of E and TCh as well as between E and LDL-Ch. BT correlated partially with LDL-Ch level. No correlations were found between the levels of T, SHBG, DHEA-S, FSH, LH and lipid profile. The level of DHEA-s revealed negative correlation with age, while the level of SHBG increased with ageing leading to the decrease of the value of BT but not total T. None of studied hormones correlated with coronary indexes. Our results suggest that estradiol and BT may promote the formation of atherogenic lipid profile leading to atherosclerosis in men.

Adult↗
PubMedDate not supplied

Testicular pathology in 46,XY dysgenetic male pseudohermaphroditism: an approach to pathogenesis of testis cancer.

Eleven children with dysgenic male pseudohermaphroditism (DMP) and 18 boys with isolated penile hypospadias, all with 46,XY karyotype, were studied. Testicular dysgenesis was associated with significantly lower testosterone response to human chorionic gonadotropin (0.9 +/- 0.2 ng/mL) than it was in hypospadias (3.3 +/- 0.1 ng/mL), and with significantly higher mean serum follicle-stimulating hormone (FSH) levels (8.4 +/- 2.3 IU/L vs 1.5 +/- 0.3 IU/L). Gonadoblastoma, a tumor that arises from the sex cords, was found in more than 1/4 of patients with DMP, whereas testicular carcinoma in situ (CIS) cells were present in all of these patients. Forty-two percent to 98% of CIS cells revealed an aneuploid pattern of nuclear DNA, indicating that most of them are neoplastic cells. In patients with hypospadias, CIS was not seen, and no other abnormalities were detected. In children with DMP, the percentage of tubules populated with germ cells was significantly lower than it was in those with hypospadias (48.3% +/- 10.6% vs 92.4% +/- 4.0%). The total number of germ cells (CIS cells + spermatogonia) did not differ significantly between the 2 groups, but the number of spermatogonia was significantly reduced in children with DMP (0.08 +/- 0.05 vs 3.65 +/- 0.2), suggesting impaired differentiation of gonocytes to spermatogonia. The following significant correlations were present with DMP: 1) the higher the seminiferous tubule cross-section area, the higher the number of CIS cells (r = 0.78); and 2) the higher the serum gonadotropin levels, the higher were tubular diameter (r = 0.93 for FSH and r = 0.75 for luteinizing hormone [LH]), area (r = 0.79 for FSH and r = 0.82 for LH), percentage of tubules populated with germ cells (r = 0.86 for FSH and r = 0.81 for LH), and number of CIS cells (r = 0.87 for FSH and r = 0.79 for LH). The results indicate that in intersex children with 46,XY karyotype, CIS occurs in dysgenetic testes in all cases and is frequently associated with gonadoblastoma. Impaired organogenesis of sex cords, relative inhibition of testosterone secretion, and the associated increased secretion of gonadotropins may create a milieu that induces or is favorable for the formation or maintenance of neoplastic lesions in dysgenetic testes early in childhood.

Child↗