[Renal function in hypertensive patients with obstructive sleep apnea]. / Nierenfunktion bei hypertensiven Patienten mit obstruktiver Schlafapnoe.

BACKGROUND: Patients with hypertension often suffer from obstructive sleep apnea (OSA). In addition to hypertension several other risk factors (hypoxemia, hyperlipidemia, and increased sympathic nerve activity) may contribute to progressive renal dysfunction in OSA patients. The aim of this study was to compare renal function in OSA-patients with and without hypertension. METHODS: 81 consecutive patients (50 males, 31 females) were screened for sleep apnea. Parameters of renal function (serum creatinine, creatinine clearance, microalbuminuria), and of lipid and glucose metabolism were correlated to polysomnographic results. RESULTS: OSA (apnea/hypopnea index [AHI] > or = 5) was found in 57 of 81 patients. Mean AHI was 26.7 +/- 26.1. Hypertension (blood pressure > or = 140/90 mmHg or use of antihypertensive drugs) occurred in 63 of 81 patients. Serum creatinine in OSA patients was significantly higher than in patients without OSA (1.11 +/- 0.15 vs. 0.91 +/- 0.12 mg/dl, p < 0.001). Serum creatinine correlated significantly with AHI. Creatinine clearance was associated with age (r = -0.314; p = 0.014) and presence of OSA (r = 0.265; p = 0.093). No correlation was shown between hypertension and serum creatinine or creatinine clearance. Microalbuminuria was not associated with OSA. CONCLUSION: Our results suggest an independent association between OSA and impaired renal function. Further prospective studies will have to be done to elucidate the pathophysiological mechanisms.

Nonreciprocal gonadal dysgenesis in hybrids of the chironomid midge Chironomus thummi. IV. Behavior of a female-specific protein, probably a vitellogenin.

Using denaturing SDS-polyacrylamide gel electrophoresis, a protein with a subunit MW of about 148,000 daltons could be detected in the fat body of females of the reciprocal hybrids of Chironomus thummi thummi and Chironomus thummi piger, which is not present in males. This protein is presumably a vitellogenin and can be found in both hybrids during the late fourth-instar larval stage until eclosion of the adults, i.e., in early vitellogenesis. After eclosion, the reciprocal hybrids behave differently concerning the 148-kd protein. In females of the piger female x thummi male cross, which are fertile and produce yolky eggs, the 148-kd protein disappears from the fat body immediately after eclosion. In females of the reciprocal cross (thummi female x piger male) which are affected by gonadal dysgenesis and in which the oocytes only rarely contain yolk, the 148-kd protein is still present in the fat body of the adult up to 50 hr after eclosion until the fat body degrades. It is concluded that the inability of the sterile thummi female x piger male females to produce yolky eggs is caused by an impaired uptake of the presumed 148-kd vitellogenin into oocytes and not by a defective vitellogenesis. The impaired vitellogenin deposition into oocytes is taken as another aberrant trait of gonadal dysgenesis of the thummi female x piger male hybrids.

C-band differentiation between the chromosomes of two subspecies of the chironomid midge Chironomus thummi.

The metaphase chromosomes of Chironomus th. thummi contain approximately 17% more pericentric C-band heterochromatin than the chromosomes of Chironomus th. piger with 11% heterochromatin. In Ch. th. thummi, the proportion of heterochromatin appeared to be much larger in metaphase chromosomes than in polytene chromosomes. This discrepancy is interpreted as being due to the specific chromosome organization and not as the result of an underreplication of heterochromatin during polytenization.

Nonreciprocal gonadal dysgenesis in Chironomus thummi hybrids: temperature sensitivity of female sterility.

In nonreciprocal hybrids of Chironomus thummi an environmental factor has been detected which, along with genetic factors, determines gonadal dysgenesis. Female hybrids of the cross Ch' thummi thummi female female x Ch. thummi piger male male show various degrees of rudimentary developed ovaries and sterility. The extent of these abnormalities is dependent on the developmental temperature of the hybrids. At a temperature of 21 degrees C approximately 90% of the females are completely sterile and at 16 degrees C only 30%. The curative effect of a temperature of 16 degrees C on sterility occurs, however, only in those hybrid females which hatch from a specific type of egg mass (class A). Females of another type of egg mass (class B) show nearly as many dysgenic ovaries as do those developed at 21 degrees C. At a developmental temperature of 21 degrees C no such differentiation between the A and B class of egg masses is possible. Ovarian dysgenesis and sterility is induced during a temperature-sensitive period which extends from the beginning of embryonic development through the first two-thirds of the first larva instar stage. The abnormalities observed must be due to a failure in the early development of the germ line and are probably initiated by an inhibition of primordial germ cell divisions.

Non-reciprocal gonadal dysgenesis in hybrids of the chironomid midge Chironomus thummi. III. Germ line specific abnormalities.

In male hybrids of the cross Chironomus thummi thummi (stock Hl) females x Ch. th. piger (stock E) males, but not the reciprocal cross, rudimentary testes develop at a growth temperature of 21 degrees C. Within the dysgenic testes of these hybrids a number of abnormalities are observed which are restricted to the germ line. Approximately 60% of the hybrid males show allocyclic chromosome behaviour in spermatogonia and spermatocyte I nuclei. Within these nuclei two groups of four chromosomes are formed which differ from one another in their state of condensation. Each chromosome group consists of three long and one short chromosome. In cases where allocycly is very pronounced, the chromosomes of both groups disintegrate into numerous unequally sized fragments at meiotic prometaphase I, and gametes are not produced. In individuals, in which the allocycly is less pronounced or absent the nuclear divisions appear to be normal but chromosome and chromatid aberrations are frequent, and the number of viable sperm is reduced. In these males, the chiasma frequency is also decreased more than 12-fold in comparison with the reciprocal, unaffected piger females x thummi males hybrids.

Identification of a polytene chromosome band containing a male sex determiner of Chironomus thummi thummi.

Hybrid males of Chironomus thummi piger female x Ch. th. thummi male crosses were backcrossed with females of both parental stocks. Fourth-instar larvae of these backcrosses showed sex specific differences in the pairing behavior of region D3d-g in chromosome arm F of salivary gland chromosome III. Analysis of the banding pattern of region D3d-g after RB and quinacrine staining demonstrated that in piger female x thummi male hybrid males a single selectively stained band occurs within this region in the heterozygous condition at map position D3e1. This band could only be found in the thummi chromosome partner, it is heterochromatic and contains AT-rich DNA. In female hybrid larvae, however, such a selectively stained band is present in neither the thummi nor the piger chromosome region D3d-g. From these results it is concluded that the selectively stained band D3e1 represents the male sex determiner of our Ch. th. thummi stock and that the male is the heterogametic sex.

The chromosomes of two Drosophila races: D. nasuta nasuta and D. nasuta albomicana. II. Differences between their microchromosomes.

The microchromosomes of the totally cross fertile Drosophila races, D. nasuta nasuta and D. nasuta albomicana have been studied in metaphase and polytene nuclei. In metaphase the microchromosome of D. n. albomicana is nearly five times longer than the homologous chromosome in D. n. nasuta. As shown by C-banding these length differences are mainly due to a massive addition of heterochromatin to the D. n. albomicana chromosome. In polytene nuclei these striking heterochromatin differences between the microchromosomes of the two Drosophila races cannot be observed. Analysis of the polytene banding pattern shows that the microchromosomes of both races differ by an inversion and by a duplication, present only in D. n. albomicana. the location and orientation of the duplicated regions in D. n. albomicana leads to a specific loop like chromosome configuration. On the basis of these differences within the Drosophila races studied it is assumed that the karyotype of D. n. albomicana is a more recent evolutionary product.

Satellite DNA of Drosophila nasuta nasuta and D. n. albomicana: localization in polytene and metaphase chromosomes.

The DNA from the two Drosophila nasuta races, D. n. nasuta and D. n. albomicana was investigated by CsCl density gradient centrifugation. D. n. nasuta has one major AT-rich satellite DNA sequence with a density of 1.664 g/cm3, while D. n. albomicana has at least three satellites with densities of 1.674 g/cm3, 1.665 g/cm3 and 1.661 g/cm3. The isolated satellite sequences hybridize in situ to all heterochromatic regions of all metaphase chromosomes of both races. In polytene chromosomes the satellite sequences hybridize exclusively to the chromocenter. All chromosomal regions hybridizing with the satellites show also bright quinacrine fluorescence.

The chromosomes of two Drosophila races: D. nasuta nasuta and D. n. albomicana. I. Distribution and differentiation of heterochromatin.

Heterochromatin distribution and differentiation in metaphase chromosomes of two morphologically identical Drosophila races, D. nasuta nasuta and D. n. albomicana, have been studied by C- and N-banding methods. -- The total heterochromatin values differ only slightly between these races. However, homologous chromosomes of the two Drosophila forms show striking differences in the size of heterochromatin regions and there is an alternating pattern in D. n. nasuta and D. n. albomicana of chromosomes which contain more, or respectively less heterochromatin than their counterparts in the other race. -- Three different N-banding patterns could be obtained depending on the conditions of the method employed: One banding pattern occurs which corresponds to the C-banding pattern. Another pattern is the reverse of the C-band pattern; the euchromatic chromosome regions and the centromeres are stained whereas the pericentric heterochromatin regions remain unstained. In the Y chromosomes of both races and in chromosome 4 of D. n. albomicana, however, the heterochromatin is further differentiated. In the third N-banding pattern only the centromeres are deeply stained. Furthermore, between the races, subtle staining differences in the pericentric heterochromatin regions can be observed as verified in F1 hybrids. On the basis of C- and N-banding results specific aspects of chromosomal differences between D. n. nasuta and D. n. albomicana are discussed.

DNA replication of a polytene chromosome section in Drosophila prior to and during puffing.

Polytene chromosome sections 63E1-6 of 3L in Drosophila melanogaster were studied by 3H-uridine and 3H-thymidine autoradiography in late third instar larvae and prepupae. In late third instar larvae 63E does not incorporate 3H-uridine. In prepupae, however, a large puff is formed in 63E which is most active in RNA synthesis. 3h-thymidine labeling patterns and frequencies of regions 61A-64C were analysed and the nonpuffed and puffed 63E sections were compared with reference sections. Both in late third instar larvae and in prepupae 63E shows late replication behavior. It is concluded that the decondensation of chromosome bands does not necessarily entail earlier and/or faster DNA replication.

Differential staining of polytene chromosome bands in Chironomus by Giemsa banding methods.

Two Giemsa banding methods (C banding and RB banding) are described which selectively stain the centromere bands of polytene salivary gland chromosomes in a number of Chironomus species. - By the C banding method the polytene chromosome appearance is changed grossly. Chromosome bands, as far as they are identifiable, are stained pale with the exception of the centromere bands and in some cases telomeres, which then are intensely stained reddish blue. - By the RB method the centromere bands are stained bright blue, whereas the remainder of the polytene bands stain red to red-violet. - Contrary to all other species examined, in Chironomus th. thummi numerous interstitial polytene chromosome bands, in addition to the centromere regions, are positively C banded and blue stained by RB banding. In the hybrid of Ch. th. thummi X Ch. th. piger only those interstitial thummi bands which are known to have a greater DNA content than their homologous piger bands are C banding positive and blue stained by the RB method whereas the homologous piger bands are C banding negative and red stained by RB banding. Ch. thummi and piger bands with an equal amount of DNA both show no C banding and stain red by RB banding. - It seems that the Giemsa banding methods used are capable of demonstrating, in addition to centromeric heterochromatin, heterochromatin in those interstitial polytene chromosome bands whose DNA content has been increased during chromosome evolution.

Correspondence of banding patterns to 3h-thymidine labeling patterns in polytene chromosomes.

3H-thymidine labeling frequencies over X chromosomal region 1A-4E of Drosophila melanogaster, were analysed with reference to chromosome sections with and without prominent bands. A correspondence was found between band sections and late start of silver grain labeling at the initial stage in combination with late labeling at the end stage of replication. A complementary situation is always to be found over puff/interband sections, where an early start of labeling at the initial stage is generally combined with early labeling completion at the end stage of replication.

Prolongation of replication time after doublings of the DNA content of polytene chromosome bands of Chironomus.

Using 3H-thymidine autoradiography, labeling frequency of homologous asynapsed chromosome bands of the hybrid of Chironomus th. thummi and Chironomus th. piger has been studied. In a number of these bands the DNA content of the thummi bands if 2, 4, 8 or 16 times as large as that of the homologous piger bands (Keyl, 1965). Those bands of CH. TH. thummi which show one doubling of their DNA content in comparison with the homologous piger bands are also labeled two times more frequently than piger. In contrast to this such a correlation between increase of labeling frequency (i.e. prolongation of replication time) and doubling of the DNA content is not observed, when thummi bands have 4, 8 or 16 times more DNA than their homologues in piger. In these cases replication time is also prolonged after each doubling. Duration of DNA synthesis increases linearly but always by a smaller factor as the corresponding DNA content is increased.