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C Kirchhoff

Publications and source records attributed to C Kirchhoff.

At least 55 records · Page 3Linked to original sources
PubMed1996

Molecular cloning and characterization of HE1, a major secretory protein of the human epididymis.

The cDNA sequence of HE1, a novel human epididymal gene product isolated by differential screening, predicts an abundant, small secretory glycopeptide. HE1 is encoded by a single copy gene and seems to be well conserved among mammals. The predicted HE1 peptide is identical to that of EPI-1, the chimpanzee homologous gene product, and to ESP14.6, the macaque homologous product. Its tentative N-terminus also shows similarity to that of a major porcine epididymal sperm-associated glycopeptide. Northern blot analysis of various bovine and rat tissues indicated that their HE1-homologous gene products showed highly increased expression in the epididymis, suggesting that the tissue distribution observed in humans is also conserved. With use of antipeptide antibodies, HE1-related antigen was shown by immunohistochemical methods to be present within the epithelium and lumen of the human corpus epididymidis. High amounts were also present in the lumen of the cauda epididymidis and deferent duct. Moreover, HE1 seemed to be associated with epididymal spermatozoa, and association with ejaculated spermatozoa remained doubtful. With Western blotting, an antiserum raised against the synthetic HE1 epitope specifically cross-reacted with proteins of human seminal plasma in the range of 25-27 kDa. An antiserum raised against chimpanzee EPI-1 recognized human seminal plasma antigens of the same apparent molecular size.

Amino Acid Sequence↗
PubMed1996

Body temperature (37 C) specifically down-regulates the messenger ribonucleic acid for the major sperm surface antigen CD52 in epididymal cell culture.

To study the role of scrotal vs. body temperature in epididymal function we established a simplified cell culture system from the dog epididymis in which the cells showed a pattern of gene expression similar to that in the human epididymis and retained many characteristics of epididymal epithelial cells. The cultured cells had an epithelial-type cytoskeleton, nuclear androgen receptor protein, and a striking temperature responsiveness. Exposure of the cells to a culture temperature of 37 C, compared to 33 C, had a fast and irreversibly suppressive effect on the levels of an abundant epididymal messenger RNA (mRNA), CE5, which represents the canine counterpart of the human CD52/HE5 mRNA, encoding a major glycosylphoshatidylinnositol (GPI)-anchored sperm membrane glycopeptide. The temperature effect on the mRNA was a direct and specific one, not mediated by temperature influences on the testis and not affecting other epididymal mRNAs. Exposure of the cells to 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (25 micrograms/ml culture medium) and cycloheximide (2 micrograms/ml) suggested that the steady state levels of CD52/CE5 mRNA may be controlled posttranscriptionally by changing the half-life of this specific mRNA in response to an extracellular temperature stimulus.

Animals↗
PubMed1994

Major human epididymis-specific gene product, HE3, is the first representative of a novel gene family.

Differential screening of a human epididymal cDNA library led to the isolation and characterization of a major epididymis-specific cDNA clone family, referred to as HE3. More detailed sequence and PCR analysis identified two different but homologous gene transcripts, HE3 alpha and HE3 beta. The former represents an mRNA of ca. 1 kb, encoding a putative small secretory polypeptide of 14903 MW. The HE3 beta transcript was only found as incomplete 3' fragments. Analysis of human genomic DNA by Southern blotting suggested the presence in the human genome of at least three independent HE3-related genes. Isolation of genomic clones for the HE3 alpha gene showed this to contain a single intron of 1.4 kb in the 5' noncoding region. Although genomic clones corresponding to HE3 beta could not be found, a third highly homologous gene, HE3 gamma, was identified as a potential pseudogene. Neither nucleotide nor encoded amino acid sequences of the HE3 gene family are related to any other known sequence in the central databases, and thus represents a novel human gene family, with at least three nonallelic members. Northern hybridization analysis showed that HE3 gene products are specifically expressed in the human epididymis, and not in any other tissue examined. Furthermore, except for the pig, no other nonprimate species has been identified to express homologous sequences in the epididymis. RNase protection assays showed that both the HE3 alpha and HE3 beta, but not the HE3 gamma genes, are expressed in the human epididymis.

Amino Acid Sequence↗
PubMed1994

Molecular cloning and characterization of a novel human sperm antigen (HE2) specifically expressed in the proximal epididymis.

A novel human cDNA encoding a small secretory glycopeptide specifically expressed within the caput and proximal corpus regions of the human epididymis, HE2, has been cloned and sequenced. Southern hybridization analysis showed it to be derived from a single-copy gene. A subclone containing the coding region of the mature peptide was used to generate the putatively encoded peptide as a 10,000 M(r) recombinant fusion protein in a bacterial expression system. This recombinant HE2 protein, as well as an oligopeptide deduced from the open-reading frame, was used to raise polyclonal antisera. Immunohistochemistry and immunofluorescence showed that the predicted HE2 peptide is present in the epididymal epithelium and on the sperm surface, where it adopts a typical antigenic pattern with a subacrosomal equatorial distribution on the sperm head.

Amino Acid Sequence↗
PubMed1994

A major messenger ribonucleic acid of the rodent epididymis encodes a small glycosylphosphatidylinositol-anchored lymphocyte surface antigen.

The adult rodent epididymis and seminal vesicles were shown by polymerase chain reaction (PCR) cloning. Northern blot analysis, and in situ hybridization to be major expression sites of an mRNA encoding a small glycosylphosphatidylinositol (GPI)-anchored cell surface antigen that has been previously described as the mouse lymphocyte differentiation antigen B7, herein referred to as MB7. Sequence comparison of the corresponding epididymal cDNAs from the mouse (MB7) and the rat (RB7) revealed an unexpected divergence in the peptide coding regions of these homologous genes. A possible functional relationship to the human sperm surface and lymphocyte differentiation antigen CDw52/HE5 is discussed with respect to the highly variable mature peptide coding regions.

Amino Acid Sequence↗
PubMed1994

Regional variation of specific gene expression in the dog epididymis as revealed by in-situ transcript hybridization.

In-situ transcript hybridization was used to characterize the regional distribution of three marker gene transcripts which are expressed abundantly in the canine epididymis. The gene products CE1, CE4 and CE5, which are the canine equivalents of the human homologues HE1, HE4 and HE5, are shown to be expressed in a tissue-specific and regionally characteristic pattern in the epididymal epithelium. CE1 mRNA was expressed very weakly in the efferent ducts but was expressed at a high level throughout the caput and corpus regions of the epididymis, decreasing somewhat in the distal cauda region. CE4 mRNA was not detectable in the efferent ducts and was only expressed moderately in the remainder of the epididymis, with greatest levels in the caput and proximal cauda regions, and decreasing in the distal cauda. CE5 mRNA showed the most marked regional variation in levels with little or no mRNA detectable in the caput and proximal corpus regions, but increasing dramatically in the distal corpus and cauda. In the transition region of the central corpus, the CE5 mRNA appeared to be expressed intermittently, giving a mottled signal appearance over the epididymal epithelium. The patterns of mRNA distribution for the three marker genes in the dog epididymis were, therefore, essentially similar to those for the equivalent human homologues, providing further support for the suitability of the dog epididymis as a model for the human.

Animals↗
PubMed1993

A major mRNA of the human epididymal principal cells, HE5, encodes the leucocyte differentiation CDw52 antigen peptide backbone.

HE5, a very abundant human epididymal gene product, was cloned by a differential screening procedure which employed testis as the primary negative control tissue. Sequencing of the HE5 cDNA showed it to be identical to that encoding the peptide backbone of the human leucocyte differentiation antigen CDw52. Since human genomic DNA contained only one cross-hybridizing fragment, this implies that both products were transcribed from the same gene. Northern blot analysis and in situ transcript hybridization revealed a highly tissue- and cell-type-specific expression pattern for HE5, showing the gene product to originate from epithelial cells of the epididymal and deferent duct. The possible identity of the HE5 product with the CDw52 antigen suggests a link between the immune and reproductive systems.

Amino Acid Sequence↗
PubMed1993

Region-specific variation of gene expression in the human epididymis as revealed by in situ hybridization with tissue-specific cDNAs.

Three tissue-specific gene probes that had been isolated by differential screening from a human epididymal cDNA library--HE1, HE2, and HE5--were employed to investigate regional specializations in the human epididymis. All 3 cDNAs were derived from major transcripts of the epithelial cells lining the epididymal duct. Each mRNA species, however, exhibited a discrete longitudinal pattern of hybridization with maxima in different regions of this organ, suggesting regional specializations of gene expression. The HE5 mRNA, which was recently shown to encode the peptide backbone of the human leukocyte differentiation antigen CDw52, showed maximum levels in the distal corpus epididymidis and in the vas deferens, whereas the HE2 mRNA was found predominantly in the caput and proximal corpus sections of the epididymis. HE1 mRNA was found in high amounts in all parts of the epididymis, displaying a 2-peak expression pattern with maxima in the distal caput and distal corpus of the epididymal duct.

Aged↗
PubMed1993

Tissue-specific gene expression as an indicator of epididymis-specific functional status in the boar, bull and stallion.

cDNA probes derived from genes expressed specifically in the human epididymis were used to examine gene expression in the epididymides of boar, bull and stallion by Northern hybridization. Two probes for the HE1 and HE4 gene products were found to recognize tissue-specific transcripts in all three species, with a regionally differential distribution within the epididymis. Additionally, antibodies recognizing the HE4 protein were shown to react specifically in the epididymis of the boar and bull. An extensive study of the boar showed that, whereas mRNA for the HE1-homologue was up-regulated markedly only at puberty, the HE4-homologue was already present at moderate levels prepubertally. The distribution of the HE1-homologue changed at sexual maturity from a maximum in the cauda epididymis in the 3-4-week-old pig, to a maximum in the corpus/caput region in the adult, while the shift was in the opposite direction for the HE4-homologue. Evidently, gene expression is not fixed regionally through epididymal development in this species. The abdominal epididymis of a hemicryptorchid pig also showed a differential change in expression for the two gene products by comparison with the scrotal testis from the same animal. The results suggest that the HE1 and HE4 gene homologues may be sensitive markers for physiological changes within the mammalian epididymis, and that the boar could prove a useful model to examine the regulation of these human epididymal transcripts.

Animals↗
PubMed1992

Excitation of cutaneous afferent nerve endings in vitro by a combination of inflammatory mediators and conditioning effect of substance P.

A broad mixture of inflammatory mediators ("inflammatory soup") was used to investigate the responsiveness of primary afferents from rat hairy skin in an in vitro skin-saphenous nerve preparation. In addition, a conditioning effect of the tachykinin substance P on chemosensitivity of nociceptors was examined. Inflammatory soup (IS) was made up in synthetic interstitial fluid from bradykinin, serotonin, histamin and prostaglandin E2 (all 10(-5) M). In addition, the potassium and the hydrogen ion concentration (7 mM, pH 7.0) and the temperature (39.5 degrees C) were elevated. The latter agents, in a control solution, did not excite nociceptors (n = 5). IS was repeatedly superfused over the receptive fields for 5 min at 10 min intervals; substance P (SP 10(-6) and 10(-5) M) was applied during the last 5 min of the interval and during the subsequent IS stimulation. IS excited more than 80% of the mechano-heat sensitive ("polymodal") afferents with slowly conducting nerve fibres (n = 72), but none of the low-threshold mechanoreceptive slow and fast conducting units (n = 17). Slow conducting afferents with high mechanical threshold (n = 35) were weakly, and less frequently (< 20%), driven by IS. A majority, but not all, of the responsive units showed tachyphylaxis upon repeated IS application. None, however, lost its responsiveness completely. Conditioning heat stimulation (32-46.5 degrees C in 20 s) did not enhance the subsequent IS response, which may indicate that sensitizing substances normally released by a noxious heat stimulus were already contained in IS. No sensitization to mechanical (von Frey) or heat stimulation could be established in the period after the IS response had subsided and after the washout was completed, respectively. A short-lived sensitization may have been overlooked under these temporal restrictions. Conditioning SP in 10(-5) M but not in 10(-6) M concentration significantly increased the IS response of polymodal C fibres, by 58% on average (n = 14). SP did not excite the units. Comparing with previous data, we conclude that there is a significant synergism between inflammatory mediators, acting to induce more intense and more sustained discharge via many nociceptors than single mediators alone could achieve. Conditioning substance P can further enhance this algogenic action. Mechanisms of interaction and relative contributions of single substances remain to be elucidated.

Animals↗
PubMed1992

Excitation of cutaneous sensory nerve endings in the rat by 4-aminopyridine and tetraethylammonium.

1. The effects of the potassium channel blockers 4-aminopyridine (4-AP) and tetraethylammonium (TEA) on cutaneous sensory nerve endings have been investigated with the use of an in vitro skin-nerve preparation from the rat. 2. Direct application of these compounds to the nerve endings, but not to the axons, induced continuous discharges in most A beta, A delta, and C fibers. There was no relationship between the fibers' responsiveness or the threshold concentration required to induce discharges and either the conduction velocity or sensory properties of the fibers. 3. The rate of induced discharges increased linearly with increasing concentrations of 4-AP. At threshold concentrations of 10(-6)-10(-5) M, low-frequency, irregular discharges developed; but at the highest concentration of 10(-3) M, a characteristic doublet or bursting discharges usually emerged. 4. During and after the induced discharges there did not appear to be an alteration in the sensitivity of the sensory nerve endings to mechanical or thermal stimuli. 5. It is concluded that the induced activity arises from an action of these potassium channel blockers at or near the action potential generator region at the nerve endings.

4-Aminopyridine↗
PubMed1991

A major human epididymis-specific cDNA encodes a protein with sequence homology to extracellular proteinase inhibitors.

The amino acid sequence of a major human epididymis-specific protein was deduced from the nucleotide sequence of its cloned cDNA. The encoded product showed characteristics of a secretory protein, with a signal peptide followed by a small (approximately 10-kDa), acidic (pI 4.3), and cysteine-rich polypeptide. The positions of half-cysteines suggested that it was a two-domain member of the family of 'four-disulfide core' proteins to which a number of proteinase inhibitors belong. Southern blot analyses of human genomic DNA showed that the transcripts originated from a single copy gene. Northern blot and in situ transcript hybridization specifically localized the HE4 (human epididymis gene product) mRNA to the epithelial cells of the epididymal duct, predominantly within the distal sections. A possible function in sperm maturation as indicated by amino acid similarities to extracellular proteinase inhibitors of genital tract mucous secretions is discussed in the context of its tissue-specific transcription.

Aged↗
PubMed1991

Discharge patterns of human C-fibers induced by itching and burning stimuli.

1. The aim of this investigation was to study the peripheral neural mechanisms of the C-fiber-mediated modalities of burning pain and itch by the use of microneurography of human unmyelinated afferents. 2. Sixteen stable recordings of single C-fibers and 6 multiunit recordings were obtained from the superficial radial nerves of volunteers. All units were excited by stimulating their receptive fields with von Frey bristles (range 10-600 mN), and all but four units were also driven by radiant heat stimulation. 3. Histamine was iontophoretically applied to the receptive fields of these units for 20 or 30 s and was found to provoke itching sensations lasting several minutes, together with wheal and flare responses. Subsequently a solution containing 20 or 30% mustard oil was applied to the receptive field of the respective unit, which provoked a sensation of burning pain. 4. One-half of the units were excited by histamine, and the median discharge rates derived from interspike intervals ranged from approximately 0.1 to 0.8 Hz. Mustard oil-induced activity was observed in all histamine-sensitive units and also in three single units and in one multiunit recording that revealed no histamine response. Median interval-derived discharge rates ranged from 0.2 to 1.2 Hz. 5. Analysis of the interspike interval distribution and of the autocorrelation function derived from the chemically induced discharges of single units provided no evidence for an encoding of itch and burning pain in different discharge patterns of units responding to histamine and to mustard oil.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Carrageenan inflammation increases bradykinin sensitivity of rat cutaneous nociceptors.

The present study examined the hypothesis that the sensitivity of polymodal nociceptors to bradykinin (BK) might be increased in inflamed tissue. Inflammation was induced in the rat dorsal hindpaw skin by subcutaneous injection of blue stained carrageenan. Three hours later skin and saphenous nerve were excised and the chemical sensitivity of mechano-heat-sensitive C- and A delta fibres was examined in vitro using repeated superfusion of the receptive fields with 10(-5) M BK. Only units within and at the border of the inflamed area showed signs of sensitization, in the form of ongoing activity and lower thresholds to heat stimuli. No sensitization to mechanical (von Frey) stimulation occurred. The incidence of BK responsiveness was significantly higher and the tachyphylaxis to repeated BK application was smaller inside the inflamed skin than outside or in unconditioned skin. Thus, more nociceptive afferents would be driven more effectively than in normal skin, supporting the particular role of BK in inflammatory pain.

Action Potentials↗
PubMed1990

Cloning and analysis of mRNAs expressed specifically in the human epididymis.

Differential cDNA screening identified four new genes that are expressed specifically in the human epididymis. Their corresponding mRNAs are relatively short, ranging from 0.7 to 1.0 kb, and belong to a class of abundant or moderately abundant transcripts. Tissue-specific expression was pronounced for all four sequences, which showed no hybridization signals with RNA from eight different human tissues. Cross-hybridization with epididymal RNAs from some non-rodent mammalian species was observed with two cDNAs; the remaining two transcripts failed to cross-hybridize with any of the animal epididymal RNAs tested.

Aged↗
PubMed1990

Sympathetic secretory response to hypercapnic acidosis in swine.

We studied the effect of graded acute hypercapnic acidosis (HA) on sympathetic neural activation in 15 juvenile farm swine in vivo. In seven animals with acute HA, plasma norepinephrine (NE) concentration increased progressively from 189 +/- 34 to 483 +/- 80 pg/ml (P less than 0.04) as arterial CO2 partial pressure (PaCO2) increased in steps from 40 to 80 Torr (pH 7.17 +/- 0.01). Plasma epinephrine (EPI) concentration increased from 30 +/- 15 to 125 +/- 66 pg/ml (P = NS) over the same change in PaCO2. At PaCO2 of 110 Torr, plasma NE increased 3.4-fold above maximal basal concentrations; plasma EPI was 1.8-fold greater than basal under the same conditions. With HA, systemic vascular resistance (SVR) decreased from 1,748 +/- 110 to 1,392 +/- 145 dyn.s.cm-5 (P less than 0.0002), cardiac output (CO) increased from 3.4 +/- 0.3 to 4.3 +/- 0.3 l/min (P less than 0.01), and heart rate (HR) increased from 117 +/- 11 to 154 +/- 17 beats/min (P less than 0.03). To demonstrate that catecholamine secretion was related directly to acidosis caused by an increase in PaCO2, HCO3- was infused in eight other swine to buffer extracellular acute HA (pH 7.37 +/- 0.01 at PaCO2 of 80 Torr). Buffering attenuated the increase in plasma NE, which remained within the normal range at PaCO2 of 80 Torr. The decrease in SVR and increases in CO and HR also were also attenuated by HCO3- buffering of HA. We demonstrate the effects of graded acute HA on endogenous secretion of catecholamine and on the associated hemodynamic responses in swine.(ABSTRACT TRUNCATED AT 250 WORDS)

Acidosis↗
PubMed1988

Retrotransposon-like sequences are expressed in Y chromosomal lampbrush loops of Drosophila hydei.

The DNA sequence family micropia consists of repeated DNA sequences that occur dispersed in the genome of Drosophila hydei. Members of this DNA sequence family were recovered from two recombinant DNA clone banks obtained by microdissection of the two Y chromosomal lampbrush loop threads and pseudonucleolus from primary spermatocyte nuclei. Nucleotide sequence analysis of two of the recombinant DNA clones revealed homology to the DNA region coding for a reverse transcriptase-like protein in retroviruses and retrotransposons. Homologous tissue-specific transcripts of a size of 1.2 x 10(3) base-pairs were found in testes. Transcript in-situ hybridization shows that at least parts of these transcripts are synthesized in these Y chromosomal lampbrush loops, which were originally used for microdissection. Also the cytoplasm of primary spermatocytes contains homologous RNA species. These observations are discussed in the context of lampbrush loop function and evolution.

Amino Acid Sequence↗