Gene expression profiles of the collecting duct in the mouse renal inner medulla

Gene expression profiles of the collecting duct in the mouse renal inner medulla.

BACKGROUND

Gene expression profiles, constructed from 1000 to 2000 cloned cDNA sequences, depict their relative abundance of expression in a tissue. Establishing such a profile for mouse inner renal medullary collecting ducts (IMCDs), we compared expression patterns with those in other tissues including proximal tubule.

METHODS

A nonbiased 3'-end cDNA library was prepared from microdissected mouse IMCDs. Single-pass sequencing of 2000 randomly selected cDNA clones collected short sequences (approximate length, 250 bp) following poly (A), called gene signatures (GS). Identical sequences were considered a single GS. GS occurrence was quantitated to yield a list of expressed genes indicating their abundance.

RESULTS

Among 2000 clones, 1613 types of transcripts were found in IMCDs; 155 were identical or homologous to reported genes. The gene most expressed in IMCDs was alphaB-crystallin, a small stress (heat-shock) protein that is also a major structural protein in the ocular lens. According to Northern analysis, renal expression of this mRNA was induced by dehydration, presumably via tissue hypertonicity. However, expression did not change with acute NaCl loading. Also, a new member of the glutathione-S-transferase family was identified by comparing the IMCD expression profile with those of other tissues.

CONCLUSION

With our database of genes expressed in mouse IMCDs, we are devising an IMCD-specific microarray to study gene-expression responses to various physiologic alterations.

Bryophyte 5S rDNA was inserted into 45S rDNA repeat units after the divergence from higher land plants

The 5S ribosomal RNA genes (5S rDNA) are located independently from the 45S rDNA repeats containing 18S, 5.8S and 26S ribosomal RNA genes in higher eukaryotes. Southern blot and fluorescence in situ hybridization analyses demonstrated that the 5S rDNAs are encoded in the 45S rDNA repeat unit of a liverwort, Marchantia polymorpha, in contrast to higher plants. Sequencing analyses revealed that a single-repeat unit of the M. polymorpha nuclear rDNA, which is 16,103 bp in length, contained a 5S rDNA downstream of 18S, 5.8S and 26S rDNA. To our knowledge, this is the first report on co-localization of the 5S and 45S rDNAs in the rDNA repeat of land plants. Furthermore, we detected a 5S rDNA in the rDNA repeat of a moss, Funaria hygrometrica, by a homology search in a database. These findings suggest that there has been structural re-organization of the rDNAs after divergence of the bryophytes from the other plant species in the course of evolution.

Clinical evaluation of repeat apheresis donors in Japan

BACKGROUND AND OBJECTIVES

To ascertain the safety of repeat apheresis donation, hematological and biochemical tests were performed on 511 donors with a donation rate of over 6 times per year for a period of 12-19 months.

MATERIALS AND METHODS

Repeat donors who had apheresis more than 6 times in the previous year were chosen. Data for the repeat donors at the start of the experiments were compared with those at the end of the study. Blood samples were taken prior to donation. Serum protein, albumin, immunoglobulin G, A, and M, serum ferritin levels were determined by biochemical tests.

RESULTS

When compared to prospective donors of 400 ml, WBC, lymphocytes, and serum ferritin levels were lower in a roughly frequency-dependent manner in female and male donor groups at the beginning of the study. All the data for the male group remained almost constant with increasing frequency of apheresis donation. However, in the female group, ferritin levels significantly decreased with over 21 donations.

CONCLUSIONS

The present data showed that the serum ferritin level of the female donors decreased the most with increasing frequency of apheresis donation. The cumulative RBC left in the collecting chamber and for the laboratory test is discussed in relation to a possible cause of iron deficiency in frequent apheresis donors.

[Clinical experiences and postoperative results with partially implantable middle ear implant]

A partially implantable middle ear implant using an ossicular vibrator of a piezoelectric ceramic bimorph has recently been developed in Japan as a new rehabilitative method for hearing. Four patients at the Miyazaki Medical College Hospital were implanted with this device between September 1994 and October 1996. Implantation of the internal component was performed under local anesthesia after confirmation of sufficient sensitivity to the ossicular vibrator in an intraoperative vibratory hearing test. All patients regained socially useful hearing with the middle ear implant without any foreign body reactions or recurrence of otitis media. None of the cases showed any elevations of bone conduction thresholds 2 to 4 years postoperatively. Natural and clear sounds without interference noise and howling due to acoustic feedback were highly satisfactory in all patients. However, the first case, who had an implant in an ear following cholesteatoma surgery using the intact canal wall technique, experienced about a 10dB deterioration of the average hearing level with the implant 2 years after implantation. Gradual deterioration appeared to be caused by the retracted tympanic membrane interfering with the mobility of the ossicular vibrator. The following three cases were implanted in ears previously operated on by radical mastoidectomy, showing stable or improving hearing results with the implant. Closure of the external canal skin at the cartilaginous portion at the time of implantation seemed appropriate to maintain a sufficient middle ear space for the ossicular vibrator to work properly. Our case study confirms that the partially implantable middle ear implant is a safe and useful tool for patients with mixed deafness which cannot be satisfactorily rehabilitated by tympanoplasty and/or a conventional hearing aid.

[Causative organisms of acute otitis media and acute sinusitis in children and their susceptibility of oral beta-lactam antibiotics]

The clinical efficacy of cefditoren pivoxil (CDTR-PI) was evaluated for 43 pediatric patients with acute otitis media or acute sinusitis. The causative organisms were identified and their susceptibilities to 6 oral beta-lactam antibiotics were measured; ampicillin (ABPC), cefaclor (CCL), cefdinir (CFDN), cefditoren pivoxil (CDTR-PI), cefteram pivoxil (CFTM-PI) and cefpodoxime proxetil (CPDX-PR). The ages of 43 patients were distributed from 4 months to 10 years and 7 months, and especially children under 4 years accounted for 72% (31 cases). In 22 cases (51%), Haemophilus influenzae or Streptococcus pneumoniae were identified as the pathogens, but in 18 cases, no causative organisms were defined. Treatment by CDTR-PI was successful in 12 cases out of 15 evaluable cases in which H. influenzae or S. pneumoniae were identified as the main causative organisms. From the susceptibility testing of them, some strains of H. influenzae were found to be ABPC-resistant and some strains of S. pneumoniae were benzylpenicillin (PCG)-resistant. To support above clinical evaluation of CDTR-PI, susceptibility testings on clinically isolated H. influenzae (81 strains) and S. pneumoniae (79 strains) were performed using above mentioned 6 oral beta-lactam antibiotics. The MIC80s against H. influenzae were; CDTR-PI 0.06 microgram/ml, CCL 2 micrograms/ml, CPDX-PR 0.125 microgram/ml, CFTM-PI 0.03 microgram/ml, CFDN 1 microgram/ml and ABPC 1 microgram/ml. Those against S. pneumoniae were; CDTR-PI 0.5 microgram/ml, CCL > 4 micrograms/ml, CPDX-PR 2 micrograms/ml, CFTM-PI 1 microgram/ml, CFDN 2 micrograms/ml and ABPC 1 microgram/ml. From those results, it was concluded that CDTR-PI or CFTM-PI may be preferable for the treatment of acute otitis media and acute sinusitis in children.

[Pulmonary malignant fibrous histiocytoma (inflammatory type) showing intracavitary fungus ball-like shadow]

We report a rare case of primary malignant fibrous histiocytoma of the lung showing intracavitary fungus ball-like shadows. Fiberoptic bronchoscopy revealed no visible tumor, but adenocarcinoma cells were detected in samples of lavage fluid from the cavitary lesion. Staging procedures (T 2 N 0 M 0) confirmed that there were no metastatic lesions. A complete resection of the left lower lobe was performed. The tumor showed polypoid growth that obstructed a small peripheral bronchus, and formed a cavitary lesion. It was histologically diagnosed as an inflammatory type of malignant fibrous histiocytoma, and consisted of atypical histiocyte-like cells, neutrophils, lymphocytes, foamy cells, and fibroblast-like cells in a storiform pattern. The patient has been in complete remission for 3 years after surgery.

Two mRNA species encoding calcium-dependent protein kinases are differentially expressed in sexual organs of Marchantia polymorpha through alternative splicing

In plants, calcium-dependent calmodulin-independent protein kinases (CDPKs) are the predominant calcium-regulated protein kinases and their genes are encoded by a multigene family. A CDPK gene was cloned from a liverwort, Marchantia polymorpha, which showed a high level of sequence similarities to other higher plant CDPK genes. The liverwort CDPK gene consisted of 9 exons and 8 introns. The 6th and 7th exons (Exon 6A and Exon 6B) were almost identical except for 4-amino acid substitutions, both of which coded for EF-hands in the calcium-binding domain. RT-PCR analysis revealed that two species of mature mRNA containing either Exon 6A or Exon 6B were generated from a single CDPK gene by mutually exclusive alternative splicing. Both histidine-tagged fusion proteins derived from cDNAs containing either Exon 6A or Exon 6B exhibited calcium-dependent protein kinase activity in vitro. Preferential accumulation of the mature mRNA with Exon 6A detected in male sexual organ implies possible sexual control of the ratio between the two CDPK isozymes through alternative splicing. Functions and evolution of CDPKs are discussed based on the structure and expression of the liverwort CDPK gene.

Glowing podocytes in living mouse: transgenic mouse carrying a podocyte-specific promoter

Green fluorescence protein (GFP) has been utilized as a marker of gene expression due to the great advantage in its simple and quick detectability. We generated transgenic mice carrying a GFP cDNA under the control of a beta-actin/beta-globin promoter (CX promoter) and cytomegalovirus enhancer. The green luminescence derived from GFP was apparent in skeletal muscle, pancreas, heart and kidney, but not in other tissues. The GFP expression in the kidney was localized in podocytes. Moreover, in situ hybridization of GFP showed that the transcriptional level was highly active in the podocytes. These results suggested that the glowing green fluorescence would be a useful in vivo marker of podocyte in these transgenic lines in the physiological and pathophysiological state, and that the CX promoter could allow a podocyte-specific expression of a molecule of interest in kidney.

Autologous blood donation preceding coronary artery bypass graft operation in a hemodialysis patient

A 67-year-old male hemodialysis patient with abdominal aortic aneurysm and triple vessel coronary heart disease required autologous blood donation because of his blood type of Rh(-) before cardiovascular surgery. We performed autologous red blood cell and plasma collection by the switch back method with recombinant human erythropoietin therapy during the 5 weeks before the operation. Autologous platelet collection was also made the day before the operation. These autologous blood donations were safely and successfully performed along with hemodialysis. There was some caution taken for these procedures. The ultrafiltration rate had to be adjusted for blood collection or blood transfusion during hemodialysis in order not to disturb fluid balance. It was necessary to monitor the hyperkalemia of the stored autologous packed red blood cells. For platelet collection, blood in the extracorporeal circuit had to be concentrated because of the presence of renal anemia. Coronary artery bypass graft was safely and successfully performed with the autologous blood only.

Mechanisms underlying cerebrovascular effects of cigarette smoking in rats in vivo

BACKGROUND AND PURPOSE

The effects of acute smoking on cerebral circulation are controversial. This study was designed (1) to clarify any differences between the effects of cigarette smoking and nicotine infusion and between the effects of single- and multiple-cigarette smoking on cerebral vessels and (2) to probe the mechanism(s) underlying the vascular responses.

METHODS

In pentobarbital-anesthetized, mechanically ventilated Sprague-Dawley rats, pial vessel diameters were measured with the use of a cranial window preparation. We studied the effects of (1) 60 puffs per minute of mainstream cigarette smoke from cigarettes having 2 nicotine levels (0.1 and 1 mg per cigarette), (2) administration of nicotine (0.05 mg per body IV), and (3) repeated smoking (four 1 mg nicotine-containing cigarettes at 30-minute intervals) (n=6 each).

RESULTS

Inhalation of smoke from a 0.1 or 1 mg nicotine-containing cigarette for 1 minute caused pial arterioles to constrict at 30 seconds (7.2% and 7.3%, respectively) and then to dilate (peak at 5 to 10 minutes; 4.6% and 17.9%, respectively). Nicotine infusion caused pial vasodilation (35.7%) without an initial vasoconstriction. Repeated smoking suppressed the pial vasodilation but not the initial vasoconstriction. The vasodilation induced by a single cigarette was greatly inhibited by pretreatment with mecamylamine or glibenclamide and attenuated by propranolol or Nomega-nitro-L-arginine methyl ester; the initial vasoconstriction was inhibited by seratrodast, a thromboxane A2 receptor antagonist (n=6 in each case).

CONCLUSIONS

Single-cigarette smoking had a significant biphasic effect on cerebral arteriolar tone. The vasodilation was attenuated by repeated smoking. The vasodilation is most likely an effect of nicotine, at least in part mediated via sympathetic activation, NO production, and K+ channel activation. The vasoconstriction is partially due to thromboxane A2 induced by cigarette smoke.

Coexistence of nuclear DNA-encoded tRNAVal(AAC) and mitochondrial DNA-encoded tRNAVal(UAC) in mitochondria of a liverwort Marchantia polymorpha

The liverwort Marchantia polymorpha mitochondrial DNA encodes almost all tRNAs required for mitochondrial translation except for the isoleucine (AUU, AUC) and threonine (ACA, ACG) codons, while the missing tRNAs are supplied in part by the nucleus and imported in mitochondria. In this paper, we report a finding of two radically different nuclear tRNAVal(AAC) genes and import of the corresponding tRNA isoacceptors in M.polymorpha mitochondria. This finding is surprising since the mtDNA encodes the gene for tRNAVal(UAC), which alone was considered sufficient for translating all four valine codons GUN by the U/N wobble mechanism. The present results suggest for the first time that the import of ncDNA-encoded tRNAs may result in decoding overlaps in plant mitochondria. The coexistence of nuclear DNA-encoded tRNAVal(AAC) and mitochondrial DNA-encoded tRNAVal(UAC) in liverwort mitochondria and the significance for the decoding mechanism as well as evolution of tRNA import are discussed.

Isolation of genes identified in mouse renal proximal tubule by comparing different gene expression profiles

An expression profile is a list based on a large scale sequencing of 1000 cDNA clones, showing the expressed genes and the abundance of their transcripts in a given cell or tissue (Okubo K et al: Nature Genet 2:173, 1992). We constructed an expression profile of mouse renal proximal tubules (PT) carefully isolated by microdissection in order to characterize its gene expression. Altogether 1000 clones were analyzed; there were 646 types of transcripts in PT, among which 196 were identical or homologous to the previously reported genes. The most abundant transcript was kidney-androgen regulated protein. By comparing the expression profile of PT with those obtained from other sources, several genes were identified only in PT. They included known transcripts and transcripts that were not homologous to the known genes. Three (GS4001, 3991, and 4059) of the non-homologous genes were analyzed by Northern blotting and in situ hybridization, and GS4001 and 4059 were predominantly expressed in the kidney, whereas GS3991 was detected in the liver as well as in the kidney. The sequence analysis of the full-size cDNAs demonstrated that GS4001 was a new member of aspartic proteinases and GS4059 was a novel gene. It also revealed that GS3991 was a mouse homologue of SA gene known to be expressed in PT. The expression profile of mouse PT and its comparison with those of other tissues and cells provide an alternate way of isolating genes predominantly expressed in PT, and also provides probes to study the molecular mechanisms of gene expression in the kidney.

[A case of IAHS (infection associated hemophagocytic syndrome) successfully treated with etoposide]

This report details a case of infection associated hemophagocytic syndrome (IAHS). A 20-year-old female was admitted to our hospital with persistent high fever in July, 1994. Physical examination revealed high body temperature (40 degrees C), marked hepatosplenomegaly and no superficial lymph node swelling. Laboratory examination revealed leukopenia and abnormal liver function on admission. Serum ferritin levels were surprisingly elevated. The coagulation tests showed high FDP and D-dimer. Specific viral antibody titers were not elevated such as Epstein-Barr virus or Cytomegalovirus. Bone marrow examination revealed histiocytic hyperplasia with hemophagocytosis, and the histiocytes were well matured. We diagnosed IAHS. Corticosteroids were administered on the 3rd hospital day (methylprednisolone 1 g/day, 3 days), but persistent high fever and laboratory findings did not improve. So we tried etoposide (etoposide 200 mg/day, 5 days) therapy on the 13th hospital day. After administration of etoposide, she failed to recover from severe leukopenia and suffered from meningitis. We administered G-CSF, gamma-globulin and antibiotics for intensive supportive therapy. As the leukocyte count increased, her symptoms and laboratory data improved. There was no hemophagocytosis in her bone marrow before discharge. Recently, etoposide is said to be effective for reactive monocytic proliferation. Administration of etoposide was very effective for IAHS, although corticosteroids, were ineffective.

Spinal conduction block by intrathecal ketamine in dogs

In addition to its use for intravenous (I.V.) anesthesia, ketamine can provide pain relief in humans when administered spinally. To elucidate the mechanisms of intrathecal (I.T.) ketamine analgesia, we observed differences in the effects of I.V. and I.T. ketamine on intraspinal evoked potentials (ISEPs) in 28 dogs anesthetized with pentobarbital. Bipolar extradural electrodes were inserted at the cervical and lumbar regions of the spinal cord for recording descending ISEPs represented by the two negative deflections, Waves I and II. I.V. ketamine 2 and 10 mg/ kg did not affect the amplitude and latency of Wave I, whereas the large dose (10 mg/kg) significantly decreased the amplitude but not the latency of Wave II. I.T. ketamine 1 and 5 mg/kg caused significant dose-dependent decreases in both Wave I and II amplitudes and prolongations of both Wave I and II latencies. These I.T. effects on ISEPs are consistent with previous in vitro observations that ketamine blocks axonal conduction. We conclude that axonal conduction block may contribute to the analgesic mechanism of I.T. ketamine.

[Detection of nucleotide mutation by direct sequencing method using non-radio isotopic marker]

We report a protocol which can analyze DNA by the dideoxy method. First, we prepared DNA from paraffin specimen of colon cancer and normal tissue by the method using proteinase and phenol. Polymerase chain reaction (PCR) was performed as follows. The primers used were oligonucleotides corresponding to the sequence of exon 5 on p53. An initial denaturing step was carried out at 94 degrees C for 2 min. Products were amplified for 40 cycles at 94 degrees C for 1 min, 60 degrees C for 1 min, and 72 degrees C for 1 min. Specific PCR products derived from p53 gene were purified. Protocol for the PCR-sequencing reaction: The reaction mixture was divided into four 4 microliters fraction. Each fraction was mixed with 2 microliters of NTP solution including non-RI dideoxynucleotides (TOYOBO). PCR was carried out as follows: an initial denaturing step at 94 degrees C for 1 min, then 30 cycles at 94 degrees C for 1 min, 60 degrees C for 1 min, and 72 degrees C for 1 min. Prior to loading in a denaturing 8% polyacrylamide-6M Urea gel, the samples were heated to 94 degrees C for 2 min then quickly chilled in ice-water. Electrophoresis was carried out at 1000V for 3hr and transcribed to a nylon membrane. The ladders of DNA were obtained by Non-RI Detection Kit (TOYOBO). We determined the sequence of 167 nucleotides. Results indicated that the point mutations in DNA could be easily detected.

The canine sodium/myo-inositol cotransporter gene: structural organization and characterization of the promoter

The sodium/myo-inositol cotransporter (SMIT) is a plasma membrane protein catalyzing transfer of myo-inositol into cells against a considerable concentration gradient using the electrochemical potential of sodium across the cell membrane. Transcription of the SMIT gene is markedly stimulated when cells are exposed to a hypertonic environment resulting in increased abundance of SMIT mRNA and increased SMIT activity. The increased accumulation of myo-inositol protects cells from the deleterious effects of hypertonicity. In an effort toward understanding transcriptional regulation, we cloned canine genomic DNA fragments containing the SMIT gene. The gene is 37 kb in size consisting of 2 exons and a large intron of 25 kb. The entire open reading frame is in the second exon. The promoter of the gene is highly active due to a GC-rich sequence. Ribonuclease protection assay using a riboprobe complementary to the 5' end of the gene confirmed that the promoter of the gene is stimulated by hypertonicity. The promoters and regulatory sequences of the SMIT gene and the betaine transporter gene, another gene regulated by hypertonicity, appear to be different.

Osmolarity in renal medulla of transgenic mice regulates transcription via 5'-flanking region of canine BGT1 gene

Betaine is a major compatible osmolyte accumulated in the mammalian kidney medulla and in Madin-Darby canine kidney cells in response to hypertonicity. The accumulation is the result of an increase in maximal velocity of the Na(+)- and Cl-coupled betaine transporter designated BGT1. We have previously cloned the canine BGT1 gene and identified a tonicity-responsive enhancer element (TonE) in its 5'-flanking region. Here we report studies of transgenic mice that have in their genome 2.4 kb of the 5'-flanking region of the canine BGT1 gene in front of a chloramphenicol acetyl-transferase (CAT) reporter. Expression of CAT mRNA was detected only in the renal medulla and was increased by experimental manipulations that increase the tonicity of the renal medulla and decreased by manipulations that decrease medullary tonicity. We conclude that the 2.4-kb 5'-flanking region of the BGT1 gene mediates an increase in transcription in response to hyperosmolarity in the renal medulla.

Transcriptional activation of a hybrid promoter composed of cytomegalovirus enhancer and beta-actin/beta-globin gene in glomerular epithelial cells in vivo

The aim of this study was to seek a promoter, transactivated selectively in renal cells in vivo by using transgenic (tg) mouse technology. We generated two kinds of tg mouse lines carrying a green fluorescence protein (GFP) cDNA driven either by cytomegalovirus enhancer and beta-actin/beta-globin promoter (CX-GFP) or by elongation factor 1alpha promoter (EF-GFP), and investigated the expression of GFP in the kidney. Microscopic examination of the renal tissues in CX-GFP-tg mice revealed that GFP was expressed only in glomeruli, mainly epithelial cells, but not in tubules, arteries and interstitium. Moreover, in situ hybridization demonstrated that GFP mRNA expression was localized in the glomerular cells. In contrast, GFP was not detectable in the kidney in any of the lines of EF-GFP-tg mouse. To exclude the possible involvement of the GFP cDNA as an enhancer, we constructed tg mice carrying the CX promoter driving a human CD4 cDNA. It was confirmed that the expression patterns of human CD4 in the kidney were quite similar to those of GFP in the kidney of CX-GFP-tg mice. These results strongly suggest that CX promoter could be transactivated in glomerular epithelial cells in vivo.

Accumulation of nuclear-encoded tRNA(Thr) (AGU) in mitochondria of the liverwort Marchantia polymorpha

The mitochondrial genome of the liverwort Marchantia polymorpha does not encode the full complement of tRNAs for the threonine and isoleucine codon boxes. To find the missing tRNA genes specifically for tRNA(Thr) in mitochondria, we have searched the genomic library and identified two clones (pTT1 and pTT2), encoding the identical tRNA(Thr) (AGU) gene copy with different 5'- and 3'-flanking sequences. By northern analysis, we demonstrate considerable accumulation of the nuclear encoded tRNA(Thr) and moderate expression of native tRNA(Thr) (GGU) in mitochondria. Nonetheless, the imported and native tRNA(Thr) species together are not sufficient to translate all four threonine codons used in liverwort mitochondria, implicating mitochondrial import of at least one additional threonine isoacceptor tRNA.

Leucocytoclastic vasculitis associated with mixed cryoglobulinaemia and hepatitis C virus infection

Mixed cryoglobulinaemia is frequently associated with chronic hepatitis. We report a patient with mixed cryoglobulinaemia, hepatitis C virus (HCV) infection and palpable purpura. The skin manifestations were diagnosed as leucocytoclastic vasculitis in view of both the clinical appearance and the histological findings. In this study, we demonstrated the presence of IgG-class anti-HCV-antibody, HCV-RNA and IgA-class rheumatoid factor in the cryoprecipitate. These results suggest that the cryoglobulinaemia in this case was caused by aggregation of an immune complex comprised of HCV and anti-HCV antibody with IgA-type-rheumatoid factor, and that this led to a cutaneous vasculitis.

Ooplasmic round spermatid nuclear injection procedures as an experimental treatment for nonobstructive azoospermia

PURPOSE

Our objective was to apply ooplasmic round spermatid nuclear injections for the treatment of nonobstructive azoospermia.

MATERIALS

Participants were nine azoospermic men who had previously undergone diagnostic testicular biopsy. Spermatogenetic arrest was diagnosed at the round spermatid stage (n = 6) or primary spermatocyte stage (n = 3). A second (therapeutic) testicular biopsy was performed and round spermatid nuclei were recovered from all the participants.

RESULTS

Forty-nine mature oocytes were successfully injected with nuclei and then cultured for 72 hr. Twenty-four embryos were transferred to nine women. No pregnancy was achieved.

CONCLUSIONS

Round spermatids can be recovered from therapeutic testicular biopsy material of men negative for round spermatids in previous routine diagnostic testicular biopsy specimens. Round spermatid nuclear injections may play a role in the treatment of nonobstructive azoospermia.