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Biomedical subjects

R M Nakamura

Publications and source records attributed to R M Nakamura.

At least 37 records · Page 2Linked to original sources

Female urethral syndrome. A female prostatitis?

The cause of the female urethral syndrome has previously been obscure, as it has been associated by definition with a lack of objective findings but a plethora of subjective complaints of retropubic pressure, dyspareunia, urinary frequency, and dysuria. There is now strong evidence that the microscopic paraurethral glands connected to the distal third of the urethra in the prevaginal space are homologous to the prostate. They stain histologically for prostate-specific antigen and, like the prostate, are subject to both infection and cancer. The most important aspect of recognizing this microscopic "female prostate" as an anatomic feature is that its infections may completely explain many cases of the urethral syndrome. Further, the diagnosis is not elusive if trained clinicians palpate for localized and objective paraurethral tenderness through the anterior vagina wall to one or both sides of the urethra. Treatment parallel to that for male prostatitis is usually rewarded by the elimination of symptoms and the objective finding of the loss of tenderness of the paraurethral glands. As with prostatitis, the localized problem often recurs. It is time to alert primary care physicians to this disorder and to eliminate the widespread practice of treating affected women with either invasive urethral dilation or tranquilizers.

Cystitis↗

[Detection of rifampicin-resistant strains of Mycobacterium tuberculosis by a non-radioactive PCR-SSCP method].

PCR-SSCP method to detect genetic mutations in rpoB gene as a marker of rifampicin-resistance was developed by Telenti et al., and we have modified it applying non-radioactive PhastSystem for more practical use in the detection of rifampicin-resistance of Mycobacterium tuberculosis. PCR products amplified with the primers specific to rpoB gene using extracted DNA from 89 strains of M. tuberculosis were sequenced and the amino acid sequences were morphism was determined by the PhastSystem. The bands were stained by silver staining. Among 89 strains of M. tuberculosis, 43 were confirmed as rifampicin-resistant (RFPr) and 46 were rifampicin-sensitive (RFPs) by the culture on the drug-containing media. All of the 43 RFPr strains had one or more mutations in the DNA sequence of rpoB gene, while none of the RFPs strains had such mutations. However, by PCR-SSCP, only 20 out of 43 RFPr strains showed clear differences in the band pattern of electrophoresis from that of RFPs strains. Other 23 RFPr strains had only slight differences in the band pattern of the PCR-SSCP from that of RFPs strains. But it was noticed that the main bands of RFPr strains were distinguishable from the main bands of RFPs strains even their patterns were similar. Thus, it is possible to apply a non-radioactive PCR-SSCP for the detection of rifampicin resistance of M. tuberculosis with further improvement of the condition of gel electrophoresis or staining techniques.

Amino Acid Sequence↗

Delayed-type hypersensitivity to a recombinant mycobacterial antigen, MPB64, in guinea pigs sensitized to Mycobacterium tuberculosis or Mycobacterium bovis BCG.

Recombinant MPB64 (rMPB64), a mycobacterial antigen, was obtained from an Escherichia coli clone transformed with a recombinant expression vector, pMAL64c. The rMPB64 was examined for the activity to elicit delayed-type hypersensitivity (DTH) in guinea pigs injected with liver Mycobacterium tuberculosis H37Rv or live M. bovis BCG Tokyo. It was found that rMPB64 has the same reactivity as native MPB64 (nMPB64) or MPT64 (nMPT64) and the potency to elicit DTH was 13.4 times higher than that of PPD. Because MPB64 is secreted only by living M. tuberculosis and some strains of BCG, it is possible to use this antigen for the diagnosis of tuberculosis.

Amino Acid Sequence↗

Low-dose growth hormone-releasing factor may enhance folliculogenesis in regularly menstruating women: a preliminary study.

OBJECTIVE: To evaluate the effect of low-dose GH-releasing factor (GRF) on folliculogenesis in regularly menstruating women. DESIGN: Prospective clinical trial where individual patients served as their own control. SETTING: Outpatient Reproductive Endocrine/Infertility Clinic of the Los Angeles County-University of Southern California Medical Center, Los Angeles, California. PATIENTS: Seven regularly menstruating women. INTERVENTION: During treatment cycles, subjects received 100 micrograms SC GRF on cycle days 2 to 11 and were observed during a control cycle. MAIN OUTCOME MEASURES: Follicle number and diameter, as well as endometrial thickness were all assessed by vaginal ultrasound and blood was obtained for serum FSH, LH, E2, P, GH, insulin-like growth factor 1 (IGF-1), and insulin-like growth factor binding protein-3. RESULTS: During cycles treated with GRF, GH, and IGF-1 levels were normal. However, follicular growth rates and E2 to FSH ratios were significantly higher. The day of the peak E2 to follicular diameter ratio after GRF was earlier than in control cycles. Endometrial growth rates were also greater with GRF. CONCLUSIONS: Our data, although preliminary, support the hypothesis that low doses of GRF may independently stimulate the ovary and enhance folliculogenesis.

Adult↗

Identification of Mycobacterium intracellulare by a polymerase chain reaction using species-specific primers.

SETTING: The polymerase chain reaction (PCR) is a rapid and specific method used to amplify a certain DNA fragment. It is applicable to rapid diagnosis of mycobacterial infections. By use of species-specific primers, it is possible to identify mycobacteria by PCR. In this study, a newly constructed primer was tested for specificity for Mycobacterium intracellulare in the PCR. OBJECTIVE: M. intracellulare is one of the most frequently found bacteria in opportunistic infection in AIDS, and rapid identification of this species is important. The purpose of this study was to construct a primer specific to this species as a suitable tool for identification. DESIGN: PCR products of M. tuberculosis and M. intracellulare, obtained by using the primers YNP-1 and YNP-2, were sequenced and compared. They showed a difference in the base sequences. A sequence unique to M. intracellulare was used as the primer specific to this species. Various mycobacterial and non-mycobacterial DNAs were used as the primer specific to this species. Various mycobacterial and non-mycobacterial DNAs were used as the template to evaluate the specificity of the newly constructed primers, YNP-7 and YNP-8. Sputum samples were also examined by PCR using the primers. RESULTS: In total 25 species of culture mycobacterial and non-mycobacterial strains and 76 sputum samples were tested by PCR. Only M. intracellulare DNA was amplified with PCR using the primers YNP-7/8. CONCLUSION: The specificity of the newly constructed primers for M. intracellulare was confirmed.

Bacterial Typing Techniques↗

Secretion of MPB64 antigen by a recombinant clone of Mycobacterium smegmatis: characterization and application for the diagnosis of tuberculosis.

MPB64, a specific antigen to Mycobacterium tuberculosis complex (TB complex), was produced and secreted by a clone of M. smegmatis-MPB64 where the structural gene of MPB64 was inserted using a new mycobacteria, E. coli shuttle plasmid pNIS vector. Antibodies against the recombinant MPB64 (rMPB64) were used for the reverse particle latex agglutination (RPLA) test to detect the MPB64 antigen rapidly. RPLA tests were applied to the shock cultures and the clinical isolates of mycobacteria to identify TB complex. RPLA with anti-MPB64 antibody-coated latex beads completely distinguished TB complex from other mycobacteria. Thus, it is suggested that RPLA with anti-MPB64 antibody would be a new, easy and inexpensive method for the rapid diagnosis of tuberculosis.

Antigens, Bacterial↗

Protection of mice from Mycobacterium avium infection by recombinant interleukin-12.

Treatment with interleukin-12 (IL-12) significantly reduced the number of viable bacteria in mice infected with Mycobacterium avium. IL-12 itself, however, could not inhibit directly mycobacterial growth in vitro. IL-12 exerts antimycobacterial activity in vivo with a low level of toxicity, possibly by enhancing the host defense against the infection.

Animals↗

Production, analysis, and characterization of reference materials for prostate-specific antigen.

OBJECTIVE: To produce a set of three reference materials that mimic sera from patients with prostate disorders in the prostate-specific antigen (PSA) concentration range important for clinical screening for prostate cancer (approximately 0.5, approximately 4.0, and approximately 10.0 ng/mL), to analyze these reference materials in a large number of clinical laboratories using a variety of commercially available methods, and to characterize the molecular forms of PSA in them. METHODS: Units of serum from healthy individuals and from patients with varying degrees of elevated PSA were pooled, lyophilized, and distributed along with conventionally prepared, semen-supplemented proficiency testing samples to laboratories participating in the College of American Pathologists Basic Ligand Survey. The reference material and one of the standard Survey samples were fractionated by Sephacryl S-200-HR gel filtration chromatography. RESULTS: The Abbott IMx, Hybritech Tandem-E, Hybritech Tandem-R, and Tosoh AIA-Pack all measured PSA in the reference material fairly equally (agreement within +/- 12%). In contrast, the Abbott IMx results in the semen-supplemented Survey specimens were as much as 1.8-fold higher than the other three assays. Characterization of the molecular forms showed the reference material was approximately 90% alpha 1-antichymotrypsin-bound PSA, whereas the semen-supplemented Survey specimens were approximately 40% alpha 1-antichymotrypsin-bound PSA, which largely explained the difference in assay recoveries. CONCLUSIONS: Semen-free materials containing only endogenous PSA much more closely mimic real clinical specimens and should prove useful in efforts to standardize clinical PSA assays.

Blood↗

Selective type IV collagen defects in the urothelial basement membrane in interstitial cystitis.

PURPOSE: The study sought to identify changes in the urothelial basement membrane (UBM) associated with interstitial cystitis (IC). MATERIALS AND METHODS: Immunohistochemical assessment of bladder biopsies from IC patients and controls was compared with clinical and histologic findings. RESULTS: Selective decreases or loss of type IV collagen staining, but not laminin, were found in the UBM of 5 of 11 IC patients with no change in type IV collagen staining of other bladder wall sites. CONCLUSIONS: The loss of type IV collagen may represent a primary or secondary event and could alter the UBM's role in permeability, thereby contributing to the pathogenesis of IC in the subset of IC patients exhibiting this change.

Adult↗

Contemporary concepts for the clinical and laboratory evaluation of systemic lupus erythematosus and "lupus-like" syndromes.

Systemic lupus erythematosus (SLE) is a nonorgan-specific autoimmune disease which affects multiple organ systems and is multifactorial in etiology. SLE is the prototypic systemic rheumatic disease with immune dysregulation characterized by (1) polyclonal activation of B-cells and (2) production of a large spectrum of autoantibodies with a marked preference for nuclear and intracellular antigens. The clinical and laboratory manifestations and criteria for classification and diagnosis of systemic lupus erythematosus, lupus-like syndromes, and various subsets of systemic lupus erythematosus, are reviewed. The differential diagnosis of SLE and related diseases is described with correlation of specific intracellular autoantibodies.

Antibodies, Antinuclear↗

Current status of available standards for quality improvement of assays for detection of autoantibodies to nuclear and intracellular antigens.

Considerable progress has been made in the improvement of clinical assays for the detection of autoantibodies to nuclear and intracellular antigens with the use of available World Health Organization (WHO) and Arthritis Foundation/Centers for Disease Control (AF/CDC) standards. The ultimate goal of standardization is for various clinical laboratory test results to be interchangeable and for an exchange of data to be done with confidence. This report discusses the available standards. In addition, significant technical problems and variations in methodologies for the detection of autoantibodies to intracellular antigens noted during a 4-year study by a European Consensus Study Group are detailed. Currently, there is a need for a future generation of reference preparations and standards that will show specific antibody reactivity on sensitive enzymes and immunoblotting assays. Standardization efforts should be done to characterize specific nuclear and cellular antigen preparations that may be of natural or of recombinant technology origin.

Antibodies, Antinuclear↗

Factors influencing changes in the clinical immunology laboratory.

The clinical immunology laboratory is primarily concerned with tests for diagnosing disease and monitoring the therapy and course of diseases mediated by immune mechanisms. In the future, the immunology laboratory will provide test services on a disease-oriented basis and will utilize assays of humoral and cellular immunity, as well as other assays based on molecular techniques. The laboratory scientist will work closely with clinicians and provide interactive consultation. The major factors that will influence future laboratory tests are: (a) governmental regulations, (b) healthcare economics, (c) advances in technology, and (d) advances in development and use of therapeutic agents. Here I discuss the interplay of these factors and their likely effect on the future role of the immunology laboratory.

Allergy and Immunology↗

Modulation of cytotoxic activity of resident macrophages by postsurgical macrophages.

The purpose of this study was to determine if the secretion of cytotoxic molecules, such as tumor necrosis factor or toxic oxygen molecules, by resident peritoneal macrophages is modulated by postsurgical macrophages elicited by peritoneal trauma. Resident macrophages were collected from nonsurgical rabbits and cultured in vitro with either spent media from cultures of postsurgical macrophages harvested at various times or with varying concentrations of standard cytokines. Superoxide anion (O2-) production of resident macrophages increased with exposure to spent culture media from macrophages obtained after intestinal reanastomosis (3, 6, 12, 24 hr). This increase reached maximal levels by 6 hr after surgery and thereafter decreased to resident levels by 24 hr after surgery. Exposure of resident macrophages to spent media from cells collected after peritoneal sidewall abrasion (1, 3, 5, 7, 10, 14 days) elevated the production of O2- on Postsurgical Days 3 and 5; however, no effect was observed following exposure to spent media of macrophages harvested on Postsurgical Day 14. Interleukin-1 alpha (IL-1 alpha), transforming growth factor beta (TGF-beta), and tumor necrosis factor alpha (TNF alpha) stimulated phorbol ester-induced O2- production by resident macrophages in a concentration-dependent manner. The secretion of TNF activity by resident macrophages increased following exposure to spent media of macrophages harvested 6 to 24 hr after intestinal surgery. IL-1 alpha, TGF-beta, and TNF alpha elevated the secretion of TNF activity by resident macrophages in a concentration-dependent manner.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗