Biomedical subjects

D G Rogers

Publications and source records attributed to D G Rogers.

46 records · Page 3Linked to original sources

PubMed1985

Partial deficiency in 17-ketosteroid reductase presenting as gynecomastia.

We report a 14 year-old male with severe, long-lasting gynecomastia. Baseline serum androstenedione levels were elevated compared to testosterone levels (330 ng/dl vs 28 ng/dl). In order to evaluate testosterone biosynthesis by this patient in more detail, androstenedione, testosterone, dehydroepiandrosterone (DHEA) and estradiol responses to a single dose of hCG were measured. The responses observed were different from those reported in normal males in two respects: 1) there was no immediate rise in testosterone two to four hours after the injection of hCG, and 2) levels of androstenedione and estradiol at 24, 36 and 48 hours after injection were much higher than expected. We postulate that a partial defect in testicular 17-ketosteroid reductase activity was responsible for the abnormal androstenedione to testosterone ratio in our patient. This, in turn, lead to an increased peripheral synthesis of estrogens and marked gynecomastia.

17-Hydroxysteroid Dehydrogenases↗

PubMed1985

Application of the peroxidase-antiperoxidase technique for the detection of enterotoxigenic Escherichia coli K99 pilus antigen in paraffin-embedded tissues.

The peroxidase-antiperoxidase (PAP) technique was evaluated as a method for detecting enterotoxigenic Escherichia coli (ETEC) K99 pilus antigen in paraffin-embedded tissues of swine. Antigenic reactivity was optimal when tissues were processed in cold methanol according to a modified method of Sainte-Marie. This method of processing adequately preserved tissue morphology. The PAP technique was applicable to tissues where endogenous peroxidase activity was minimal.

Animals↗

PubMedDate not supplied

The effect of puberty on the development of early diabetic microvascular disease in insulin-dependent diabetes.

We studied the prevalence of early diabetic retinopathy and nephropathy in 21 prepubertal and 55 late-pubertal subjects with insulin-dependent diabetes (IDD). All subjects had IDD of 5-7 years duration at the time of evaluation. The prevalence of early diabetic retinopathy was significantly greater in the late-pubertal subjects than prepubertal subjects (33% vs. 9.5%, P = 0.05), despite similar glycosylated hemoglobin values between the two groups (11.7 +/- 2.7% vs. 10.1 +/- 1.6%) at the time of evaluation. Nephropathy was infrequent in late-pubertal subjects (9%), and absent in the prepubertal subjects. We hypothesize that puberty plays an important role in the development of microvascular complications of IDD, and that increases in growth factors, sex hormones and deterioration in glycemic control at the time of puberty may each enhance the development of diabetic microvascular disease.

Adolescent↗

PubMedDate not supplied

Glycemic control and bone age are independently associated with muscle capillary basement membrane width in diabetic children after puberty.

This study was undertaken to examine the possible relationships between muscle capillary basement membrane width (CBMW) and glycemic control, bone age, chronologic age, and duration of diabetes in young patients with insulin-dependent diabetes mellitus (IDDM) during different stages of pubertal development. We studied 49 males and 43 females (age, 7-20 yr) with IDDM for up to 16 yr for whom bone age and glycosylated hemoglobin (HbA1c) data were available at the time of right quadriceps muscle biopsy. Based on pubic hair Tanner stage, subjects were assigned to prepubertal (Tanner I), pubertal (Tanner II and III), and postpubertal (Tanner IV and V) groups. In 30 pubertal and prepubertal subjects, none of the variables studied was significantly correlated with CBMW. This is attributable in part to the small number of subjects in each group. In 62 postpubertal subjects, CBMW was correlated with age (r = .27, P = .03), bone age (r = .43, P = .0005), and postpubertal duration of diabetes (r = .38, P = .003) but not total duration of diabetes. In the postpubertal subjects, CBMW was correlated with HbA1c at the time of biopsy (r = .31, P = .01) but correlated more strongly with the mean of HbA1c values obtained during the 1- and 2-yr periods before biopsy (r = .37, P = .01, and r = .54, P = .03, respectively). An analysis of covariance revealed that the slopes for the regression of loge CBMW on HbA1c differed significantly (P = .02) among the three groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMedDate not supplied

An evaluation of inactivated infectious coryza vaccines containing a double-emulsion adjuvant system.

The efficacy of experimental inactivated infectious coryza vaccines produced by a commercial vaccine manufacturer was evaluated. The vaccines, containing as the adjuvant phase either a double-emulsion mineral oil system or aluminum-hydroxide gel, were administered to 6-week-old chickens as a single dose. Some vaccines were a monovalent product containing a Page serovar C Haemophilus paragallinarum strain, and others were a bivalent product containing both Page serovar A and serovar C strains. After 3 weeks, all chickens were challenged by infraorbital sinus inoculation of virulent H. paragallinarum, either Page serovar C (strain HP31) or Page serovar A (strain HP14). The monovalent serovar C double-emulsion-based vaccines gave significant protection against a serovar C challenge, with the level of protection varying from 60% to 100%. The monovalent serovar C aluminum-hydroxide-gel vaccine also gave significant protection (94%) against a serovar C challenge. The bivalent double-emulsion vaccine gave significant protection against challenge from both serovars (100% for serovar C and 83% for serovar A). Although no major adverse reactions were detected, some chickens receiving both the double-emulsion vaccines and the aluminum-hydroxide vaccine developed relatively minor granulomatous reactions at the site of injection.

Adjuvants, Immunologic↗

PubMedDate not supplied

Evaluation of a panel of monoclonal antibodies in the subtyping of Haemophilus paragallinarum.

A panel of four monoclonal antibodies (MAbs) was evaluated, using a hemagglutination-inhibition test, for its ability to subtype 76 isolates of Haemophilus paragallinarum. The results of the MAb reactions were compared with the results of both the Page and Kume serotyping schemes (the serovars of the Page scheme correspond to the serogroups of the Kume scheme). One MAb (E5C12D10) was raised against a Page serovar A strain and the remaining MAbs (F2E6, D6D8D5, and B3E6F9) against a Page serovar C strain. Six different reaction patterns were found among the 76 isolates of H. paragallinarum. There was total correlation between the MAb reaction pattern and the Page scheme, and thus the Kume scheme, to the serogroup level. All 19 Page serovar A (= Kume serogroup A) strains reacted only with MAb E5C12D10, whereas all five Page serovar B (= Kume serogroup B) strains failed to react with any of the MAbs. All 52 remaining strains were Page serovar C (= Kume serogroup C), and all failed to react with MAb E5C12D10 but showed varying reaction patterns with the three other MAbs. Although the MAbs recognized four subdivisions within Kume serogroup C, these subdivisions differed from the four Kume C serovars. This panel of MAbs can be used to assign isolates of H. paragallinarum to either Page serovars or Kume serogroups. Although the subdivisions recognized by the MAbs within the Page serovar C strains do not correspond to the Kume serovars, they may be useful in epidemiological applications.

Animals↗

PubMedDate not supplied

Epidemiologic studies on infectious coryza outbreaks in northern New South Wales, Australia, using serotyping, biotyping, and chromosomal DNA restriction endonuclease analysis.

The epidemiology of 16 cases of infectious coryza, an upper respiratory tract disease of chickens caused by Haemophilus paragallinarum, was investigated in a retrospective study. The cases occurred over a 14-month period on 10 farms in northern New South Wales. The available field data indicated that the cases formed six unrelated outbreaks. The 16 isolates of H. paragallinarum were subjected to serotyping by the Page and Kume schemes and biotyping based on carbohydrate fermentation and antimicrobial drug-resistance patterns. As well, newer fingerprinting techniques--plasmid profiles, whole-cell protein profiles, immunoblots of whole-cell protein profiles and total DNA restriction endonuclease analysis (REA)--were evaluated. Antimicrobial biotyping and REA profile typing proved most useful, allowing the recognition of three groups among the isolates. The other techniques gave either limited or no subdivision among the isolates. The combined results of the laboratory study indicated that, rather than six unrelated outbreaks, the 16 isolates represented three pairs of related outbreaks. This study represents the first application of sensitive biotyping and fingerprinting techniques to outbreaks of infectious coryza. The results have established that farms can be repeatedly infected with a single strain of H. paragallinarum that re-emerges at intervals. This study also obtained the first detailed evidence that replacement stock are a major source of infectious coryza.

Animals↗

PubMedDate not supplied

Evaluation of two monoclonal antibodies for serotyping Haemophilus paragallinarum.

Two monoclonal antibodies (MAbs) were evaluated for their ability to serotype 108 isolates of Haemophilus paragallinarum. One MAb (E5C12D10) was raised against a Page serovar A strain and the other (F2E6) against a Page serovar C strain. In both dot blot and hemagglutination-inhibition tests, MAb E5C12D10 recognized the type strains of Page serovar A and Kume serovars A-1, A-2, A-3, and A-4. MAb F2E6 recognized the type strains of Page serovar C and Kume serovars C-1, C-2, and C-3. Neither antibody recognized the type strains of Page serovar B or Kume serovars B-1 and C-4. When evaluated with 97 field isolates in a dot blot test, the MAbs serotyped 81 isolates, which was better than agglutinin typing by the Page scheme (69 isolates serotyped). The field isolates that did not react with the MAbs were either Page serovar B/Kume serovar B-1 (three isolates), Page serovar C/Kume serovar C-4 (12 isolates), or nontypable by either the Page or Kume scheme (one isolate).

Animals↗

PubMedDate not supplied

Outer-membrane proteins of Haemophilus paragallinarum.

The outer-membrane protein (OMP) profiles of four isolates of Haemophilus paragallinarum (0083, 0222, Modesto, and HP31) were examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. OMPs were isolated by sonic disruption followed by differential centrifugation and selective solubilization in Triton X-100. Although the isolates had similar profiles overall, two distinct OMP profile types, based on the variable molecular weight of a protein termed OMP C (39,000 or 38,000), were found. In addition, OMP C was found to be a heat-modifiable protein--being either absent or present in only minor amounts if the preparations were not heated at 100 C. Major and minor OMPs, some common to all four isolates, were recognized in immunoblots by an immune serum to isolate HP31.

Animals↗

PubMedDate not supplied

Biotyping of Haemophilus paragallinarum isolates using hemagglutinin serotyping, carbohydrate fermentation patterns, and antimicrobial drug resistance patterns.

Three techniques, a hemagglutinin (HA) serotyping scheme, carbohydrate fermentation patterns, and antimicrobial drug resistance patterns, were used to examine 92 isolates of Haemophilus paragallinarum. The results were used to create biotyping schemes. The carbohydrate fermentation and antimicrobial drug resistance patterns each resulted in the identification of five biovars. With both of these techniques, a large majority of the isolates fell into one biovar: 81% were biochemical biovar I and 73% were antimicrobial biovar I. However, by combining the results of these techniques with those of the HA serotyping, a much greater discrimination could be achieved. The combined use of hemagglutinin serotyping, biochemical biotyping and antimicrobial biotyping appears to provide a suitable approach for epizootiological studies on infectious coryza.

Bacterial Typing Techniques↗