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Biomedical subjects

J D Kirby

Publications and source records attributed to J D Kirby.

At least 19 recordsLinked to original sources
PubMed1992

Microalbuminuria in systemic sclerosis.

A prospective study was performed to determine urinary albumin excretion in a group of 28 patients with systemic sclerosis. At the initial screen one patient had proteinuria and three had microalbuminuria. One year later these abnormalities persisted and in two of of the patients serum creatinine had significantly increased. In addition, a further three patients had developed microalbuminuria. In a control group of 10 patients with primary Raynaud's disease none had microalbuminuria. In a second control group of 16 patients with unrelated skin diseases one patient had microalbuminuria and one proteinuria, but both these patients had a history of hypertension. It is concluded that microalbuminuria is more common in patients with systemic sclerosis than in patients of equivalent age with other dermatological conditions but no vascular disease.

Adult↗
PubMed1992

Hemostatic abnormalities in Sneddon's syndrome.

Sneddon's syndrome is a rare condition comprising widespread livedo retucularis and multiple episodes of transient cerebral ischemia. Treatment to date has been empirical. The hemostatic/thrombotic status of 4 patients with Sneddon's syndrome was studied by a unique technique, hemostatometry, which measures primary hemostasis (shear-induced platelet plug formation), the overall coagulation, and thrombolysis (dislodgment of the hemostatic plugs) from nonanticoagulated blood. In all 4 patients, platelet reactivity, which shows itself in the initial phase of the hemostatic reaction, was enhanced. The overall hemostasis, in which the generation of thrombin by activated platelets plays the decisive role, was enhanced in 3 patients. Three of the 4 patients had hypercoagulation, and in 3, spontaneous thrombolysis was inhibited. Treatment was commenced with aspirin and nifedipine, and patients were monitored both clinically and by serial hemostatometry over two years. One patient had one further transient ischemic episode; the other 3 remained asymptomatic. Thus, the observed clinical improvement correlated with improvement of the hemostatic profile.

Adult↗
PubMed1992

Developmental hormonal profiles accompanying the neonatal hypothyroidism-induced increase in adult testicular size and sperm production in the rat.

Neonatal treatment with the reversible goitrogen 6-N-propyl-2-thiouracil (PTU) results in a near doubling of testicular size and a 25% increase in the efficiency of spermatogenesis, without affecting circulating testosterone (T) levels in adult rats. The objectives of the present study were to examine the effects of neonatal PTU treatment on the pattern of testicular growth and circulating levels of anterior pituitary (FSH, LH, PRL, GH, and TSH), gonadal [immunoreactive inhibin-alpha (irI alpha) and T], and thyroid (T3 and T4) hormones over the first 100 days of life. Treatment of rats with PTU from birth to 24 days of age significantly reduced testicular weights between 10 and 60 days of age. However, the duration of testicular growth was extended in treated males, resulting in a 68% increase at 100 days of age. Serum gonadotropin levels in treated males were reduced throughout the experimental period, typically remaining between 50-70% of control levels. The characteristic robust prepubertal FSH peak was absent in PTU-treated males. Initially high until 20 days of age, irI alpha levels characteristically declined to adult levels (200-300 pg/ml) in control males. In treated males, irI alpha levels were reduced during the period of hypothyroidism, increased between 30 and 60 days, and then declined, but remained significantly higher (1.7- to 2-fold greater) than those observed in control males. Serum T levels were similar in treated and control males. Control males demonstrated increased T levels beginning at 45 days of age, earlier than observed in treated males; however, similar peak T levels were observed in all males. PTU treatment significantly suppressed serum GH and PRL and led to a 14-fold increase in circulating TSH during the period of treatment. However, unlike the gonadotropins, these hormones returned to control levels after PTU treatment, suggesting that the reduced levels of FSH and LH observed are not due to a generalized reduction in pituitary function. Serum T4 and T3 levels returned to control levels within 15 days after the removal of PTU. These results demonstrate that the neonatal PTU treatment-induced increases in adult testicular size and sperm production were not due to increased levels of FSH at any point in development. On the contrary, the observed increases occur in spite of chronically reduced FSH levels.

Aging↗
PubMed1992

Induction of immunity to spermatozoa in male domestic fowl and effects on fertility.

Male fowl were immunized intravenously (i.v.) or intramuscularly (i.m.) with spermatozoa to assess the effects of immunity to spermatozoa on fertility. Histological and immunofluorescence evaluations of testis and ductus deferens tissues after 24 weeks of immunizations revealed immune cell infiltration and immunoglobulin associated with spermatozoa. The long-term immunization regimen resulted in significant antisperm antibody titres in the immunized groups. When semen from i.v.-immunized males was used to inseminate females, fertility over 7 days was reduced (P less than 0.05). A subsequent experiment using a 10-week i.v. immunization scheme also led to high antisperm titres. Spermatozoa from these males were characterized by lower fertility and duration of fertility than those of controls (P less than 0.05). As in mammals, a reduction in fertility may result from exposure of avian males to sperm antigens.

Animals↗
PubMed1992

Analysis of the combined effect of the spermatozoal degeneration allele (Sd) and homozygosity of the rose comb allele (R) on the duration of fertility of roosters (Gallus domesticus).

Roosters homozygous for the rose comb allele (R/R) are subfertile. Likewise, roosters bearing the dominant spermatozoal degeneration allele (Sd) are subfertile. The objective of the present research was to see whether these effects were cumulative. Domestic fowl were bred in order to obtain males representing the following genotypes: R/r+ sd+/sd+, R/r+ Sd/sd+, R/R sd+/sd+, and R/R Sd/sd+. Duplicate fertility trials were conducted with Single Comb White Leghorn hens. In each trial, ejaculates were pooled according to genotype. The insemination dose was 1 x 10(8) viable spermatozoa per hen, and eggs were collected over a 21-day interval following a single intravaginal insemination. Fertility over the 21-day period was 53 +/- 2.1 (SEM), 36 +/- 1.6, 21 +/- 2.1, and 11 +/- 1.2%, respectively. Therefore, the effect of homozygosity for the R allele and the presence of the Sd allele were cumulative in the depression of fertility.

Alleles↗
PubMed1991

Infusion of a stable prostacyclin analogue, iloprost, to patients with peripheral vascular disease: lack of antiplatelet effect but risk of thromboembolism.

PURPOSE: Prostacyclin, a potent inhibitor of platelet function and vasodilator, has been used to treat peripheral vascular disease. The aim of this study was to monitor the thrombotic status of patients treated by infusion of a stable prostacyclin analogue, iloprost. PATIENTS AND METHODS: Thirteen patients with peripheral vascular disease underwent iloprost infusion for 3 days (8 hours each day) in a dose ranging from 0.5 to 2 ng/kg/minute. Variable parameters of thrombosis such as platelet reactivity (shear-induced hemostatic plug formation and thrombus formation on a collagen fiber), coagulation, and spontaneous thrombolysis (dislodgment of hemostatic plugs) were measured from non-anticoagulated blood samples by hemostatometry immediately before and 1 hour after the infusion and on the last day, 4 hours after initiation of the infusion. RESULTS: Analysis of data from all patients 1 hour after the infusion showed no changes in platelet reactivity and spontaneous thrombolysis, but coagulation was significantly enhanced. In four patients, significant platelet hyperreactivity was observed after the infusion. Four of the five patients tested while undergoing iloprost infusion showed an enhanced thrombotic reaction and markedly enhanced coagulation. Iloprost employed in vitro in a concentration that corresponds to the therapeutic peak blood level caused no inhibition of platelet function but significantly enhanced coagulation. The threshold in vitro iloprost concentration at which anti-platelet effect and increased spontaneous thrombolysis were observed was twice that of the therapeutic blood level. CONCLUSIONS: These findings challenge the view that antagonism of platelet function is an important factor of iloprost therapy. Furthermore, platelet hyperreactivity in some patients and markedly enhanced coagulation during and after infusion of iloprost in general, represent a risk of thromboembolism, especially as patients are already in a prethrombotic condition.

Adult↗
PubMed1991

Familial mastocytosis: a clinical, immunophenotypic, light and electron microscopic study.

A women and her daughter both developed diffuse cutaneous mastocytosis in early infancy. The immunophenotypes of the cutaneous mast cells in the two cases were shown to be identical: leucocyte common antigen (CD45) and macrophage/monocyte marker EBM11 were both strongly positive, HLA-DR was positive and CD25 was weakly positive. The peripheral lymphocytes of the patients were analysed by flow cytometry and this revealed that there was no increase in the activation markers HLA-DR and CD25, contrary to recent claims that lymphocytes have a contributory role in driving mast-cell proliferation. Mast-cell granules in both cases were found on electron microscopy to have an abnormal ultrastructure. The close similarity between the two cases at clinical, immunophenotypic and ultrastructural levels strongly suggests that genetic factors are important in the development of this type of mastocytosis.

Adult↗
PubMed1991

Comparative metabolism of spermatozoa from subfertile Delaware and Wyandotte roosters.

Sperm metabolism was determined via reduction of 2-(p-iodophenyl)-3-(p-nitrophenyl)-5-phenyl tetrazolium chloride (INT) to formazan. When the reaction mixture contained cyanide, which blocks cytochrome oxidase and thus maximizes intermediate electron transfer to INT, and calcium which stimulates fowl sperm motility, the metabolic capacity of spermatozoa from subfertile Delaware and Wyandotte roosters was 90 and 63% of that of spermatozoa from fertile Leghorn roosters. When the assay was performed at 40 degrees C without calcium or cyanide, no difference in metabolism was observed between Delaware and Leghorn spermatozoa (P greater than 0.05). However, the metabolism of Wyandotte spermatozoa was 66% of that observed with Delaware or Leghorn spermatozoa. These results provide further evidence that heritable subfertility in Delaware and Wyandotte roosters is attributable to distinct sperm defects.

Animals↗
PubMed1991

An improved procedure for intramagnal insemination of the chicken.

Intramagnal insemination is a useful technique in the analysis of spermatozoal function. Precise deposition of spermatozoa requires the use of laparotomy. However, hen-day egg production can be adversely affected by such a procedure. The present work demonstrates that postoperative hen-day egg production is affected by choice of anesthetic. Hens anesthetized with a mixture of ketamine and xylazine prior to laparotomy laid 14% fewer eggs (P less than .05) when compared with intact controls. In contrast, the postoperative hen-day egg production of hens anesthetized with xylazine alone was comparable with that of intact controls (P greater than .05). Furthermore, the use of xylazine alone increased the ease of handling sedated hens and decreased recovery time. Therefore, xylazine is recommended for anesthetizing hens prior to laparotomy.

Anesthesia↗
PubMed1991

Analysis of poultry fertility data. 2. Comparison of long- and short-term fertility trials.

The purpose of the present study was to determine the effect of egg collection interval on interpretation of fertility trial results. Low-fertility (LF) and randombred (RB) Delaware hens were inseminated with spermatozoa from LF or RB Delaware roosters. Three replicate trials were performed for each cross. Eggs were collected for 21 days following insemination. Fertility was analyzed with a log odds model following logit transformation. Separate analyses were performed on data collected throughout the first 7 days and the entire egg collection interval. Duration of fertility over the 21-day interval was analyzed by iterative least squares. Whereas the 21-day egg collection interval afforded detection of differences between males and between females, no differences were observed following analysis of data from the 7-day interval. Differences in reproductive efficiency also were detected when data were analyzed by iterative least squares. Thus, the value of a fertility trial is, in part, determined by the length of the egg collection interval.

Animals↗
PubMed1991

Research note: evaluation of humoral and delayed hypersensitivity responses in cockerels reared under constant light or a twelve hour light:twelve hour dark photoperiod.

Immature cockerels were reared under constant light [24 h light (L):0 h dark (D)] or a 12L:12D photoperiod in order to evaluate the effect of constant light on immunoresponsiveness. At 10 wk of age males were immunized with SRBC, with reimmunization occurring either 3 or 8 wk later. Animals reared under constant light had lower (P less than .05) anti-SRBC antibody titers than the 12L:12D males. Additionally, the pattern of the antibody response following secondary immunizations were different, with 24L:0D males exhibiting no increase in antibody titers between Days 3 and 9 postinjection. Delayed hypersensitivity responses of 24L:0D males were lower (P less than .05) than those of 12- or 16-wk-old 12L:12D males. Taken together, these results suggest that circadian light:dark cycles may play a role in modulating the immune system.

Animals↗
PubMed1990

Effect of immunization of sexually immature pullets against poly-alpha-L-glutamic acid on long-term fertility.

Poly-alpha-L-glutamic acid (PGA) is a polypeptide synthesized within the upper oviduct and uterovaginal junction of the hen. Sexually immature pullets were immunized against PGA. These virgin pullets, and immunized and non-immunized controls, were inseminated at 25 weeks of age and then monthly throughout a 30-week egg production interval. While birds immunized against PGA were free of PGA as evidenced by an absence of immunoprecipitation when rabbit anti-PGA serum was overlayed with oviduct extract, immunization had no effect on long-term fertility and therefore is unlikely to have an immunosuppressive or antigen-masking biological role with respect to spermatozoa. We suggest instead that PGA could act as a calcium binding protein.

Animals↗
PubMed1990

Analysis of poultry fertility data.

Single Comb White Leghorn (SCWL) hens were inseminated intravaginally with spermatozoa from either SCWL or subfertile Delaware roosters in three replicate fertility trials. Overall fertility was analyzed with a log odds model following logit transformation. Duration of fertility was analyzed by iterative least squares. Hens inseminated with spermatozoa from SCWL males laid a higher proportion of fertilized eggs over a longer interval than those inseminated with spermatozoa from affected Delawares. Log-odds and logistic models may have advantages over the more traditional methods of evaluation. This is particularly true in regard to the distribution and normalization of error variances via the logit transformation and removal of nonadditivity via logistic regression.

Analysis of Variance↗