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Biomedical subjects

L A Frank

Publications and source records attributed to L A Frank.

At least 19 recordsLinked to original sources
PubMed2003

Steroid hormone concentration profiles in healthy intact and neutered dogs before and after cosyntropin administration.

The purpose of this study was to determine steroid hormone concentration profiles in healthy intact and neutered male and female dogs. Seventeen intact female dogs, 20 intact male dogs, 30 spayed female dogs, and 30 castrated male dogs were used in this study. Serum samples were collected before and 1h after cosyntropin administration, and serum concentrations were determined for cortisol, progesterone, 17-OH progesterone (17-OHP), dehydroepiandrosterone sulfate (DHEAS), androstenedione, testosterone, and estradiol. Intact male dogs had greater concentrations of DHEAS, androstenedione, and testosterone. Intact female dogs had greater concentrations of progesterone. There was no significant difference in estradiol concentration among the four groups. Intact male dogs had lower concentrations of cortisol post-stimulation. DHEAS and testosterone did not increase in response to ACTH in intact males, and estradiol concentrations did not increase in response to ACTH in any group. Results from this study will enhance interpretation of suspected adrenal and/or gonadal disorders of dogs. Because estradiol concentrations were similar in all groups of dogs, measuring estradiol may not be a useful diagnostic test. Cortisol concentrations for intact male dogs with hyperadrenocorticism may be lower than those of female or neutered dogs.

17-alpha-Hydroxyprogesterone↗
PubMed2001

Steroidogenic response of adrenal tissues after administration of ACTH to dogs with hypercortisolemia.

OBJECTIVE: To evaluate adrenal sex hormone concentrations in neutered dogs with hypercortisolemia. DESIGN: Case series. ANIMALS: 11 neutered dogs with hypercortisolemia. PROCEDURE: Serum samples obtained before and 1 hour after administration of ACTH were evaluated for concentrations of cortisol, progesterone, testosterone, dehydroepiandrosterone sulfate or androstenedione or both, and 17-hydroxyprogesterone. RESULTS: For all dogs, concentrations of 1 or more adrenal sex hormones were substantially greater than reference range values before or after administration of ACTH. Testosterone concentration was not greater than reference range values in any of the dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Results emphasize the importance of ruling out hypercortisolemia before measuring adrenal sex hormone concentrations as a means of diagnosing adrenal hyperplasia syndrome (alopecia X) in dogs.

17-alpha-Hydroxyprogesterone↗
PubMed2001

Role of conservative residue Cys158 in the formation of an active photoprotein complex of obelin.

Using site directed mutagenesis, the conservative residue Cys158 of recombinant apoobelin was substituted for serine (C158S, S-mutant) or alanine (C158A, A-mutant). These point mutations resulted in significant changes in the apoobelin structure accompanied by slowing of photoprotein complex formation, decrease of its stability, and changing of its bioluminescence characteristics. The enzymatic properties of the photoprotein decreased in the series: wild-type protein > S-mutant > A-mutant. This is consistent with rank of nucleophilicity SH > OH > CH(3) of cysteine, serine, and alanine side chain functional groups, respectively. Possible mechanisms of the involvement of the apoobelin Cys158 SH-group in the formation of the enzyme-substrate complex are considered.

Alanine↗
PubMed2000

Cortisol concentrations following stimulation of healthy and adrenopathic dogs with two doses of tetracosactrin.

A prospective study was undertaken to compare intravenous tetracosactrin at doses of 5 microg/kg and 250 microg for diagnosing hyperadrenocorticism in dogs. Both healthy dogs and dogs with pituitary-dependent hyperadrenocorticism were evaluated with the two doses of the drug, and serum cortisol concentrations were compared at 60 minutes post-stimulation. Some of the dogs had additional samples taken at 90 and 120 minutes. For four dogs with hyperadrenocorticism, timed samples were also obtained at 150, 180 and 240 minutes post-injection. Cortisol concentrations 60 minutes after stimulation with either 5 microg/kg or 250 microg intravenous tetracosactrin were similar for both healthy dogs and dogs with hyperadrenocorticism. The lower dose can therefore be used for diagnosing hyperadrenocorticism in dogs.

Adrenocortical Hyperfunction↗
PubMed1999

Effect of oral melatonin administration on sex hormone, prolactin, and thyroid hormone concentrations in adult dogs.

OBJECTIVE: To determine the effect of oral melatonin (MT) administration on serum concentrations of sex hormones, prolactin, and thyroxine in dogs. DESIGN: Prospective study. ANIMALS: 8 male and 8 female adult sexually intact dogs. PROCEDURE: 5 male and 5 female dogs were treated with MT (1.0 to 1.3 mg/kg [0.45 to 0.59 mg/lb] of body weight), PO, every 12 hours for 28 days; the other 6 dogs were used as controls. Blood samples were collected on days 0, 14, and 28, and serum concentrations of estradiol-17 beta, progesterone, testosterone, androstenedione, 17-hydroxyprogesterone (17-HP), dihydroepiandrostenedione sulfate (DHEAS), prolactin, and thyroxine were determined. On day 5, serum MT concentrations were measured before and periodically for up to 8 hours after MT administration in 4 treated dogs. RESULTS: Female dogs treated with MT had significant decreases in serum estradiol, testosterone, and DHEAS concentrations between days 0 and 28. Male dogs treated with MT had significant decreases in serum estradiol and 17-HP concentrations between days 0 and 28. Serum MT concentrations increased significantly after MT administration and remained high for at least 8 hours. Prolactin and thyroxine concentrations were unaffected by treatment. CONCLUSIONS AND CLINICAL RELEVANCE: Melatonin is well absorbed following oral administration and may alter serum sex hormone concentrations.

17-alpha-Hydroxyprogesterone↗
PubMed1998

Comparison of production of Staphylococcus intermedius exotoxin among clinically normal dogs, atopic dogs with recurrent pyoderma, and dogs with a single episode of pyoderma.

OBJECTIVE: To determine whether exotoxin production by Staphylococcus intermedius is an important factor in recurrence of pyoderma in atopic dogs. DESIGN: Prospective clinical study. ANIMALS: 30 client-owned dogs (10 clinically normal dogs, 10 atopic dogs with recurrent pyoderma, and 10 dogs with a single episode of pyoderma). PROCEDURE: Specimens for bacterial culturing were obtained from a pustule or papule of affected dogs or from skin of clinically normal dogs. Staphylococcus intermedius was isolated and processed. Supernatants were analyzed for staphylococcal exotoxins. Types of lesions and severity of pruritus were assessed for each dog. RESULTS: Exotoxins A and C were detected in S intermedius isolated from 1 clinically normal dog. In the atopic group, exotoxin C was isolated from 1 dog, exotoxins A and C were isolated from 1 dog, and exotoxin C and toxic shock syndrome toxin-1 were isolated from 1 dog. Exotoxins were isolated from 2 dogs with a single episode of pyoderma (exotoxin C, 1 dog; exotoxins A and C, 1 dog). Lesion types and severity of pruritus varied greatly among dogs with pyoderma and were not associated with detection of exotoxin or type of exotoxin. CLINICAL IMPLICATIONS: Exotoxins were identified from few isolates of S intermedius, and we did not observe an association between type of lesions or severity of pruritus and detection of exotoxins. Production of exotoxin by S intermedius does not play a role in the recurrent nature of pyoderma in atopic dogs or on type of lesion or severity of pruritus associated with pyoderma.

Animals↗
PubMed1998

Comparison of serum cortisol concentrations in clinically normal dogs after administration of freshly reconstituted versus reconstituted and stored frozen cosyntropin.

OBJECTIVE: To evaluate the biological stability of reconstituted cosyntropin after storage at -20 C for 2, 4, and 6 months. DESIGN: Prospective study. ANIMALS: 10 clinically normal dogs. PROCEDURE: Serum cortisol concentrations in dogs were determined before and 1 hour after administration of freshly reconstituted cosyntropin (synthetic ACTH) or cosyntropin that had been reconstituted and stored frozen at -20 C in plastic syringes for 2, 4, and 6 months. Cosyntropin was administered at 5 micrograms/kg (2.3 micrograms/lb) of body weight, i.v. RESULTS: Baseline serum cortisol concentrations were similar at each sampling time. Compared with the effects of freshly reconstituted cosyntropin, administration of cosyntropin that had been frozen did not have a significantly different effect on serum cortisol concentrations. CLINICAL IMPLICATIONS: Cosyntropin can be reconstituted and stored frozen at -20 C in plastic syringes for 6 months with no adverse effects on bioactivity of the polypeptide.

Animals↗
PubMed1997

Repeated physical and cytologic characterizations of subcutaneous postvaccinal reactions in cats.

OBJECTIVES: To examine local reactions and short-term cytologic responses of cats to administration of rabies virus (RV); FeLV; and combined feline rhinotracheitis, calicivirus, and panleukopenia virus (FRCPV) vaccines. ANIMALS: 9 healthy 6- to 7-month-old specific-pathogen-free cats. PROCEDURE: One-milliliter doses of the aforementioned vaccines were administered SC (at different sites) to healthy, specific-pathogen-free cats. Each cat also received 1 ml of sterile saline solution SC as a control. Injection sites were visually examined and palpated daily for 4 weeks. Palpable lesions were measured by use of calipers. Temperature of the vaccination sites was measured weekly by use of a thermocouple. Aspirates were taken from vaccination sites weekly, and smears were submitted for cytologic analysis. RESULTS: There were no significant differences in lesion surface temperature among injection sites at any time. Injections of saline solution and FeLV vaccine resulted in no palpable lesions. The FRCPV vaccine elicited a minor reaction in 1 of the 9 cats. The RV vaccine caused palpable lesions in all cats. Smears of the aspirates from the sites of saline injection were poorly cellular. Cellularity of aspirates from the sites of FRCPV and FeLV vaccinations was moderate at week 1, and decreased with time. Inflammatory infiltrates were composed principally of lymphocytes, with fewer neutrophils and macrophages. In contrast, cellularity of aspirates from RV vaccination sites increased for 21 days and was characterized by increasing numbers of lymphocytes and macrophages. CONCLUSIONS: RV vaccine used in this study induced palpable lesions in many cats. In contrast, FRCPV and FeLV vaccines elicited less severe lesions. CLINICAL RELEVANCE: Subcutaneous administration of killed virus vaccines in cats may result in palpable lesions that are detected by clients or clinicians. Aspiration cytologic examination may reveal a different characteristic pattern of cells that is dependent on the individual vaccine and time elapsed from vaccination.

Alphaherpesvirinae↗
PubMed1996

Plasma observations at Io with the Galileo spacecraft.

Plasma measurements made during the flyby of Io on 7 December 1995 with the Galileo spacecraft plasma analyzers reveal that the spacecraft unexpectedly passed directly through the ionosphere of Io. The ionosphere is identified by a dense plasma that is at rest with respect to Io. This plasma is cool relative to those encountered outside the ionosphere. The composition of the ionospheric plasmas includes O++, O+ and S++, S+, and SO2+ ions. The plasma conditions at Io appear to account for the decrease in the magnetic field, without the need to assume that Io has a magnetized interior.

Extraterrestrial Environment↗
PubMed1996

Use of proZZ-obelin fusion protein in bioluminescent immunoassay.

Obelin is a photoprotein that emits light by Ca2+-binding. To develop a bioluminescent immunoassay based on the light emission property of obelin, we have expressed the apoobelin fusion protein with ZZ-domain of S. aureus protein A in E. coli by recombinant DNA techniques. The proZZ-obelin expressed was purified by one-step affinity chromatography on IgG-Agarose. The purified proZZ-obelin has both the luminescent activity of obelin and the IgG-binding ability of ZZ-domain. The specific activity of fusion protein was 8.5 X 10(15) photons per mg of protein.

Animals↗
PubMed1996

Distribution and appearance of elastic fibers in the dermis of clinically normal dogs and dogs with solar dermatitis and other dermatoses.

OBJECTIVE: To determine the distribution and amount of elastic fibers in the dermis of clinically normal dogs and dogs with dermatoses, particularly solar dermatitis. DESIGN: Skin specimens from 7 anatomic sites were obtained from 19 clinically normal dogs after euthanasia to evaluate the normal distribution of elastic fibers. Biopsy specimens also were obtained from 34 dogs with dermatoses, including 16 with solar dermatitis. Tissue sections were stained with H&E, Verhoeff-van Gieson, and periodic acid-Schiff. ANIMALS: 19 clinically normal dogs and 34 dogs with dermatoses. PROCEDURE: Numbers of elastic fibers were graded subjectively. Comparisons between clinically normal dogs and dogs with dermatoses were made. RESULTS: Normal elastic fibers were present in low numbers in the dermis of adult dogs, regardless of anatomic site or presence or severity of dermatitis. Condensed elastotic material was visualized in only 2 dogs with solar dermatitis. In both dogs, the elastotic material was Verhoeff-van Gieson and periodic acid-Schiff stain positive but was not visible with H&E stain. The most frequent histopathologic finding in the dermis of dogs with solar dermatitis was superficial dermal fibrosis. CONCLUSIONS: The dermis of clinically normal dogs does not contain abundant elastic fibers. Alterations of elastic fibers in dogs with solar dermatitis are rare. Superficial dermal fibrosis may be a better indicator of solar damage.

Animals↗
PubMed1995

Mn(2+)-activated luminescence of the photoprotein obelin.

The light emission of obelin may be initiated by Mn2+ under alkaline conditions. The luminescence takes place in a pH range from 7 to 12 with a sharp optimum at 11.75. The first-order rate constant for Mn(2+)-activated luminescence decay is more than 9 s-1, while that for Ca(2+)-activated luminescence decay is only 6.9 s-1. The Mn2+ concentration-effect curve for obelin determined with simple dilutions of manganese salt is a sigmoid curve. The slope of the curve is moderately dependent on the pH and was not more than 1 within the pH range tested. The maximal light emission, which is initiated by 3.6 x 10(-5) M Mn2+ at pH 11.75 was about 10% of the maximal Ca(2+)-activated luminescence. Mg2+ ions inhibit the Mn(2+)-activated luminescence of obelin. The addition of OH. and O2- scavengers did not influence the Mn(2+)-activated luminescence, but when singlet oxygen quenchers were added, the Mn(2+)-dependent light emission was inhibited. This suggests that the 1O2 might be formed and itself be responsible for chromophore oxidation attended with light emission. NEM and Na2S2O4 inhibit the Mn(2+)-initiated light emission of obelin completely, showing that endogenous hydroperoxide and SH-group(s) of the photoprotein are essential for both Ca(2+)-activated and Mn(2+)-activated light emission of obelin.

Aequorin↗
PubMed1993

Comparison of the efficacy of cefadroxil and generic and proprietary cephalexin in the treatment of pyoderma in dogs.

We compared efficacy of cefadroxil and generic and proprietary cephalexin in treatment of pyoderma in dogs. Forty-four dogs were randomly assigned to receive 1 of the 3 preparations at 22 to 35 mg/kg body weight, every 12 hours. Dogs were examined at the conclusion of treatment period and assessed as to degree of improvement. All 3 cephalosporins were effective and safe antibiotics for the treatment of pyoderma in dogs.

Animals↗
PubMed1992

Comparison of serum cortisol concentration before and after intradermal testing in sedated and nonsedated dogs.

Serum cortisol concentration was evaluated in 71 dogs before and after a stressful procedure was performed. Thirty dogs were skin tested with sedation (group S), 21 dogs were skin tested without sedation (group NS), and 20 dogs had other dermatologic procedures performed (group C). Group-S dogs had significant (P less than 0.001) decrease in serum cortisol concentration after skin testing, compared with baseline values. In contrast, dogs of groups NS and C had significant (P less than 0.001) increase in poststress serum cortisol concentration. Mean cortisol concentration after stress was significantly lower for dogs of group S, compared with that for dogs of the other 2 groups. The second part of the analysis consisted of determining the number of false-negative skin test results for dogs of groups S and NS and comparing these with serum cortisol concentration. Difference in the number of suspected atopic dogs with negative skin test results (false-negative) was not evident between groups S and NS. Also, difference was not apparent between cortisol concentration in dogs that had positive or false-negative skin test results in either group. This finding indicates that high serum cortisol concentration does not affect results of skin testing in suspected atopic dogs.

Animals↗