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Biomedical subjects

J H Smith

Publications and source records attributed to J H Smith.

At least 145 records · Page 8Linked to original sources
PubMed1987

Pathogenesis of Sarcocystis falcatula in the budgerigar. II. Pulmonary pathology.

Sarcocystis falcatula is a protozoan parasite which obligatorily alternates its definitive host, the opossum (Didelphis virginiana), and a uniquely wide range of avian intermediate hosts. The disease produced by this coccidian parasite in intermediate hosts was studied in the budgerigar bird (Melopsittacus undulatus). Early schizogony occurs in pulmonary endothelial cells, resulting in endothelial cell hypertrophy, capillary obstruction preceding endothelial lysis, acute endophlebitis, and chronic periphlebitis. These impede outflow of the pulmonary vascular system resulting in interstitial, subpneumocytic, and then air-space edema. The edema is associated with retraction and degeneration of squamous pneumocytic processes, loss of the myelinoid "surfactant" covering over the pneumocytes, and atelectasis of the respiratory labyrinth. Epithelial repair is effected by migration of granular pneumocytes (normally confined to the parabronchi and their atria) down the infundibula and into the respiratory labyrinth. This pattern of injury and repair is comparable to diffuse alveolar damage (acute interstitital pneumonitis) of mammals despite the markedly different structure of the avian lung. The implications of this peculiar tissue tropism are discussed.

Animals↗
PubMed1986

Microscopic and submicroscopic anatomy of the parabronchi, air sacs, and respiratory space of the budgerigar (Melopsittacus undulatus).

The normal microscopic and submicroscopic structure of the lower respiratory tract of the budgerigar (Melopsittacus undulatus) is described and compared with other birds and mammals. Granular (type II) pneumocytes are confined to linings of air sacs, parabronchi, and their atria; however, their secretions (surfactant) cover the surfaces of the infundibula and respiratory space. Infundibula extend from the atria and give rise to the air capillaries, which branch and anastomose freely with those of adjacent infundibula and other parabronchi (interparabronchial septa are not found). Infundibula and the respiratory labyrinth are lined by a continuous epithelium of squamous pneumocytes, whose perikarya are concentrated in the infundibula and whose peripheral cytoplasm is markedly attenuated. The squamous pneumocytes of the respiratory labyrinth share a basal lamina with the blood capillaries that they envelop.

Animals↗
PubMed1986

Induction of renal and hepatic mixed function oxidases in the hamster and guinea pig.

A marked species difference exists in the induction of renal and hepatic mixed function oxidase (MFO) activity between rats and rabbits. However, little is known about MFO induction in these organs from other laboratory animals. Male Golden Syrian hamsters and male Hartley guinea pigs were administered phenobarbital (PB) or beta-napthoflavone (BNF) at 70 and 40 mg/kg, respectively, as daily i.p. injections for 4 days. Polybrominated biphenyl (PBB) (Firemaster BP-6) was given as a single i.p. injection (50 mg/kg). Hamster hepatic microsomal ethoxyresorufin-O-deethylase (EROD) and benzphetamine-N-demethylase (BPND) were selectively induced by BNF and PB, respectively. PBB administration induced both hamster hepatic EROD and BPND. In contrast, hepatic microsomal MFO activity from the guinea pig was inducible by PB, PBB and BNF. Renal microsomal MFO activity in both species was inducible by BNF and PBB as arylhydrocarbon hydroxylase and EROD were induced approximately 10-fold. On the other hand, hamster BPND was induced by PB whereas guinea pig MFO activity was unaffected. Total renal cytochrome P-450 content was not affected by any of these inducers in either species. These data demonstrate selective patterns of induction in both hamster and guinea pig liver and kidney suggesting the involvement of multiple forms of cytochrome P-450.

Animals↗
PubMed1986

The effect of thyroxine (T4) administration on plasma levels of tri-iodothyronine (T3) and T4 in male white-tailed deer.

Plasma concentrations of thyroxine (T4) and tri-iodothyronine (T3) were monitored for 6 hr in mature male white-tailed deer following i.m. administration of synthetic T4. Oral administration of 600, 800 and 1000 micrograms of T4 was mostly ineffectual in increasing plasma levels of T3 and T4. On the other hand i.m. administration of similar doses of T4 was followed by a higher degree of increase in T3 and lesser degree of increase in T4 levels. It appears that high doses of T4 (e.g. 1000 micrograms) are less effective in raising plasma values of T3 or T4 than low or intermediate doses.

Animals↗
PubMed1986

The pathobiology of Schistosoma haematobium infection in humans.

Schistosoma haematobium infection is a common occurrence in Africa and the Middle East and is the world's leading cause of hematuria. Since more North Americans are venturing into endemic areas and more residents of endemic areas are seeking medical care in North America, pathologists must be able not only to diagnose urinary schistosomiasis but also to provide advice as to further therapy. These endeavors mandate knowledge of the pathobiologic features of the disease. The severity and frequency of the sequelae of urinary schistosomiasis (hydroureter, hydronephrosis, bladder ulcer, and polyposis) and of its complications (bacterial urinary tract infection, renal failure, urothelial cancers) depend on the intensity of infection, i.e., worm burden and tissue egg burden, and the duration of infection. Significant differences in gross and microscopic morphology, clinical laboratory findings, and optimal mode of treatment exist between active (during active egg deposition) and inactive (after cessation of oviposition) disease. Moreover, nearly half of the severe sequelae and complications occur during the inactive phase of the disease, when diagnosis is most difficult. The manifestations of this disease are manifold and complex, and firm understanding of the pathobiologic features is necessary if pathologists are to understand their role in the direction of treatment.

Female↗
PubMed1986

Long-term effect of wholemeal bread on stool weight, transit time, fecal bile acids, fats, and neutral sterols.

Stool weight, fecal constituents, bile acids, fat, neutral sterols, and intestinal transit time were recorded in 28 subjects over 18 mo. During the first 12 mo the subjects ate white bread. They were studied for an initial period of 7 days, and after 6 mo (study period 1). For the first 6 mo they ate their usual intake of bread, they then increased their white bread intake by 62 g/day for 6 mo (study period 2). The subjects ate a self-selected diet throughout the 18 mo study. During the last 6 mo (study period 3) the subjects replaced white bread by the same amount of wholemeal bread as in study period 2. No increase in stool weight occurred until study period 3 when there was an increase of 20%. There developed a linear relationship between stool weight and intestinal transit time which was not found during the initial first and second study periods. A seasonal influence on serum cholesterol was not observed during the wholemeal bread period. Fecal bile acid excretion was unchanged throughout the experiment.

Aged↗
PubMed1986

Antler cycle and thermolabile and thermostable alkaline phosphatase in white-tailed deer; circannual and circadian rhythms and variation after thyroxine, dexamethasone and ACTH administration.

The plasma levels of thermolabile (TLAP) and thermostable (TSAP) alkaline phosphatase were investigated in adult male white-tailed deer. Distinct seasonal variation of TLAP (with highly elevated levels in July) were observed, whereas TSAP exhibits low concentration with a small increase in October. No circadian rhythm was found for TLAP or TSAP. A close correlation (r = 0.98) between TLAP activity and antler weight was found. Administration of ACTH or dexamethasone were ineffective in influencing AP activity. On the other hand, variations of triiodothyronine (T3) levels in plasma induced by thyroxine (T4) injections correlated well with concentration of TLAP.

Adrenocorticotropic Hormone↗
PubMed1986

The relationship between age and genotype and the growth of commercial meat strain chickens.

Sex-linked dwarf male (dw/dw) and female (dw/-) chickens from a commercial meat strain, grew significantly slower than genetically normal broilers (Dw/Dw). The differences were evident at 2 weeks of age and they remained constant with age, at least through 8 weeks. The dwarfs in turn grew significantly faster than genetically normal (Dw/Dw) but slow-growing roaster strain chicks. Heterozygous (Dw/dw) normal, fast-growing male broilers grew significantly faster than the normal and roaster chicks but weighed 8% less than the normal broilers at 8 weeks. Abdominal fat accretion was greatest in the dwarf chicks and least in the slow-growing roaster strain when comparisons were made at the same age and the same body weight. Pectoralis muscle growth was greater in the broiler strain when equal age and weight comparisons were made. Gastrocnemius muscle growth, however, was greatest in the slow-growing roaster chicks.

Adipose Tissue↗
PubMed1986

The relationship between age and genotype and circulating concentrations of triiodothyronine (T3), thyroxine (T4), and growth hormone in commercial meat strain chickens.

The presence of the sex-linked dwarf gene (dw) in homozygous male (dw/dw) and female (dw/-) meat strain chickens is associated with a significant reduction in circulating levels of triiodothyronine (T3). Heterozygous (Dw/dw) male broiler strain chickens have T3 concentrations similar to those in homozygous (Dw/Dw) male broilers. Genetically normal (Dw/Dw) but significantly slower growing roaster strain male meat chickens had consistently higher T3 than the faster growing broilers at all ages in one experiment but only at 8 weeks in a second experiment. Age and not growth rate appears to have a greater influence on serum T3 concentrations in the slow- and fast-growing normal strains. Growth hormone levels were significantly higher in the dwarf chickens at all ages and in all three experiments. The heterozygous and homozygous broilers had similar GH levels and the slow-growing, genetically normal roasters had intermediate concentrations between the broiler and dwarf lines. GH was influenced to a greater extent by the rate of body weight gain than by increasing age in the genetically normal fast and slow growing strains.

Aging↗
PubMed1986

Growth and development of broiler breeders. 1. Effect of early plane of nutrition and growth rate.

In two experiments, male and female broiler breeders were reared on two different planes of growth as a result of early nutritional treatment. The starter treatment(s) consisted of a 19.5% crude protein, (CP), 2970 kcal diet from 0 to 14 days and 15.5% CP, 2750 kcal ration from 2 to 10 weeks. The birds in the grower treatment were fed the latter diet from 0 to 10 weeks. Both treatments were ad libitum fed from 0 to 3 weeks and then restricted to meet the breeder's recommended body weight targets. In Experiment 1, the starter treatment resulted in significantly heavier body weights at 3 weeks of age but not at later ages. The initiation of feed restriction was necessarily more severe for those chicks fed the starter diet. This restriction resulted in a significantly smaller liver at 10 weeks of age in breeder cockerels and dwarf breeder females. Vaccination titers [Newcastle, Infectious Bursal Disease (IBD),] and response to sheep red blood cells (SRBC) brachial vein injection were not affected by treatment. In a second experiment, there were no differences in bursa, spleen, or thymus weights between starter and grower treatments at 10 weeks of age, and the liver weights were again significantly larger in the grower treatment. One treatment of dwarf and normal pullets was overly restricted from 3 to 10 weeks (Grower-R), and lighter body weights were obtained at all ages. Only the spleen in the normal breeders was significantly smaller at 10 weeks of age in this treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Nutritional Physiological Phenomena↗
PubMed1986

Patterns of Schistosoma haematobium egg distribution in the human lower urinary tract. I. Noncancerous lower urinary tracts.

Schistosoma haematobium egg burdens (eggs/g of tissue) of 17 anatomic segments of lower urinary tracts from 32 unselected Egyptian autopsies have been determined by tissue digestion and replicate counts of aliquots of the digestate. There were three anatomic patterns of egg distribution in these lower urinary tracts: apical, basal and diffuse. Regression of egg burdens of each of the anatomic segments as the dependent variable against egg burdens of the entire lower urinary burden yielded a good fit for 15 of 17 of these segments. Statistical analyses revealed that many of these equations for discrete anatomic segments can be combined, generally giving one equation for anatomic regions which are in continuity, indicating that the female worm lives and oviposits in specified venous plexes. These equations also suggest that there are differences in the rates, duration and onset of egg accumulation which may be responsible for schistosomal obstructive uropathy as a cause of death in fairly young individuals.

Adolescent↗
PubMed1986

Patterns of Schistosoma haematobium egg distribution in the human lower urinary tract. II. Obstructive uropathy.

In a series of 32 unselected consecutive autopsies of Egyptian male adults, we found a significant prevalence of schistosomal obstructive uropathy (SOU) and of precursor lesions of stenosis, fibrosis and induration of the ureters (62.5%). Lower urinary tracts with obstructive uropathy had a significantly higher total egg burden (TEB) than did lower urinary tracts with any other type of gross lesion (i.e., benign prostatic hypertrophy, other urethral outlet obstruction, or SOU precursor lesions). In turn, lower urinary tracts with any type of gross change had higher egg burdens than did tracts which appeared grossly normal. Lower urinary tracts with any type of gross lesion had significantly larger seminal vesicles than did tracts which were grossly normal. Moreover, relative weight of seminal vesicles could be correlated with the S. haematobium egg burdens in the seminal vesicles. In a series of lower urinary tracts taken from unselected consecutive American autopsies, seminal vesicle weight could be correlated with increase in prostatic weight in those tracts with prostatic hypertrophy; the same correlation could not be found in tracts without prostatic hypertrophy. Thus, seminal vesicle hypertrophy appears to correlate with obstructive uropathy in general, not solely obstructive uropathy of schistosomal origin. Digital evaluation of seminal vesicle size may be useful in the clinical evaluation of such patients.

Adolescent↗
PubMed1986

Patterns of Schistosoma haematobium egg distribution in the human lower urinary tract. III. Cancerous lower urinary tracts.

The distribution of S. haematobium eggs in urinary bladders containing tumors and removed at surgery has been studied; the majority of these tumors are well differentiated squamous cell carcinomas. The same three anatomic patterns of egg accumulation described in part I of this series (noncancerous lower urinary tracts) were found in these cancerous bladders, but, in addition, most of the tumors were surrounded by a collar of heavy S. haematobium egg deposition. The egg burdens in these collars were, on the average, twice the average egg burden in the remainder of the urinary bladder. These collars do not seem to be artifacts created by growth of the tumor and subsequent displacement of the adjacent normal tissue, creating a region of heavy egg concentrations; rather, these heavy S. haematobium egg concentrations seem to act as promoters of urothelial carcinogenesis.

Adenocarcinoma↗
PubMed1986

A solution to declining autopsy rates--the Decedent Affairs Office.

Can the decline in autopsy rates be reversed by solving logistical problems that impede or deter permissions and arrangements? The authors report an increase in the autopsy rate at their institution after a Decedent Affairs Office was established. Furthermore, the time between death and autopsy has been greatly narrowed, thus providing optimal tissue for diagnosis. As an additional benefit, the number of organ donations has also risen.

Autopsy↗
PubMed1986

Drug residues in milk after intrauterine injection of oxytetracycline, lincomycin-spectinomycin, and povidone-iodine in cows with metritis.

A study was conducted to document the maximum retention times of antimicrobial residues in milk after their use in intrauterine treatment of metritis in lactating cows and to evaluate several risk factors hypothesized to influence the retention time of these drugs. Oxytetracycline (3 g), lincomycin-spectinomycin (2 g of one-third lincomycin and two-thirds spectinomycin), or povidone-iodine (6 g) were given to cows with metritis by intrauterine route. The Bacillus stearothermophilus var calidolactis disk assay was performed on each milk sample. Of the 61 cows treated with oxytetracycline, 30 had residues in their postinjection milk for variable periods (range, 12.5 to 44.0 hours; mean, 26.6 +/- 10.3). Of the 47 cows treated with lincomycin-spectinomycin, 17 had residues in their postinjection milk for various periods (range, 14.5 to 24 hours; mean, 19.5 +/- 8.9). Povidone-iodine was not detected in milk. Because a high number of cows (n = 61) were treated with oxytetracycline, only data from these cows were used in testing the influence of 3 factors (severity of metritis, time after parturition when cows with metritis were treated, and parity) on maximum retention of the drug in milk. Severity of metritis did not have a significant influence (P greater than or equal to 0.1) on the maximum retention time of the drug. The retention time decreased linearly with the increase of time after parturition when the cow with metritis was treated. First lactation cows had a significantly (P less than or equal to 0.01) shorter retention time than did older cows.

Animals↗
PubMed1985

Monocytic leukemia in infancy. A review of eight children.

The clinical and pathologic features of eight infants with monocytic leukemia are reviewed. The children were all aged 12 months or less at diagnosis and had a high incidence of extramedullary features, skin infiltration being particularly common. The diagnosis was established by conventional morphologic and cytochemical techniques. Using the French-American-British (FAB) classification, five infants had FAB 5a disease, and three had FAB 5b. The difficulties in making the diagnosis from extramedullary sites and the overlap that exists at this age between monocytic leukemia, true histiocytic lymphoma, and malignant histiocytosis are discussed. The treatments given to the group and their response are reviewed. Five of the patients received VP-16-213 and cyclophosphamide as primary induction chemotherapy, a combination that merits further evaluation in leukemia with monocytic features.

Female↗
PubMed1985

Role of intrarenal biotransformation in chloroform-induced nephrotoxicity in rats.

Various ketonic agents potentiate the hepatic and renal toxicity of halogenated solvents in mice and rats. Characteristics of CHCl3 nephrotoxicity and of 2-hexanone potentiation were evaluated in adult male Fischer 344 rats pretreated with vehicle (oil, 10 ml/kg, po) or 2-hexanone (10 mmol/kg, po) 18 hr prior to CHCl3 exposure. In contrast to the liver, little metabolism of 14CHCl3 by renal cortical microsomes from vehicle- or 2-hexanone-pretreated rats was detected. However, CHCl3 produced a concentration-related dysfunction when added to renal cortical slices from Fischer 344 or Sprague-Dawley rats. The degree of CHCl3 toxicity in vitro was not altered when renal cortical slices were preincubated with CHCl3 (8.5 microliter) under an atmosphere of carbon monoxide. In renal cortical slices, deuterated-CHCl3 was less toxic than CHCl3. Although 2-hexanone pretreatment increased renal slice metabolism of 14CHCl3 twofold, this increase was not associated with an increase in nephrotoxicity after direct exposure of slices to CHCl3 (0 to 10 microliter) in vitro. CHCl3 (0.5 ml/kg, ip) did not alter renal cortical glutathione concentrations in vehicle or 2-hexanone pretreated rats. The association of 14CHCl3-derived radiolabel was increased over control by 2-hexanone pretreatment in protein, lipid, and acid soluble fractions from the renal cortex by approximately two-, two-, and fivefold, respectively. In conclusion, renal cytochrome P-450 did not appear to mediate CHCl3 metabolism and nephrotoxicity in the rat to the extent observed previously in mice. 2-Hexanone appeared to potentiate nephrotoxicity by a mechanism different than that observed in rat liver.

Animals↗