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Biomedical subjects

J A Collins

Publications and source records attributed to J A Collins.

At least 91 records · Page 5Linked to original sources
PubMed1985

Effects of dexamethasone, progesterone, and testosterone on IOP and GAGs in the rabbit eye.

The effects of steroids on intraocular pressure and on aqueous outflow pathway (AOP) and adjacent anterior segment tissue glycosaminoglycans (GAGs) were studied in New Zealand Red rabbits treated for 4 wk with dexamethasone, hydroxymethyl-progesterone and methyl-testosterone. Only topical administration of dexamethasone resulted in a significant increase in intraocular pressure. The eyes were labeled in vitro for 1 hr with GAG precursors, [3H]-glucosamine and [35S]-sulfate, and maintained as whole organ cultures. The GAGs were biochemically isolated, fractionated by gel filtration chromatography and subjected to selective GAG degradative procedures. The total content of hyaluronic acid and chondroitin sulfate was analyzed by high performance liquid chromatography. In dexamethasone-treated eyes, the total content of hyaluronic acid was decreased in the AOP, although the specific activity of [3H]-glucosamine did not change. The total content of chondroitin sulfate was increased in the AOP and iris-ciliary body, while the specific activity of the [35S]-label was decreased in the AOP, iris-ciliary body, and sclera. The changes in the AOP GAGs in dexamethasone-treated eyes may be important factors for the development of dexamethasone-induced ocular hypertension in the rabbit.

Animals↗
PubMed1984

A proportional hazards analysis of the clinical characteristics of infertile couples.

Evaluated were methods of ordering the many possible predictors of infertility outcome. The clinical characteristics of infertile couples were studied with respect to the occurrence of pregnancy during follow-up, by means of the methods of survival analysis. Among 1,297 couples who were infertile for 12 months or more, the cumulative pregnancy rate at 36 months with 95% confidence limits was 49% +/- 4%. The proportional hazards analysis identified three independent predictors of the occurrence of pregnancy from the couple's history (with P values in brackets): a history of pregnancy in the partnership (0.0001); shorter duration of infertility (0.0001); and shorter length of marriage (0.005). The predictors arising from the diagnostic process (with P values in brackets) were: fewer infertility diagnoses (0.0001); a favorable primary clinical diagnosis (0.001); and the presence of any tubal disease, regardless of the primary clinical diagnosis (0.001). The analysis selected an economical set of significant predictor variables and demonstrated that a longer period of contraception was associated with a lower pregnancy rate among infertile couples. Also, three simple questions from the history were nearly equivalent to the entire diagnostic process as predictors of the outcome.

Adult↗
PubMed1984

Clinical factors affecting pregnancy rates among infertile couples.

In a follow-up study of 1297 couples registered at a Nova Scotia infertility clinic with a complaint of infertility of at least 12 months' duration, the cumulative pregnancy rate at 36 months, with 95% confidence limits, was found to be 49 +/- 4%. The predictors of pregnancy by univariate analysis were a favourable primary clinical diagnosis (p less than 0.001), a duration of infertility of less than 3 years (p less than 0.001), a single diagnosis for the infertility (p less than 0.001), a previous pregnancy in the partnership (p = 0.001) and a length of marriage of less than 4 years (p = 0.002). Proportional hazards analysis confirmed these variables as predictors of pregnancy. The highest cumulative pregnancy rates after 12 and 36 months of follow-up were observed in cases of ovulation deficiency, and the lowest were seen in cases of tubal defects. However, before the process of diagnosing infertility begins, useful prognostic information can be determined from the length of marriage, the duration of infertility and the partnership's history of previous pregnancy.

Adult↗
PubMed1984

Microbiological and histological findings in the fallopian tubes of women using various contraceptive methods.

The oviducts of seventy-three women undergoing sterilization by partial salpingectomy were submitted for microbiological and histologic studies. Twenty women were intrauterine device users, twenty-five women were oral contraceptive pill users and twenty-eight women used natural or barrier methods of contraception. Among intrauterine device users, there was an excess of mild and severe acute inflammatory histologic changes involving both the lumen and the tubal mucosa. Five of the eight intrauterine device users with acute inflammatory change had sterile tubal cultures.

Bacteriological Techniques↗
PubMed1984

Hypersensitivity reaction to doxorubicin.

A 42-year-old woman with synovial sarcoma developed a skin flare during doxorubicin therapy. With a subsequent dose, erythema, urticaria, and asthma occurred, despite pretreatment with antihistamines. Skin flares occur in about three percent of patients receiving doxorubicin. Rarely, generalized urticaria, angioneurotic edema, or anaphylaxis occur. Local reactions may represent molecular extravasation through vessels, or histamine release from mast cells or basophils. Generalized reactions may involve alternative complement-activation pathways. Pretreatment with antihistamines or corticosteroids sometimes is helpful in preventing recurrences.

Adult↗
PubMed1984

The postcoital test as a predictor of pregnancy among 355 infertile couples.

Late follicular phase postcoital tests in 355 infertile couples (selected to exclude severe defects in ovulation, seminal or tubal function) were scored for mucus characteristics and sperm motility. Cervical mucus characteristics were associated with postcoital sperm motility (P less than 0.001) but not with pregnancy. Postcoital sperm motility in cervical mucus was strongly associated with total motile sperm count per ejaculate (F = 5.38, P less than 0.001). Postcoital sperm motility was a weak predictor of pregnancy when more than five motile sperm were observed per high power microscopic field. When the log rank tests for postcoital sperm motility were repeated in groups with low (less than 10 million) and high (10 million or more) total motile sperm count per ejaculate, the association between postcoital sperm motility and pregnancy was not statistically significant. Regression analysis controlling for other potential predictors revealed no independent association between postcoital sperm motility and the later occurrence of pregnancy in this group of infertile couples.

Adult↗
PubMed1983

Treatment-independent pregnancy among infertile couples.

We analyzed a two- to seven-year follow-up of 1145 infertile couples to determine the frequency of pregnancy occurring independently of treatment. Pregnancy occurred in 246 of 597 treated couples (41 per cent) and in 191 of 548 untreated couples (35 per cent). Thirty-one per cent of the pregnancies in treated couples occurred more than 3 months after the last medical treatment or more than 12 months after adnexal surgery. These pregnancies plus the 191 pregnancies in untreated couples constituted the category of "treatment-independent pregnancies" and accounted for 61 per cent of all pregnancies; for 44 per cent of those among couples with ovulation deficiency; for 61 per cent of those in couples with endometriosis, tubal defects, or seminal deficiencies; and for 96 per cent of those in couples with cervical factors or idiopathic infertility. We conclude that the potential for a spontaneous cure of infertility is high, that treatment for many classes of infertility should be evaluated by randomized clinical trials, and that in such trials random assignment of subjects to untreated control groups would be ethically acceptable.

Counseling↗
PubMed1983

Spontaneous hepatic hemorrhage during pregnancy.

Spontaneous rupture of the liver during pregnancy seems to represent an extreme vascular complication of toxemia. The very high mortality rate has generally been attributable to uncontrolled hemorrhage. However, control of the hemorrhage may not be sufficient to achieve recovery. Hepatic dysfunction may proceed to necrosis associated with multiple organ failure, even after successful hemostasis. Although ligation of the hepatic artery has been successful in controlling hemorrhage in hepatic trauma, this maneuver may contribute to injury in patients with this lesion in whom there is a preexisting hepatic abnormality. In this brief review, the relationship of the underlying pathology to a variety of therapeutic measures in the context of a catastrophic complication of pregnancy are discussed.

Adult↗
PubMed1983

Age-related changes in the cerebrospinal fluid outflow glycosaminoglycans.

The glycosaminoglycan distribution patterns of the cerebrospinal fluid (CSF) outflow pathway, dura mater and cerebral cortex of young New Zealand red rabbits and 1-, 3- and 12-week-old C-57 mice were identified by analyses of the glycosaminoglycan moieties and by the use of zone electrophoresis. The glycosaminoglycans were identified by specific degradation procedures, i.e., hyaluronate lyase, chondroitin ABC lyase, endo-beta-D-galactosidase and nitrous acid treatment. The CSF outflow pathway and dura mater glycosaminoglycan components were primarily hyaluronic acid and chondroitin sulfate-dermatan sulfate, whereas the cerebral cortex glycosaminoglycan components were hyaluronic acid, chondroitin sulfate-dermatan sulfate, keratan sulfate and heparan sulfate. The glycosaminoglycan components of the dura mater and cerebral cortex decreased and those of the CSF outflow pathway increased as a function of age. These results demonstrate the feasibility of analyses of the CSF outflow pathway glycosaminoglycan components and suggest that topographical changes in the glycosaminoglycan distribution profiles may contribute to the pattern of cerebrospinal fluid outflow.

Age Factors↗
PubMed1983

Use of plasma volume substitutes and plasma in developing countries.

Plasma and plasma substitutes are used in the treatment of various conditions such as haemorrhage and shock. This article examines the role of crystalloids, artificial colloids, human plasma, human albumin, and plasma protein fraction, in the treatment of such patients, with particular reference to peripheral health facilities in developing countries.It is concluded that 0.9% saline, together with 5-6% dextrose, is of particular importance in this situation since it is easy to produce locally, is stable at high temperatures, and has a low cost/benefit ratio. The second priority is to ensure the availability of a limited quantity of one or more colloid plasma substitutes. In the field of plasma, fresh frozen or fresh liquid plasma is most useful for the treatment of various haemostatic derangements and follow-up treatment of severe burns, since it contains the widest spectrum of therapeutically useful components and can be produced locally with an acceptable degree of difficulty.The treatment of severe diarrhoea with special alkaline electrolyte solutions and oral rehydration solutions is also outlined.

Burns↗
PubMed1983

Aqueous outflow pathway complex carbohydrate synthesis in vitro.

A technique is described for examining the in vitro synthesis of glycosaminoglycans and glycoproteins in the aqueous outflow pathway (AOP). New Zealand red rabbit eyes were maintained at near-physiologic conditions and were infused by anterior chamber exchange with 30 muCi [3H] glucosamine and 100 muCi [35S] sulfate. At 0.5, 1.0, and 2.0 hours, the anterior segment tissues were dissected, isolated, and fractionated by gel filtration chromatography on Sephadex G-50 columns. The elution profiles demonstrated an increase of labeled material with time in the glycosaminoglycan (GAG) fractions and in the glycopeptide fractions. The relative rate of synthesis of labeled material was: central cornea greater than peripheral cornea greater than iris-ciliary body greater than AOP greater than anterior sclera. In order to characterize the profiles of each tissue, the isolated material was analyzed for hexosamine, hexuronic acid, and sulfate. The AOP cells synthesized a heterogenous mixture of GAGs and glycoproteins which biochemically appeared to be distinct from other anterior segment tissues. In addition, the percent distribution of GAG polymers in each tissue was determined by selective GAG degradative procedures and by gel filtration chromatography. The AOP cells synthesized four types of GAGs, and the percent distribution of the labeled GAGs was different from the other tissues. The present results suggest that this technique may provide a well-controlled method to probe the metabolic activity of complex carbohydrates in the AOP and in the anterior segment.

Animals↗
PubMed1982

The pathophysiology of hemorrhagic shock.

It is difficult to summarize such a complex series of problems. Both the pathophysiology of hemorrhage and the details of its treatment are far from being fully defined in spite of the inherent simplicity of the challenge involved. The questions how much, what kind, and when still apply to such fundamental issues as the fluids given for resuscitation, red cells necessary for extensive hemorrhage and the hemostatic components. We are not clear as to what, if anything, can be done to improve antibacterial and antimicrobial defense mechanisms after a major hemorrhage. There are tantalizing leads as to specific measures that can be taken to prevent other potential complications but some maneuvers that may minimize the change for one complication may worsen the chance for others. We must, of course, continue to strive to try to reduce the complications of treatment itself, which are probably small but still significant. There is certainly much yet to be learned in both the fundamental and practical spheres.

Acidosis↗