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Biomedical subjects

J Bain

Publications and source records attributed to J Bain.

At least 91 records · Page 5Linked to original sources
PubMed1983

Efficacy of needle biopsy in postradiation thyroid disease.

Retrospective review was carried out of 124 patients with nodular disease of the thyroid gland and a history of radiation exposure who had undergone needle aspiration biopsy. Latency period from time of radiation varied from 2 to 50 years; but in 92 patients it exceeded 2 decades. Our patient group included those with occupational exposure and a past history of radiation for cancer. Incidence of cancer in the entire group was 49% but, for solitary lesions, this was increased to 56%, while only a 30% incidence of cancer was found in cases of multinodular goiters. Accuracy of needle aspiration biopsy overall was 74%: for the group with cancer--90%, for the group with adenomas--65%, and for the group with "benign" tumors--83%. Further assessment of needle technique indicated a sensitivity of 70%, specificity of 90%, positive predictive value of 90%, and negative predictive value of 83% to 65%. The accuracy could be increased to 84% if all adenomas were considered as possible malignancies. Eighteen percent of our patients had second tumors in the head and neck or breast area. Near-total thyroidectomy was considered to be the preferred procedure without accidental nerve injury and was done in one case of hypoparathyroidism after excision of an extensive tracheal invasive cancer. No evidence of death, recurrence, or metastasis as a result of thyroid cancer has been noted. While needle biopsy is indispensable to intelligent management, the history of radiation to the head and neck area must be preeminent in the selection of patients for surgical treatment. Conservative management appears to be reasonable in those patients with "benign" cytology, a less than 1 cm nodule, multinodularity, a functioning thyroid scan result, but persistence in the face of a lack of response to conservative management does not appear to be warranted.

Adenoma↗
PubMed1983

Sexual development, maturation, and behavior.

The Y chromosome directs the primitive gonad to develop into a testis. Without a Y chromosome an ovary will develop, but that ovary will not be normal unless two X chromosomes are present. Active intervention is needed for male differentiation; internal male structures will not be found unless sufficient and effective testosterone is secreted by the immature testis to develop the wolffian duct system into the internal male reproductive tract. The testis must also secrete mullerian regression factor to cause the demise of the internal female duct structures. Finally, enough 5-alpha-reductase activity must be present to convert testosterone into dihydrotestosterone for the normal virilization of the male external genitalia. Without testosterone or its receptor sites, without dihydrotestosterone, and without mullerian regression factor, the reproductive system is female. Early in life, a child assumes both a gender identity (an awareness of what sex he or she belongs to) and a gender role (behavior deemed to be more or less characteristic of one sex or the other). As puberty is passed, sexual orientation becomes more obvious, although the development of that orientation has probably been in the making since early childhood. Early developmental hormone milieu and social environment undoubtedly all play a role in subsequent sexual behavioral patterns, but the extent to which each of these impacts upon that behavior still remains unknown.

Adolescent↗
PubMed1982

Carbonic anhydrase activity in skeletal muscle fiber types, axons, spindles, and capillaries of rat soleus and extensor digitorum longus muscles.

Carbonic anhydrase (CA) activities were studied in soluble extracts and cryostat sections of skeletal muscles from prepubertal and postpubertal rats. Acetazolamide inhibition was utilized to distinguish between activities of the acetazolamide-sensitive (CA I and II) and acetazolamide-resistant (CA III) forms of the enzyme. The inhibition studies indicated that fast-twitch oxidative-glycolytic muscle fibers contained both the sensitive and resistant forms of CA. Acetazolamide-sensitive activity was localized within muscle fibers, axons, myelin, and capillaries. Axoplasmic staining was restricted to subpopulations of myelinated axons in both the dorsal and ventral roots. Soleus muscles exhibited significantly greater activity of CA III than extensor digitorum longus muscles at all ages examined. CA III was richest in slow-twitch oxidative and intrafusal fibers. During puberty, soleus muscle fibers matured and converted from fast-twitch oxidative-glycolytic to slow-twitch oxidative fibers. There was a shift from the sensitive to the resistant form of CA; CA III activity increased about sevenfold. This activity peaked earlier in the muscles of female rats than male rats. These results demonstrated a complex distribution of CA isozymes in the neuromuscular system and pointed out that isozyme content depends on both the type of muscle and the age and sex of the animal.

Acetazolamide↗
PubMed1981

Immunological control of hepatotoxicity and parasite egg excretion in Schistosoma mansoni infections: stage specificity of the reactivity of immune serum in T-cell deprived mice.

Within seven weeks of infection with 200 Schistosoma mansoni cercariae, T-cell deprived mice have been shown to suffer from extensive microvesicular damage to hepatocytes, and an inability to excrete parasite eggs at the same rate as comparably infected, immunologically intact controls. Administration of serum (CIS) from chronically infected, immunologically intact donors prevented the development of microvesicular cell damage and partially restored egg excretion rates in infected deprived mice. Serum pools obtained from mice injected either with intact S. mansoni eggs or with a homogenate of eggs emulsified in Freund's complete adjuvant (FCA) were as effective as CIS in preventing hepatotoxicity and restoring the rate of egg excretion in infected deprived recipients. The degree of protection of liver tissue afforded by immune sera could be monitored either by histopathological examination of liver sections or by estimation of serum transaminase concentrations, the results from both assays being generally in agreement. Sera from donor mice injected with cercarial or worm antigens in FCA were relatively inactive either in protecting against S. mansoni-induced liver damage or in reconstituting egg excretion rates in infected deprived mice. Serum from donor mice infected with 25 cercariae became hepato-protective between 49 and 53 days after infection of the donors, and the degree of hepatoprotective activity and egg excretion reconstituting capacity in the serum of 25 cercariae-infected donors was shown to increase between 8 and 16 weeks after infection. Increasing the size of infection of the serum donors to 100 cercariae gave only a marginal increase of hepatoprotective activity at 7 weeks when compared with serum donors infected with 25 cercariae for 7 weeks. Liver parenchymal cells of very heavily infected, immunologically intact mice were found to show microvesicular damage similar to that in livers of infected deprived mice, and administration of CIS to these normal mice was histopathologically protective. However, the elevated serum transaminase concentrations obtaining in the infected normal mice were not reduced to any extent by CIS. The results obtained from serum-reconstituted deprived mice are discussed in terms of the contribution they may make to a better understanding of the host-parasite relationship in immunologically intact mice.

Animals↗
PubMed1981

Identification and partial purification of an antigen (omega 1) from Schistosoma mansoni eggs which is putatively hepatotoxic in T-cell deprived mice.

T-cell deprived mice heavily infected with Schistosoma mansoni suffer from severe microvesicular damage to hepatocytes within seven weeks of infection. The damage can be prevented by administration of serum (CIS) obtained from mice chronically infected with S. mansoni or from mice immunized with intact or homogenized S. mansoni eggs. Reaction of serum samples from individual chronically infected mice in immunoelectrophoresis with S. mansoni egg homogenate has enabled the identification of at least 12 distinct immuno precipitation reactions. Precipitating antibody against one S. mansoni egg antigen, omega 1, has been detected in all mice with patent chronic infections, and anti-omega 1 antibody is the most concentrated of the precipitating anti-egg antibody species in pooled CIS. Pooled serum obtained from infected intact mice reacting predominantly against omega 1 was found partially to prevent the hepatotoxicity reaction on transfer to infected deprived mice. Serum samples from mice injected with egg homogenate fractionated either by preparative electrophoresis or by cation exchange chromatography, and containing antibodies reactive with antigen omega 1 in immunoprecipitation, were fully protective against liver cell damage induced by S. mansoni in deprived mice. Sera from mice immunized with other S. mansoni egg fractions, and which did not contain antibodies reactive with omega 1, were not hepatoprotective. Antigen omega 1 is compared and contrasted with other S. mansoni egg antigens that have been described.

Animals↗
PubMed1981

Spontaneous hypoglycemia associated with hemangiopericytoma of the kidney.

We report the third case of renal hemangiopericytoma associated with spontaneous hypoglycemia. The clinical and pathological features suggest that excessive glucose storage by the tumor is an important factor in the pathogenesis of the hypoglycemia. Other possible mechanisms producing hypoglycemia associated with mesenchymal tumors are reviewed.

Adult↗
PubMed1980

The pathological effects of immunosuppression of Schistosoma mansoni-infected mice, with particular reference to survival and hepatotoxicity after thymectomy and treatment with antithymocyte serum, and treatment with hydrocortisone acetate.

The effects of various immunosuppressive regimes on the survival and liver pathology of mice infected with Schistosoma mansoni were investigated. T-cell deprivation before infection (by adult thymectomy and subsequent anti-thymocyte serum administration), or treatment with hydrocortisone or cyclophosphamide or azathioprine after infection, all reduced survival of infected mice when compared with immunologically intact, infected mice. T-cell deprivation or steroids produced severe liver damage in infected mice despite a reduction in the size of the peri-oval granulomatous inflammatory reaction. Administration of chronic infection serum reduced liver damage in both T-cell-deprived and steroid-treated animals, but improved survival only in the deprived animals and not to the level seen in normal infected mice. The liver damage in immunosuppressed mice was not due to opportunistic bacterial infection. Thus, although immunosuppression reduced the granulomatous response to schistosome eggs in the livers of infected mice (as it does to eggs injected intravenously into the lungs), survival time was decreased. The relevance of these findings to human S. mansoni infections is discussed.

Animals↗
PubMed1980

The combined use of oral medroxyprogesterone acetate and methyltestosterone in a male contraceptive trial programme.

A male contraceptive trial was undertaken in 23 men using a combination of oral medroxyprogesterone acetate (MPA) and oral methyltestosterone (MeT). The men were divided into four groups according to varying drug dosages and were followed for 15 months (control - 3 months, treatment - 6 months, follow-up - 6 months). The parameters assessed included sperm count and motility, serum gonadotropins and sex steroids, and several biochemical and hematological tests. A questionnaire dealing with side-effects and changes in sexual function was administered intermittently. Although sperm count was suppressed (most dramatically at the highest drug doses, MPA 20mg,MeT 20mg), it was not suppressed to infertile levels. Sperm motility was unaltered; LH was modestly suppressed, FSH was not suppressed; testosterone was suppressed even at low doses; dihydrotestosterone responses were inconsistent. No significant biochemical abnormalities or side-effects occurred although some men experienced mild transient acne, gynecomastia and decreased testicular size. We conclude that in the doses used in this trial, the combination of MPA and MeT is not effective for male contraceptive, purposes and that higher doses may induce severe and undesirable side-effects.

Clinical Trials as Topic↗
PubMed1980

Factors affecting the acquisition of resistance against Schistosoma mansoni in the mouse. V. Reduction in the degree of resistance to reinfection after chemotherapeutic elimination of recently patent primary infections.

Effective treatment of mice with six to eight week-old patent S. mansoni infections with any one of five schistosomicidal agents (Oxamniquine, Praziquantel, potassium antimony tartrate, Niridazole and Hycanthone) resulted in a reduction in the degree of resistance to homologous challenge in the treated animals when compared with the level of resistance to reinfection observed in untreated mice with intact primary infections. Mice challenged five to six weeks after treatment with Praziquantel, Niridazole or Hycanthone demonstrated a lower level of resistance than mice challenged within 10 days of the termination of the chemotherapeutic schedules. Direct comparison of Praziquantel with potassium antimony tartrate indicated that treatment with the former drug allowed retention of a greater level of acquired resistance than the antimonial in the immediate post-treatment period. Resistance to reinfection in Hycanthone-treated mice was not restored by intravenous injection of S. mansoni eggs before challenge.

Animals↗
PubMed1980

Factors affecting the acquisition of resistance against Schistosoma mansoni in the mouse. The effect of varying the route and the number of primary infections, and the correlation between the size of the primary infection and the degree of resistance that is acquired.

Mice given primary infections of Schistosoma mansoni by percutaneous or subcutaneous routes were found to acquire a higher degree of resistance against homologous challenge after 7--8 weeks than mice infected intraperitoneally. Mice infected by the intraperitoneal route tended to have smaller worm burdens than those infected with the same number of cercariae by the other two routes and this may, in part, have contributed to the relative lack of efficacy of intraperitoneal infections in inducing resistance to re-infection. The same degree of resistance was acquired after primary percutaneous infection irrespective of whether it was administered in 3 equivalent weekly doses, or the same total number of cercariae was administered as a single infection. The same degree of resistance was also observed when a percutaneous challenge was administered on the same or a different skin site to that which received the percutaneous primary infection. The degree of resistance to re-infection acquired after a percutaneous primary infection correlated well with the size of the primary worm burden and the number of eggs in the intestine and liver, but did not correlate with the number of eggs in the lungs.

Animals↗
PubMed1980

Plasma ACTH, cortisol, LH, FSH, testosterone, and dihydrotestosterone responses to bromocriptine in normal men.

The effects of an initial oral 2.5 mg dose of bromocriptine and of a similar dose after treatment with 2.5--5 mg daily for one week on plasma concentrations of ACTH, cortisol, LH, FSH, testosterone, and dihydrotestosterone were studied in normal men. In addition to its suppressive effects on plasma concentrations of prolactin and catecholamines which have been reported previously, a single dose of bromocriptine produced small increases in plasma ACTH and cortisol. Neither a single dose of bromocriptine nor treatment for one week altered plasma concentrations of LH and FSH. Plasma concentrations of testosterone and dihydrotestosterone were not altered by a single dose of bromocriptine, but small increases in both were noted in some subjects after treatment for one week.

Adrenocorticotropic Hormone↗
PubMed1980

Serum protein concentrations during Schistosoma mansoni infection in intact and T-cell deprived mice. II. Immunoglobulin G and antibodies specific for heterologous erythrocytes.

Mice infected with from twenty to fifty Schistosoma mansoni cercariae were found to have elevated serum IgG concentrations following patency of the infection, and the parasite-induced increase in concentration of IgG was dependent on the possession by the host of an intact T-cell lymphocyte pool. Following passive transfer of hyperimmune anti-sheep erythrocyte (SRBC) antibody, there was a more rapid decrease of haemolytic and haemagglutinating antibody titres in S. mansoni-infected, immunologically intact recipients than in uninfected intact mice, and infected or uninfected T-cell deprived mice. However, primary and secondary active immunization with SRBC resulted in similar patterns of serum antibody titre increase and decay in infected and uninfected intact mice over a time course of 140 days. The number of direct and indirect haemolytic plaque-forming (PFC) cells per million spleen cells was similar in S. mansoni-infected and uninfected immunologically intact mice 6 days after either primary or secondary challenge with SRBC. It is concluded that S. mansoni-infected immunologically intact mice challenged with heterologous erythrocytes synthesize anti-erythrocyte antibody at a greater rate than similarly challenged, uninfected mice.

Animals↗
PubMed1979

Factors affecting the acquisition of resistance against Schistosoma mansoni in the mouse: III. The failure of primary infections with cercariae of one sex to induce resistance to reinfection.

Mice which were given a primary infection consisting of male or female Schistosoma mansoni cercariae alone failed to acquire the same degree of resistance against homologous challenge as did mice with a bisexual primary infection. The degree of resistance acquired by "single-sex"-infected mice was not augmented either by increasing the number of cercariae administered in the primary infection, or by increasing the interval between primary infection and challenge, or by injection of S. mansoni eggs. The results are discussed in relation to previous observations on the capacity of "single-sex" schistosome infections to induce resistance.

Animals↗
PubMed1979

Gonadal function in males treated with cyclophosphamide for nephrotic syndrome.

Analysis of semen from 16 patients treated with cyclophosphamide for nephrotic syndrome showed azoospermia in three and oligospermia in seven. Analysis was normal in the other six. Prolonged treatment, particularly with larger total dosage, was associated with a higher incidence of gonadal dysfunction. Recovery was not evident at follow-up, 2 years and 9 months to 9 years and 1 month after cessation of the therapy. Limitation of treatment with cyclophosphamide to 8 weeks/course (2.5 mg/kg/day) minimizes this side effect without greatly increasing the rate of relapse of the nephrotic syndrome in the first 2 years after therapy.

Adolescent↗
PubMed1979

Effects of bromocriptine on plasma catecholamines in normal men.

Administration of a single oral 2.5 mg dose of bromocriptine (Brc), a dopamine (DA) receptor agonist, to normal male volunteers results in comparable marked decreases in resting supine plasma concentrations of DA (decrement 2 h after drug administration was 67 +/- 5%; mean +/- SE), norepinephrine (NE; 63 +/- 3%) and epinephrine (E; 65 +/- 5%); decreases in all three plasma catecholamine (CA) concentrations were significant at p less than 0.001. This effect of Brc on plasma CAs was initiated more rapidly and was of briefer duration than the suppressive effect on serum prolactin (Prl). When Brc was administered daily for 1 week, its effect on plasma CAs had terminated within 4 h of its adninistration. A further oral dose after administration of Brc for 1 week produced identical suppressive effects on plasma CAs to those observed following the 1st dose. Brc did not prevent the incremental response of plasma DA, NE and E to standing. Also, orthostatic hypotension occurred on occasion, in spite of normal plasma CA responses to standing. Brc did not affect basal serum concentrations of luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone or dihydrotestosterone. These data describing a suppressive effect of Brc on plasma DA, NE and E suggest that Brc inhibits release of these CAs from peripheral sympathetic nerve endings and adrenal medulla, and acts at least in part through presynaptic CA receptors in the brain. The suppressive effect of Brc on plasma CAs may prove useful as a test of normal presynaptic CA mechanisms.

Adult↗
PubMed1979

Relationship of seminal plasma testosterone and dihydrotestosterone to sperm count and motility in man.

A radioimmunoassay previously described for serum T and DHT was adapted for use in the measurement of these hormones in seminal plasma. The seminal plasmas of 273 semen specimens were assayed for T and DHT concentration. Mean levels of these hormones for various sperm count and sperm motility categories were determined. We found that: (1) the DHT level of the azoospermic group was significantly lower than all other groups; (2) the T level of the group whose mean sperm count exceeded 40 x 10(6)/ml was higher than that of all other groups; (3) the DHT level of the group with absent sperm motility was lower than the level of all other groups; and (4) changes in sperm motility were not accompanied by changes in T levels. We concluded that idiopathic male subfertility as evidenced by oligospermia, azoospermia, and decreased sperm motility may be related to insufficient androgen production due to a primary intratesticular defect.

Cell Count↗