Characterization and hemodynamic implications of renal vascular angiotensin II receptors in SHR

The intrarenal renin-angiotensin system (RAS) contributes to the increased renal vascular resistance and reactivity observed in spontaneously hypertensive rats (SHR) and to the pathogenesis of high blood pressure (BP). Thus, we decided to characterize angiotensin II (ANG II) receptors in the renal arteries and glomeruli of 16-week-old SHR and their age-matched, normotensive Wistar-Kyoto (WKY) controls. SHR had significantly higher BP (153 +/- 4 v 96 +/- 10 mmHg) and heart weight (440 +/- 5 v 327 +/- 4 g/100 g body weight) than WKY rats. There was no difference in plasma renin activity between strains. Radioligand binding assays using non-peptide antagonists for AT1 (losartan) and AT2 (PD 123319) showed that renal preglomerular microvessels and glomeruli expressed a single receptor population (AT1) for ANG II. AT1 density tended to be lower in glomeruli of SHR compared to WKY (377 +/- 45 v 555 +/- 74 fmol/mg protein), but was significantly higher in preglomerular vessels (93 +/- 7 v 57 +/- 1 fmol/mg protein). No difference in receptor affinity was found in either preparation. Isolated kidney perfusion revealed that at low flow (3-10 ml/min), perfusion pressure was similar in both strains; however, at higher flow levels, SHR showed higher reactivity and less compliance than their controls. In addition, SHR presented a higher renal vascular reactivity to ANG II (but not to arterenol) than WKY rats. Thus, upregulation of ANG II receptors in the renal vasculature may mediate the hyperreactivity to ANG II observed in SHR kidney.

Modulation of Ca2+ and Na+ transport by taurine in heart and vascular smooth muscle

Using the whole-cell voltage clamp technique, taurine was found to affect different types of various ionic currents including T and L-type Ca2+ currents, slow Na+ and fast Na+ currents as well as the delayed outward K+ current. Also, in normal situations, taurine had no effect on the Na(+)-Ca2+ exchange current. The effect of taurine on the different types of ionic currents appears to depend on [Ca2+]o and [Ca2+]i and may also vary according to the tissue or cell type studied. Using standard Ca2+ imaging techniques, short-term exposure (10 to 20 min) of single heart cells and aortic vascular smooth muscle cells was found to increase total intracellular free Ca2+ in a dose-dependent manner. However, using 3-dimensional Ca2+ and Na+ imaging techniques, long-term exposure of heart and vascular smooth muscle cells to taurine was found to decrease both nuclear and cytosolic Ca2+ without significantly changing either nuclear or cytosolic Na+ levels. Long-term exposure to taurine was found to prevent cytosolic and nuclear increases of Ca2+ induced by permanent depolarization of heart cells with high [K+]o. This preventive effect of taurine on nuclear Ca2+ overload was associated with an increase of both cytosolic and nuclear free Na+. Thus, the effect of long-term exposure to taurine on intranuclear Ca2+ overload in heart cells seems to be mediated via stimulation of sarcolemma and nuclear Ca2+ outflow through the Na(+)-Ca2+ exchanger.

Multidrug drug resistance in pediatric sarcomas

PURPOSE

Although P-glycoprotein overexpression is an important cause of multidrug resistance in vitro, whether this resistance mechanism is equally applicable to the clinic has still to be fully established. This review has examined the immunohistochemical and molecular biologic tools used to evaluate soft tissue sarcomas of children and adults, in order to determine whether P-glycoprotein can limit the efficacy of chemotherapy.

DESIGN

Because soft tissue sarcomas are successfully treated by cytotoxic substrates of P-glycoprotein in many, but not all children, these tumors may be useful models for determining whether this drug efflux transporter is a clinically relevant cause of chemoresistance.

RESULTS

Certain studies of acute myelogenous leukemia, lymphoma, and myeloma in adults and rhabdomyosarcoma, neuroblastoma, and acute lymphoblastic leukemia in children have provided the best current evidence for a strong corelation between the expression of P-glycoprotein and outcome of chemotherapy. Based on these observations, several clinical trials have been initiated to determine whether pharmacologic chemosensitization improves chemotherapy responses and cure rates in P-glycoprotein-expressing malignancies. Thus, early identification of lower levels of P-glycoprotein in tumors that still might respond to chemosensitizer-modulated chemotherapy may be highly pertinent to conducting more informative multidrug resistance reversal trials.

CONCLUSION

The question of whether the multidrug resistance P-glycoprotein is a clinically relevant cause of chemoresistance may ultimately be answered by the successful prevention of chemotherapy failure by chemosensitizers that specifically reverse this drug efflux mechanism.

Multidrug resistance in pediatric malignancies

PURPOSE

Increased expression of P-glycoprotein is an important cause of multidrug resistance in tumor cell lines in vitro. Whether this mechanism is equally relevant as a cause of clinical chemoresistance has not been established and is currently being investigated. This review has examined the immunohistochemical and molecular biologic tools suitable for assessing P-glycoprotein expression in patient samples and methodologic issues important for evaluating the results of clinical studies. Current evidence that supports a role for P-glycoprotein in limiting the efficacy of cancer chemotherapy has been reviewed.

DESIGN

Malignancies that have been successfully treated by chemotherapeutic substrates of P-glycoprotein, in which a proportion of patients still fail therapy, may be the most useful models for determining whether this drug efflux transporter is a clinically relevant cause of chemoresistance.

RESULTS

Studies of acute myelogenous leukemia, lymphoma, and myeloma in adults have so far provided the best evidence for a relevant role for P-glycoprotein as a cause of clinical multidrug resistance. A similar strong association has been observed between the expression of P-glycoprotein and outcome of treatment in certain malignancies in children, such as neuroblastoma, rhabdomyosarcoma, and acute lymphoblastic leukemia. Some apparent controversies related to this issue of clinical relevance may be explained by the differences in P-glycoprotein detection techniques, methodology, and experimental designs used in different studies. Because several clinical trials have already been initiated to determine whether pharmacologic chemosensitization improves the outcome of chemotherapy in certain malignancies, the successful verification of multidrug resistance limiting the cure rates of these tumors becomes a more critical issue, and identification of those patients with lower levels of P-glycoprotein expression early in the course of their disease, when they are most likely to benefit from multidrug resistance reversal, has assumed an even greater relevance.

CONCLUSION

The clinical relevance of the multidrug resistance P-glycoprotein may ultimately be confirmed by the successful prevention of chemotherapy failure by chemosensitizers that specifically reverse this drug efflux mechanism.

Severe symptomatic osteopenia in a man with pigmented micronodular adrenal hyperplasia

The authors describe the unusual case of a 52-year-old man with Cushing's syndrome caused by bilateral pigmented micronodular adrenal hyperplasia. The only features of hypercortisolism were hypertension and severe symptomatic osteopenia with vertebral, rib, and scapular fractures. Four years after bilateral adrenalectomy, the bone density had increased slightly, but the patient remained osteopenic and continued to have vertebral compression fractures. This case report emphasizes the importance of an indepth search for secondary causes of osteoporosis, including evaluation of adrenal function in patients who have unexplained osteoporosis. Early diagnosis and treatment is imperative to prevent severe bone loss and associated skeletal morbidity.

Regulation of slow calcium channels of myocardial cells and vascular smooth muscle cells by cyclic nucleotides and phosphorylation

The slow Ca2+ channels (L-type) of the heart are stimulated by cAMP. Elevation of cAMP produces a very rapid increase in number of slow channels available for voltage activation during excitation. The probability of a Ca2+ channel opening and the mean open time of the channel are increased. Therefore, any agent that increases the cAMP level of the myocardial cell will tend to potentiate ICa, Ca2+ influx, and contraction. The action of cAMP is mediated by PK-A and phosphorylation of the slow Ca2+ channel protein or an associated regulatory protein (stimulatory type). The myocardial slow Ca2+ channels are also regulated by cGMP, in a manner that is opposite or antagonistic to that of cAMP. We have demonstrated this at both the macroscopic level (whole-cell voltage clamp) and the single-channel level. The effect of cGMP is mediated by PK-G and phosphorylation of a protein, as for example, a regulatory protein (inhibitory-type) associated with the Ca2+ channel. Introduction of PK-G intracellularly causes a relatively rapid inhibition of ICa(L) in both chick and rat heart cells. Such inhibition occurs for both the basal and stimulated ICa(L). In addition, the cGMP/PK-G system was reported to stimulate a phosphatase that dephosphorylates the Ca2+ channel. In addition to the slower indirect pathway--exerted via cAMP/PK-A--there is a faster more-direct pathway for ICa(L) stimulation by the beta-adrenergic receptor. This latter pathway involves direct modulation of the channel activity by the alpha subunit (alpha s*) of the Gs-protein. In vascular smooth muscle cells the two pathways (direct and indirect) also appear to be present, although the indirect pathway produces inhibition of ICa(L). PK-C and calmodulin-PK also may play roles in regulation of the myocardial slow Ca2+ channels. Both of these protein kinases stimulate the activity of these channels. Thus, it appears that the slow Ca2+ channel is a complex structure, including perhaps several associated regulatory proteins, which can be regulated by a number of factors intrinsic and extrinsic to the cell, and thereby control can be exercised over the force of contraction of the heart.

Expression of activin/inhibin subunit messenger ribonucleic acids by gonadotroph adenomas

As an initial step in determining whether activin could play a role in the development of gonadotroph adenomas, we attempted to determine if activin/inhibin subunit messenger ribonucleic acids (mRNAs) are expressed by these pituitary tumors. We selected 19 pituitary adenomas that had been excised by transsphenoidal surgery and determined by immunocytochemical criteria to be gonadotroph adenomas. Total RNA was extracted from these adenomas and reverse transcribed. The resulting pit-1 complementary DNA, expected to be present only in somatotroph, lactotroph, and thyrotroph cells, was amplified by the polymerase chain reaction to test the possibility that the adenoma tissue was contaminated by normal pituitary tissue. Only the 10 adenomas that did not express pit-1 mRNA were subjected to further analysis by polymerase chain reaction amplification of the adenoma reverse transcriptase products for the activin/inhibin beta B-, beta A-. and alpha-subunits. All 10 adenomas expressed beta B-subunit, none of the 10 expressed the beta A-subunit, and 6 of the 10 expressed the alpha-subunit. We conclude that gonadotroph adenomas express mRNAs for activin/inhibin beta B- and alpha-subunits. The relationship of beta B expression to the pathogenesis of gonadotroph adenomas remains to be determined.

A sensitive multilayer immunoalkaline phosphatase method for detection of P-glycoprotein in leukemic and tumor cells in the bone marrow

BACKGROUND

Relatively low levels of the multidrug resistance P-glycoprotein have correlated with poor prognosis in rhabdomyosarcoma, neuroblastoma, acute myelogenous leukemia, lymphoma, myeloma and breast carcinoma. A sensitive, nonradioactive method, less costly and time-consuming than the present molecular biologic techniques, is desirable for direct measurement of P-glycoprotein in tumor cells versus normal cells.

EXPERIMENTAL DESIGN

We have devised an immunoalkaline phosphatase method using four antibody layers to amplify the primary signal considerably and refined staining conditions to optimize the 'signal-to-noise' ratio. Immunoalkaline phosphatase is preferred to immunoperoxidase for testing leukemic and tumor cells in bone marrow, because it avoids myeloperoxidase staining in myeloblasts and myeloid progenitors that interferes with P-glycoprotein interpretation.

RESULTS

Multilayer immunoalkaline phosphatase detected low levels of P-glycoprotein overexpression, that could not be identified by conventional immunoperoxidase or immunoblot, in a low-resistance (8-fold) cell line with a barely detectable transcript. Our technique also detected increased P-glycoprotein in malignant cells in bone marrow of relapsed acute lymphoblastic leukemia (10/11), acute myelogenous leukemia (2/2), lymphoma (1/1), neuroblastoma (7/7), and rhabdomyosarcoma (2/2). Increased P-glycoprotein was not identified at diagnosis in 6 patients with acute lymphoblastic leukemia, and two with stage IV and three with stage IVS neuroblastoma that remained relapse-free in the long-term, but was detected in 4 patients with stage IV neuroblastoma and three with rhabdomyosarcoma who ultimately relapsed.

CONCLUSIONS

Our new technique is more sensitive than conventional immunoperoxidase and immunoblot for assaying P-glycoprotein in low-resistance cell lines. It may be potentially applicable for detecting low levels of P-glycoprotein overexpression in leukemic and tumor cells in bone marrow. Early identification of low levels of multidrug resistance may be clinically relevant by allowing poor-prognostic patients to receive alternative therapy.

Multidrug resistance. Clinical opportunities in diagnosis and circumvention

Increased P-glycoprotein expression has been shown to be the molecular cause of multidrug resistance in tumor cell lines. Sensitive immunohistochemical and molecular biologic techniques have been developed to detect P-glycoprotein/mdr1 mRNA expression in clinical samples of tumors. We have reviewed the tools now available for assessment of P-glycoprotein expression in the clinic, the current evidence for a relevant role of the protein in mediation of resistance to chemotherapy, and one strategy used to overcome therapeutic failures due to multidrug resistance. It is now recognized that low levels of increased P-glycoprotein/mdr1 mRNA can occur at diagnosis and during the course of treatment in some cases of acute myelogenous leukemia, non-Hodgkin's lymphoma, multiple myeloma, breast carcinoma, rhabdomyosarcoma and undifferentiated sarcoma of children, neuroblastoma, and retinoblastoma, and these relatively low levels of mdr1 overexpression appear to be associated with poor prognosis. In contrast, it has not been established whether a multidrug resistance mechanism is the rate-limiting factor in response to chemotherapy in carcinomas that arise from tissues normally expressing increased P-glycoprotein. Clinical trials have been initiated to determine whether pharmacologic chemosensitization improves the outcome of chemotherapy-treated malignancies. Preliminary results suggest that chemosensitizers can modulate the effects of increased P-glycoprotein in low-expressing tumors for which effective multiagent chemotherapy is available. Further research is needed for more potent chemosensitizers or combinations of agents that can be used more effectively. The successful circumvention of chemotherapy failure by chemosensitizers will ultimately establish the clinical relevance of the P-glycoprotein efflux mechanism.

Cerebral hemorrhage from amyloid angiopathy and coronary thrombolysis

Coronary thrombolysis with streptokinase or tissue plasminogen activator is useful for the treatment of acute myocardial infarction in selected patients. This treatment is associated with local hemorrhagic complications and age-related cerebral hemorrhage. Coronary thrombolysis is contraindicated in patients with transient cerebral ischemia and stroke, arterial hypertension, cerebral trauma, cerebral aneurysms, and arteriovenous malformations, because of the risk of cerebral hemorrhage. We report the occurrence of a cerebral hemorrhage related to cerebral amyloid angiopathy in a patient who underwent thrombolysis and treatment with heparin for acute myocardial infarction. Despite normal coagulation parameters, the cerebral hematoma enlarged over 36 hours, as documented by sequential computed tomographic scans, to produce significant mass effect, which prompted surgical evacuation. Histological examination of the resected specimen demonstrated the strong affinity for Congo red and yellow-green birefringence that are characteristic of cerebral amyloid angiopathy. Hemostasis was difficult to achieve, as the divided or disrupted amyloid-laden cortical vessels failed to vasoconstrict, their contractile elements replaced by amyloid beta protein. The patient died of recurrent myocardial ischemia 3 days postoperatively. The incidence of cerebral amyloid angiopathy increases with advancing age. It must be considered as a potential source of cerebral hemorrhage in elderly patients undergoing thrombolysis for cardiac ischemia. Such an occurrence presents a difficult challenge because cardiac function is compromised, the coagulation profile may be altered, the cerebral hematoma is life threatening, and intracranial hemostasis is difficult to achieve.

P-glycoprotein expression as a predictor of the outcome of therapy for neuroblastoma

BACKGROUND AND METHODS

Multidrug resistance in chemotherapy for cancer is characterized by increased genetic expression of P-glycoprotein, which acts as an ATP-dependent drug-efflux pump. To determine whether P-glycoprotein levels are of prognostic value in such cases, we measured these levels immunohistochemically in a retrospective study of sequential tumor samples from 67 children with neuroblastoma.

RESULTS

P-glycoprotein was not detected in pretreatment samples from either of the 2 patients with Stage I disease, any of the 21 with Stage II disease, or any of the 8 with Stage IVS disease, but it was detected in the samples from 1 of the 17 patients with Stage III disease (6 percent) and 12 of the 19 with Stage IV disease (63 percent). Of the 44 patients with nonlocalized neuroblastoma (Stage III, IVS, or IV), 26 of the 31 who were negative for P-glycoprotein had a complete response to primary treatment, as compared with 6 of the 13 who were positive for P-glycoprotein (84 percent vs. 46 percent, P = 0.0232 by Fisher's exact test). Log-rank analysis of outcome, with simultaneous stratification according to tumor stage and age, showed that the group that was negative for P-glycoprotein had significantly longer relapse-free survival (P = 0.0011) and overall survival (P = 0.0373) than the group that was positive.

CONCLUSIONS

Expression of P-glycoprotein before treatment may predict the success or failure of therapy for nonlocalized neuroblastoma. Neuroblastoma may be a promising tumor to treat with anticancer drug therapy combined with a chemosensitizing agent capable of reversing P-glycoprotein-mediated multidrug resistance.

Multidrug-resistant phenotype in retinoblastoma correlates with P-glycoprotein expression

Chemotherapy plays an important role in therapy for patients with extraocular and metastatic retinoblastoma. The authors used chemotherapy for management of selected patients with uncontrolled intraocular tumors or tumors larger and more posteriorly located than those conventionally treated with local cryotherapy or photocoagulation. Rapid regrowth of some tumors after an initial excellent chemotherapy response led us to investigate the hypothesis that failure of treatment is caused by P-glycoprotein-related multidrug resistance. By using a sensitive immunoperoxidase method, increased P-glycoprotein was detected in five multidrug-resistant and two selectively plant alkaloid-resistant retinoblastoma cell lines and in the intraocular and metastatic tumors from which they were derived. In four chemotherapy-treated cases, increased P-glycoprotein in the tumor samples correlated with clinically relevant drug resistance. None of the four chemosensitive tumor cell lines had increased P-glycoprotein expression. Continuous surveillance of P-glycoprotein levels in metastatic retinoblastoma may be a useful guide to drug therapy.

Immunohistochemical detection of P-glycoprotein: prognostic correlation in soft tissue sarcoma of childhood

Increased expression of P-glycoprotein is associated with multidrug resistance (MDR) in many cell lines. Significant levels of P-glycoprotein have been detected in a number of human tumors. The purpose of this study was to determine whether P-glycoprotein expression correlates with both response to chemotherapy and prognosis in soft tissue sarcoma of childhood. In a retrospective study, biopsy samples from 30 cases of rhabdomyosarcoma (RMS) and undifferentiated sarcoma (US) treated at The Hospital for Sick Children in Toronto were analyzed using a semiquantitative immunohistochemical procedure. P-glycoprotein was detected in nine patients, four at diagnosis, and five at subsequent biopsy. All nine patients relapsed after a clinical response (complete [CR] 55%, partial [PR] 45%) to chemotherapy. Twenty of 21 patients with consistently P-glycoprotein-negative tumors received chemotherapy and they all responded clinically (CR 80%, PR 20%). Only one of these 20 patients has relapsed. The probability of relapse-free survival was significantly different (P less than .000000012) in chemotherapy-treated patients whose tumors contained detectable levels of P-glycoprotein (n = 9), compared with those whose tumors contained no detectable P-glycoprotein (n = 20). The overall probability of survival was also significantly different in these two groups (P less than .0000267). Both relapse-free and overall survivals remained statistically different in the two groups of patients when analyzed by the log-rank method, after adjustment for differences in stages and sites. The incidence of other adverse prognostic factors in the two groups, for example, younger and older ages, low pretreatment lymphocyte counts, large tumors, and unfavorable histology were not significantly different. Thus, detectable P-glycoprotein appears to be an important adverse prognostic factor in children with soft tissue sarcoma, and consistent absence of the protein is associated with a favorable prognosis.

Campylobacter pylori and duodenal ulcers: the gastrin link

The possibility that Campylobacter pylori (CP) in the gastric antrum stimulates gastrin release in duodenal ulcer (DU) disease was examined in 31 patients. The 25 patients with antral colonisation with CP had higher basal and meal-stimulated plasma gastrin concentrations, and higher peak acid output (PAO), than did the 6 without CP in the autumn.

[Q fever infectious endocarditis. Apropos of a new case]

We report a case of Coxiella burnetii endocarditis in a 42-year old man presenting with a long-known cardiac murmur and an infectious syndrome of several months duration. The aetiological diagnosis, delayed by the lack of knowledge of a primary Q fever, was established by serology. The infection responded to tetracycline combined with cotrimoxazole, but a valve replacement performed for haemodynamic reasons was followed by serious complications. We remind the readers that Q fever endocarditis must be considered as a possible diagnosis in all cases of endocarditis with negative blood cultures and that specific serological examinations in search of anti-phase I antibodies of the IgA type should be performed as soon as possible, using the indirect immunofluorescence technique. Attention is drawn to the different serological responses of the three clinical types of Q fever infection and to the cellular immunity associated with that disease.

A sensitive method for immunocytochemical detection of P-glycoprotein in multidrug-resistant human ovarian carcinoma cell lines

P-glycoprotein, a molecular weight 170 kilodalton membrane component can be accurately detected in a series of human ovarian carcinoma cells with increasing degrees of multidrug resistance by using a modified immunoperoxidase "sandwich" method. Drug-resistant derivatives were selected from a drug-sensitive parent ovarian carcinoma cell line, SKOV3, by continuous exposure to increasing concentrations of the cytotoxic drug vincristine. These cells had corresponding overexpression of P-glycoprotein demonstrable at both protein and mRNA levels. Monoclonal antibodies against P-glycoprotein localized staining for P-glycoprotein to the plasma membrane and the Golgi region in individual drug-resistant cells, in proportion to their P-glycoprotein expression. P-glycoprotein was not demonstrable in drug-sensitive SKOV3 cells by either immunoblotting or immunocytochemical staining methods. The immunocytochemical staining method allowed detection of P-glycoprotein in the least drug-resistant cell line with as low as 8-fold relative resistance to vincristine. This method is as sensitive as Northern blot, and more sensitive than standard Western blot in detection of P-glycoprotein. We conclude that this highly sensitive immunocytochemical staining method for P-glycoprotein can be suitable for determination of P-glycoprotein expression in biopsy samples of tumors, and it can be a powerful diagnostic and prognostic tool in the study of the natural history of drug resistance. This may have important applications in the clinical management of cancer chemotherapy.

The regulatory role of NZB T lymphocytes in the production of anti-DNA antibodies in vitro

Murine lupus is characterized by the production of numerous autoantibodies and immune complex glomerulonephritis. Anti-DNA antibodies are the hallmark of this disorder and may be associated pathogenetically with the glomerulonephritis. The cellular mechanisms underlying the regulation of the production of anti-DNA antibodies may prove to be the fundamental abnormalities responsible for the lupus syndrome seen in these mice. By using a system of spontaneous anti-DNA antibody production in vitro, we have determined that such production is characteristic of autoimmune NZB and MRL-lpr/lpr mice but not of the nonautoimmune control strains. Additional examination of the cellular mechanisms involved in the regulation of this response in NZB mice revealed: 1) this response is markedly T cell dependent, 2) NZB T cells are essential for maximal production of this autoantibody, and 3) NZB T cells actively interfere with normal immune regulatory mechanisms that lead to the production of anti-DNA antibodies spontaneously in vitro by nonautoimmune syngeneic B lymphocytes. Although these studies of anti-DNA antibody production in vitro disagree with previous work by others they successfully reproduce the results obtained earlier in experiments performed in vivo.

The regulatory role of NZB T lymphocytes in the production of anti-DNA antibodies in vitro

Murine lupus is characterized by the production of numerous autoantibodies and immune complex glomerulonephritis. Anti-DNA antibodies are the hallmark of this disorder and may be associated pathogenetically with the glomerulonephritis. The cellular mechanisms underlying the regulation of the production of anti-DNA antibodies may prove to be the fundamental abnormalities responsible for the lupus syndrome seen in these mice. By using a system of spontaneous anti-DNA antibody production in vitro, we have determined that such production is characteristic of autoimmune NZB and MRL-lpr/lpr mice but not of the nonautoimmune control strains. Additional examination of the cellular mechanisms involved in the regulation of this response in NZB mice revealed: 1) this response is markedly T cell dependent, 2) NZB T cells are essential for maximal production of this autoantibody, and 3) NZB T cells actively interfere with normal immune regulatory mechanisms that lead to the production of anti-DNA antibodies spontaneously in vitro by nonautoimmune syngeneic B lymphocytes. Although these studies of anti-DNA antibody production in vitro disagree with previous work by others they successfully reproduce the results obtained earlier in experiments performed in vivo.

Effect of external factors on gonadal activity and body mass of male golden hamsters (Mesocricetus auratus)

Effects of photoperiod, temperature and food and water availability on body and testicular mass of golden hamsters were investigated. Lack of water or food inhibited body growth. Short photoperiod (LD 8:16) enhanced body growth in males fed 'poor diet' but it had no effect in animals on 'high quality diet'. Cold exposure diminished body growth in animals with access to water but not in those deprived of water. It is suggested that lowered motor activity is mainly responsible for body mass gain of animals kept under the short photoperiod. All stressful factors (water deprivation, 'poor diet' or cold) induced involution of testes. The time course of testicular involution was similar to that induced by short photoperiod. Testicular involution was, after several weeks, followed by spontaneous recrudescence. Combination of stressful external cues speeded up testicular involution. Since the testicular involution induced by water deprivation, "poor diet" and cold also occurred in animals kept in constant light or under long photoperiod (which are known to produce functional pinealectomy) it is concluded that the inhibitory effects of stressful external factors on testes are not mediated by the pineal. The decrease in testosterone production induced by external cues precedes changes in testicular mass. In individuals kept in the cold, testosterone production remains low, in spite of spontaneous recrudescence of the testes. No simple relationship between testosterone concentration in the blood and testicular mass was observed. The mass of the interscapular brown adipose tissue (ISBAT) changes strikingly during the hibernation cycle. Immediately after exposure to cold it decreases and stays at the low level for 40 days.(ABSTRACT TRUNCATED AT 250 WORDS)

[Role of ketotifen in the immunotherapy of atopic asthmatics]

The place of KETOTIFEN in the immunotherapy for atopic asthmatic patients (confirmed by cutaneous test and RAST) has been determined by a study conducted on 48 patients divided into two randomly selected parallel groups. Group one received 2 mg/d. Ketotifen treatment together with a desensitization. Group two: only had a specific hyposensitization treatment. The study was contacted over a period of 18 weeks and showed that the number of local reaction in group one was half as numerous as in group two. In conclusion, KETOTIFEN may be practised an immunotherapy to house dust and acarians, without any difficulties, and with a fast progression.

Donor-specific antibodies in renal allograft recipients. A reevaluation of the 51Cr-release assays comparing fibroblast and lymphoid target cells

Donor-specific alloantibody was monitored in recipients of 81 renal allografts by 51Cr release assays. Complement-dependent cytotoxicity and antibody-dependent cell-mediated cytotoxicity were both followed. In addition to the conventional lymphoid target cells nonlymphoid target cells, namely fibroblasts from the donor, were used. Although antibody against donor lymphoid cells was found more frequently, associations with graft loss and with rejection were greater with antibody against fibroblasts. The superior association of antibody against fibroblasts with clinical events suggests that wider use of nonlymphoid target cells would be of value in studies of alloantibody responses in renal transplant recipients.

Possible association of donor blood group A with higher alloantibody responses after renal transplantation

Donor-specific alloantibody responses were studied in 55 patients receiving their first cadaver kidney transplant, using 51Cr release assays for complement-dependent cytotoxicity and antibody-dependent cell-mediated cytotoxicity against two types of donor targets: fibroblasts and lymphoid cells. When patients with pretransplant donor-specific antibody were excluded, the alloantibody responses were significantly more frequent in recipients of blood group A kidneys than in recipients of non-A (P = .004). The association was seen with both lymphocyte and fibroblast target cells, but was stronger when fibroblast targets were used. The association could not be explained adequately by differences in transfusion status or in graft survival between the A and non-A groups. The results suggest that certain types of alloantibody response against the graft are more vigorous in recipients of group A kidneys than in other recipients. Such responses may contribute to the tendency of group A patients to show poorer graft survival in some studies.