Calcium antagonists in prevention of hypertension and stroke in stroke-prone spontaneously hypertensive rats

To investigate the effect of Calcium antagonists (Ca-An) with different tissue specificity in the development of hypertension and stroke in salt-loading SHRSP, three experiments were conducted. In experiment I (1), 50 8-week-old male SHRSP were divided into three groups and given nifedipine (NF, 32 mg/kg/day), menidipine (MN 32 mg/kg/day) and placebo (control group) respectively. In the control group 83.3% (15/18) died of stroke and 17 showed renal vascular sclerosis. Their average lifespan was 84 days. NF and MN significantly reduced systolic blood pressure (SBP), and no stroke of renal vascular sclerosis developed. In experiment I (2), 54 7-week-old male SHRSP were divided into three groups (18 in each group). They were treated with nimodipine (NM) 20 mg/kg/day, 2 mg/kg/day and placebo respectively. NM (20 mg/kg/day) markedly lowered SBP and postponed the onset of stroke. Only 11% died in 17 weeks. NM (2 mg/kg/day did not lower SBP but postpond the onset of stroke. In experiment II (1), 29 10-week-old female SHRSP were divided into three groups: Group A was given NF 32 mg/kg/day, group B was parathyroidectomized (PTX) and group C served as control. PTX group did not lower SBP but could postpone the onset of stroke. In experiment II (2), 33 male SHRSP were divided into three groups and ticated as described above in experiment II (1) (11 in each group). Seven weeks after the experiment, the brain blood flow of NF group was significantly greater (67.5%) than that of the control and PTX groups. In experiment III, 27 7-week-old male SHRSP were divided into three groups as described above in experiment I (2).(ABSTRACT TRUNCATED AT 250 WORDS)

Molecular emission and electronic structure of associated chlorophyll a

We report the wavelength-selective Raman and fluorescence spectra of monomeric and aggregate species of chlorophyll a in solution. The excitation profile for the molecular emission of the various chlorophyll complexes permit the construction of part of the electronic energy level diagram. For a T-shaped dimeric chlorophyll a, pseudo-exciton splittings of 667 cm−1 in the Soret and 397 cm−1 in the Qy bands are obtained.

Himbacine recognizes a high affinity subtype of M2 muscarinic cholinergic receptors in the rat cerebral cortex

The in vitro receptor binding properties of a muscarinic antagonist himbacine have been studied in rat cerebral cortical, cardiac and ileal membranes. Himbacine displayed high affinity (KH = 2.94 nM) for 19%, and low affinity (KL = 71.2 nM) for the remaining muscarinic receptors in rat cerebral cortex. This high affinity of himbacine agrees with its affinity for the 62% of cerebral cortical [3H]AF-DX 116 binding sites (KH = 2.30 nM). The affinity of himbacine for cardiac receptors (Ki = 9.06 nM) and ileal receptors (Ki = 12.4 nM) was the same. Therefore, himbacine appears to be a high-affinity M2-selective ligand which recognizes a subtype of M2 receptors in the cerebral cortex.

Severe obstructive sleep apnea in a child with osteopetrosis

The clinical features of a 5-year-old patient with osteopetrosis and severe obstructive sleep apnea are presented. The patient responded to tonsillectomy, adenoidectomy, uvulectomy, and tracheostomy. The tracheostomy was later removed. Osteopetrosis, while rare, may be added to the list of causes of obstructive sleep apnea.

Effects of gossypol on the activity of kidney (Na+ + K+)-ATPase and the functions of erythrocyte membrane

Gossypol extracted from cottonseed oil, reputed to exert contraceptive action in males, may induce a side effect of hypokalemia. The cellular and molecular mechanisms by which gossypol produces hypokalemia are not quite understood. We have examined the inhibitory effect of gossypol on the activity of (Na+ + K+)-ATPase purified from the outer medulla of rabbit kidney, the half maximal inhibitory concentration (IC50) is 6.5 micron. The kinetic studies using this enzyme preparation show that gossypol is noncompetitive with ATP, Mg2+, Na+ and K+ with apparent Ki of 15.0, 13.0, 14.0 and 4.4 micron, respectively. On the other hand, in order to estimate the effects of gossypol on membrane transport of intact cells, we have investigated the effects of gossypol on the activity of (Na+ + K+)-ATPase, membrane integrity and permeability of human erythrocytes. It shows that gossypol inhibited the enzyme activity (greater than 5 micron) and expressed the hemolysis (greater than 50 micron) in vitro in a concentration-dependent manner, and increased the K+-efflux of the cells (10-40 micron). The above effects are antagonized by 1-2% bovine serum albumin. The data demonstrate that gossypol is a specific and potent membrane active agent. These results may be relevant to the in vivo actions of gossypol.

Auditory function in sickle cell anemia

Auditory acuity and central auditory processing were assessed in 22 patients with sickle cell anemia, 13 of whom were chronically transfused, and compared with a control black population. Pure tone air conduction thresholds were within normal limits for all patients, and mean Speech Reception Threshold for each ear was normal at 10 dB. All subjects exhibited type A tympanograms. Central auditory processing was assessed by the Competing Sentence Test and Binaural Fusion Test. No significant differences were found among transfused, nontransfused, and control patients. Abnormal auditory function does not appear to be a common problem in patients with sickle cell disease.

Fused cells of frog proximal tubule: I. Basic membrane properties

Proximal tubular cells of the frog (Rana esculenta) kidney were fused within an isolated tubule portion to giant cells according to the polyethylene-glycol fusion method. Cell membrane potentials (Vm) were measured while cells were superfused with various experimental solutions. Rapid concentration step-changes of different ions allowed to calculate the respective transference numbers (tion). In some experiments the specific cell membrane resistances (Rm) were evaluated by measuring Vm induced by short current pulses injected into the cell with a second electrode. The experiments reveal: i) Fused cells of the proximal tubule exhibit a Vm of -49.5 +/- 1.6 mV (n = 65). ii) Addition of glucose to the perfusate yields a transient depolarization, consistent with a rheogenic Na/glucose cotransport system. iii) In absence of organic substrates the whole cell membrane conductance is made up of K+ and HCO3-. iv) There is a positive relationship between Vm and tK+ and a negative relationship between Vm and tHCO3-. v) HCO3--induced Vm changes are attenuated or abolished when Na+ is replaced with choline+, consistent with a rheogenic Na+/HCO3- cotransport system. vi) Replacement of Na+ by choline+ depolarizes Vm and increases Rm by about 50%; addition of 3 mmol/liter Ba2+ to the Na+-free perfusate increases Rm by about 58% compared to the initial control value. vii) There is no measurable cell membrane Cl- conductance. We conclude that fused cells of proximal tubule exert both luminal and peritubular membrane properties. In absence of organic substrates the cell membrane potential is determined by the HCO3- and K+ transport systems.

[3H]AF-DX 116 labels subsets of muscarinic cholinergic receptors in rat brain and heart

The in vitro binding properties of the novel muscarinic antagonist [3H]AF-DX 116 were studied using a rapid filtration technique. Association and dissociation rates of [3H]AF-DX 116 binding were rapid at 25 degrees C (2.74 and 2.70 X 10(7) min-1 M-1 for K+1; 0.87 and 0.93 min-1 for k-1) but 20-40 times slower at 0-4 degrees C (0.13 and 0.096 X 10(7) min-1 M-1 for k+1; 0.031 and 0.022 min-1 for k-1 in cerebral cortical and cardiac membranes, respectively). Kinetic dissociation constants (Kds) were estimated to be 31.8 nM and 30.9 nM at 25 degrees C; 23.1 nM and 0-4 degrees C for the cerebral cortex and heart, respectively. In saturation studies, [3H]AF-DX 116 labeled 29 percent of the total [3H](-)QNB binding sites in the cerebral cortical membranes and 87 percent in the cardiac membranes, with Kd values of 28.9 nM and 17.9 nM, respectively. Muscarinic antagonists inhibited [3H]AF-DX 116 binding in a rank order of potency of atropine greater than dexetimide greater than AF-DX 116 greater than PZ greater than levetimide in both tissues. Except for PZ/[3H]AF-DX 116 and AF-DX 116/[3H]AF-DX 116 in the cerebral cortex, all the antagonist competition curves had Hill coefficients close to one. Carbachol and oxotremorine produced shallow inhibition curves against [3H]AF-DX 116 binding in both tissues. Regional distribution studies with [3H](-)QNB, [3H]PZ and [3H]AF-DX 116 showed that most of the muscarinic receptors in the cerebral cortex, hippocampus, nucleus accumbens and corpus striatum are of the M1 subtype while those in the brainstem, cerebellum and other lower brain regions are of the M2 subtype. These results indicate that [3H]AF-DX 116 is a useful probe for the study of heterogeneity of muscarinic cholinergic receptors.

Cell membrane potential: a signal to control intracellular pH and transepithelial hydrogen ion secretion in frog kidney

The dependence of intracellular pH (pHi) and transepithelial H+ secretion on the cell membrane potential (Vm) was tested applying pH-sensitive and conventional microelectrodes in giant cells fused from single epithelial cells of the diluting segment and in intact tubules of the frog kidney. An increase of extracellular K+ concentration from 3 to 15 mmol/l decreased Vm from -49 +/- 4 to -29 +/- 1 mV while pHi increased from 7.44 +/- 0.04 to 7.61 +/- 0.06. Addition of 1 mmol/l Ba2+ depolarized Vm from -45 +/- 3 to -32 +/- 2 mV, paralleled by an increase of pHi from 7.46 +/- 0.04 to 7.58 +/- 0.03. Application of 0.05 mmol/l furosemide hyperpolarized Vm from -48 +/- 3 to -53 +/- 3 mV and decreased pHi from 7.47 +/- 0.05 to 7.42 +/- 0.05. In the intact diluting segment of the isolated-perfused frog kidney an increase of peritubular K+ concentration from 3 to 15 mmol/l increased the luminal pH from 7.23 +/- 0.08 to 7.41 +/- 0.08. Addition of Ba2+ to the peritubular perfusate also increased luminal pH from 7.35 +/- 0.07 to 7.46 +/- 0.07. Addition of furosemide decreased luminal pH from 7.32 +/- 0.03 to 7.24 +/- 0.05. We conclude: cell depolarization reduces the driving force for the rheogenic HCO3- exit step across the basolateral cell membrane. HCO3- accumulates in the cytoplasm and pHi increases. An alkaline pHi inactivates the luminal Na+/H+ exchanger. This diminishes transepithelial H+ secretion. Cell hyperpolarization leads to the opposite phenomenon. Thus, pHi serves as signal transducer between cell voltage and Na+/H+ exchange.

A parallel architecture for discrete relaxation algorithm

Discrete relaxation techniques have proven useful in solving a wide range of problems in digital signal and digital image processing, artificial intelligence, operations research, and machine vision. Much work has been devoted to finding efficient hardware architectures. This paper shows that a conventional hardware design for a Discrete Relaxation Algorithm (DRA) suffers from O(n2m3) time complexity and O(n2m2) space complexity. By reformulating DRA into a parallel computational tree and using a multiple tree-root pipelining scheme, time complexity is reduced to O(nm), while the space complexity is reduced by a factor of 2. For certain relaxation processing, the space complexity can even be decreased to O(nm). Furthermore, a technique for dynamic configuring an architectural wavefront is used which leads to an O(n) time highly concurrent DRA3 architecture.

Inhibition of streptomycin-dependent mutation in Escherichia coli on the lytic growth of bacteriophage lambda

Spontaneous streptomycin-dependent mutants (StrDA) were isolated from Escherichia coli C600. On C600 StrD, the lytic growth of phage lambda Nam and lambda cI857 was inhibited. After E. coli lysogenic strain 1.1485 (lambda cI857) mutated to StrDA, induction of lambda was decreased greatly. On StrDA of E. coli strains C600 and 1.1485 (lambda cI857), the plating efficiencies and burst sizes of phage T4 and T7 remained normal. Since StrDA is a mutation in the structural gene for ribosomal protein S12, the results obtained in the present study suggest that ribosomes of the StrDA mutants inhibit the lytic growth of lambda phage. The possibility that StrDA ribosomes inhibit the expression of lambda N gene is discussed based on the comparison of the genetic background of lambda cI857 and lambda Nam.

Aldosterone activates Na+/H+ exchange and raises cytoplasmic pH in target cells of the amphibian kidney

The hypothesis was tested if the mineralocorticoid hormone aldosterone stimulates Na+/H+ exchange in "giant cells" fused from individual target cells of the distal nephron of the frog kidney. By means of microelectrodes, steady-state intracellular pH (pHi) and pHi recovery from an acid load were recorded continuously while the fused cells were exposed to aldosterone. Twenty minutes after addition of the hormone, pHi started to rise and reached a new steady state after about 60 min (delta pHi = 0.28 +/- 0.01). After hormone treatment, pHi recovered significantly faster in response to an intracellular acid load. The diuretic drug amiloride blocked pHi recovery. Experiments in intact tubules showed that aldosterone induces H+ and K+ secretion. Thus, intracellular alkalosis, mediated by Na+/H+ exchange, could serve as a signal that activates pH-sensitive K+ channels of the luminal cell membrane.

Evidence for Na+ dependent rheogenic HCO3- transport in fused cells of frog distal tubules

The mechanism of HCO3- transport was studied applying microelectrodes in "giant" cells fused from single epithelial cells of the diluting segment of frog kidney. A sudden increase of extracellular HCO3- concentration from 10 to 20 mmol/l at constant pH hyperpolarized the cell membrane potential of the fused cell. This cell-voltage response was totally abolished by 10(-3) mol/l SITS and significantly reduced by 10(-4) mol/l acetazolamide or by omission of Na+ from the extracellular perfusate. Removal of Na+ from the perfusate caused a transient depolarization. Reapplication of Na+ induced a transient hyperpolarization. 10(-3) mol/l SITS abolished the cell-voltage response to removal and reapplication of Na+. In the intact diluting segment of the isolated perfused frog kidney peritubular perfusion of 10(-4) mol/l acetazolamide reduced the limiting transepithelial electrochemical gradient for H+ significantly from 30 +/- 4 mV to 14 +/- 3 mV. The results suggest: In the diluting segment of the frog kidney a Na+-dependent rheogenic HCO3- transport system exists across the peritubular cell membrane. This rheogenic peritubular Na+/HCO3- cotransporter cooperates with a Na+/H+ exchanger in the luminal membrane, thus driving HCO3- reabsorption. Reabsorption of HCO3- and secretion of H+ depend upon the presence of carbonic anhydrase.

Childhood monosomy 7 syndrome: clinical and in vitro studies

The clinical and cell growth characteristics of 11 children with monosomy 7 presenting as preleukemia (eight cases) or acute nonlymphoblastic leukemia (three cases) were studied. Anemia was common to all patients, with nine showing leukocytosis, seven thrombocytopenia, and one thrombocytosis. There was a striking predominance of males (M/F ratio, 10:1) and a young median age (3 years). Preleukemia evolved to acute nonlymphoblastic leukemia in five patients and to myelofibrosis in one. In vitro studies of bone marrow progenitor cells cultured in leukocyte feeder-stimulated agar revealed abnormal cell proliferative patterns, most often an increased number of small clusters, for all 11 subjects. The cells of some preleukemic patients showed increased growth even in the absence of an exogenous source of colony-stimulating factor, suggesting autonomous growth or possibly autocrine stimulation. Combination chemotherapy or bone marrow transplantation failed to induce complete remission in the seven patients who were treated. Our findings in these 11 cases confirm the poor prognosis of monosomy 7 presenting as preleukemia in children. The in vitro studies suggest an association between altered cell growth in vitro and clinical evolution to frank leukemia.

Intravenous gamma globulin for thrombocytopenia in children with Evans syndrome

We describe three patients with Evans syndrome (immune hemolytic anemia and immune thrombocytopenia) who were refractory to conventional therapy, including steroids and splenectomy in all of the patients, vincristine in two, and cyclophosphamide in one. The patients were then treated with modified intravenous gamma globulin 0.4 g/kg/day for 5 consecutive days. Two patients failed to respond, but the third had a clinical remission after gamma globulin therapy. Given the usual chronic and relapsing course of Evans syndrome and the poor response to conventional therapy, we recommend that high dose i.v. gamma globulin be considered an alternative therapy in the management of these patients.

Low levels of prostaglandins in human milk after purification by high performance liquid chromatography

In order to validate methodology for quantifying arachidonic acid metabolites in human milk, we measured five prostaglandins (PGs) using radioimmunoassay (RIA): PGE2, PGF2 alpha, thromboxane B2 (TXB2), 6-keto-PGF1 alpha (6KF1 alpha) and 13,14-dihydro-15-keto-PGF2 alpha (DHKF2 alpha). RIA was performed after extraction with C18 Sep-Pak cartridge and/or further purification with reverse-phase high performance liquid chromatography (rp-HPLC). Recovery was monitored throughout the purification steps. Confirming findings of previously reported studies, we found PGE and the PGF2 alpha metabolite, DHKF2 alpha to be the major PGs in extracted human milk. After HPLC purification, however, no predominant PG was found, and the PG levels, especially those of PGE2 and DHKF2 alpha, were considerably lower than levels in the extracted sample. A noteworthy finding was the presence of immunoreactive substances in HPLC fractions not within the area of the PG peak; this suggests that the decreased levels of PGs in human milk measured by RIA after rp-HPLC are due to the elimination of the nonspecific immunoreactive materials present in the sample.

Nontransferrin-bound serum iron in thalassemia and sickle cell patients

Nontransferrin-bound iron (NTBI) was separated from transferrin bound iron (TBI) by DEAE-Sephadex-CDS filtration. TBI is eluted with Tris-NaCl buffer, NTBI that is retained on the column is eluted with citric acid. NTBI was identified in serum from thalassemia and sickle cell patients. Normal serum contained less than 6% NTBI as compared with 15-18% in patient's sera. NTBI levels were decreased significantly after 8 hr chelation with deferoxamine (DFO).

One-stage reconstruction of esophageal defect by free transfer of jejunum: treatment and complications

We report on 20 patients with esophageal defects that were reconstructed by jejunum transplant with the help of microsurgical techniques. Sixteen attempts were successful, for a success rate of 80%. Three types of reconstruction were used: free jejunum transfer, free jejunum flap transfer, and partially pedicled jejunum transfer with the distal portion revascularized. This article emphasizes the complications of these procedures, including tearing of the jejunum mesentery, thrombosis at the anastomotic stoma, balloon-like distention of the cervical portion of the transferred jejunum, strangulation at the diaphragm foramen, and stenosis of the anastomotic stoma between the remnant of the esophagus and the transferred jejunum. Measures for prevention and treatment of these complications are also discussed.

A case-control study of trophoblastic diseases in the People's Republic of China

A case-control study is currently under way in Beijing, People's Republic of China, involving approximately 165 patients with invasive moles or choriocarcinoma, 165 with hydatidiform moles, and 330 population controls, who were matched to the patients with invasive moles or choriocarcinoma on age and interval since last pregnancy. The interviews are focused on a number of suspected risk factors, including previous pregnancy outcomes, history of hydatidiform mole, medical factors, drug usage, family history, and diet. A brief background of the study and methods as established through a previous pilot study are given.

Vascular metatarsophalangeal to ankylosed temporomandibular joint replacement

Four cases of unilateral temporomandibular (TM) joint ankylosis were successfully treated by metatarsophalangeal to TM joint replacement by microvascular technique. Results 6 to 20 months postoperatively were encouraging. Further follow-up studies are necessary to evaluate the long-term results.

Lymphocyte phenotype and function in chronically transfused children with sickle cell disease

Immunologic studies were performed on mononuclear cells from ten chronically transfused children with sickle cell disease, and the results were compared with those from five other groups: 21 sickle cell patients who were not receiving regular transfusions, 6 chronically transfused children with other forms of refractory anemia, 10 previously splenectomized children, 5 boys with hemophilia A, and 27 normal adult controls. The helper:suppressor T cell ratios (T4:T8) in all groups except hemophiliacs were normal, were unrelated to the number of units transfused, and were not suggestive of findings reported for patients with the acquired immune deficiency syndrome (AIDS) or groups at risk for the syndrome. Percentages of T3, T4, and T8 cells were low in sickle cell and splenectomized patients, but not in chronically transfused patients with other anemias. Serum IgG was frequently elevated, and IgG synthesis in vitro was increased relative to IgM synthesis in sickle cell patients. Coculture experiments indicated that such findings may stem from a selective increase in IgG synthesis by B cells. Thus, transfused sickle cell patients have a particular pattern of immunologic abnormalities that is distinct from that seen in AIDS.

Ouabain decreases apparent potassium-conductance in proximal tubules of the amphibian kidney

According to a previous study from this laboratory, the electrochemical gradient for potassium across the peritubular cell membrane of proximal tubules in the isolated perfused frog kidney increases following the application of ouabain. In order to test, if this phenomenon were due to a decrease of potassium conductance, the effects of ouabain on cell membrane resistances and the sensitivity of the peritubular cell membrane potential difference (PDpt) to step changes of peritubular potassium and bicarbonate concentration were studied. In the absence of ouabain, PDpt averaged -60 +/- 3 mV (n = 25). A step increase of peritubular potassium concentration from 3 to 18 mmol/l (pH 8.07) depolarizes PDpt (delta PDk) by +24 +/- mV (n = 8). An increase of bicarbonate from 20 to 40 mmol/l (pH 8.07) hyperpolarizes PDpt (delta PDb) by -2.8 +/- 0.4 mV (n = 9). The resistance of the luminal and peritubular cell membranes in parallel (Rm) amounts to 45 +/- 9 k omega cm (tubule length) (n = 4) and the voltage divider ratio (VDR) to 1.4 +/- 0.2 (n = 7). The resistance of the cellular cable (cellular core, Rc) approaches 131 +/- 37 M omega/cm (n = 4). Peritubular application of 0.1 mmol/l ouabain leads to a gradual decline of PDpt (t1/2 approx. 30 min), to an increase of Rm, a decrease of delta PDk and an increase of delta PDb. VDR and Rc are not changed significantly. The data point to a functional link between the sodium/potassium ATPase and the potassium conductance of the peritubular cell membrane.

Hemothorax and hemomediastinum in patients with hemophilia

Three patients with hemophilia presented with hemothoraces which resolved within 1-3 weeks following treatment with factor concentrates. Drainage of blood was not necessary. Eight previously reported cases are reviewed, and therapy and complications are summarized. We suggest that treatment of this rare complication of hemophilia with factor concentrates and avoidance of surgical intervention is indicated.

Mechanism of hydrogen ion transport in the diluting segment of frog kidney

Transepithelial H+ transport was studied in diluting segments of the isolated-perfused kidney of rana esculenta. The experiments were performed in controls as well as in K+-adapted and Na+-adapted animals (exposed to 50 mmol/l KCl or NaCl, resp. for at least 3 days). Conventional and single-barreled, liquid ion-exchanger H+-sensitive microelectrodes were applied in the tubule lumen to evaluate transepithelial H+ net flux (JHte) as well as limiting transepithelial electrical and H+ electrochemical potential differences (PDte, EHte) and luminal pH at zero net flux conditions. The measurements were made in absence (control) and presence of furosemide (5 X 10(-5) mol/l) or amiloride (10(-3) mol/l). EHte (lumen positive vs ground) was 19 +/- 3 mV in controls, 43 +/- 3 mV in K+ adapted but about zero in Na+ adapted animals. Using the corresponding PDte-values, steady state luminal pH of 7.63 +/- 0.05, 7.13 +/- 0.05 and 8.02 +/- 0.02 was calculated for the respective groups of animals (peritubular pH 7.80). In parallel, significant secretory JHte (from blood to lumen) was found in controls (14 +/- 2 pmol X cm-2 X s-1) which was stimulated by K+ adaptation (61 +/- 8 pmol X cm-2 X s-1) but reversed in direction by Na+-adaptation (-8 +/- 1 pmol X cm-2 X s-1). Amiloride inhibited secretory JHte.(ABSTRACT TRUNCATED AT 250 WORDS)